Android --- 图片的特效处理

（转）http://blog.csdn.net/sunboy_2050/article/details/6713255

1. 图片放缩

    // zoom 放缩
    public static Bitmap zoomBitmap(Bitmap bitmap, int w, int h) {
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        Matrix matrix = new Matrix();

        float scaleWidth = w / (float) width;
        float scaleHeight = h / (float) height;
        matrix.postScale(scaleWidth, scaleHeight);

        Bitmap bitmap2 = Bitmap.createBitmap(bitmap, 0, 0, width, height,
                matrix, true);
        return bitmap2;
    }

2. 获得圆角图片

    // Round Corner Bitmap 获得圆角图片
    public static Bitmap getRoundCornerBitmap(Bitmap bitmap, float roundPX /*圆角的半径*/) {
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();

        Bitmap bitmap2 = Bitmap.createBitmap(width, height, Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap2);

        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, width, height);
        final RectF rectF = new RectF(rect);

        paint.setColor(color);
        paint.setAntiAlias(true);
        canvas.drawARGB(0, 0, 0, 0);
        canvas.drawRoundRect(rectF, roundPX, roundPX, paint);

        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);

        return bitmap2;
    }

3. 获得带倒影的图片

    // Reflect Bitmap 获得带倒影的图片
    public static Bitmap createReflectedBitmap(Bitmap bitmap) {
        //倒影和图片本身的间距
        final int reflectedGap = 4;
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();

        Matrix matrix = new Matrix();
        matrix.preScale(1, -1);

        Bitmap reflectedImage = Bitmap.createBitmap(bitmap, 0, height / 2,
                width, height / 2, matrix, false);
        Bitmap reflectedBitmap = Bitmap.createBitmap(width,
                (height + height / 2), Config.ARGB_8888);

        Canvas canvas = new Canvas(reflectedBitmap);
        canvas.drawBitmap(bitmap, 0, 0, null);
        Paint defaultPaint = new Paint();
        canvas.drawRect(0, height, width, height + reflectedGap, defaultPaint);
        canvas.drawBitmap(reflectedImage, 0, height + reflectedGap, null);

        Paint paint = new Paint();
        LinearGradient shader = new LinearGradient(0, bitmap.getHeight(), 0,
                reflectedBitmap.getHeight() + reflectedGap, 0x70ffffff,
                0x00ffffff, TileMode.CLAMP);
        paint.setShader(shader);
        paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
        canvas.drawRect(0, height, width, reflectedBitmap.getHeight()
                + reflectedGap, paint);

        return reflectedBitmap;
    }