课程链接：Android图像处理-打造美图秀秀从它开始

安卓中图像处理主要通过两种方式：改变颜色矩阵，改变像素点

public static Bitmap handleImageEffect(Bitmap bm, float hue, float saturation, float lum) {
        Bitmap bmp = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bmp);
        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);

        ColorMatrix hueMatrix = new ColorMatrix();
        hueMatrix.setRotate(0, hue);
        hueMatrix.setRotate(1, hue);
        hueMatrix.setRotate(2, hue);

        ColorMatrix saturationMatrix = new ColorMatrix();
        saturationMatrix.setSaturation(saturation);

        ColorMatrix lumMatrix = new ColorMatrix();
        lumMatrix.setScale(lum, lum, lum, 1);

        ColorMatrix imageMatrix = new ColorMatrix();
        imageMatrix.postConcat(hueMatrix);
        imageMatrix.postConcat(saturationMatrix);
        imageMatrix.postConcat(lumMatrix);

        paint.setColorFilter(new ColorMatrixColorFilter(imageMatrix));
        canvas.drawBitmap(bm, 0, 0, paint);

        return bmp;
    }

这里以实现图片的怀旧效果为例：

public static Bitmap handleImagePixelsOldPhoto(Bitmap bm) {
        Bitmap bmp = Bitmap.createBitmap(bm.getWidth(), bm.getHeight(),
                Bitmap.Config.ARGB_8888);
        int width = bm.getWidth();
        int height = bm.getHeight();
        int color = 0;
        int r, g, b, a, r1, g1, b1;

        int[] oldPx = new int[width * height];
        int[] newPx = new int[width * height];

        bm.getPixels(oldPx, 0, bm.getWidth(), 0, 0, width, height);
        for (int i = 0; i < width * height; i++) {
            color = oldPx[i];
            a = Color.alpha(color);
            r = Color.red(color);
            g = Color.green(color);
            b = Color.blue(color);

            r1 = (int) (0.393 * r + 0.769 * g + 0.189 * b);
            g1 = (int) (0.349 * r + 0.686 * g + 0.168 * b);
            b1 = (int) (0.272 * r + 0.534 * g + 0.131 * b);

            if (r1 > 255) {
                r1 = 255;
            }
            if (g1 > 255) {
                g1 = 255;
            }
            if (b1 > 255) {
                b1 = 255;
            }

            newPx[i] = Color.argb(a, r1, g1, b1);
        }
        bmp.setPixels(newPx, 0, width, 0, 0, width, height);
        return bmp;
    }