SharedElementCallback.java 文件源码

public Parcelable onCaptureSharedElementSnapshot(View sharedElement, Matrix viewToGlobalMatrix, RectF screenBounds) {
    Bitmap bitmap;
    if (sharedElement instanceof ImageView) {
        ImageView imageView = (ImageView) sharedElement;
        Drawable d = imageView.getDrawable();
        Drawable bg = imageView.getBackground();
        if (d != null && bg == null) {
            bitmap = createDrawableBitmap(d);
            if (bitmap != null) {
                Bundle bundle = new Bundle();
                bundle.putParcelable(BUNDLE_SNAPSHOT_BITMAP, bitmap);
                bundle.putString(BUNDLE_SNAPSHOT_IMAGE_SCALETYPE, imageView.getScaleType().toString());
                if (imageView.getScaleType() != ScaleType.MATRIX) {
                    return bundle;
                }
                float[] values = new float[9];
                imageView.getImageMatrix().getValues(values);
                bundle.putFloatArray(BUNDLE_SNAPSHOT_IMAGE_MATRIX, values);
                return bundle;
            }
        }
    }
    int bitmapWidth = Math.round(screenBounds.width());
    int bitmapHeight = Math.round(screenBounds.height());
    bitmap = null;
    if (bitmapWidth > 0 && bitmapHeight > 0) {
        float scale = Math.min(1.0f, ((float) MAX_IMAGE_SIZE) / ((float) (bitmapWidth * bitmapHeight)));
        bitmapWidth = (int) (((float) bitmapWidth) * scale);
        bitmapHeight = (int) (((float) bitmapHeight) * scale);
        if (this.mTempMatrix == null) {
            this.mTempMatrix = new Matrix();
        }
        this.mTempMatrix.set(viewToGlobalMatrix);
        this.mTempMatrix.postTranslate(-screenBounds.left, -screenBounds.top);
        this.mTempMatrix.postScale(scale, scale);
        bitmap = Bitmap.createBitmap(bitmapWidth, bitmapHeight, Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        canvas.concat(this.mTempMatrix);
        sharedElement.draw(canvas);
    }
    return bitmap;
}