Android ImageView Zoom-in and Zoom-Out
I want to Zoom-in and Zoom-out an Android ImageView. I tried most of the samples but in all of them the image in the ImageView itself is getting Zoomed-in and Zoomed-out, while I want to Zoom-in and Zoom-out the ImageView. I want to increase the ImageView width and height while Zooming-in and reduce the ImageView width and height while Zooming-out. How do I achieve that?
go through this: stackoverflow.com/questions/9846914/…
Google has provided an example for making zoom in/out view: developer.android.com/training/animation/zoom.html
check out this answer its awesome and
one line of code
This example from Android is pretty solid, step by step instructions and source code provided. developer.android.com/training/animation/zoom.html
Take an advantage of github.com/rahulkapoor1/ZommableLoadingImageView
N
Nikunj Paradva
Please follow the below class, that is used for Zoom in and Zoom Out for ImageView.
import android.app.Activity;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.os.Bundle;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
public class ZoomInZoomOut extends Activity implements OnTouchListener
{
private static final String TAG = "Touch";
@SuppressWarnings("unused")
private static final float MIN_ZOOM = 1f,MAX_ZOOM = 1f;
// These matrices will be used to scale points of the image
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
// The 3 states (events) which the user is trying to perform
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// these PointF objects are used to record the point(s) the user is touching
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ImageView view = (ImageView) findViewById(R.id.imageView);
view.setOnTouchListener(this);
}
@Override
public boolean onTouch(View v, MotionEvent event)
{
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
float scale;
dumpEvent(event);
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK)
{
case MotionEvent.ACTION_DOWN: // first finger down only
matrix.set(view.getImageMatrix());
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
Log.d(TAG, "mode=DRAG"); // write to LogCat
mode = DRAG;
break;
case MotionEvent.ACTION_UP: // first finger lifted
case MotionEvent.ACTION_POINTER_UP: // second finger lifted
mode = NONE;
Log.d(TAG, "mode=NONE");
break;
case MotionEvent.ACTION_POINTER_DOWN: // first and second finger down
oldDist = spacing(event);
Log.d(TAG, "oldDist=" + oldDist);
if (oldDist > 5f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
Log.d(TAG, "mode=ZOOM");
}
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG)
{
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY() - start.y); // create the transformation in the matrix of points
}
else if (mode == ZOOM)
{
// pinch zooming
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 5f)
{
matrix.set(savedMatrix);
scale = newDist / oldDist; // setting the scaling of the
// matrix...if scale > 1 means
// zoom in...if scale < 1 means
// zoom out
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
view.setImageMatrix(matrix); // display the transformation on screen
return true; // indicate event was handled
}
/*
* --------------------------------------------------------------------------
* Method: spacing Parameters: MotionEvent Returns: float Description:
* checks the spacing between the two fingers on touch
* ----------------------------------------------------
*/
private float spacing(MotionEvent event)
{
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float) Math.sqrt(x * x + y * y);
}
/*
* --------------------------------------------------------------------------
* Method: midPoint Parameters: PointF object, MotionEvent Returns: void
* Description: calculates the midpoint between the two fingers
* ------------------------------------------------------------
*/
private void midPoint(PointF point, MotionEvent event)
{
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
/** Show an event in the LogCat view, for debugging */
private void dumpEvent(MotionEvent event)
{
String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE","POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
StringBuilder sb = new StringBuilder();
int action = event.getAction();
int actionCode = action & MotionEvent.ACTION_MASK;
sb.append("event ACTION_").append(names[actionCode]);
if (actionCode == MotionEvent.ACTION_POINTER_DOWN || actionCode == MotionEvent.ACTION_POINTER_UP)
{
sb.append("(pid ").append(action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
sb.append(")");
}
sb.append("[");
for (int i = 0; i < event.getPointerCount(); i++)
{
sb.append("#").append(i);
sb.append("(pid ").append(event.getPointerId(i));
sb.append(")=").append((int) event.getX(i));
sb.append(",").append((int) event.getY(i));
if (i + 1 < event.getPointerCount())
sb.append(";");
}
sb.append("]");
Log.d("Touch Events ---------", sb.toString());
}
}
N
Nicolas Tyler
The other implementations here all have some kind of a flaw. so i basically mixed them up and came up with this.
Create a custom view like this:
ZoomableImageView.java:
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class ZoomableImageView extends ImageView
{
Matrix matrix = new Matrix();
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
static final int CLICK = 3;
int mode = NONE;
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 4f;
float[] m;
float redundantXSpace, redundantYSpace;
float width, height;
float saveScale = 1f;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public ZoomableImageView(Context context, AttributeSet attr)
{
super(context, attr);
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix.setTranslate(1f, 1f);
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener()
{
@Override
public boolean onTouch(View v, MotionEvent event)
{
mScaleDetector.onTouchEvent(event);
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction())
{
//when one finger is touching
//set the mode to DRAG
case MotionEvent.ACTION_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
//when two fingers are touching
//set the mode to ZOOM
case MotionEvent.ACTION_POINTER_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = ZOOM;
break;
//when a finger moves
//If mode is applicable move image
case MotionEvent.ACTION_MOVE:
//if the mode is ZOOM or
//if the mode is DRAG and already zoomed
if (mode == ZOOM || (mode == DRAG && saveScale > minScale))
{
float deltaX = curr.x - last.x;// x difference
float deltaY = curr.y - last.y;// y difference
float scaleWidth = Math.round(origWidth * saveScale);// width after applying current scale
float scaleHeight = Math.round(origHeight * saveScale);// height after applying current scale
//if scaleWidth is smaller than the views width
//in other words if the image width fits in the view
//limit left and right movement
if (scaleWidth < width)
{
deltaX = 0;
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
}
//if scaleHeight is smaller than the views height
//in other words if the image height fits in the view
//limit up and down movement
else if (scaleHeight < height)
{
deltaY = 0;
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
}
//if the image doesnt fit in the width or height
//limit both up and down and left and right
else
{
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
}
//move the image with the matrix
matrix.postTranslate(deltaX, deltaY);
//set the last touch location to the current
last.set(curr.x, curr.y);
}
break;
//first finger is lifted
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
// second finger is lifted
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true;
}
});
}
@Override
public void setImageBitmap(Bitmap bm)
{
super.setImageBitmap(bm);
bmWidth = bm.getWidth();
bmHeight = bm.getHeight();
}
public void setMaxZoom(float x)
{
maxScale = x;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener
{
@Override
public boolean onScaleBegin(ScaleGestureDetector detector)
{
mode = ZOOM;
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector)
{
float mScaleFactor = detector.getScaleFactor();
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale)
{
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
}
else if (saveScale < minScale)
{
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);
if (origWidth * saveScale <= width || origHeight * saveScale <= height)
{
matrix.postScale(mScaleFactor, mScaleFactor, width / 2, height / 2);
if (mScaleFactor < 1)
{
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1)
{
if (Math.round(origWidth * saveScale) < width)
{
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
}
else
{
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
}
}
}
}
else
{
matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
}
}
return true;
}
}
@Override
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width = MeasureSpec.getSize(widthMeasureSpec);
height = MeasureSpec.getSize(heightMeasureSpec);
//Fit to screen.
float scale;
float scaleX = width / bmWidth;
float scaleY = height / bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = 1f;
// Center the image
redundantYSpace = height - (scale * bmHeight) ;
redundantXSpace = width - (scale * bmWidth);
redundantYSpace /= 2;
redundantXSpace /= 2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);
setImageMatrix(matrix);
}
}
Then add the image like this:
ZoomableImageView touch = (ZoomableImageView)findViewById(R.id.IMAGEID);
touch.setImageBitmap(bitmap);
Add the view like this in XML:
<PACKAGE.ZoomableImageView
android:id="@+id/IMAGEID"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
its up to you what scaletype you prefer.
I didn't say you should change the scaletype to fitXy... And if you change the code its not my fault that it does not work. I provided you with a working solution that i've used before.
I will add comments, but its not that complicated,
saveScale is the current scale value of the image, minScale being the smallest it can go and maxScale is the most the image can scale.
No need to use
setOnTouchListener() you can just override public boolean onTouchEvent(MotionEvent event)
Doesn't work when image is inside ViewPager. Shows empty screen. While similar solutions and derived projects work
V
Vishal Yadav
Simple way:
PhotoViewAttacher pAttacher;
pAttacher = new PhotoViewAttacher(Your_Image_View);
pAttacher.update();
Add below line in build.gradle:
compile 'com.commit451:PhotoView:1.2.4'
Good, but this is only for imageview. How to attach a Class extended by View to this attacher. Have you any idea,
This works very well. I trid other answers and they did not work, or did not work properly.
This is an outdated version. See the repo for instructions for latest PhotoView: github.com/chrisbanes/PhotoView
Although the PhotoView according to above links instructions it does not work. Your answer (PhotoViewAttacher) seems to work
S
Simulant
Make two java classes
Zoom class
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.view.KeyEvent;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
public class Zoom extends View {
private Drawable image;
ImageButton img,img1;
private int zoomControler=20;
public Zoom(Context context){
super(context);
image=context.getResources().getDrawable(R.drawable.j);
//image=context.getResources().getDrawable(R.drawable.icon);
setFocusable(true);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//here u can control the width and height of the images........ this line is very important
image.setBounds((getWidth()/2)-zoomControler, (getHeight()/2)-zoomControler, (getWidth()/2)+zoomControler, (getHeight()/2)+zoomControler);
image.draw(canvas);
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(keyCode==KeyEvent.KEYCODE_DPAD_UP){
// zoom in
zoomControler+=10;
}
if(keyCode==KeyEvent.KEYCODE_DPAD_DOWN){
// zoom out
zoomControler-=10;
}
if(zoomControler<10){
zoomControler=10;
}
invalidate();
return true;
}
}
make second class
import android.app.Activity;
import android.os.Bundle;
public class Zoomexample extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(new Zoom(this));
}
}
i got error in... image=context.getResources().getDrawable(R.drawable.j); I copy an image in drawable folder. I renamed the image to j.. I got j cannot be resolved or is not a field..
@chinna_82, the image should be j.png and you should place it in Drawable folder. Then refresh your project and the error shouldn't be
how can i zoom outside of viewpager means a whole screen?
