RoundedBitmapDrawable.java 文件源码

private void updatePaint() {
  Bitmap bitmap = getBitmap();
  if (mLastBitmap == null || mLastBitmap.get() != bitmap) {
    mLastBitmap = new WeakReference<Bitmap>(bitmap);
    mPaint.setShader(new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP));
    mIsShaderTransformDirty = true;
  }
  if (mIsShaderTransformDirty) {
    mPaint.getShader().setLocalMatrix(mTransform);
    mIsShaderTransformDirty = false;
  }
}