c# 添加图片水印,可以指定水印位置+生成缩略图
图片上传函数，进行判断是否加水印，做出两种处理方式：
/**////<summary>
///上传图片代码
///</summary>
///<paramname="image_file">HtmlInputFile控件</param>
///<paramname="ImgPath">存放的文件夹绝对位置</param>
///<paramname="ImgLink">生成的图片的名称带后缀</param>
///<returns></returns>
publicboolUpPic(System.Web.UI.HtmlControls.HtmlInputFileimage_file,stringImgPath,stringImgLink)
{
if(image_file.PostedFile.FileName!=null&&image_file.PostedFile.FileName.Trim()!="")
{
try
{
if(!System.IO.Directory.Exists(ImgPath))
{
System.IO.Directory.CreateDirectory(ImgPath);
}
//生成缩略图
this.GreateMiniImage((ImgPath+ "\\"+"old_"+ImgLink),(ImgPath+ "\\"+"mini_"+ImgLink),50,50);
//如果显示水印
if(ShowWatermark)
{
image_file.PostedFile.SaveAs(ImgPath+"\\"+"old_"+ImgLink);
//加水印
this.addWaterMark((ImgPath+"\\"+"old_"+ImgLink),(ImgPath+"\\"+ImgLink));
}
else
{
image_file.PostedFile.SaveAs(ImgPath+"\\"+ImgLink);
}
returntrue;
}
catch
{
returnfalse;
}
}
else
{
returnfalse;
}
}
加水印的函数如下:
填加图片函数，需要下面两个函数的支持，当然也可以写到一起，不过那看起来就很冗长了。
/**////<summary>
///添加图片水印
///</summary>
///<paramname="oldpath">原图片绝对地址</param>
///<paramname="newpath">新图片放置的绝对地址</param>
privatevoidaddWaterMark(stringoldpath,stringnewpath)
{
try
{
System.Drawing.Imageimage=System.Drawing.Image.FromFile(oldpath);
Bitmapb=newBitmap(image.Width,image.Height,PixelFormat.Format24bppRgb);
Graphicsg=Graphics.FromImage(b);
g.Clear(Color.White);
g.SmoothingMode=SmoothingMode.HighQuality;
g.InterpolationMode=InterpolationMode.High;
g.DrawImage(image,0,0,image.Width,image.Height);
if(如果需要填加水印)
{
switch(水印类型)
{
//是图片的话
case"WM_IMAGE":
this.addWatermarkImage(g,Page.Server.MapPath(Watermarkimgpath),WatermarkPosition,image.Width,image.Height);
break;
//如果是文字
case"WM_TEXT":
this.addWatermarkText(g,WatermarkText,WatermarkPosition
,image.Width,image.Height);
break;
}
b.Save(newpath);
b.Dispose();
image.Dispose();
}
}
catch
{
if(File.Exists(oldpath))
{
File.Delete(oldpath);
}
}
finally
{
if(File.Exists(oldpath))
{
File.Delete(oldpath);
}
}
}
加水印文字 /**////<summary>
///加水印文字
///</summary>
///<paramname="picture">imge对象</param>
///<paramname="_watermarkText">水印文字内容</param>
///<paramname="_watermarkPosition">水印位置</param>
///<paramname="_width">被加水印图片的宽</param>
///<paramname="_height">被加水印图片的高</param>
privatevoidaddWatermarkText(Graphicspicture,string_watermarkText,string_watermarkPosition,int_width,int_height)
{
int[]sizes=newint[]{16,14,12,10,8,6,4};
FontcrFont=null;
SizeFcrSize=newSizeF();
for(inti=0;i<7;i++)
{
crFont=newFont("arial",sizes[i],FontStyle.Bold);
crSize=picture.MeasureString(_watermarkText,crFont);
if((ushort)crSize.Width<(ushort)_width)
break;
}
floatxpos=0;
floatypos=0;
switch(_watermarkPosition)
{
case"WM_TOP_LEFT":
xpos=((float)_width*(float).01)+(crSize.Width/2);
ypos=(float)_height*(float).01;
break;
case"WM_TOP_RIGHT":
xpos=((float)_width*(float).99)-(crSize.Width/2);
ypos=(float)_height*(float).01;
break;
case"WM_BOTTOM_RIGHT":
xpos=((float)_width*(float).99)-(crSize.Width/2);
ypos=((float)_height*(float).99)-crSize.Height;
break;
case"WM_BOTTOM_LEFT":
xpos=((float)_width*(float).01)+(crSize.Width/2);
ypos=((float)_height*(float).99)-crSize.Height;
break;
}
StringFormatStrFormat=newStringFormat();
StrFormat.Alignment=StringAlignment.Center;
SolidBrushsemiTransBrush2=newSolidBrush(Color.FromArgb(153,0,0,0));
picture.DrawString(_watermarkText,crFont,semiTransBrush2,xpos+1,ypos+1,StrFormat);
SolidBrushsemiTransBrush=newSolidBrush(Color.FromArgb(153,255,255,255));
picture.DrawString(_watermarkText,crFont,semiTransBrush,xpos,ypos,StrFormat);
semiTransBrush2.Dispose();
semiTransBrush.Dispose();
}