A
Aman Srivastava
I have improved the answer I got from stack for flawless ZOOM (two finger) / ROTATION (two finger) / DRAG (Single finger).
https://i.stack.imgur.com/wRYvn.png
//============================XML code==================
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.flochat.imageviewzoomforstack.MainActivity">
<ImageView
android:id="@+id/imageview_trash"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/trash" />
</LinearLayout>
//============================Java code==========================
public class MainActivity extends AppCompatActivity {
ImageView photoview2;
float[] lastEvent = null;
float d = 0f;
float newRot = 0f;
private boolean isZoomAndRotate;
private boolean isOutSide;
private static final int NONE = 0;
private static final int DRAG = 1;
private static final int ZOOM = 2;
private int mode = NONE;
private PointF start = new PointF();
private PointF mid = new PointF();
float oldDist = 1f;
private float xCoOrdinate, yCoOrdinate;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
photoview2 = findViewById(R.id.imageview_trash);
photoview2.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
view.bringToFront();
viewTransformation(view, event);
return true;
}
});
}
private void viewTransformation(View view, MotionEvent event) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
xCoOrdinate = view.getX() - event.getRawX();
yCoOrdinate = view.getY() - event.getRawY();
start.set(event.getX(), event.getY());
isOutSide = false;
mode = DRAG;
lastEvent = null;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if (oldDist > 10f) {
midPoint(mid, event);
mode = ZOOM;
}
lastEvent = new float[4];
lastEvent[0] = event.getX(0);
lastEvent[1] = event.getX(1);
lastEvent[2] = event.getY(0);
lastEvent[3] = event.getY(1);
d = rotation(event);
break;
case MotionEvent.ACTION_UP:
isZoomAndRotate = false;
if (mode == DRAG) {
float x = event.getX();
float y = event.getY();
}
case MotionEvent.ACTION_OUTSIDE:
isOutSide = true;
mode = NONE;
lastEvent = null;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
lastEvent = null;
break;
case MotionEvent.ACTION_MOVE:
if (!isOutSide) {
if (mode == DRAG) {
isZoomAndRotate = false;
view.animate().x(event.getRawX() + xCoOrdinate).y(event.getRawY() + yCoOrdinate).setDuration(0).start();
}
if (mode == ZOOM && event.getPointerCount() == 2) {
float newDist1 = spacing(event);
if (newDist1 > 10f) {
float scale = newDist1 / oldDist * view.getScaleX();
view.setScaleX(scale);
view.setScaleY(scale);
}
if (lastEvent != null) {
newRot = rotation(event);
view.setRotation((float) (view.getRotation() + (newRot - d)));
}
}
}
break;
}
}
private float rotation(MotionEvent event) {
double delta_x = (event.getX(0) - event.getX(1));
double delta_y = (event.getY(0) - event.getY(1));
double radians = Math.atan2(delta_y, delta_x);
return (float) Math.toDegrees(radians);
}
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (int) Math.sqrt(x * x + y * y);
}
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
}
//========================Just pass any view which you want to zoom/rotate/drag to viewTransformation() method. Very applicable for textview zoom. It will not pixelate text.
excellent solution, nice approach. Thank You
Z
Zain
It's old, but this may help someone else.
Below TouchImageView class supports both zooming in/out on either pinch or double tap
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class TouchImageView extends ImageView implements GestureDetector.OnGestureListener, GestureDetector.OnDoubleTapListener {
Matrix matrix;
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
int viewWidth, viewHeight;
static final int CLICK = 3;
float saveScale = 1f;
protected float origWidth, origHeight;
int oldMeasuredWidth, oldMeasuredHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public TouchImageView(Context context) {
super(context);
sharedConstructing(context);
}
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
sharedConstructing(context);
}
GestureDetector mGestureDetector;
private void sharedConstructing(Context context) {
super.setClickable(true);
this.context = context;
mGestureDetector = new GestureDetector(context, this);
mGestureDetector.setOnDoubleTapListener(this);
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix = new Matrix();
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
mScaleDetector.onTouchEvent(event);
mGestureDetector.onTouchEvent(event);
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(curr);
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float fixTransX = getFixDragTrans(deltaX, viewWidth,
origWidth * saveScale);
float fixTransY = getFixDragTrans(deltaY, viewHeight,
origHeight * saveScale);
matrix.postTranslate(fixTransX, fixTransY);
fixTrans();
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
}
});
}
public void setMaxZoom(float x) {
maxScale = x;
}
@Override
public boolean onSingleTapConfirmed(MotionEvent e) {
return false;
}
@Override
public boolean onDoubleTap(MotionEvent e) {
// Double tap is detected
Log.i("MAIN_TAG", "Double tap detected");
float origScale = saveScale;
float mScaleFactor;
if (saveScale == maxScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
} else {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
}
matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2,
viewHeight / 2);
fixTrans();
return false;
}
@Override
public boolean onDoubleTapEvent(MotionEvent e) {
return false;
}
@Override
public boolean onDown(MotionEvent e) {
return false;
}
@Override
public void onShowPress(MotionEvent e) {
}
@Override
public boolean onSingleTapUp(MotionEvent e) {
return false;
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
return false;
}
@Override
public void onLongPress(MotionEvent e) {
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
return false;
}
private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = detector.getScaleFactor();
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
if (origWidth * saveScale <= viewWidth
|| origHeight * saveScale <= viewHeight)
matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2,
viewHeight / 2);
else
matrix.postScale(mScaleFactor, mScaleFactor,
detector.getFocusX(), detector.getFocusY());
fixTrans();
return true;
}
}
void fixTrans() {
matrix.getValues(m);
float transX = m[Matrix.MTRANS_X];
float transY = m[Matrix.MTRANS_Y];
float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale);
float fixTransY = getFixTrans(transY, viewHeight, origHeight
* saveScale);
if (fixTransX != 0 || fixTransY != 0)
matrix.postTranslate(fixTransX, fixTransY);
}
float getFixTrans(float trans, float viewSize, float contentSize) {
float minTrans, maxTrans;
if (contentSize <= viewSize) {
minTrans = 0;
maxTrans = viewSize - contentSize;
} else {
minTrans = viewSize - contentSize;
maxTrans = 0;
}
if (trans < minTrans)
return -trans + minTrans;
if (trans > maxTrans)
return -trans + maxTrans;
return 0;
}
float getFixDragTrans(float delta, float viewSize, float contentSize) {
if (contentSize <= viewSize) {
return 0;
}
return delta;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
viewWidth = MeasureSpec.getSize(widthMeasureSpec);
viewHeight = MeasureSpec.getSize(heightMeasureSpec);
//
// Rescales image on rotation
//
if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight
|| viewWidth == 0 || viewHeight == 0)
return;
oldMeasuredHeight = viewHeight;
oldMeasuredWidth = viewWidth;
if (saveScale == 1) {
// Fit to screen.
float scale;
Drawable drawable = getDrawable();
if (drawable == null || drawable.getIntrinsicWidth() == 0
|| drawable.getIntrinsicHeight() == 0)
return;
int bmWidth = drawable.getIntrinsicWidth();
int bmHeight = drawable.getIntrinsicHeight();
Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight);
float scaleX = (float) viewWidth / (float) bmWidth;
float scaleY = (float) viewHeight / (float) bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
// Center the image
float redundantYSpace = (float) viewHeight
- (scale * (float) bmHeight);
float redundantXSpace = (float) viewWidth
- (scale * (float) bmWidth);
redundantYSpace /= (float) 2;
redundantXSpace /= (float) 2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = viewWidth - 2 * redundantXSpace;
origHeight = viewHeight - 2 * redundantYSpace;
setImageMatrix(matrix);
}
fixTrans();
}
}
Usage: You can replace your ImageView with TouchImageView in both XML & java
1. For XML
<?xml version="1.0" encoding="utf-8"?>
<com.example.android.myapp.TouchImageView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/imViewedImage"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clickable="true"
android:focusable="true" />
2. For Java
TouchImageView imViewedImage = findViewById(R.id.imViewedImage);
I start it with setImageURI(imageUri) and every image appears black... The view does get the correct size, height and different attributes but doesnt display anything no matter the image.
@SuppressWarnings thanks for notifying that, I am not sure if I tried to set it programmatically; need to look back.. and will mention you for any workaround :)
This works but it's not zooming into the zone where you double-tap + pinch to zoom have a certain limitation.
A
Anjula
just use this class : TouchImageView
Follow our community guidelines . Do not provide external links because links in the future may not be accessible. Furthermore, give some snippet code.
a
alexbirkett
This is yet another implementation based on the code posted by Nicolas Tyler.
The following bugs are fixed:
Setting minScale to a number less than 1 now works
You don't need to use setImageBitmap() to set the image (you can use, for example setImageResource()
All constructors now work properly
The following things, amongst others are tidied up:
An OnTouchListener is not used, it's not necessary because the the class can just implement the onTouchEvent() method.
The assignment right = width * saveScale - width - (2 * redundantXSpace * saveScale); has been simplified to right = (originalBitmapWidth * saveScale) - width Which, in my option, is much less confusing.
Some member variables are removed (more state can probably be removed from this class)
It's not perfect but here you go:
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.widget.ImageView;
/**
* Created by alex on 23/02/16.
* Based on code posted by Nicolas Tyler here:
* https://stackoverflow.com/questions/6650398/android-imageview-zoom-in-and-zoom-out
*/
public class ZoomableImageView extends ImageView {
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
float scaleFactor = detector.getScaleFactor();
float newScale = saveScale * scaleFactor;
if (newScale < maxScale && newScale > minScale) {
saveScale = newScale;
float width = getWidth();
float height = getHeight();
right = (originalBitmapWidth * saveScale) - width;
bottom = (originalBitmapHeight * saveScale) - height;
float scaledBitmapWidth = originalBitmapWidth * saveScale;
float scaledBitmapHeight = originalBitmapHeight * saveScale;
if (scaledBitmapWidth <= width || scaledBitmapHeight <= height) {
matrix.postScale(scaleFactor, scaleFactor, width / 2, height / 2);
} else {
matrix.postScale(scaleFactor, scaleFactor, detector.getFocusX(), detector.getFocusY());
}
}
return true;
}
}
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
static final int CLICK = 3;
private int mode = NONE;
private Matrix matrix = new Matrix();
private PointF last = new PointF();
private PointF start = new PointF();
private float minScale = 0.5f;
private float maxScale = 4f;
private float[] m;
private float redundantXSpace, redundantYSpace;
private float saveScale = 1f;
private float right, bottom, originalBitmapWidth, originalBitmapHeight;
private ScaleGestureDetector mScaleDetector;
public ZoomableImageView(Context context) {
super(context);
init(context);
}
public ZoomableImageView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public ZoomableImageView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
private void init(Context context) {
super.setClickable(true);
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int bmHeight = getBmHeight();
int bmWidth = getBmWidth();
float width = getMeasuredWidth();
float height = getMeasuredHeight();
//Fit to screen.
