2.6图像对比度调整函数

[函数名称]

图像对比度调整函数ContrastAdjustProcess(WriteableBitmap src, doublecontrastValue)

[函数代码]

       ///<summary>

       /// Contrast adjust process.

       ///</summary>

       ///<param name="src">Source image.</param>

       ///<param name="contrastValue">Contrast value, from -1 to 1.</param>

       ///<returns></returns>

       publicstaticWriteableBitmap ContrastAdjustProcess(WriteableBitmap src,double contrastValue)////6对比度调整

       {

           if(src!=null )

           {

           int w = src.PixelWidth;

           int h = src.PixelHeight;

           WriteableBitmap contrastImage =newWriteableBitmap(w,h);

           byte[] temp = src.PixelBuffer.ToArray();

           for (int i = 0; i < temp.Length; i += 4)

           {

               temp[i] =Convert.ToByte((((temp[i] - 127.5) * contrastValue + temp[i]) > 255 ? 255 : ((temp[i] - 127.5) * contrastValue + temp[i])) < 0 ? 0 : (((temp[i] - 127.5) * contrastValue + temp[i]) > 255 ? 255 : ((temp[i] - 127.5) * contrastValue + temp[i])));

               temp[i + 1] =Convert.ToByte((((temp[i + 1] - 127.5) * contrastValue + temp[i + 1]) > 255 ? 255 : ((temp[i + 1] - 127.5) * contrastValue + temp[i + 1])) < 0 ? 0 : (((temp[i + 1] - 127.5) * contrastValue + temp[i + 1]) > 255 ? 255 : ((temp[i + 1] - 127.5) * contrastValue + temp[i + 1])));

               temp[i + 2] =Convert.ToByte((((temp[i + 2] - 127.5) * contrastValue + temp[i + 2]) > 255 ? 255 : ((temp[i + 2] - 127.5) * contrastValue + temp[i + 2])) < 0 ? 0 : (((temp[i + 2] - 127.5) * contrastValue + temp[i + 2]) > 255 ? 255 : ((temp[i + 2] - 127.5) * contrastValue + temp[i + 2])));

           }

           Stream sTemp = contrastImage.PixelBuffer.AsStream();

           sTemp.Seek(0,SeekOrigin.Begin);

           sTemp.Write(temp, 0, w * 4 * h);

           return contrastImage;

           }

           else

           {

               returnnull;

           }  

       }