使用canvas.drawBitmapMesh扭曲图像

private Bitmap bitmap;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LinearLayout linearLayout = (LinearLayout) findViewById(R.id.main);
linearLayout.addView(new MyView(this, R.drawable.late));
}

private class MyView extends View {
private final int width = 20;
private final int height = 20;
private final int count = (width + 1) * (height + 1);
private final float[] verts = new float[count * 2];
private final float[] orig = new float[count * 2];

public MyView(Context context, int drawableId) {
super(context);
setFocusable(true);
bitmap = BitmapFactory.decodeResource(getResources(), drawableId);
float bitmapWidth = bitmap.getWidth();
float bitmapHeight = bitmap.getHeight();
int index = 0;
for (int y = 0; y <= height; y++) {
float fy = bitmapHeight * y / height;
for (int x = 0; x <= width; x++) {
float fx = bitmapWidth * x / width;
orig[index * 2 + 0] = verts[index * 2 + 0] = fx;
orig[index * 2 + 1] = verts[index * 2 + 1] = fy;
index += 1;
}
}
setBackgroundColor(Color.WHITE);
}

@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
}

@Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmapMesh(bitmap, width, height, verts, 0, null, 0, null);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
float cx = event.getX();
float cy = event.getY();
for (int i = 0; i < count * 2; i += 2) {
float dx = cx - orig[i + 0];
float dy = cy - orig[i + 1];
float dd = dx * dx + dy * dy;
float d = (float) Math.sqrt(dd);
float pull = 80000 / ((float) (dd * d));
if (pull >= 1) {
verts[i + 0] = cx;
verts[i + 1] = cy;
} else {
verts[i + 0] = orig[i + 0] + dx * pull;
verts[i + 1] = orig[i + 1] + dy * pull;
}
}
invalidate();
return true;
}
}