float scale = width > height ? height / bmHeight : width / bmWidth;
matrix.setScale(scale, scale);
saveScale = 1f;
originalBitmapWidth = scale * bmWidth;
originalBitmapHeight = scale * bmHeight;
// Center the image
redundantYSpace = (height - originalBitmapHeight);
redundantXSpace = (width - originalBitmapWidth);
matrix.postTranslate(redundantXSpace / 2, redundantYSpace / 2);
setImageMatrix(matrix);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
mScaleDetector.onTouchEvent(event);
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
//when one finger is touching
//set the mode to DRAG
case MotionEvent.ACTION_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
//when two fingers are touching
//set the mode to ZOOM
case MotionEvent.ACTION_POINTER_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = ZOOM;
break;
//when a finger moves
//If mode is applicable move image
case MotionEvent.ACTION_MOVE:
//if the mode is ZOOM or
//if the mode is DRAG and already zoomed
if (mode == ZOOM || (mode == DRAG && saveScale > minScale)) {
float deltaX = curr.x - last.x;// x difference
float deltaY = curr.y - last.y;// y difference
float scaleWidth = Math.round(originalBitmapWidth * saveScale);// width after applying current scale
float scaleHeight = Math.round(originalBitmapHeight * saveScale);// height after applying current scale
boolean limitX = false;
boolean limitY = false;
//if scaleWidth is smaller than the views width
//in other words if the image width fits in the view
//limit left and right movement
if (scaleWidth < getWidth() && scaleHeight < getHeight()) {
// don't do anything
}
else if (scaleWidth < getWidth()) {
deltaX = 0;
limitY = true;
}
//if scaleHeight is smaller than the views height
//in other words if the image height fits in the view
//limit up and down movement
else if (scaleHeight < getHeight()) {
deltaY = 0;
limitX = true;
}
//if the image doesnt fit in the width or height
//limit both up and down and left and right
else {
limitX = true;
limitY = true;
}
if (limitY) {
if (y + deltaY > 0) {
deltaY = -y;
} else if (y + deltaY < -bottom) {
deltaY = -(y + bottom);
}
}
if (limitX) {
if (x + deltaX > 0) {
deltaX = -x;
} else if (x + deltaX < -right) {
deltaX = -(x + right);
}
}
//move the image with the matrix
matrix.postTranslate(deltaX, deltaY);
//set the last touch location to the current
last.set(curr.x, curr.y);
}
break;
//first finger is lifted
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
// second finger is lifted
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true;
}
public void setMaxZoom(float x) {
maxScale = x;
}
private int getBmWidth() {
Drawable drawable = getDrawable();
if (drawable != null) {
return drawable.getIntrinsicWidth();
}
return 0;
}
private int getBmHeight() {
Drawable drawable = getDrawable();
if (drawable != null) {
return drawable.getIntrinsicHeight();
}
return 0;
}
}
Great job. I modified a bit your code. I disabled the ability to move the image on X or Y if the width or height is less then display's bounds
@ROHITPARMAR I will post a new comment with my class.
is there a way to restore the scaling of image when the
ImageView is double tapped?
Thanks! Works nice. If you use this widget inside
ViewPager, some difficulties appear. 1) A scale is not reset to 1 after moving forward and backward. 2) If you try to shift a picture, the movement is slow and short. And you can occasionally move to next picture. It's not a problem of the solution, but you should realize a new behaviour.
You added
getWidth() and getHeight() in onScale method, where is the implementation of them?
C
Community
I made my own custom imageview with pinch to zoom. There is no limits/borders on Chirag Ravals code, so user can drag the image off the screen.
Here is the CustomImageView class:
public class CustomImageVIew extends ImageView implements OnTouchListener {
private Matrix matrix = new Matrix();
private Matrix savedMatrix = new Matrix();
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
private int mode = NONE;
private PointF mStartPoint = new PointF();
private PointF mMiddlePoint = new PointF();
private Point mBitmapMiddlePoint = new Point();
private float oldDist = 1f;
private float matrixValues[] = {0f, 0f, 0f, 0f, 0f, 0f, 0f, 0f, 0f};
private float scale;
private float oldEventX = 0;
private float oldEventY = 0;
private float oldStartPointX = 0;
private float oldStartPointY = 0;
private int mViewWidth = -1;
private int mViewHeight = -1;
private int mBitmapWidth = -1;
private int mBitmapHeight = -1;
private boolean mDraggable = false;
public CustomImageVIew(Context context) {
this(context, null, 0);
}
public CustomImageVIew(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CustomImageVIew(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
this.setOnTouchListener(this);
}
@Override
public void onSizeChanged (int w, int h, int oldw, int oldh){
super.onSizeChanged(w, h, oldw, oldh);
mViewWidth = w;
mViewHeight = h;
}
public void setBitmap(Bitmap bitmap){
if(bitmap != null){
setImageBitmap(bitmap);
mBitmapWidth = bitmap.getWidth();
mBitmapHeight = bitmap.getHeight();
mBitmapMiddlePoint.x = (mViewWidth / 2) - (mBitmapWidth / 2);
mBitmapMiddlePoint.y = (mViewHeight / 2) - (mBitmapHeight / 2);
matrix.postTranslate(mBitmapMiddlePoint.x, mBitmapMiddlePoint.y);
this.setImageMatrix(matrix);
}
}
@Override
public boolean onTouch(View v, MotionEvent event){
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
mStartPoint.set(event.getX(), event.getY());
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if(oldDist > 10f){
savedMatrix.set(matrix);
midPoint(mMiddlePoint, event);
mode = ZOOM;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
case MotionEvent.ACTION_MOVE:
if(mode == DRAG){
drag(event);
} else if(mode == ZOOM){
zoom(event);
}
break;
}
return true;
}
public void drag(MotionEvent event){
matrix.getValues(matrixValues);
float left = matrixValues[2];
float top = matrixValues[5];
float bottom = (top + (matrixValues[0] * mBitmapHeight)) - mViewHeight;
float right = (left + (matrixValues[0] * mBitmapWidth)) -mViewWidth;
float eventX = event.getX();
float eventY = event.getY();
float spacingX = eventX - mStartPoint.x;
float spacingY = eventY - mStartPoint.y;
float newPositionLeft = (left < 0 ? spacingX : spacingX * -1) + left;
float newPositionRight = (spacingX) + right;
float newPositionTop = (top < 0 ? spacingY : spacingY * -1) + top;
float newPositionBottom = (spacingY) + bottom;
boolean x = true;
boolean y = true;
if(newPositionRight < 0.0f || newPositionLeft > 0.0f){
if(newPositionRight < 0.0f && newPositionLeft > 0.0f){
x = false;
} else{
eventX = oldEventX;
mStartPoint.x = oldStartPointX;
}
}
if(newPositionBottom < 0.0f || newPositionTop > 0.0f){
if(newPositionBottom < 0.0f && newPositionTop > 0.0f){
y = false;
} else{
eventY = oldEventY;
mStartPoint.y = oldStartPointY;
}
}
if(mDraggable){
matrix.set(savedMatrix);
matrix.postTranslate(x? eventX - mStartPoint.x : 0, y? eventY - mStartPoint.y : 0);
this.setImageMatrix(matrix);
if(x)oldEventX = eventX;
if(y)oldEventY = eventY;
if(x)oldStartPointX = mStartPoint.x;
if(y)oldStartPointY = mStartPoint.y;
}
}
public void zoom(MotionEvent event){
matrix.getValues(matrixValues);
float newDist = spacing(event);
float bitmapWidth = matrixValues[0] * mBitmapWidth;
float bimtapHeight = matrixValues[0] * mBitmapHeight;
boolean in = newDist > oldDist;
if(!in && matrixValues[0] < 1){
return;
}
if(bitmapWidth > mViewWidth || bimtapHeight > mViewHeight){
mDraggable = true;
} else{
mDraggable = false;
}
float midX = (mViewWidth / 2);
float midY = (mViewHeight / 2);
matrix.set(savedMatrix);
scale = newDist / oldDist;
matrix.postScale(scale, scale, bitmapWidth > mViewWidth ? mMiddlePoint.x : midX, bimtapHeight > mViewHeight ? mMiddlePoint.y : midY);
this.setImageMatrix(matrix);
}
/** Determine the space between the first two fingers */
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float)Math.sqrt(x * x + y * y);
}
/** Calculate the mid point of the first two fingers */
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
}
This is how you can use it in your activity:
CustomImageVIew mImageView = (CustomImageVIew)findViewById(R.id.customImageVIew1);
mImage.setBitmap(your bitmap);
And layout:
<your.package.name.CustomImageVIew
android:id="@+id/customImageVIew1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginBottom="15dp"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp"
android:layout_marginTop="15dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:scaleType="matrix"/> // important
OK, best implementation so far. My main issue with this implementation is that from the get go the image is displayed at 1:1 ratio and we cannot perform zoom out. Apart from that, it is my fav implementation thus far on this thread
g
goRGon
I think Chirag Ravals' answer is great!
The only thing it could be improved is moving all this code inside some class like:
PinchZoomImageView extends ImageView {...
