Android imageview从缩放图像中获取像素颜色

Question

我的家庭自动化应用程序具有以下功能:人们可以使用平面图和仪表板将图像上传到手机,以便控制家庭自动化软件.我让他们上传了两张图片:一张带有他们想要显示的图片的可见图片,另一张带有纯色的颜色图,对应于他们想要从可见图像中定位区域的对象.两个图像必须具有相同的大小,以像素为单位.当他们点击屏幕时,我希望能够从colormap覆盖图中获取颜色,然后我继续执行与该颜色相关联的操作.问题是,图像的缩放让我感到困惑.他们使用的图像可能比设备屏幕大,所以我缩放它们以便它们适合显示器.我现在不需要捏缩放功能,但我可能会在以后实现它.现在,我只想让图像以最大尺寸显示,以便它适合屏幕.所以,我的问题是,我怎么能修改这个代码,以便我可以从缩放的图像中获得正确的接触点颜色.图像缩放本身似乎工作正常.它被缩放并正确显示.我只是无法获得正确的接触点.

 final Bitmap bm = decodeSampledBitmapFromFile(visible_image, size, size);
 if (bm!=null) {
    imageview.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
    imageview.setImageBitmap(bm);
 }

 final Bitmap bm2 = decodeSampledBitmapFromFile(image_overlay, size, size);
 if (bm2!=null) {
    overlayimageview.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
    overlayimageview.setImageBitmap(bm2);

    imageview.setOnTouchListener(new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent mev) {
            DecodeActionDownEvent(v, mev, bm2);
            return false;
        }

    });
 }

 private void DecodeActionDownEvent(View v, MotionEvent ev, Bitmap bm2)
 {
    xCoord = Integer.valueOf((int)ev.getRawX());
    yCoord = Integer.valueOf((int)ev.getRawY());
    try {
        // Here's where the trouble is.
        // returns the value of the unscaled pixel at the scaled touch point?
        colorTouched = bm2.getPixel(xCoord, yCoord); 
    } catch (IllegalArgumentException e) {
        colorTouched = Color.WHITE; // nothing happens when touching white
    }
 }

 private static Bitmap decodeSampledBitmapFromFile(String fileName, 
         int reqWidth, int reqHeight) {
     // code from 
     // http://developer.android.com/training/displaying-bitmaps/load-bitmap.html
     final BitmapFactory.Options options = new BitmapFactory.Options();
     options.inJustDecodeBounds = true;
     BitmapFactory.decodeFile(fileName, options);

     // Calculate inSampleSize
     options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

     // Decode bitmap with inSampleSize set
     options.inJustDecodeBounds = false;
     return BitmapFactory.decodeFile(fileName, options);
 }

 private static int calculateInSampleSize(
      BitmapFactory.Options options, int reqWidth, int reqHeight) {
     // code from 
     // http://developer.android.com/training/displaying-bitmaps/load-bitmap.html
     // Raw height and width of image
     final int height = options.outHeight;
     final int width = options.outWidth;
     int inSampleSize = 1;

     if (height > reqHeight || width > reqWidth) {
       if (width > height) {
          inSampleSize = Math.round((float)height / (float)reqHeight);
       } else {
          inSampleSize = Math.round((float)width / (float)reqWidth);
       }
     }
     return inSampleSize;
 }

Answer 1

我想到了.我换了

 xCoord = Integer.valueOf((int)ev.getRawX());
 yCoord = Integer.valueOf((int)ev.getRawY());

同

 Matrix inverse = new Matrix();
 v.getImageMatrix().invert(inverse);
 float[] touchPoint = new float[] {ev.getX(), ev.getY()};
 inverse.mapPoints(touchPoint);
 xCoord = Integer.valueOf((int)touchPoint[0]);
 yCoord = Integer.valueOf((int)touchPoint[1]);