GlideCircleTransform.java 文件源码

private static Bitmap circleCrop(BitmapPool pool, Bitmap source) {
    if (source == null) return null;
    int size = Math.min(source.getWidth(), source.getHeight());
    int x = (source.getWidth() - size) / 2;
    int y = (source.getHeight() - size) / 2;
    // TODO this could be acquired from the pool too
    Bitmap squared = Bitmap.createBitmap(source, x, y, size, size);
    Bitmap result = pool.get(size, size, Bitmap.Config.ARGB_8888);
    if (result == null) {
        result = Bitmap.createBitmap(size, size, Bitmap.Config.ARGB_8888);
    }
    Canvas canvas = new Canvas(result);
    Paint paint = new Paint();
    paint.setShader(new BitmapShader(squared, BitmapShader.TileMode.CLAMP, BitmapShader.TileMode.CLAMP));
    paint.setAntiAlias(true);
    float r = size / 2f;
    canvas.drawCircle(r, r, r, paint);
    return result;
}