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package org.fox.ttrss;
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.drawable.Drawable;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import com.bogdwellers.pinchtozoom.ImageMatrixTouchHandler;
// Based on https://github.com/martinwithaar/PinchToZoom/blob/master/pinchtozoom/src/main/java/com/bogdwellers/pinchtozoom/view/ImageViewPager.java
// mLastMotionX is a simplified version of ViewPager's MotionEvent logic
public class PagerAwareImageMatrixTouchHandler extends ImageMatrixTouchHandler {
/**
* NOT Thread safe! (But it all happens on the UI thread anyway)
*/
private static final float[] VALUES = new float[9];
private static final float SCALE_THRESHOLD = 1.2f;
private float mLastMotionX;
public PagerAwareImageMatrixTouchHandler(Context context) {
super(context);
}
@Override
public boolean onTouch(View view, MotionEvent event) {
super.onTouch(view, event);
if (event.getPointerCount() > 1) {
view.getParent().requestDisallowInterceptTouchEvent(true);
return true;
}
if (event.getAction() != MotionEvent.ACTION_MOVE)
{
return true;
}
float x = event.getX(0);
float dx = x - mLastMotionX;
mLastMotionX = x;
ImageView iv = (ImageView) view;
Drawable drawable = iv.getDrawable();
if (drawable != null) {
float vw = iv.getWidth();
float vh = iv.getHeight();
float dw = drawable.getIntrinsicWidth();
float dh = drawable.getIntrinsicHeight();
Matrix matrix = iv.getImageMatrix();
matrix.getValues(VALUES);
float tx = VALUES[Matrix.MTRANS_X] + dx;
float sdw = dw * VALUES[Matrix.MSCALE_X];
boolean blockScroll = VALUES[Matrix.MSCALE_X] / centerInsideScale(vw, vh, dw, dh) > SCALE_THRESHOLD && !translationExceedsBoundary(tx, vw, sdw) && sdw > vw; // Assumes x-y scales are equal
view.getParent().requestDisallowInterceptTouchEvent(blockScroll);
}
return true;
}
/**
* <p>Returns the scale ratio between view and drawable for the longest side.</p>
*
* @param vw
* @param vh
* @param dw
* @param dh
* @return
*/
public static final float centerInsideScale(float vw, float vh, float dw, float dh) {
return vw / vh <= dw / dh ? vw / dw : vh / dh;
}
/**
* <p>Determines whether a translation makes the view exceed the boundary of a drawable.</p>
*
* @param tx
* @param vw
* @param dw
* @return
*/
public static final boolean translationExceedsBoundary(float tx, float vw, float dw) {
return dw >= vw && (tx > 0 || tx < vw - dw);
}
}
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