C# 修改图片背景颜色
现在有一个业务，判断图片的背景是否为透明
如果为透明则修改图片的背景为白色
如果不透明则不修改图片的背景颜色

透明图片可下载
http://l5.yunpan.cn/lk/91sunoz3vc



------解决方案--------------------
public Bitmap PTransparentAdjust(Bitmap src)
{
try
{
int w = src.Width;
int h = src.Height;
Bitmap dstBitmap = new Bitmap(src.Width, src.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
System.Drawing.Imaging.BitmapData srcData = src.LockBits(new Rectangle(0, 0, w, h), System.Drawing.Imaging.ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
System.Drawing.Imaging.BitmapData dstData = dstBitmap.LockBits(new Rectangle(0, 0, w, h), System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
unsafe
{
byte* pIn = (byte*)srcData.Scan0.ToPointer();
byte* pOut = (byte*)dstData.Scan0.ToPointer();
byte* p;
int stride = srcData.Stride;
int r, g, b, a;
for (int y = 0; y < h; y++)
{
for (int x = 0; x < w; x++)
{
p = pIn;
b = pIn[0];
g = pIn[1];
r = pIn[2];
a = pIn[3];
if (a == 0)
{
pOut[1] = (byte)255;
pOut[2] = (byte)255;
pOut[3] = (byte)255;
pOut[0] = (byte)255;
}
else
{
pOut[1] = (byte)g;
pOut[2] = (byte)r;
pOut[3] = (byte)a;
pOut[0] = (byte)b;
}
pIn += 4;
pOut += 4;
}
pIn += srcData.Stride - w * 4;
pOut += srcData.Stride - w * 4;
}
src.UnlockBits(srcData);
dstBitmap.UnlockBits(dstData);
return dstBitmap;
}
}
catch (Exception e)
{
MessageBox.Show(e.Message.ToString());
return null;
}

}

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引用:
public Bitmap PTransparentAdjust(Bitmap src)
{
try
{
int w = src.Width;
int h = src.Height;
Bitmap dstBitmap = new Bitmap(src.Width, src.Height, System.Drawing.Imaging.PixelFormat……