在Asp.net中为图像加入水印信息

using system.drawing;
using system.io;
using system.drawing.imaging;

        private void addtexttoimg(string filename,string text)
        {
            if(!file.exists(mappath(filename)))
            {
                throw new filenotfoundexception("the file don't exist!");
            }
            
            if( text == string.empty )
            {
                return;
            }
            //还需要判断文件类型是否为图像类型，这里就不赘述了，前端框架分享

            system.drawing.image image = system.drawing.image.fromfile(mappath(filename));
            bitmap bitmap = new bitmap(image,image.width,image.height);
            graphics g = graphics.fromimage(bitmap);

            float fontsize = 12.0f;             //字体大小
            float textwidth = text.length*fontsize;  //文本的长度
            //下面定义一个矩形区域，以后在这个矩形里画上白底黑字
            float rectx = 0;        
            float recty = 0;
            float rectwidth = text.length*(fontsize+8);
            float rectheight = fontsize+8;
            //声明矩形域
            rectanglef textarea = new rectanglef(rectx,recty,rectwidth,rectheight);

            font font = new font("宋体",fontsize);   //定义字体
            brush whitebrush = new solidbrush(color.white);   //白笔刷，画文字用
            brush blackbrush = new solidbrush(color.black);   //黑笔刷，画背景用

            g.fillrectangle(blackbrush,rectx,recty,rectwidth,rectheight);            

            g.drawstring(text,font,whitebrush,textarea);
            memorystream ms = new memorystream( );
            //保存为jpg类型
            bitmap.save(ms,imageformat.jpeg);

            //输出处理后的图像，这里为了演示方便，我将图片显示在页面中了
            response.clear();
            response.contenttype = "image/jpeg";
            response.binarywrite( ms.toarray() );

            g.dispose();
            bitmap.dispose();
            image.dispose();
        }

调用时很简单，前端ui分享

addtexttoimg("me.jpg","程序人生https://www.iteye.com/topic/1132907/");

一切ok了，感觉.net确实好强大，这些功能在asp中可是奢侈品了，而在.net环境中却能轻而易举的完成！