ASP.NET：动态地为图像添加“水印”

我认为这个过程是采取cpu power ether在php,ether.net上的asp.net.因此,图像缓存模式是此类工作的必需品.

这是一些基本代码.在此代码中,您必须更改水印的位置和图像的大小.水印可以是具有透明的png图像.

public void MakePhoto(...parametres...)
    {
        Bitmap outputImage = null;
        Graphics g = null;

        try
        {                
            // the final image
            outputImage = new Bitmap(OutWidth,OutHeight,PixelFormat.Format24bppRgb);

            g = Graphics.FromImage(outputImage);
            g.CompositingMode = CompositingMode.SourceCopy;
            Rectangle destRect = new Rectangle(0,OutWidth,OutHeight);

            // the photo
            using (var BasicPhoto = new Bitmap(cBasicPhotoFileOnDisk))
            {
                g.DrawImage(BasicPhoto,destRect,BasicPhoto.Width,BasicPhoto.Height,GraphicsUnit.Pixel);
            }

            g.CompositingMode = CompositingMode.SourceOver;
            // the watermark
            using (var WaterMark = new Bitmap(cWaterMarkPhotoOnDisk))
            {
                Rectangle destWaterRect = new Rectangle(0,OutHeight);

                g.DrawImage(WaterMark,destWaterRect,GraphicsUnit.Pixel);
            }

            outputImage.Save(TheFileNameTosaveIt,ImageFormat.Jpeg);

        }
        catch (Exception x)
        {
            Debug.Assert(false);
            ... log your error,and send an error image....                
        }
        finally
        {
            if (outputImage != null)
                outputImage.Dispose();

            if (g != null)
                g.Dispose();
        }
    }

如果您希望自定义句柄,则上述代码为stand,但您只更改了保存行.就像是.

public void ProcessRequest (HttpContext context)    
{
    context.Response.ContentType = "image/jpeg";

    // add you cache here
    context.Response.Cache.SetExpires(DateTime.Now.AddMinutes(200));
    context.Response.Cache.SetMaxAge(new TimeSpan(0,200,0));
    context.Response.BufferOutput = false;


    ..... the above code....
    outputImage.Save(context.Response.OutputStream,ImageFormat.Jpeg);
    ..... the above code....


    context.Response.End();
}