//代码已经修改，可以按比率还填加图片水印，不过如果背景图片和水印图片太不成比率的话（指水印图片要大于背景图片的1/4），出来的效果不是很好。
水印图片/**////<summary>
///加水印图片
///</summary>
///<paramname="picture">imge对象</param>
///<paramname="WaterMarkPicPath">水印图片的地址</param>
///<paramname="_watermarkPosition">水印位置</param>
///<paramname="_width">被加水印图片的宽</param>
///<paramname="_height">被加水印图片的高</param>
privatevoidaddWatermarkImage(Graphicspicture,stringWaterMarkPicPath,string_watermarkPosition,int_width,int_height)
{
Imagewatermark=newBitmap(WaterMarkPicPath);
ImageAttributesimageAttributes=newImageAttributes();
ColorMapcolorMap=newColorMap();
colorMap.OldColor=Color.FromArgb(255,0,255,0);
colorMap.NewColor=Color.FromArgb(0,0,0,0);
ColorMap[]remapTable={colorMap};
imageAttributes.SetRemapTable(remapTable,ColorAdjustType.Bitmap);
float[][]colorMatrixElements={
newfloat[]{1.0f,0.0f,0.0f,0.0f,0.0f},
newfloat[]{0.0f,1.0f,0.0f,0.0f,0.0f},
newfloat[]{0.0f,0.0f,1.0f,0.0f,0.0f},
newfloat[]{0.0f,0.0f,0.0f,0.3f,0.0f},
newfloat[]{0.0f,0.0f,0.0f,0.0f,1.0f}
};
ColorMatrixcolorMatrix=newColorMatrix(colorMatrixElements);
imageAttributes.SetColorMatrix(colorMatrix,ColorMatrixFlag.Default,ColorAdjustType.Bitmap);
intxpos=0;
intypos=0;
intWatermarkWidth=0;
intWatermarkHeight=0;
doublebl=1d;
//计算水印图片的比率
//取背景的1/4宽度来比较
if((_width>watermark.Width*4)&&(_height>watermark.Height*4))
{
bl=1;
}
elseif((_width>watermark.Width*4)&&(_height<watermark.Height*4))
{
bl=Convert.ToDouble(_height/4)/Convert.ToDouble(watermark.Height);
}else
if((_width<watermark.Width*4)&&(_height>watermark.Height*4))
{
bl=Convert.ToDouble(_width/4)/Convert.ToDouble(watermark.Width);
}
else
{
if((_width*watermark.Height)>(_height*watermark.Width))
{
bl=Convert.ToDouble(_height/4)/Convert.ToDouble(watermark.Height);
}
else
{
bl=Convert.ToDouble(_width/4)/Convert.ToDouble(watermark.Width);
}
}
WatermarkWidth=Convert.ToInt32(watermark.Width*bl);
WatermarkHeight=Convert.ToInt32(watermark.Height*bl);
switch(_watermarkPosition)
{
case"WM_TOP_LEFT":
xpos=10;
ypos=10;
break;
case"WM_TOP_RIGHT":
xpos=_width-WatermarkWidth-10;
ypos=10;
break;
case"WM_BOTTOM_RIGHT":
xpos=_width-WatermarkWidth-10;
ypos=_height-WatermarkHeight-10;
break;
case"WM_BOTTOM_LEFT":
xpos=10;
ypos=_height-WatermarkHeight-10;
break;
}
picture.DrawImage(watermark,newRectangle(xpos,ypos,WatermarkWidth,WatermarkHeight),0,0,watermark.Width,watermark.Height,GraphicsUnit.Pixel,imageAttributes);
watermark.Dispose();
imageAttributes.Dispose();
}
生成缩略图函数
/**////<summary>
///生成缩略图
///</summary>
///<paramname="oldpath">原图片地址</param>
///<paramname="newpath">新图片地址</param>
///<paramname="tWidth">缩略图的宽</param>
///<paramname="tHeight">缩略图的高</param>
privatevoidGreateMiniImage(stringoldpath,stringnewpath,inttWidth,inttHeight)
{
try
{
System.Drawing.Imageimage=System.Drawing.Image.FromFile(oldpath);
doublebl=1d;
if((image.Width<=image.Height)&&(tWidth>=tHeight))
{
bl=Convert.ToDouble(image.Height)/Convert.ToDouble(tHeight);
}
elseif((image.Width>image.Height)&&(tWidth<tHeight))
{
bl=Convert.ToDouble(image.Width)/Convert.ToDouble(tWidth);
}
else
if((image.Width<=image.Height)&&(tWidth<=tHeight))
{
if(image.Height/tHeight>=image.Width/tWidth)
{
bl=Convert.ToDouble(image.Width)/Convert.ToDouble(tWidth);
}
else
{
bl=Convert.ToDouble(image.Height)/Convert.ToDouble(tHeight);
}
}
else
{
if(image.Height/tHeight>=image.Width/tWidth)
{
bl=Convert.ToDouble(image.Height)/Convert.ToDouble(tHeight);
}
else
{
bl=Convert.ToDouble(image.Width)/Convert.ToDouble(tWidth);
}
}
Bitmapb=newBitmap(image,Convert.ToInt32(image.Width/bl),Convert.ToInt32(image.Height/bl));
b.Save(newpath);
b.Dispose();
image.Dispose();
}
catch{}
}
