Utils.java 文件源码

public static void setBackground(View v, Bitmap bm) {

        if (bm == null) {
            v.setBackgroundResource(0);
            return;
        }

        int vwidth = v.getWidth()/4;
        int vheight = v.getHeight()/4;
        int bwidth = bm.getWidth();
        int bheight = bm.getHeight();
        float scalex = (float) vwidth / bwidth;
        float scaley = (float) vheight / bheight;
        float scale = Math.max(scalex, scaley) * 1.3f;

        Bitmap.Config config = Bitmap.Config.ARGB_8888;
        Bitmap bg = Bitmap.createBitmap(vwidth, vheight, config);
        Canvas c = new Canvas(bg);
        Paint paint = new Paint();
        paint.setAntiAlias(true);
        paint.setFilterBitmap(true);
        ColorMatrix greymatrix = new ColorMatrix();
        greymatrix.setSaturation(0);
        ColorMatrix darkmatrix = new ColorMatrix();
        darkmatrix.setScale(1f, 1f, 1f, .1f);
        greymatrix.postConcat(darkmatrix);
        ColorFilter filter = new ColorMatrixColorFilter(greymatrix);
        paint.setColorFilter(filter);
        Matrix matrix = new Matrix();
        matrix.setTranslate(-bwidth/2, -bheight/2); // move bitmap center to origin
        matrix.postRotate(10);
        matrix.postScale(scale, scale);
        matrix.postTranslate(vwidth/2, vheight/2);  // Move bitmap center to view center
        c.drawBitmap(bm, matrix, paint);
        v.setBackgroundDrawable(new BitmapDrawable(bg));
    }