Develop Reference

How to returned image to original position when zoomout - AndroidX

I want to return my image to original position when I zoom out my image and the the image scale is smaller than the first initial image size
#Override
public boolean onTouch(View v, MotionEvent event)
{
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
float scale = 0;
dumpEvent(event);
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK)
{
case MotionEvent.ACTION_DOWN: // first finger down only
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_UP: // first finger lifted
mode = NONE;
break;
case MotionEvent.ACTION_POINTER_UP:// second finger lifted
/*matrix.set(savedMatrix);*/
/*view.setScaleType(ImageView.ScaleType.CENTER);*/
Log.v("/h/", ""+scale);
mode = ZOOMOUT;
//When release back to position
matrix.set(savedMatrix);
Log.d(TAG, "mode=ZOOMOUT");
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
if(scale>1) {
//Zoom In
}else if(scale<1) {
//Zoom Out
}
matrix.postScale(scale, scale, mid.x, mid.y);
Log.v("/h/", ""+scale+mode);
}
}
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);
}

Set savedMatrix to view.getImageMatrix() on ACTION_DOWN.
Do zoom/drag changes on a separate matrix
On ACTION_UP or ACTION_POINTER_UP set original matrix back to imageview.
view.setImageMatrix(savedMatrix)

How I can retrieve information on a canvas

I want to do a "zoomable paint", I mean a paint that I can zoom/zoom out and pan/drag the canvas and then draw on it.
I have a problem that I can't solve: when I draw while the canvas is zoomed, I retrieve the X and Y coordinate and effectively drawing it on the canvas. But these coordinates are not correct because of the zoomed canvas.
I tried to correct these (multiply by (zoomHeigh/screenHeight)) but I can't find a way to retrieve where I must draw on the original/none-zoomed screen
This is my code :
public class PaintView extends View {
public static int BRUSH_SIZE = 20;
public static final int DEFAULT_COLOR = Color.BLACK;
public static final int DEFAULT_BG_COLOR = Color.WHITE;
private static final float TOUCH_TOLERANCE = 4;
private float mX, mY;
private SerializablePath mPath;
private Paint mPaint;
private ArrayList<FingerPath> paths = new ArrayList<>();
private ArrayList<FingerPath> tempPaths = new ArrayList<>();
private int currentColor;
private int backgroundColor = DEFAULT_BG_COLOR;
private int strokeWidth;
private boolean emboss;
private boolean blur;
private boolean eraser;
private MaskFilter mEmboss;
private MaskFilter mBlur;
private Bitmap mBitmap;
private Canvas mCanvas;
private Paint mBitmapPaint = new Paint(Paint.DITHER_FLAG);
public boolean zoomViewActivated = false;
//These two constants specify the minimum and maximum zoom
private static float MIN_ZOOM = 1f;
private static float MAX_ZOOM = 5f;
private float scaleFactor = 1.f;
private ScaleGestureDetector detector;
//These constants specify the mode that we're in
private static int NONE = 0;
private static int DRAG = 1;
private static int ZOOM = 2;
private int mode;
//These two variables keep track of the X and Y coordinate of the finger when it first
//touches the screen
private float startX = 0f;
private float startY = 0f;
//These two variables keep track of the amount we need to translate the canvas along the X
//and the Y coordinate
private float translateX = 0f;
private float translateY = 0f;
//These two variables keep track of the amount we translated the X and Y coordinates, the last time we
//panned.
private float previousTranslateX = 0f;
private float previousTranslateY = 0f;
int currentPositionX = 0;
int currentPositionY = 0;
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
#Override
public boolean onScale(ScaleGestureDetector detector) {
scaleFactor *= detector.getScaleFactor();
scaleFactor = Math.max(MIN_ZOOM, Math.min(scaleFactor, MAX_ZOOM));
return true;
}
}
public ArrayList<FingerPath> getDividedPaths(float i){
for(FingerPath p : this.paths){
Matrix scaleMatrix = new Matrix();
scaleMatrix.setScale(i, i);
p.path.transform(scaleMatrix);
}
return this.paths;
}
public ArrayList<FingerPath> getPaths() {
return paths;
}
public void dividePath(float i) {
for(FingerPath p : this.paths){
Matrix scaleMatrix = new Matrix();
scaleMatrix.setScale(i, i);
p.path.transform(scaleMatrix);
}
}
public void setPaths(ArrayList<FingerPath> paths){
this.paths = paths;
}
public void setStrokeWidth(int value){
strokeWidth = value;
}
public PaintView(Context context) {
this(context, null);
detector = new ScaleGestureDetector(getContext(), new ScaleListener());
}
public PaintView(Context context, AttributeSet attrs) {
super(context, attrs);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(DEFAULT_COLOR);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setXfermode(null);
mPaint.setAlpha(0xff);
mEmboss = new EmbossMaskFilter(new float[] {1, 1, 1}, 0.4f, 6, 3.5f);
mBlur = new BlurMaskFilter(5, BlurMaskFilter.Blur.NORMAL);
detector = new ScaleGestureDetector(getContext(), new ScaleListener());
}
public void init(DisplayMetrics metrics) {
int height = metrics.heightPixels;
int width = metrics.widthPixels;
mBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
mCanvas = new Canvas(mBitmap);
currentColor = DEFAULT_COLOR;
strokeWidth = BRUSH_SIZE;
}
public void normal() {
emboss = false;
blur = false;
eraser = false;
}
public void emboss() {
emboss = true;
blur = false;
eraser = false;