and adding there initial Image Matrix initialization to prevent zooming after the first tap:
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
matrix = new Matrix(this.getImageMatrix());
}
BTW, this will fix a bug mentioned by Muhammad Umar and Baz
P.S. Having Max and Min zoom limits could be also useful. E.g Max zoom is 2X and min zoom is the original scale when the image is fitted to screen:
static final int MAX_SCALE_FACTOR = 2;
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
// Getting initial Image matrix
mViewMatrix = new Matrix(this.getImageMatrix());
mMinScaleMatrix = new Matrix(mViewMatrix);
float initialScale = getMatrixScale(mViewMatrix);
if (initialScale < 1.0f) // Image is bigger than screen
mMaxScale = MAX_SCALE_FACTOR;
else
mMaxScale = MAX_SCALE_FACTOR * initialScale;
mMinScale = getMatrixScale(mMinScaleMatrix);
}
@Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
// We set scale only after onMeasure was called and automatically fit image to screen
if(!mWasScaleTypeSet) {
view.setScaleType(ImageView.ScaleType.MATRIX);
mWasScaleTypeSet = true;
}
float scale;
dumpEvent(event);
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: // first finger down only
mCurSavedMatrix.set(mViewMatrix);
start.set(event.getX(), event.getY());
mCurrentMode = DRAG;
break;
case MotionEvent.ACTION_UP: // first finger lifted
case MotionEvent.ACTION_POINTER_UP: // second finger lifted
mCurrentMode = NONE;
float resScale = getMatrixScale(mViewMatrix);
if (resScale > mMaxScale) {
downscaleMatrix(resScale, mViewMatrix);
} else if (resScale < mMinScale)
mViewMatrix = new Matrix(mMinScaleMatrix);
else if ((resScale - mMinScale) < 0.1f) // Don't allow user to drag picture outside in case of FIT TO WINDOW zoom
mViewMatrix = new Matrix(mMinScaleMatrix);
else
break;
break;
case MotionEvent.ACTION_POINTER_DOWN: // first and second finger down
mOldDist = spacing(event);
Helper.LOGD(TAG, "oldDist=" + mOldDist);
if (mOldDist > 5f) {
mCurSavedMatrix.set(mViewMatrix);
midPoint(mCurMidPoint, event);
mCurrentMode = ZOOM;
Helper.LOGD(TAG, "mode=ZOOM");
}
break;
case MotionEvent.ACTION_MOVE:
if (mCurrentMode == DRAG) {
mViewMatrix.set(mCurSavedMatrix);
mViewMatrix.postTranslate(event.getX() - start.x, event.getY() - start.y); // create the transformation in the matrix of points
} else if (mCurrentMode == ZOOM) {
// pinch zooming
float newDist = spacing(event);
Helper.LOGD(TAG, "newDist=" + newDist);
if (newDist > 1.f) {
mViewMatrix.set(mCurSavedMatrix);
scale = newDist / mOldDist; // setting the scaling of the
// matrix...if scale > 1 means
// zoom in...if scale < 1 means
// zoom out
mViewMatrix.postScale(scale, scale, mCurMidPoint.x, mCurMidPoint.y);
}
}
break;
}
view.setImageMatrix(mViewMatrix); // display the transformation on screen
return true; // indicate event was handled
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////// PRIVATE SECTION ///////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// These matrices will be used to scale points of the image
private Matrix mViewMatrix = new Matrix();
private Matrix mCurSavedMatrix = new Matrix();
// These PointF objects are used to record the point(s) the user is touching
private PointF start = new PointF();
private PointF mCurMidPoint = new PointF();
private float mOldDist = 1f;
private Matrix mMinScaleMatrix;
private float mMinScale;
private float mMaxScale;
float[] mTmpValues = new float[9];
private boolean mWasScaleTypeSet;
/**
* Returns scale factor of the Matrix
* @param matrix
* @return
*/
private float getMatrixScale(Matrix matrix) {
matrix.getValues(mTmpValues);
return mTmpValues[Matrix.MSCALE_X];
}
/**
* Downscales matrix with the scale to maximum allowed scale factor, but the same translations
* @param scale
* @param dist
*/
private void downscaleMatrix(float scale, Matrix dist) {
float resScale = mMaxScale / scale;
dist.postScale(resScale, resScale, mCurMidPoint.x, mCurMidPoint.y);
}
For some reason,
matrix = new Matrix(this.getImageMatrix()); line makes the image disappear for me. Do you know why?
If you do it inside onMeasure() the matrix will just obtain the correct value according to current View zoom default scale. And this matrix will be used only after the next interaction with user (tap for example). And when did you image disappear?
@goRGon Hi, In my application i set image with fit to screen. And i want to zoom apart from screen size which is working fine. And I need to zoom out,drag,rotate the image which is done only outside of the screen not inside of the screen. pls help me how to do it.
A
Aggressor
I got the most helpful answer from @Nicolas Tyler but I had issues with how the syntax and logic worked. I also did not want any Alpha space and my Algebra was rusty! After 3 days I have put together my own version of this.
My answer differs from @Nicolas Tyler with the following:
Different variable names which I found made more sense in underlying contextual uses This Pinch-Zoom image class does NOT show alpha space and will let you zoom in and out and still not let you over/under pan an image and reveal alpha space Added deep comments to the matrix section to explain what was going on with the math involved This image class will also let you pass in a resourceId and it will create a bitmap from it Much simpler algorithms for both scaling and translation and few variables Changing the image within this will cause it to zoom in/out such that the new image takes up the view container
A great resource refresher on Algebra can be found here: https://youtu.be/IiXB6tYtY4w?t=4m12s That video covers the core of Scalar and Translation matrixes (and will help you make sense of the MTRANS_X and MTRANS_Y stuff). If you have questions ask and I will do my best to answer (but I am NO Algebra expert).
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class iImage extends ImageView
{
static final int NONE_MODE = 0;
static final int DRAG_MODE = 1;
static final int ZOOM_MODE = 2;
int _mode = NONE_MODE;
Matrix _matrix = new Matrix();
PointF _previousPoint = new PointF();
PointF _startPoint = new PointF();
float _currentScale = 1f;
float _minScale = 1f;
float _maxScale = 3f;
float[] _arrayOf9Floats;
float _bitmapWidth, _bitmapHeight,_displayWidth, _displayHeight;
ScaleGestureDetector _scaleDetector;
Context _context;
public iImage(Context context)
{
super(context);
super.setClickable(true);
_context = context;
_scaleDetector = new ScaleGestureDetector(context, new ScaleListener());
_arrayOf9Floats = new float[9];
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
return handleTouch(v, event);
}
});
}
private boolean handleTouch(View v, MotionEvent event)
{
_scaleDetector.onTouchEvent(event);
//Contrary to how this line looks, the matrix is not setting the values from the arrayOf9Floats, but rather taking the
//matrix values and assigning them into the arrayOf9Floats. I extremely dislike this syntax and I think
//it should have been written as _arrayOf9Floats = _matrix.getValues() but that's Android for you!!!
_matrix.getValues(_arrayOf9Floats);
//Look at https://youtu.be/IiXB6tYtY4w?t=4m12s , it shows scale, rotate, and translate matrices
//If you look at the translate matrix, you'll see that the 3rd and 6th values are the values which represent x and y translations respectively
//this corresponds to the 2nd and 5th values in the array and hence why the MTRANS_X and MTRANS_Y have the constants 2 and 5 respectively
float xTranslate = _arrayOf9Floats[Matrix.MTRANS_X];
float yTranslate = _arrayOf9Floats[Matrix.MTRANS_Y];
PointF currentEventPoint = new PointF(event.getX(), event.getY());
switch (event.getAction())
{
//First finger down only
case MotionEvent.ACTION_DOWN:
_previousPoint.set(event.getX(), event.getY());
_startPoint.set(_previousPoint);
_mode = DRAG_MODE;
break;
//Second finger down
case MotionEvent.ACTION_POINTER_DOWN:
_previousPoint.set(event.getX(), event.getY());
_startPoint.set(_previousPoint);
_mode = ZOOM_MODE;
break;
case MotionEvent.ACTION_MOVE:
if (_mode == ZOOM_MODE || _mode == DRAG_MODE )
{
float deltaX = currentEventPoint.x - _previousPoint.x;
float deltaY = currentEventPoint.y - _previousPoint.y;
//In matrix terms, going right is + and going left is +
//Moving the image right past 0 means it will show alpha space on the left so we dont want that
//Keep in mind this is a TOP LEFT pivot point, so we dont want the top left to be past 0 lest we have alpha space
if(xTranslate + deltaX > 0)
{
//get absolute of how much into the negative we would have gone
float excessDeltaX = Math.abs(xTranslate + deltaX);
//take that excess away from deltaX so X wont got less than 0 after the translation
deltaX = deltaX - excessDeltaX;
}
//Going left we dont want the negative value to be less than the negative width of the sprite, lest we get alpha space on the right
//The width is going to be the width of the bitmap * scale and we want the - of it because we are checking for left movement
//We also need to account for the width of the DISPLAY CONTAINER (i.e. _displayWidth) so that gets subtracted
//i.e. we want the max scroll width value
float maxScrollableWidth = _bitmapWidth * _currentScale - _displayWidth;
if(xTranslate + deltaX < -maxScrollableWidth)
{
//this forces the max possible translate to always match the - of maxScrollableWidth
deltaX = -maxScrollableWidth - xTranslate;
}
//repeat for Y
if(yTranslate + deltaY > 0)
{
float excessDeltaY = Math.abs(yTranslate + deltaY);
deltaY = deltaY - excessDeltaY;
}
float maxScrollableHeight = _bitmapHeight * _currentScale - _displayWidth;
if(yTranslate + deltaY < -maxScrollableHeight)
{
//this forces the max possible translate to always match the - of maxScrollableWidth
deltaY = -maxScrollableHeight - yTranslate;
}
_matrix.postTranslate(deltaX, deltaY);
_matrix.getValues(_arrayOf9Floats);
//System.out.println(_matrix);
_previousPoint.set(currentEventPoint.x, currentEventPoint.y);
}
break;
case MotionEvent.ACTION_POINTER_UP:
_mode = NONE_MODE;
break;
}
setImageMatrix(_matrix);
invalidate();
return true;
}
@Override
public void setImageBitmap(Bitmap bm)
{
super.setImageBitmap(bm);
_bitmapWidth = bm.getWidth();
_bitmapHeight = bm.getHeight();
invalidate();
}
@Override
public void setImageResource(int resid)
{
Bitmap bitmapImage = BitmapFactory.decodeResource(_context.getResources(), resid);
setImageBitmap(bitmapImage);
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener
{
@Override
public boolean onScaleBegin(ScaleGestureDetector detector)
{
_mode = ZOOM_MODE;
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector)
{
float scaleFactor = detector.getScaleFactor();
float originalScale = _currentScale;
_currentScale *= scaleFactor;
//Zoom in too much
if (_currentScale > _maxScale) {
_currentScale = _maxScale;
scaleFactor = _maxScale / originalScale;
}//Zoom out too much
else if (_currentScale < _minScale) {
_currentScale = _minScale;
scaleFactor = _minScale / originalScale;
}
_matrix.postScale(scaleFactor,scaleFactor);
return true;
}
}
@Override
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
_displayWidth = MeasureSpec.getSize(widthMeasureSpec);
_displayHeight = MeasureSpec.getSize(heightMeasureSpec);
adjustScale();
}
private void adjustScale()
{
//Fit to display bounds with NO alpha space
float scale;
float scaleX = _displayWidth / _bitmapWidth;
float scaleY = _displayHeight / _bitmapHeight;
scale = Math.max(scaleX, scaleY);
_matrix.setScale(scale, scale);
setImageMatrix(_matrix);
_currentScale = scale;
_minScale = scale;
}
public void setMaxZoom(float maxZoom){_maxScale = maxZoom;}
public void setMinZoom(float minZoom) {_minScale = minZoom;}
}
What is the meaning of "alpha space"?
It work's great and really is a much cleaner solution than the original. One thing you missed though is that the scale gesture always scale to the top left corner of the image, instead of in between the fingers. i'm going to try and fix it, so if you have any hints for me it would be much appreciated. Thanks!
I found that replacing
mMatrix.postScale(scaleFactor, scaleFactor); with mMatrix.postScale(scaleFactor, scaleFactor, detector.getFocusX(), detector.getFocusY()); inside public boolean onScale(ScaleGestureDetector detector) is doing the trick when you zoom in. more code is needed to support zoom out. but for now, it is enough for me.
