GDI+图片毛玻璃效果的实现

来源：互联网发布：张韶涵妈妈知乎编辑：程序博客网时间：2024/06/06 05:26

分享一个图片毛玻璃效果的算法
原理：
从原像素的某个范围内随机选取一部分像素，讲其进行Alpha混合模糊得到目标像素值
下面上代码：

/// <summary>
        /// 对颜色数组进行混合
        /// </summary>
        /// <param name="colors"></param>
        /// <returns></returns>
        public static Color BlendColor(Color[] colors)
        {
            if (colors.Length <= 0)
                return Color.Transparent;
            ulong asum = 0, rsum = 0, gsum = 0, bsum = 0;
            for (int i = 0, len = colors.Length; i < len; i++)
            {
                asum += colors[i].A;
                rsum += (ulong)(colors[i].A*colors[i].R);
                gsum += (ulong)(colors[i].G*colors[i].A);
                bsum += (ulong)(colors[i].B*colors[i].A);
            }
            if (asum == 0)
                return Color.Transparent;
            rsum /= asum;
            gsum /= asum;
            bsum /= asum;
            asum /= (ulong)colors.Length;
            return Color.FromArgb((int)asum, (int)rsum, (int)gsum, (int)bsum);
        }
 
        /// <summary>
        /// 毛玻璃效果
        /// </summary>
        /// <param name="srcBmp">源图片</param>
        /// <param name="minRadius">最小离散半径</param>
        /// <param name="maxRadius">最大离散半径</param>
        /// <param name="samples">采样点数</param>
        /// <returns></returns>
        public static Bitmap FrostedEffect(Bitmap srcBmp, int minRadius, int maxRadius, int samples)
        {
            int width = srcBmp.Width;
            int height = srcBmp.Height;
            Bitmap targBmp = new Bitmap(width, height, srcBmp.PixelFormat);
            BitmapData srcData = srcBmp.LockBits(new Rectangle(0, 0, width, height), 
                ImageLockMode.ReadOnly, srcBmp.PixelFormat);
            BitmapData targData = targBmp.LockBits(new Rectangle(0, 0, width, height),
                ImageLockMode.WriteOnly, targBmp.PixelFormat);
            int pxsize = Image.GetPixelFormatSize(srcBmp.PixelFormat) / 8;//像素大小
            bool bAlpha = Image.IsAlphaPixelFormat(srcBmp.PixelFormat);
            int offset = srcData.Stride - srcData.Width * pxsize;
            Random rand = new Random();
            Color[] sampleColors = new Color[samples];
            unsafe
            {
                byte* srcptr = (byte*)srcData.Scan0;
                for (int i = 0; i < height; i++)
                {
                    for (int j = 0; j < width; j++)
                    {
                        for (int s = 0; s < samples; s++)
                        {
                            double d = rand.Next(minRadius, maxRadius);
                            double angle = rand.NextDouble() * Math.PI * 2;
                            double p = Math.Sin(angle);
                            int samh = (int)(i + Math.Sin(angle) * d);
                            int samw = (int)(j + Math.Cos(angle) * d);
                            samh = samh < 0 ? 0 : samh > height - 1 ? height - 1 : samh;
                            samw = samw < 0 ? 0 : samw > width ? width : samw;
                            byte* ptr = srcptr + samh * srcData.Stride + samw * pxsize;
                            if (bAlpha)
                                sampleColors[s] = Color.FromArgb(*(ptr + 3), *(ptr + 2), *(ptr + 1), *ptr);
                            else
                                sampleColors[s] = Color.FromArgb(*(ptr + 2), *(ptr + 1), *ptr);
                        }
                        Color col = BlendColor(sampleColors);
                        byte* targptr = (byte*)targData.Scan0 + srcData.Stride * i + j*pxsize;
                        *targptr = col.B;
                        *(targptr + 1) = col.G;
                        *(targptr + 2) = col.R;
                        if (bAlpha)
                            *(targptr + 3) = col.A;
                    }
                }
            }
            srcBmp.UnlockBits(srcData);
            targBmp.UnlockBits(targData);
            return targBmp;
        }
给个效果图