一个制作水印的方法

//方法作用:生成水印图片

//sourceFile:要生成水印的图片文件

//WaterMarkFile:存放水印的图片文件

//saveFile:存放水印的图片文件

public static bool MakeWaterImage(string sourceFile,string waterMarkFile,string saveFile)

{

bool result;

try

{

//原图

Bitmap sImage = new Bitmap(sourceFile);

int sWidth = sImage.Width;

int sHeight = sImage.Height;

//水印图

Bitmap wImage = new Bitmap(waterMarkFile);

int wWidth = wImage.Width;

int wHeight = wImage.Height;

//make Graphics.

Graphics g = Graphics.FromImage(sImage);

int x; //临时变量

int y; //监时变量

int x1; //原图和水印图的宽度差

int y1; //原图和水印图的高度差

int w; //生成的水印图的宽度

int h; //生成的水印图的高度

int al; //alpha

int rl; //Red

int gl; //Green

int bl; //Blue

if(sWidth > wWidth)

{

x1 = sWidth - wWidth;

y1 = sHeight - wHeight;

w = wWidth;

h = wHeight;

}

else

{

x1 = 0;

y1 = 0;

w = sWidth;

h = sHeight;

}

//开始绘图

for(x = 1; x < w; x++)

{

for(y = 1; y < h; y++)

{

al = wImage.GetPixel(x,y).A;

rl = wImage.GetPixel(x,y).R;

gl = wImage.GetPixel(x,y).G;

bl = wImage.GetPixel(x,y).B;

al = 70;

if(rl + 25 < 255)

rl += 25;

if(gl + 25 < 255)

gl += 25;

if(bl + 25 < 255)

bl += 25;

g.DrawEllipse(new Pen(new SolidBrush(Color.FromArgb(al,rl,gl,bl))),x1+x,y1+y,1,1);

}

}

g.Save();

sImage.Save(saveFile);

result = true;

}

catch

{

result = false;

}

return result;

}

但这个不能在GIF格式上加图片。。