Can anyone tell me how to initialize it? In mainactivity. I removed
android:src and android:scaleType from the xml file. How to add the image which is in "drawable" folder to it.
There are some issues with this: * The initial zoom is wrong (Possible solution use
scale = Math.min(scaleX, scaleY); in adjustScale(). * The zooming does not follow the mid point between fingers
j
jmtsilva69
This code works and implement the double tap to return to original image size.
1st step - In your xml layout put this:
<com.****.*****.TouchImageView
android:id="@+id/action_infolinks_splash"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="@mipmap/myinfolinks_splash"
android:layout_gravity="center"
android:gravity="center"
android:scaleType="fitCenter"
android:contentDescription="@string/aboutSupport_description_image"/>
2nd step- Create a file (TouchImageView.java) with the TouchImageView class:
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class TouchImageView extends ImageView {
Matrix matrix;
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
float redundantXSpace, redundantYSpace, origRedundantXSpace, origRedundantYSpace;
int viewWidth, viewHeight;
static final int CLICK = 3;
static final float SAVE_SCALE = 1f;
float saveScale = SAVE_SCALE;
protected float origWidth, origHeight;
int oldMeasuredWidth, oldMeasuredHeight;
float origScale, bottom, origBottom, right, origRight;
ScaleGestureDetector mScaleDetector;
GestureDetector mGestureDetector;
Context context;
public TouchImageView(Context context) {
super(context);
sharedConstructing(context);
}
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
sharedConstructing(context);
}
private void sharedConstructing(Context context) {
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix = new Matrix();
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
boolean onDoubleTapEvent = mGestureDetector.onTouchEvent(event);
if (onDoubleTapEvent) {
// Reset Image to original scale values
mode = NONE;
bottom = origBottom;
right = origRight;
last = new PointF();
start = new PointF();
m = new float[9];
saveScale = SAVE_SCALE;
matrix = new Matrix();
matrix.setScale(origScale, origScale);
matrix.postTranslate(origRedundantXSpace, origRedundantYSpace);
setImageMatrix(matrix);
invalidate();
return true;
}
mScaleDetector.onTouchEvent(event);
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(curr);
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float fixTransX = getFixDragTrans(deltaX, viewWidth, origWidth * saveScale);
float fixTransY = getFixDragTrans(deltaY, viewHeight, origHeight * saveScale);
matrix.postTranslate(fixTransX, fixTransY);
fixTrans();
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK) performClick();
break;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
}
});
mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onDoubleTapEvent(MotionEvent e) {
return true;
}
});
}
public void setMaxZoom(float x) {
maxScale = x;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = detector.getScaleFactor();
//float mScaleFactor = (float) Math.min(Math.max(.95f, detector.getScaleFactor()), 1.05);
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
right = viewWidth * saveScale - viewWidth - (2 * redundantXSpace * saveScale);
bottom = viewHeight * saveScale - viewHeight - (2 * redundantYSpace * saveScale);
if (origWidth * saveScale <= viewWidth || origHeight * saveScale <= viewHeight)
matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2, viewHeight / 2);
else
matrix.postScale(mScaleFactor, mScaleFactor, detector.getFocusX(), detector.getFocusY());
fixTrans();
return true;
}
}
void fixTrans() {
matrix.getValues(m);
float transX = m[Matrix.MTRANS_X];
float transY = m[Matrix.MTRANS_Y];
float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale);
float fixTransY = getFixTrans(transY, viewHeight, origHeight * saveScale);
if (fixTransX != 0 || fixTransY != 0)
matrix.postTranslate(fixTransX, fixTransY);
}
float getFixTrans(float trans, float viewSize, float contentSize) {
float minTrans, maxTrans;
if (contentSize <= viewSize) {
minTrans = 0;
maxTrans = viewSize - contentSize;
} else {
minTrans = viewSize - contentSize;
maxTrans = 0;
}
if (trans < minTrans)
return -trans + minTrans;
if (trans > maxTrans)
return -trans + maxTrans;
return 0;
}
float getFixDragTrans(float delta, float viewSize, float contentSize) {
if (contentSize <= viewSize) {
return 0;
}
return delta;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
viewWidth = MeasureSpec.getSize(widthMeasureSpec);
viewHeight = MeasureSpec.getSize(heightMeasureSpec);
//
// Rescales image on rotation
//
if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight || viewWidth == 0 || viewHeight == 0) return;
oldMeasuredHeight = viewHeight;
oldMeasuredWidth = viewWidth;
if (saveScale == 1) {
// Fit to screen.
float scale;
int bmWidth,bmHeight;
Bitmap bm = BitmapFactory.decodeResource(context.getResources(), R.mipmap.myinfolinks_splash);
bmWidth = bm.getWidth();
bmHeight = bm.getHeight();
int w = bmWidth;
int h = bmHeight;
viewWidth = resolveSize(w, widthMeasureSpec);
viewHeight = resolveSize(h, heightMeasureSpec);
float scaleX = (float) viewWidth / (float) bmWidth;
float scaleY = (float) viewHeight / (float) bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
saveScale = SAVE_SCALE;
origScale = scale;
// Center the image
redundantYSpace = (float) viewHeight - (scale * (float) bmHeight);
redundantXSpace = (float) viewWidth - (scale * (float) bmWidth);
redundantYSpace /= (float) 2;
redundantXSpace /= (float) 2;
origRedundantXSpace = redundantXSpace;
origRedundantYSpace = redundantYSpace;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = viewWidth - 2 * redundantXSpace;
origHeight = viewHeight - 2 * redundantYSpace;
right = viewWidth * saveScale - viewWidth - (2 * redundantXSpace * saveScale);
bottom = viewHeight * saveScale - viewHeight - (2 * redundantYSpace * saveScale);
origRight = right;
origBottom = bottom;
setImageMatrix(matrix);
}
fixTrans();
}
}
And finally, make the call in your main activity:
TouchImageView imgDisplay = (TouchImageView) messageView.findViewById(R.id.id_myImage);
imgDisplay.setMaxZoom(2f);
imgDisplay.setImageResource(R.drawable.myImage);
I saw lots of code and after my adjustments it's working. Enjoy!
For better perform change this line: Bitmap bm = BitmapFactory.decodeResource(context.getResources(), R.mipmap.myinfolinks_splash); for this one: ImageView img = (ImageView) findViewById(R.id.action_infolinks_splash);
And you don't need this (it's already set in the xml layout): imgDisplay.setImageResource(R.mipmap.myinfolinks_splash);
Skizo- this: ImageView img = (ImageView) findViewById(R.id.action_infolinks_splash)
Skizo- this: ImageView img = (ImageView) findViewById(R.id.action_infolinks_splash) it's for to get the width&height image programmatically. Yesterday i improve the code to rescale and i use only xxhdpi jpg image (1026px x 770px), like that i make smaller app and the image adjust for all screen size sucessfuly.
In xml: <***.****.TouchImageView android:id="@+id/action_infolinks_about_support" android:layout_width="match_parent" android:layout_height="wrap_content" android:src="@mipmap/myinfolinks_about_support" android:scaleType="centerInside" android:contentDescription="@string/aboutSupport_description_image"/>
P
Pramesh Bhalala
Step 1: First you add dependencies in build.gradle(Module:app) file.
dependencies {
implementation 'com.jsibbold:zoomage:1.2.0'
}
Step 2: Next create a class
ImageFullScreenFragment.java
public class ImageFullScreenFragment{
private ZoomageView ImageZoomageView;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = null;
try {
view = inflater.inflate(R.layout.fragment_image_full_screen, container, false);
ImageZoomageView = view.findViewById(R.id.imageViewImageFullScreen);
ImageZoomageView.setImageResource(R.drawable.image);
} catch (Exception e) {
e.printStackTrace();
}
return view;
}
Step 3 : Next create a layout xml file
fragment_image_full_screen.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="8dp"
xmlns:app="http://schemas.android.com/apk/res-auto">
<com.jsibbold.zoomage.ZoomageView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:zoomage_restrictBounds="false"
app:zoomage_animateOnReset="true"
app:zoomage_autoResetMode="UNDER"
app:zoomage_autoCenter="true"
app:zoomage_zoomable="true"
app:zoomage_translatable="true"
app:zoomage_minScale="0.6"
app:zoomage_maxScale="8"
android:id="@+id/imageViewImageFullScreen"
/>
</RelativeLayout>
OutPut:-
https://i.stack.imgur.com/l5vRq.png
https://i.stack.imgur.com/9gdNN.png
https://i.stack.imgur.com/v6Hj5.png
j
j0k
You should put the image in webview and work with that. Zoom in / out controls are available in webview.
http://xjaphx.wordpress.com/2011/09/18/using-webview-as-a-image-zoom-view-control/
http://androidforums.com/android-lounge/121522-how-display-image-sdcard-webview.html
J
Josh Crozier
Try the following:
package com.example.nwssugeoinformationmobileapplication;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Intent;
import android.util.FloatMath;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View.OnTouchListener;
import android.widget.TabHost;
import android.widget.TabHost.TabSpec;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.RectF;
import android.graphics.drawable.Drawable;
import android.view.View;
import android.widget.ImageView;
public class MainActivity extends Activity implements OnTouchListener {
private static final String TAG = "Touch";
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
private ImageView view;
private float[] matrixValues = new float[9];
private float maxZoom;
private float minZoom;
private float height;
private float width;
private RectF viewRect;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TabHost th = (TabHost) findViewById (R.id.tabhost);
th.setup();
TabSpec specs = th.newTabSpec("tag1");
specs.setContent(R.id.tab1);
specs.setIndicator("Map");
th.addTab(specs);
specs = th.newTabSpec("tag2");
specs.setContent(R.id.tab2);
specs.setIndicator("Search");
th.addTab(specs);
view = (ImageView) findViewById(R.id.imageView1);
Drawable bitmap = getResources().getDrawable(R.drawable.map);
view.setImageDrawable(bitmap);
view.setOnTouchListener(this);
matrix.setTranslate(1f, 1f);
view.setImageMatrix(matrix);
}
@Override
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
if(hasFocus){
init();
}
}
private void init() {
maxZoom = 2;
minZoom = 1f;
height = view.getDrawable().getIntrinsicHeight();
width = view.getDrawable().getIntrinsicWidth();
viewRect = new RectF(0, 0, view.getWidth(), view.getHeight());
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menus, menu);
return true;
}
public boolean onOptionsItemSelected(MenuItem item) {
if(item.getItemId()== R.id.item1){
Log.d("Tracks", "Track Us was Clicked");
startActivity(new Intent (MainActivity.this, Tracklocation.class ));
}
if(item.getItemId()== R.id.item2){
Log.d("Updates", "Updates was Clicked");
startActivity(new Intent (MainActivity.this, Updates.class ));
}
if(item.getItemId()== R.id.item3){
Log.d("About Us", "About Us was Clicked");
startActivity(new Intent (MainActivity.this, Horoscope.class ));
}
return super.onOptionsItemSelected(item);
}
@Override
public boolean onTouch(View v, MotionEvent rawEvent) {
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
dumpEvent(rawEvent);
// Handle touch events here...