}
public void blur() {
emboss = false;
blur = true;
eraser = false;
}
public void eraser() {
eraser = true;
}
public void cancel(){
if(paths.size() != 0){
tempPaths.add(paths.get(paths.size()-1));
paths.remove(paths.size()-1);
invalidate();
}
}
public void redo(){
if(tempPaths.size() != 0){
paths.add(tempPaths.get(tempPaths.size()-1));
tempPaths.remove(tempPaths.size()-1);
invalidate();
}
}
public void clear() {
backgroundColor = DEFAULT_BG_COLOR;
paths.clear();
normal();
invalidate();
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.save();
//We're going to scale the X and Y coordinates by the same amount
canvas.scale(scaleFactor, scaleFactor);
//If translateX times -1 is lesser than zero, let's set it to zero. This takes care of the left bound
if((translateX * -1) < 0) {
translateX = 0;
}
//This is where we take care of the right bound. We compare translateX times -1 to (scaleFactor - 1) * displayWidth.
//If translateX is greater than that value, then we know that we've gone over the bound. So we set the value of
//translateX to (1 - scaleFactor) times the display width. Notice that the terms are interchanged; it's the same
//as doing -1 * (scaleFactor - 1) * displayWidth
else if((translateX * -1) > (scaleFactor - 1) * getWidth()) {
translateX = (1 - scaleFactor) * getWidth();
}
if(translateY * -1 < 0) {
translateY = 0;
}
//We do the exact same thing for the bottom bound, except in this case we use the height of the display
else if((translateY * -1) > (scaleFactor - 1) * getHeight()) {
translateY = (1 - scaleFactor) * getHeight();
}
//We need to divide by the scale factor here, otherwise we end up with excessive panning based on our zoom level
//because the translation amount also gets scaled according to how much we've zoomed into the canvas.
canvas.translate(translateX / scaleFactor, translateY / scaleFactor);
/* The rest of your canvas-drawing code */
mCanvas.drawColor(backgroundColor);
if(paths != null){
for (FingerPath fp : paths) {
mPaint.setColor(fp.color);
mPaint.setStrokeWidth(fp.strokeWidth);
mPaint.setMaskFilter(null);
if (fp.emboss)
mPaint.setMaskFilter(mEmboss);
else if (fp.blur)
mPaint.setMaskFilter(mBlur);
if(fp.eraser) {
mPaint.setColor(DEFAULT_BG_COLOR);
}
mCanvas.drawPath(fp.path, mPaint);
}
}
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
canvas.restore();
}
private void touchStart(float x, float y) {
mPath = new SerializablePath();
FingerPath fp = new FingerPath(currentColor, emboss, blur, eraser, strokeWidth, mPath);
paths.add(fp);
tempPaths = new ArrayList<>();
mPath.reset();
mPath.moveTo(x, y);
mX = x;
mY = y;
}
private void touchMove(float x, float y) {
float dx = Math.abs(x - mX);
float dy = Math.abs(y - mY);
if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
mPath.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
mX = x;
mY = y;
}
}
private void touchUp() {
mPath.lineTo(mX, mY);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if(zoomViewActivated){
boolean dragged = false;
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
mode = DRAG;
//We assign the current X and Y coordinate of the finger to startX and startY minus the previously translated
//amount for each coordinates This works even when we are translating the first time because the initial
//values for these two variables is zero.
startX = event.getX() - previousTranslateX;
startY = event.getY() - previousTranslateY;
break;
case MotionEvent.ACTION_MOVE:
translateX = event.getX() - startX;
translateY = event.getY() - startY;
//We cannot use startX and startY directly because we have adjusted their values using the previous translation values.
//This is why we need to add those values to startX and startY so that we can get the actual coordinates of the finger.
double distance = Math.sqrt(Math.pow(event.getX() - (startX + previousTranslateX), 2) +
Math.pow(event.getY() - (startY + previousTranslateY), 2)
);
if(distance > 0) {
dragged = true;
}
break;
case MotionEvent.ACTION_POINTER_DOWN:
mode = ZOOM;
break;
case MotionEvent.ACTION_UP:
mode = NONE;
dragged = false;
//All fingers went up, so let's save the value of translateX and translateY into previousTranslateX and
//previousTranslate
previousTranslateX = translateX;
previousTranslateY = translateY;
currentPositionX += previousTranslateX;
currentPositionY += previousTranslateY;
break;
case MotionEvent.ACTION_POINTER_UP:
mode = DRAG;
//This is not strictly necessary; we save the value of translateX and translateY into previousTranslateX
//and previousTranslateY when the second finger goes up
previousTranslateX = translateX;
previousTranslateY = translateY;
break;
}
detector.onTouchEvent(event);
//We redraw the canvas only in the following cases:
//
// o The mode is ZOOM
// OR
// o The mode is DRAG and the scale factor is not equal to 1 (meaning we have zoomed) and dragged is
// set to true (meaning the finger has actually moved)
if ((mode == DRAG && scaleFactor != 1f && dragged) || mode == ZOOM) {
invalidate();
}
}else{
float x = event.getX()*(getHeight()/scaleFactor)/getHeight()+currentPositionX;
float y = event.getY()*(getWidth()/scaleFactor)/getWidth()+currentPositionY;
switch(event.getAction()) {
case MotionEvent.ACTION_DOWN :
touchStart(x, y);
invalidate();
break;
case MotionEvent.ACTION_MOVE :
touchMove(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP :
touchUp();
invalidate();
break;
}
}
return true;
}
}

