Android图片特效:黑白特效、圆角效果、高斯模糊

1.黑白效果

/**
     * 将彩色图转换为黑白图
     *
     * @param 位图
     * @return 返回转换好的位图
     */
    public static bitmap converttoblackwhite(bitmap bmp) {
        int width = bmp.getwidth(); // 获取位图的宽
        int height = bmp.getheight(); // 获取位图的高

        int[] pixels = new int[width * height]; // 通过位图的大小创建像素点数组

        bmp.getpixels(pixels, 0, width, 0, 0, width, height);
        int alpha = 0xff << 24;
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                int grey = pixels[width * i + j];

                int red = ((grey & 0x00ff0000) >> 16);
                int green = ((grey & 0x0000ff00) >> 8);
                int blue = (grey & 0x000000ff);

                grey = (int) (red * 0.3 + green * 0.59 + blue * 0.11);
                grey = alpha | (grey << 16) | (grey << 8) | grey;
                pixels[width * i + j] = grey;
            }
        }
        bitmap newbmp = bitmap.createbitmap(width, height, config.rgb_565);
        newbmp.setpixels(pixels, 0, width, 0, 0, width, height);
        return newbmp;
    }

2.图片圆角

/**
     * 转换成圆角
     *
     * @param bmp
     * @param roundpx
     * @return
     */
    public static bitmap converttoroundedcorner(bitmap bmp, float roundpx) {

        bitmap newbmp = bitmap.createbitmap(bmp.getwidth(), bmp.getheight(),
                config.argb_8888);
        // 得到画布
        canvas canvas = new canvas(newbmp);

        final int color = 0xff424242;
        final paint paint = new paint();
        final rect rect = new rect(0, 0, bmp.getwidth(), bmp.getheight());
        final rectf rectf = new rectf(rect);

        paint.setantialias(true);
        canvas.drawargb(0, 0, 0, 0);
        paint.setcolor(color);
        // 第二个和第三个参数一样则画的是正圆的一角，否则是椭圆的一角
        canvas.drawroundrect(rectf, roundpx, roundpx, paint);

        paint.setxfermode(new porterduffxfermode(mode.src_in));
        canvas.drawbitmap(bmp, rect, rect, paint);

        return newbmp;
    }

3.高斯模糊

/**
     * 高斯模糊
     *
     * @param bmp
     * @return
     */
    public static bitmap converttoblur(bitmap bmp) {
        // 高斯矩阵
        int[] gauss = new int[] { 1, 2, 1, 2, 4, 2, 1, 2, 1 };

        int width = bmp.getwidth();
        int height = bmp.getheight();
        bitmap newbmp = bitmap.createbitmap(width, height,
                bitmap.config.rgb_565);

        int pixr = 0;
        int pixg = 0;
        int pixb = 0;

        int pixcolor = 0;

        int newr = 0;
        int newg = 0;
        int newb = 0;

        int delta = 16; // 值越小图片会越亮，越大则越暗

        int idx = 0;
        int[] pixels = new int[width * height];
        bmp.getpixels(pixels, 0, width, 0, 0, width, height);
        for (int i = 1, length = height - 1; i < length; i++) {
            for (int k = 1, len = width - 1; k < len; k++) {
                idx = 0;
                for (int m = -1; m <= 1; m++) {
                    for (int n = -1; n <= 1; n++) {
                        pixcolor = pixels[(i + m) * width + k + n];
                        pixr = color.red(pixcolor);
                        pixg = color.green(pixcolor);
                        pixb = color.blue(pixcolor);

                        newr = newr + pixr * gauss[idx];
                        newg = newg + pixg * gauss[idx];
                        newb = newb + pixb * gauss[idx];
                        idx++;
                    }
                }

                newr /= delta;
                newg /= delta;
                newb /= delta;

                newr = math.min(255, math.max(0, newr));
                newg = math.min(255, math.max(0, newg));
                newb = math.min(255, math.max(0, newb));

                pixels[i * width + k] = color.argb(255, newr, newg, newb);

                newr = 0;
                newg = 0;
                newb = 0;
            }
        }

        newbmp.setpixels(pixels, 0, width, 0, 0, width, height);

        return newbmp;
    }