switch (rawEvent.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
start.set(rawEvent.getX(), rawEvent.getY());
Log.d(TAG, "mode=DRAG");
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(rawEvent);
Log.d(TAG, "oldDist=" + oldDist);
if (oldDist > 10f) {
savedMatrix.set(matrix);
midPoint(mid, rawEvent);
mode = ZOOM;
Log.d(TAG, "mode=ZOOM");
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
Log.d(TAG, "mode=NONE");
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
matrix.set(savedMatrix);
// limit pan
matrix.getValues(matrixValues);
float currentY = matrixValues[Matrix.MTRANS_Y];
float currentX = matrixValues[Matrix.MTRANS_X];
float currentScale = matrixValues[Matrix.MSCALE_X];
float currentHeight = height * currentScale;
float currentWidth = width * currentScale;
float dx = rawEvent.getX() - start.x;
float dy = rawEvent.getY() - start.y;
float newX = currentX+dx;
float newY = currentY+dy;
RectF drawingRect = new RectF(newX, newY, newX+currentWidth, newY+currentHeight);
float diffUp = Math.min(viewRect.bottom-drawingRect.bottom, viewRect.top-drawingRect.top);
float diffDown = Math.max(viewRect.bottom-drawingRect.bottom, viewRect.top-drawingRect.top);
float diffLeft = Math.min(viewRect.left-drawingRect.left, viewRect.right-drawingRect.right);
float diffRight = Math.max(viewRect.left-drawingRect.left, viewRect.right-drawingRect.right);
if(diffUp > 0 ){
dy +=diffUp;
}
if(diffDown < 0){
dy +=diffDown;
}
if( diffLeft> 0){
dx += diffLeft;
}
if(diffRight < 0){
dx += diffRight;
}
matrix.postTranslate(dx, dy);
} else if (mode == ZOOM) {
float newDist = spacing(rawEvent);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 10f) {
matrix.set(savedMatrix);
float scale1 = newDist / oldDist;
matrix.getValues(matrixValues);
float currentScale = matrixValues[Matrix.MSCALE_X];
// limit zoom
if (scale1 * currentScale > maxZoom) {
scale1 = maxZoom / currentScale;
} else if (scale1 * currentScale < minZoom) {
scale1 = minZoom / currentScale;
}
matrix.postScale(scale1, scale1, mid.x, mid.y);
}
}
break;
}
view.setImageMatrix(matrix);
return true;
}
@SuppressWarnings("deprecation")
private void dumpEvent(MotionEvent event) {
String names[] = { "DOWN", "UP", "MOVE", "CANCEL", "OUTSIDE",
"POINTER_DOWN", "POINTER_UP", "7?", "8?", "9?" };
StringBuilder sb = new StringBuilder();
int action = event.getAction();
int actionCode = action & MotionEvent.ACTION_MASK;
sb.append("event ACTION_").append(names[actionCode]);
if (actionCode == MotionEvent.ACTION_POINTER_DOWN
|| actionCode == MotionEvent.ACTION_POINTER_UP) {
sb.append("(pid ").append(
action >> MotionEvent.ACTION_POINTER_ID_SHIFT);
sb.append(")");
}
sb.append("[");
for (int i = 0; i < event.getPointerCount(); i++) {
sb.append("#").append(i);
sb.append("(pid ").append(event.getPointerId(i));
sb.append(")=").append((int) event.getX(i));
sb.append(",").append((int) event.getY(i));
if (i + 1 < event.getPointerCount())
sb.append(";");
}
sb.append("]");
Log.d(TAG, sb.toString());
}
/** Determine the space between the first two fingers */
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return FloatMath.sqrt(x * x + y * y);
}
/** Calculate the mid point of the first two fingers */
@SuppressLint("FloatMath")
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
}
a
a54studio
I needed something similar, but needed the ability to get the dimensions easily and also drag/drop. I based this off of the answer @Nicolas Tyler gave and modified it from there.
The features are pinch zoom in/out, long press to vibration/highlighted drag/drop.
To use it add this CustomZoomView class to your project.
public class CustomZoomView extends View implements View.OnTouchListener, View.OnLongClickListener{
private Paint mPaint;
Vibrator v;
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
static final int MOVE = 3;
private int mode = NONE;
Rect src;
Rect mTempDst = new Rect();
Rect dst = new Rect();
Bitmap mBitmap;
private int mBitmapWidth = -1;
private int mBitmapHeight = -1;
private PointF mStartPoint = new PointF();
private PointF mMiddlePoint = new PointF();
private PointF mStartDragPoint = new PointF();
private PointF mMovePoint = new PointF();
private float oldDist = 1f;
private float scale;
private float oldEventX = 0;
private float oldEventY = 0;
private float oldStartPointX = 0;
private float oldStartPointY = 0;
private int mViewWidth = -1;
private int mViewHeight = -1;
private boolean mDraggable = false;
public CustomZoomView(Context context) {
this(context, null, 0);
}
public CustomZoomView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CustomZoomView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
this.setOnTouchListener(this);
this.setOnLongClickListener(this);
v = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
mPaint = new Paint();
mPaint.setColorFilter(new PorterDuffColorFilter(Color.argb(100,255,255,255), PorterDuff.Mode.SRC_IN));
}
@Override
public void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mViewWidth = w;
mViewHeight = h;
}
public void setBitmap(Bitmap bitmap) {
if (bitmap != null) {
src = new Rect();
src.left = 0;
src.top = 0;
src.right = bitmap.getWidth();
src.bottom = bitmap.getHeight();
mBitmap = bitmap;
mBitmapWidth = bitmap.getWidth() * 1;
mBitmapHeight = bitmap.getHeight() * 1;
dst = new Rect();
dst.left = (mViewWidth / 2) - (mBitmapWidth / 2);
dst.top = (mViewHeight / 2) - (mBitmapHeight / 2);
dst.right = (mViewWidth / 2) + (mBitmapWidth / 2);
dst.bottom = (mViewHeight / 2) + (mBitmapHeight / 2);
}
}
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
mStartPoint.set(event.getX(), event.getY());
mStartDragPoint.set(event.getX(), event.getY());
mTempDst.set(dst.left, dst.top, dst.right, dst.bottom);
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if (oldDist > 10f) {
midPoint(mMiddlePoint, event);
mode = ZOOM;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
if (mode == ZOOM) {
mBitmapWidth = dst.right - dst.left;
mBitmapHeight = dst.bottom - dst.top;
}
mode = NONE;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
mMovePoint.x = event.getX();
mMovePoint.y = event.getY();
drag(event);
} else if (mode == ZOOM) {
zoom(event);
} else if (mode == MOVE) {
move(event);
}
break;
}
return false;
}
public void move(MotionEvent event) {
int xChange = (int) (event.getX() - mStartPoint.x);
int yChange = (int) (event.getY() - mStartPoint.y);
dst.left = mTempDst.left + (xChange);
dst.top = mTempDst.top + (yChange);
dst.right = mTempDst.right + (xChange);
dst.bottom = mTempDst.bottom + (yChange);
invalidate();
}
public void drag(MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
float spacingX = eventX - mStartDragPoint.x;
float spacingY = eventY - mStartDragPoint.y;
float newPositionLeft = (dst.left < 0 ? spacingX : spacingX * -1) + dst.left;
float newPositionRight = (spacingX) + dst.right;
float newPositionTop = (dst.top < 0 ? spacingY : spacingY * -1) + dst.top;
float newPositionBottom = (spacingY) + dst.bottom;
boolean x = true;
boolean y = true;
if (newPositionRight < 0.0f || newPositionLeft > 0.0f) {
if (newPositionRight < 0.0f && newPositionLeft > 0.0f) {
x = false;
} else {
eventX = oldEventX;
mStartDragPoint.x = oldStartPointX;
}
}
if (newPositionBottom < 0.0f || newPositionTop > 0.0f) {
if (newPositionBottom < 0.0f && newPositionTop > 0.0f) {
y = false;
} else {
eventY = oldEventY;
mStartDragPoint.y = oldStartPointY;
}
}
if (mDraggable) {
if (x) oldEventX = eventX;
if (y) oldEventY = eventY;
if (x) oldStartPointX = mStartDragPoint.x;
if (y) oldStartPointY = mStartDragPoint.y;
}
}
public void zoom(MotionEvent event) {
float newDist = spacing(event);
boolean in = newDist > oldDist;
if (!in && scale < .01f) {
return;
}
scale = newDist / oldDist;
int xChange = (int) ((mBitmapWidth * scale) / 2);
int yChange = (int) ((mBitmapHeight * scale) / 2);
if (xChange > 10 && yChange > 10) { //ADDED THIS TO KEEP IT FROM GOING INVERSE
int xMidPoint = ((dst.right - dst.left) / 2) + dst.left;
int yMidPoint = ((dst.bottom - dst.top) / 2) + dst.top;
dst.left = (int) (float) (xMidPoint - xChange);
dst.top = (int) (float) (yMidPoint - yChange);
dst.right = (int) (float) (xMidPoint + xChange);
dst.bottom = (int) (float) (yMidPoint + yChange);
}
invalidate();
}
/**
* Determine the space between the first two fingers
*/
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float) Math.sqrt(x * x + y * y);
}
/**
* Calculate the mid point of the first two fingers
*/
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
@Override
public boolean onLongClick(View view) {
if (mode == DRAG) {
if ((mStartPoint.x > dst.left && mStartPoint.x < dst.right) && (mStartPoint.y < dst.bottom && mStartPoint.y > dst.top)
&& (mMovePoint.x > dst.left && mMovePoint.x < dst.right) && (mMovePoint.y < dst.bottom && mMovePoint.y > dst.top)) {
mode = MOVE;
v.vibrate(500);
}
}
return true;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mode == MOVE) {
canvas.drawBitmap(mBitmap, src, dst, null);
canvas.drawBitmap(mBitmap, src, dst, mPaint);
} else {
canvas.drawBitmap(mBitmap, src, dst, null);
}
}
}
...then add this to your activity
CustomZoomView customImageView = (CustomZoomView) findViewById(R.id.customZoomView);
customImageView.setBitmap(yourBitmap);
...and this in your view in xml.
<your.package.name.CustomZoomView
android:id="@+id/customZoomView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:longClickable="true"/>
...and add this to your manifest
<uses-permission android:name="android.permission.VIBRATE"/>
H
Hardik
Here is my solution, it is based on @alexbirkett's solution.
public class ZoomImageView extends ImageView {
// region . Static fields .