Pixel Perfect Collision detection between a custom view and an ImageView

I have a CustomView and an Image view. The CustomView is a ball that moves around the screen and bounces off the walls. The Image is a quarter circle that you can rotate in a circle on touch. I am trying to make my game so that when the filled pixels from the CustomView cross paths with the Filled pixels from the ImageView a collision is detected. The problem that I am having is I do not know how to retrieve where the filled pixels are on each view.
Here is my XML code
<com.leytontaylor.bouncyballz.AnimatedView
android:id="#+id/anim_view"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
/>
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/quartCircle"
android:layout_gravity="center_horizontal"
android:src="#drawable/quartercircle"
android:scaleType="matrix"/>
My MainActivity
public class MainActivity extends AppCompatActivity {
private static Bitmap imageOriginal, imageScaled;
private static Matrix matrix;
private ImageView dialer;
private int dialerHeight, dialerWidth;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// load the image only once
if (imageOriginal == null) {
imageOriginal = BitmapFactory.decodeResource(getResources(), R.drawable.quartercircle);
}
// initialize the matrix only once
if (matrix == null) {
matrix = new Matrix();
} else {
// not needed, you can also post the matrix immediately to restore the old state
matrix.reset();
}
dialer = (ImageView) findViewById(R.id.quartCircle);
dialer.setOnTouchListener(new MyOnTouchListener());
dialer.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
// method called more than once, but the values only need to be initialized one time
if (dialerHeight == 0 || dialerWidth == 0) {
dialerHeight = dialer.getHeight();
dialerWidth = dialer.getWidth();
// resize
Matrix resize = new Matrix();
resize.postScale((float) Math.min(dialerWidth, dialerHeight) / (float) imageOriginal.getWidth(), (float) Math.min(dialerWidth, dialerHeight) / (float) imageOriginal.getHeight());
imageScaled = Bitmap.createBitmap(imageOriginal, 0, 0, imageOriginal.getWidth(), imageOriginal.getHeight(), resize, false);
// translate to the image view's center
float translateX = dialerWidth / 2 - imageScaled.getWidth() / 2;
float translateY = dialerHeight / 2 - imageScaled.getHeight() / 2;
matrix.postTranslate(translateX, translateY);
dialer.setImageBitmap(imageScaled);
dialer.setImageMatrix(matrix);
}
}
});
}
MyOnTouchListener class:
private class MyOnTouchListener implements View.OnTouchListener {
private double startAngle;
#Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
startAngle = getAngle(event.getX(), event.getY());
break;
case MotionEvent.ACTION_MOVE:
double currentAngle = getAngle(event.getX(), event.getY());
rotateDialer((float) (startAngle - currentAngle));
startAngle = currentAngle;
break;
case MotionEvent.ACTION_UP:
break;
}
return true;
}
}
private double getAngle(double xTouch, double yTouch) {
double x = xTouch - (dialerWidth / 2d);
double y = dialerHeight - yTouch - (dialerHeight / 2d);
switch (getQuadrant(x, y)) {
case 1:
return Math.asin(y / Math.hypot(x, y)) * 180 / Math.PI;
case 2:
return 180 - Math.asin(y / Math.hypot(x, y)) * 180 / Math.PI;
case 3:
return 180 + (-1 * Math.asin(y / Math.hypot(x, y)) * 180 / Math.PI);
case 4:
return 360 + Math.asin(y / Math.hypot(x, y)) * 180 / Math.PI;
default:
return 0;
}
}
/**
* #return The selected quadrant.
*/
private static int getQuadrant(double x, double y) {
if (x >= 0) {
return y >= 0 ? 1 : 4;
} else {
return y >= 0 ? 2 : 3;
}
}
/**
* Rotate the dialer.
*
* #param degrees The degrees, the dialer should get rotated.
*/
private void rotateDialer(float degrees) {
matrix.postRotate(degrees, dialerWidth / 2, dialerHeight / 2);
dialer.setImageMatrix(matrix);
}
And my AnimatedView
public class AnimatedView extends ImageView {
private Context mContext;
int x = -1;
int y = -1;
private int xVelocity = 10;
private int yVelocity = 5;
private Handler h;
private final int FRAME_RATE = 60;
public AnimatedView(Context context, AttributeSet attrs) {
super(context, attrs);
mContext = context;
h = new Handler();
}
private Runnable r = new Runnable() {
#Override
public void run() {
invalidate();
}
};
protected void onDraw(Canvas c) {
BitmapDrawable ball = (BitmapDrawable) mContext.getResources().getDrawable(R.drawable.smallerball);
if (x<0 && y <0) {
x = this.getWidth()/2;
y = this.getHeight()/2;
} else {
x += xVelocity;
y += yVelocity;
if ((x > this.getWidth() - ball.getBitmap().getWidth()) || (x < 0)) {
xVelocity = xVelocity*-1;
}
if ((y > this.getHeight() - ball.getBitmap().getHeight()) || (y < 0)) {
yVelocity = yVelocity*-1;
}
}
c.drawBitmap(ball.getBitmap(), x, y, null);
h.postDelayed(r, FRAME_RATE);
}
public float getX() {
return x;
}
public float getY() {
return y;
}
}
My question is: How can I retrieve the filled pixels from both of these views, and pass them through a function that detects a collision.
Thanks in advance for the help!:)

You could encapsulate your images with Array of points marking your border coordinates(and update them on move/calculate them based on origin) then you'll be able to decide whether oposing object are in touch or not(if any of oposing arrays share the same point)

You really need to define "filled pixels". I assume you mean the non-transparent pixels. The easiest way to find those, is by converting your entire view into a bitmap and iterating through its pixels. You can convert a View into a Bitmap like this:
private Bitmap getBitmapFromView(View view) {
view.buildDrawingCache();
Bitmap returnedBitmap = Bitmap.createBitmap(view.measuredWidth,
view.measuredHeight,
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(returnedBitmap);
canvas.drawColor(Color.WHITE, PorterDuff.Mode.SRC_IN);
Drawable drawable = view.background;
drawable.draw(canvas);
view.draw(canvas);
return returnedBitmap;
}
You'd also need to get the absolute location of the views:
Point getViewLocationOnScreen(View v) {
int[] coor = new int[]{0, 0};
v.getLocationOnScreen(coor);
return new Point(coor[0], coor[1]);
}
Then you just have to iterate through the pixels of each Bitmap, check their colors to know whether they're "filled", and also check whether they're overlapping based on their coordination inside the bitmaps and the absolute location of the views on screen.
Iterating through a bitmap's is done like this:
for (int x = 0; x < myBitmap.getWidth(); x++) {
for (int y = 0; y < myBitmap.getHeight(); y++) {
int color = myBitmap.getPixel(x, y);
}
}
But I must say, I don't think performing this sort of heavy computations on UI thread is really a good idea. There are dozens of much better ways to detect collisions than pixel-perfect checking. This will probably come out extremely laggy.

