ImageDrawing.java 文件源码

/**
 * Drawing src bitmap to dest bitmap with applied mask.
 *
 * @param src        source bitmap
 * @param mask       bitmap mask
 * @param dest       destination bitmap
 * @param clearColor clear color
 */
public static void drawMasked(Bitmap src, Drawable mask, Bitmap dest, int clearColor) {
    clearBitmap(dest, clearColor);
    Canvas canvas = new Canvas(dest);

    canvas.drawBitmap(src,
            new Rect(0, 0, src.getWidth(), src.getHeight()),
            new Rect(0, 0, dest.getWidth(), dest.getHeight()),
            new Paint(Paint.FILTER_BITMAP_FLAG));

    if (mask instanceof BitmapDrawable) {
        ((BitmapDrawable) mask).getPaint().setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
    } else if (mask instanceof NinePatchDrawable) {
        ((NinePatchDrawable) mask).getPaint().setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
    } else {
        throw new RuntimeException("Supported only BitmapDrawable or NinePatchDrawable");
    }
    mask.setBounds(0, 0, mask.getIntrinsicWidth(), mask.getIntrinsicHeight());
    mask.draw(canvas);
    canvas.setBitmap(null);
}