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
static final int CLICK = 3;
// endregion . Static fields .
// region . Fields .
private int mode = NONE;
private Matrix mMatrix = new Matrix();
private PointF mLastTouch = new PointF();
private PointF mStartTouch = new PointF();
private float minScale = 0.5f;
private float maxScale = 4f;
private float[] mCriticPoints;
private float mScale = 1f;
private float mRight;
private float mBottom;
private float mOriginalBitmapWidth;
private float mOriginalBitmapHeight;
private ScaleGestureDetector mScaleDetector;
//endregion . Fields .
// region . Ctor .
public ZoomImageView(Context context) {
super(context);
init(context);
}
public ZoomImageView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public ZoomImageView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
// endregion . Ctor .
// region . Overrider .
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int bmHeight = getBmHeight();
int bmWidth = getBmWidth();
float width = getMeasuredWidth();
float height = getMeasuredHeight();
float scale = 1;
// If image is bigger then display fit it to screen.
if (width < bmWidth || height < bmHeight) {
scale = width > height ? height / bmHeight : width / bmWidth;
}
mMatrix.setScale(scale, scale);
mScale = 1f;
mOriginalBitmapWidth = scale * bmWidth;
mOriginalBitmapHeight = scale * bmHeight;
// Center the image
float redundantYSpace = (height - mOriginalBitmapHeight);
float redundantXSpace = (width - mOriginalBitmapWidth);
mMatrix.postTranslate(redundantXSpace / 2, redundantYSpace / 2);
setImageMatrix(mMatrix);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
mScaleDetector.onTouchEvent(event);
mMatrix.getValues(mCriticPoints);
float translateX = mCriticPoints[Matrix.MTRANS_X];
float trnslateY = mCriticPoints[Matrix.MTRANS_Y];
PointF currentPoint = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
//when one finger is touching
//set the mode to DRAG
case MotionEvent.ACTION_DOWN:
mLastTouch.set(event.getX(), event.getY());
mStartTouch.set(mLastTouch);
mode = DRAG;
break;
//when two fingers are touching
//set the mode to ZOOM
case MotionEvent.ACTION_POINTER_DOWN:
mLastTouch.set(event.getX(), event.getY());
mStartTouch.set(mLastTouch);
mode = ZOOM;
break;
//when a finger moves
//If mode is applicable move image
case MotionEvent.ACTION_MOVE:
//if the mode is ZOOM or
//if the mode is DRAG and already zoomed
if (mode == ZOOM || (mode == DRAG && mScale > minScale)) {
// region . Move image.
float deltaX = currentPoint.x - mLastTouch.x;// x difference
float deltaY = currentPoint.y - mLastTouch.y;// y difference
float scaleWidth = Math.round(mOriginalBitmapWidth * mScale);// width after applying current scale
float scaleHeight = Math.round(mOriginalBitmapHeight * mScale);// height after applying current scale
// Move image to lef or right if its width is bigger than display width
if (scaleWidth > getWidth()) {
if (translateX + deltaX > 0) {
deltaX = -translateX;
} else if (translateX + deltaX < -mRight) {
deltaX = -(translateX + mRight);
}
} else {
deltaX = 0;
}
// Move image to up or bottom if its height is bigger than display height
if (scaleHeight > getHeight()) {
if (trnslateY + deltaY > 0) {
deltaY = -trnslateY;
} else if (trnslateY + deltaY < -mBottom) {
deltaY = -(trnslateY + mBottom);
}
} else {
deltaY = 0;
}
//move the image with the matrix
mMatrix.postTranslate(deltaX, deltaY);
//set the last touch location to the current
mLastTouch.set(currentPoint.x, currentPoint.y);
// endregion . Move image .
}
break;
//first finger is lifted
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(currentPoint.x - mStartTouch.x);
int yDiff = (int) Math.abs(currentPoint.y - mStartTouch.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
// second finger is lifted
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(mMatrix);
invalidate();
return true;
}
//endregion . Overrides .
// region . Privates .
private void init(Context context) {
super.setClickable(true);
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
mCriticPoints = new float[9];
setImageMatrix(mMatrix);
setScaleType(ScaleType.MATRIX);
}
private int getBmWidth() {
Drawable drawable = getDrawable();
if (drawable != null) {
return drawable.getIntrinsicWidth();
}
return 0;
}
private int getBmHeight() {
Drawable drawable = getDrawable();
if (drawable != null) {
return drawable.getIntrinsicHeight();
}
return 0;
}
//endregion . Privates .
// region . Internal classes .
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
float scaleFactor = detector.getScaleFactor();
float newScale = mScale * scaleFactor;
if (newScale < maxScale && newScale > minScale) {
mScale = newScale;
float width = getWidth();
float height = getHeight();
mRight = (mOriginalBitmapWidth * mScale) - width;
mBottom = (mOriginalBitmapHeight * mScale) - height;
float scaledBitmapWidth = mOriginalBitmapWidth * mScale;
float scaledBitmapHeight = mOriginalBitmapHeight * mScale;
if (scaledBitmapWidth <= width || scaledBitmapHeight <= height) {
mMatrix.postScale(scaleFactor, scaleFactor, width / 2, height / 2);
} else {
mMatrix.postScale(scaleFactor, scaleFactor, detector.getFocusX(), detector.getFocusY());
}
}
return true;
}
}
// endregion . Internal classes .
}
If this doesn't work try extending android.support.v7.widget.AppCompatImageView.
Hi, Can you tell me how to use that in Main Class? I came up with this, Can you tell me what should be the next? ZoomableImageView touch =(ZoomableImageView)findViewById(R.id.image1);
O
Ovi
Method to call the About&support dialog
public void setupAboutSupport() {
try {
// The About&Support AlertDialog is active
activeAboutSupport=true;
View messageView;
int orientation=this.getResources().getConfiguration().orientation;
// Inflate the about message contents
messageView = getLayoutInflater().inflate(R.layout.about_support, null, false);
ContextThemeWrapper ctw = new ContextThemeWrapper(this, R.style.MyCustomTheme_AlertDialog1);
AlertDialog.Builder builder = new AlertDialog.Builder(ctw);
builder.setIcon(R.mipmap.ic_launcher);
builder.setTitle(R.string.action_aboutSupport);
builder.setView(messageView);
TouchImageView imgDisplay = (TouchImageView) messageView.findViewById(R.id.action_infolinks_about_support);
imgDisplay.setMaxZoom(3f);
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.myinfolinks_about_support);
int imageWidth = bitmap.getWidth();
int imageHeight = bitmap.getHeight();
int newWidth;
// Calculate the new About_Support image width
if(orientation==Configuration.ORIENTATION_PORTRAIT ) {
// For 7" up to 10" tablets
//if ((getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) == Configuration.SCREENLAYOUT_SIZE_XLARGE) {
if (SingletonMyInfoLinks.isTablet) {
// newWidth = widthScreen - (two borders of about_support layout and 20% of width Screen)
newWidth = widthScreen - ((2 * toPixels(8)) + (int)(widthScreen*0.2));
} else newWidth = widthScreen - ((2 * toPixels(8)) + (int)(widthScreen*0.1));
} else {
// For 7" up to 10" tablets
//if ((getResources().getConfiguration().screenLayout & Configuration.SCREENLAYOUT_SIZE_MASK) == Configuration.SCREENLAYOUT_SIZE_XLARGE) {
if (SingletonMyInfoLinks.isTablet) {
newWidth = widthScreen - ((2 * toPixels(8)) + (int)(widthScreen*0.5));
} else newWidth = widthScreen - ((2 * toPixels(8)) + (int)(widthScreen*0.3));
}
// Get the scale factor
float scaleFactor = (float)newWidth/(float)imageWidth;
// Calculate the new About_Support image height
int newHeight = (int)(imageHeight * scaleFactor);
// Set the new bitmap corresponding the adjusted About_Support image
bitmap = Bitmap.createScaledBitmap(bitmap, newWidth, newHeight, true);
// Rescale the image
imgDisplay.setImageBitmap(bitmap);
dialogAboutSupport = builder.show();
TextView textViewVersion = (TextView) dialogAboutSupport.findViewById(R.id.action_strVersion);
textViewVersion.setText(Html.fromHtml(getString(R.string.aboutSupport_text1)+" <b>"+versionName+"</b>"));
TextView textViewDeveloperName = (TextView) dialogAboutSupport.findViewById(R.id.action_strDeveloperName);
textViewDeveloperName.setText(Html.fromHtml(getString(R.string.aboutSupport_text2)+" <b>"+SingletonMyInfoLinks.developerName+"</b>"));
TextView textViewSupportEmail = (TextView) dialogAboutSupport.findViewById(R.id.action_strSupportEmail);
textViewSupportEmail.setText(Html.fromHtml(getString(R.string.aboutSupport_text3)+" "+SingletonMyInfoLinks.developerEmail));
TextView textViewCompanyName = (TextView) dialogAboutSupport.findViewById(R.id.action_strCompanyName);
textViewCompanyName.setText(Html.fromHtml(getString(R.string.aboutSupport_text4)+" "+SingletonMyInfoLinks.companyName));
Button btnOk = (Button) dialogAboutSupport.findViewById(R.id.btnOK);
btnOk.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
dialogAboutSupport.dismiss();
}
});
dialogAboutSupport.setOnDismissListener(new DialogInterface.OnDismissListener() {
@Override
public void onDismiss(final DialogInterface dialog) {
// the About & Support AlertDialog is closed
activeAboutSupport=false;
}
});
dialogAboutSupport.getWindow().setBackgroundDrawable(new ColorDrawable(SingletonMyInfoLinks.atualBackgroundColor));
/* Effect that image appear slower */
// Only the fade_in matters
AlphaAnimation fade_out = new AlphaAnimation(1.0f, 0.0f);
AlphaAnimation fade_in = new AlphaAnimation(0.0f, 1.0f);
AlphaAnimation a = false ? fade_out : fade_in;
a.setDuration(2000); // 2 sec
a.setFillAfter(true); // Maintain the visibility at the end of animation
// Animation start
ImageView img = (ImageView) messageView.findViewById(R.id.action_infolinks_about_support);
img.startAnimation(a);
} catch (Exception e) {
//Log.e(SingletonMyInfoLinks.appNameText +"-" + getLocalClassName() + ": ", e.getMessage());
}
}
s
shashank sachdev
Just change ACTION_MOVE_EVENT in Chirag Raval Answer to set ZOOM_IN LIMIT
float[] values = new float[9]; matrix.getValues(values);
//0.37047964 is limit for zoom in
if(values[Matrix.MSCALE_X]>0.37047964) {
matrix.set(savedMatrix);
matrix.postScale(scale, scale, mid.x, mid.y);
view.setImageMatrix(matrix);
}else if (scale>1){
matrix.set(savedMatrix);
matrix.postScale(scale, scale, mid.x, mid.y);
view.setImageMatrix(matrix);
}
M
Mahsa2
I know it is a bit late for this answer, but I hope it helps someone.
