Bitmap压缩到指定尺寸大小，获取圆角、圆形图片

  /**
     * 使用Matrix将Bitmap压缩到指定大小
     * @param bitmap
     * @param w
     * @param h
     * @return
     */
    public static Bitmap resizeBitmap(Bitmap bitmap, int w, int h)
    {
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();

        float scaleWidth = ((float) w) / width;
        float scaleHeight = ((float) h) / height;

        Matrix matrix = new Matrix();
        matrix.postScale(scaleWidth, scaleHeight);

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

    /**
     * 给Bitmap设置圆角
     * @param bitmap
     * @param roundPx  圆角值
     * @return
     */
    public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx){

        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
                .getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
        final RectF rectF = new RectF(rect);

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

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

        return output;
    }

    /**
     * 得到圆形图片
     * @param bitmap
     * @return
     */
    public static Bitmap getOvalBitmap(Bitmap bitmap){

        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap
                .getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);

        final int color = 0xff424242;
        final Paint paint = new Paint();
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());

        final RectF rectF = new RectF(rect);

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

        canvas.drawOval(rectF, paint);

        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
        canvas.drawBitmap(bitmap, rect, rect, paint);
        return output;
    }