我在捏缩放方面做了太多的研发，发现了很多安卓捏缩放的例子。
但是当我尝试放大大图像（例如：> 10 MB，12200x8521）时，它无法解码。但是内置画廊可以做到并且可以缩放。甚至没有缩放，但缩放后它显示非常干净的图像。而在上面 pichZoomView 不能像这样缩放..
我发现QuickPic应用程序具有与图库相同的缩放功能。我不知道这个产品如何像系统图库应用一样解码图像和缩放。
如果我解码完整图像，那么它会抛出OutOfMemoryException，如果我使用采样解码，那么当我缩放时它会产生模糊图像。
我已经投入了大量时间来获取画廊应用程序的源代码，但我仍然无法从源代码中找到实际的画廊缩放实现。有人有解决方案吗？或用于捏缩放实现的画廊源代码。
我投入了大量时间并从这里subsampling-scale-image-view获得了解决方案。
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.colorchart);
BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
bmpFactoryOptions.inSampleSize =9;
bmpFactoryOptions.inDither=false; //Disable Dithering mode
bmpFactoryOptions.inPurgeable=true; //Tell to gc that whether it needs free memory, the Bitmap can be cleared
bmpFactoryOptions.inInputShareable=true; //Which kind of reference will be used to recover the Bitmap data after being clear, when it will be used in the future
// bmpFactoryOptions.inTempStorage=new byte[102*1024*1024];
bmpFactoryOptions.inJustDecodeBounds = true;
i1=(ImageView)findViewById(R.id.thefeelingwheelclear);
bmp = BitmapFactory.decodeResource(getResources(),R.drawable.thefeelingwheelclear, bmpFactoryOptions);
Display display = getWindowManager().getDefaultDisplay();
int width = display.getWidth();
int height = display.getHeight();
if (bmpFactoryOptions.outWidth > width || bmpFactoryOptions.outHeight > height) {
float heightRatio = (float) height / (float) bmpFactoryOptions.outHeight;
float widthRatio = (float) width / (float) bmpFactoryOptions.outWidth;
// WHY
if(height >= 1024 )
{
heightRatio = heightRatio /1.2f;
widthRatio = widthRatio / 1.15f;
}else if(height <= 1024 && height >= 280){
heightRatio = heightRatio /1.45f;
widthRatio = widthRatio / 1.1f;
}else{
heightRatio = heightRatio /0.95f;
widthRatio = widthRatio / 0.8f;
}
float scale = widthRatio;
float scale1 = heightRatio;
matrix.setScale(scale, scale1);
} else {
matrix.setTranslate(1f, 1f);
}
realBmp = BitmapFactory.decodeResource(getResources(),R.drawable.thefeelingwheelclear);
i1.setImageBitmap(realBmp);
i1.setImageMatrix(matrix);
i1.setOnTouchListener(this);
}
@Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
view.setScaleType(ScaleType.MATRIX);
dumpEvent(event);
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
Log.d(TAG, "mode=DRAG");
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
Log.d(TAG, "oldDist=" + oldDist);
if (oldDist > 10f) {
savedMatrix.set(matrix);
midPoint(mid, event);
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);
matrix.postTranslate(event.getX() - start.x,
event.getY() - start.y);
}
else if (mode == ZOOM) {
float newDist = spacing(event);
Log.d(TAG, "newDist=" + newDist);
if (newDist > 10f) {
matrix.set(savedMatrix);
float scale = newDist / oldDist;
matrix.postScale(scale, scale, mid.x, mid.y);
}
}
break;
}
view.setImageMatrix(matrix);
return true; // indicate event was handled
}
/** 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(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 */
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);
}