I was looking for the same thing (Zoom using pinch, and dragging image) and I found this Android Developers Blog link.
Works perfect. No artifacts or what so ever. It uses ScaleGestureDetector.
S
Saurabh Bhandari
ZoomLib Link: https://drive.google.com/uc?export=download&id=0B34PUThnUsjVaHpkaGk0Z1hSRU0
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dummy_layout_for_zooming);// Activity layout
mZoomLinearLayout = (LinearLayout) findViewById(R.id.mZoomLinearLayout);// LinearLayout inside Activity layout
View v = ((LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE)).inflate(R.layout.layout_for_zoom, null, false);// View wants to zoom
v.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.FILL_PARENT));
ZoomView zoomView = new ZoomView(this);// intialize lib
zoomView.addView(v);
mZoomLinearLayout.addView(zoomView);
}
G
Gaganpreet Bagga
I think why you want to zoom-in and zoom-out the image view is because your image view is small and zooming in the image there will not let the image come out of the image view. Instead, image starts disappearing from the boundaries while zooming in. So letting the image come out of the image while we zoom in is what you want I guess.
So there are two tricks (according to me) to achieve this-
Change the layout params of the image view to cover the whole outermost view or view group at runtime while we are about to zoom-in the image. Make an expanded Image view or Full Image View (height and width = Outermost View or View Group) in xml file and set it's visibility to gone. When we are about to zoom-in the image, load the image from small Image View into full Img View, map the image in fullImgView to image in smallImgView and make it's view visible.
Trick no.1 does not work when the image View is nested very much inside other views (like in nested recycler view)
Trick no.2 works always :-)
Here is the implementation of trick no.2 -
public class ZoomOnTouchListener extends AppCompatActivity implements View.OnTouchListener {
private Matrix matrix = new Matrix();
private boolean isfullImgViewActive = false;
// above boolean gets true when when we firstly move 2 fingers on the smallImgView and in this case smallImgView gets invisible and fullImgView gets visible
// and false if smallImgView is visible and fullImgView is gone
private float[] matrixArray = new float[9];
private float orgScale;
private PointF start = new PointF();
private PointF prevP1 = new PointF();
private PointF prevP2 = new PointF();
private PointF mid = new PointF();
private float oldDist = 1f;
private ImageView mfullImgView;
private ImageView smallImgView;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mfullImgView = (ImageView)findViewById(R.id.imgView2);
mfullImgView.setVisibility(View.GONE);
smallImgView = (ImageView)findViewById(R.id.imgView);
smallImgView.setOnTouchListener(this);
}
@Override
public boolean onTouch(View v, MotionEvent event) {
//Log.i("0", "OnTouch()");
if(v instanceof ImageView) {
ImageView imgView = (ImageView) v;
boolean isImgViewSmall = (imgView == smallImgView);
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: // first finger down only
//Log.i("T", "Motion Event: ACTION_DOWN");
if(isImgViewSmall)
start.set(event.getX(), event.getY());
prevP1.set(event.getX(), event.getY());
return true;
case MotionEvent.ACTION_POINTER_DOWN: //second finger and other fingers down
prevP1.set(event.getX(0), event.getY(0));
prevP2.set(event.getX(1), event.getY(1));
oldDist = spacing(event);
midPoint(mid, event);
break;
case MotionEvent.ACTION_MOVE: //it doesn't mean fingers are moved. In this case, all pointers which are active are batched together
// this case occurs after action_down or action_pointer_down
//Log.i("Tag", event.getX()+","+event.getY());
if(event.getPointerCount() == 2) {
PointF newMid = new PointF();
midPoint(newMid,event);
float newDist = spacing(event);
float scale = newDist/oldDist;
if( !isfullImgViewActive){ // is smallImgView is visible and mfullImgView is gone
Log.i("tag", "true");
isfullImgViewActive = true;
matrix.set(imgView.getImageMatrix()); //note:- do not write matrix = imgView.getImageMatrix() because it gives the smallImgView's matrix reference to the matrix variable and changes on matrix will reflect on smallImgView
matrix.getValues(matrixArray);
orgScale = matrixArray[0];
smallImgView.setVisibility(View.INVISIBLE);
mfullImgView.setImageDrawable(smallImgView.getDrawable());
mfullImgView.setScaleType(ImageView.ScaleType.MATRIX);
mfullImgView.setVisibility(View.VISIBLE);
//To map the image of mFullImgView to that of smallImgView we have to
// translate the mFullImgView's image
matrix.postTranslate(tx, ty);
/////////////NOTE///////////////
//here (tx,ty) are coordinates of top-left corner of smallimgView and
// they MUST be relative to the origin of Outermost view or view group
// where fullImgView is placed. So find tx,ty in your case by yourself
mfullImgView.setImageMatrix(matrix);
}
if(isImgViewSmall) {
matrix.postScale(scale, scale, mid.x + tx, mid.y + ty);
}
else{
matrix.postScale(scale, scale, mid.x, mid.y);
}
oldDist = newDist;
matrix.postTranslate(newMid.x - mid.x, newMid.y - mid.y);
matrix.getValues(matrixArray);
mid.set(newMid);
prevP1.set(event.getX(0), event.getY(0));
prevP2.set(event.getX(1), event.getY(1));
}
else if(event.getPointerCount() == 1 ){
if(isfullImgViewActive) {
matrix.postTranslate(event.getX() - prevP1.x, event.getY() - prevP1.y);
matrix.getValues(matrixArray);
}
prevP1.set(event.getX(0), event.getY(0));
}
break;
case MotionEvent.ACTION_POINTER_UP: // second finger lifted
//Now if pointer of index 0 is lifted then pointer of index 1 will get index 0;
if(event.getActionIndex() == 0 && isfullImgViewActive){
Log.i("TAg", event.getActionIndex()+"");
prevP1.set(prevP2);
}
break;
case MotionEvent.ACTION_UP: // first finger lifted or all fingers are lifted
if(isImgViewSmall && !isfullImgViewActive) {
imgView.setScaleType(ImageView.ScaleType.FIT_CENTER);
int xDiff = (int) Math.abs(event.getX() - start.x);
int yDiff = (int) Math.abs(event.getY() - start.y);
if (xDiff == 0 && yDiff == 0) {
imgView.performClick();
return true;
}
}
if(isfullImgViewActive){
if(matrixArray[0] <= orgScale){ //matrixArray[0] is Scale.X value
mfullImgView.setOnTouchListener(null);
mfullImgView.setImageDrawable(null);
mfullImgView.setVisibility(View.GONE);
smallImgView.setOnTouchListener(this);
smallImgView.setScaleType(ImageView.ScaleType.FIT_CENTER);
smallImgView.setVisibility(View.VISIBLE);
isfullImgViewActive = false;
}
else if(matrixArray[0] > orgScale && isImgViewSmall){ //if the imgView was smallImgView
smallImgView.setOnTouchListener(null);
smallImgView.setScaleType(ImageView.ScaleType.FIT_CENTER);
smallImgView.setVisibility(View.GONE); // or View.INVISIBLE
mfullImgView.setOnTouchListener(this);
}
}
return true;
}
//end of Switch statement
if(isfullImgViewActive) { //active means visible
mfullImgView.setImageMatrix(matrix); // display the transformation on screen
}
return true; // indicate event was handled
}
else
return false;
}
private float spacing(MotionEvent event)
{
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float) Math.sqrt(x * x + y * y);
}
private void midPoint(PointF point, MotionEvent event)
{
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
}
NOTE:- Don't set OnClickListener to mfullImgView before setting onTouchListener to it. Setting that will let the fullImageView(if it is visible) steal the touch event of putting second finger down after lifting it for the first time because we want to let the smallImgView take all the touch events until all the fingers are lifted up for the first time.
K
Komal12
I am Using this one it is working perfectly.
<your.packagename.MyZoomableImageViewTouch
android:id="@+id/mediaImage"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:scaleType="matrix"/>
My a MyZoomableImageViewTouch class is below:
public class MyZoomableImageViewTouch extends ImageViewTouch
{
static final float SCROLL_DELTA_THRESHOLD = 1.0f;
public MyZoomableImageViewTouch(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
init();
}
public MyZoomableImageViewTouch(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public MyZoomableImageViewTouch(Context context)
{
super(context);
init();
}
private void init() {
View.OnTouchListener listener = new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
if (getScale() > 1f) {
getParent().requestDisallowInterceptTouchEvent(true);
} else {
getParent().requestDisallowInterceptTouchEvent(false);
}
return false;
}
};
setOnTouchListener(listener);
setDisplayType(DisplayType.FIT_TO_SCREEN);
}
@Override
protected float onDoubleTapPost(float scale, float maxZoom) {
if (scale != 1f) {
mDoubleTapDirection = 1;
return 1f;
}
if (mDoubleTapDirection == 1) {
mDoubleTapDirection = -1;
if ((scale + (mScaleFactor * 2)) <= maxZoom) {
return scale + mScaleFactor;
} else {
mDoubleTapDirection = -1;
return maxZoom;
}
} else {
mDoubleTapDirection = 1;
return 1f;
}
}
@Override
public boolean canScroll(int direction) {
RectF bitmapRect = getBitmapRect();
updateRect(bitmapRect, mScrollRect);
Rect imageViewRect = new Rect();
getGlobalVisibleRect(imageViewRect);
if (null == bitmapRect) {
return false;
}
if (Math.abs(bitmapRect.right - imageViewRect.right) < SCROLL_DELTA_THRESHOLD) {
if (direction < 0) {
return false;
}
}
if (Math.abs(bitmapRect.left - mScrollRect.left) < SCROLL_DELTA_THRESHOLD) {
if (direction > 0) {
return false;
}
}
return true;
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
{
if (getScale() == 1f) return false;
if (distanceX != 0 && !canScroll((int) -distanceX)) {
getParent().requestDisallowInterceptTouchEvent(false);
return false;
} else {
getParent().requestDisallowInterceptTouchEvent(true);
mUserScaled = true;
scrollBy(-distanceX, -distanceY);
invalidate();
return true;
}
}
}
your example have incomplete code, so many errors and ImageViewTouch class missing.
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ImageViewitself is set tocenterFit.case MotionEvent.ACTION_DOWN: // first finger down only matrix.set(view.getImageMatrix()); savedMatrix.set(matrix);This will copy current scaling settings to the initialmatrix