How to Draw on android ImageView after scaling it?

I have an ImageView and i want to zoom/drag on by two fingers and draw on it using one finger , but after scaling ImageView , bitmap coordinates and ImageView coordinates doesn't match , to solve this i provided onTouch like this :
#Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
final int NONE = 0;
final int DRAW = 1;
final int PINCH = 2;
float x,y;
switch (event.getAction() & MotionEvent.ACTION_MASK){
case MotionEvent.ACTION_DOWN:
drawStartX = event.getX();
drawStartY = event.getY();
imageMode = DRAW;
break;
case MotionEvent.ACTION_POINTER_DOWN:
//drag
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
x = event.getX(0) - event.getX(1);
y = event.getY(0) - event.getY(1);
oldDistance = (float) Math.sqrt(x * x + y * y);
if (oldDistance > 5f) {
savedMatrix.set(matrix);
x = event.getX(0) + event.getX(1);
y = event.getY(0) + event.getY(1);
mid.set(x / 2, y / 2);
imageMode = PINCH;
}
break;
case MotionEvent.ACTION_UP:
imageMode = NONE;
break;
case MotionEvent.ACTION_POINTER_UP:
imageMode = NONE;
break;
case MotionEvent.ACTION_MOVE:
if (imageMode == DRAW) {
float drawEndX = event.getX();
float drawEndY = event.getY();
drawTest(drawStartX/bitmapScale - xTranslate, drawStartY/bitmapScale- yTranslate,drawEndX/bitmapScale - xTranslate,drawEndY/bitmapScale - yTranslate,0);
} else if (imageMode == PINCH) {
x = event.getX(0) - event.getX(1);
y = event.getY(0) - event.getY(1);
float newDistance = (float) Math.sqrt(x * x + y * y);
matrix.set(savedMatrix);
if(newDistance > 5f) {
//drag
float dx = event.getX() - start.x;
float dy = event.getY() - start.y;
matrix.postTranslate(dx, dy);
//zoom
float scale = (newDistance / oldDistance);
matrix.postScale(scale, scale);
}
//get matrix
float[] mat = new float[9];
matrix.getValues(mat);
bitmapScale = mat[0];
xTranslate = mat[2];
yTranslate = mat[5];
}
break;
}
view.setImageMatrix(matrix);
return true;
}
drawTest is just a void that draws a line.
pic
in before scale picture i drag my finger on imageview and line drawn in exact position , but after scaling i dragged on same position but result is not right
but it's not working properly. how can i fix it ?

Android drag imageview with finger behaves strange

I'm implementing imageview drag function to my application.
I have tried with below code but it's behaves strange.when I try to drag the image
it's changes the position and during the movement it's shows like zooming the image.
I want to move the image with finger smoothly.
please help me to solve this problem
#Override
public boolean onTouch(View v, MotionEvent event) {
final int X = (int) event.getRawX();
final int Y = (int) event.getRawY();
MarginLayoutParams marginParams = new MarginLayoutParams(mImagePreView.getLayoutParams());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
_xDelta = X - marginParams.leftMargin;
_yDelta = Y - marginParams.topMargin;
break;
case MotionEvent.ACTION_MOVE:
marginParams.leftMargin = X-_xDelta;
marginParams.topMargin = Y - _yDelta;
marginParams.rightMargin = -250;
marginParams.bottomMargin = -250;
FrameLayout.LayoutParams layoutParams = new FrameLayout.LayoutParams(marginParams);
mImagePreView.setLayoutParams(layoutParams);
break;
default:
break;
}
return true;
}

RelativeLayout.LayoutParams layoutParams = (RelativeLayout.LayoutParams) mImagePreView.getLayoutParams();
layoutParams.leftMargin += offsetX;
layoutParams.topMargin += offsetY;
And there is error:
_xDelta = X - marginParams.leftMargin;
_yDelta = Y - marginParams.topMargin;
X - events in absolute coordinates, marginParams.leftMargin - coordinates are relative to the parent layout