给透明gif添加水印，画出来的图透明部分变黑色了。。。。

[寒叶gg]

using System.Drawing;
using System.Drawing.Imaging;
using System.Web;
/// <summary>
/// imagehandler1 的摘要说明
/// </summary>
public class imagehandler1 : IHttpHandler
{
    public imagehandler1()
    {
        //
        // TODO: 在此处添加构造函数逻辑
        //
        /// <summary>


    }

    #region IHttpHandler 成员

    public bool IsReusable
    {
        get { return false; }
    }
    /// 会产生graphics异常的PixelFormat
    /// </summary>
    private static System.Drawing.Imaging.PixelFormat[] indexedPixelFormats = { System.Drawing.Imaging.PixelFormat.Undefined, System.Drawing.Imaging.PixelFormat.DontCare,
System.Drawing.Imaging.PixelFormat.Format16bppArgb1555, System.Drawing.Imaging.PixelFormat.Format1bppIndexed, System.Drawing.Imaging.PixelFormat.Format4bppIndexed,
System.Drawing.Imaging.PixelFormat.Format8bppIndexed
    };
    /// <summary>
    /// 判断图片的PixelFormat 是否在 引发异常的 PixelFormat 之中
    /// </summary>
    /// <param name="imgPixelFormat">原图片的PixelFormat</param>
    /// <returns></returns>
    private static bool IsPixelFormatIndexed(System.Drawing.Imaging.PixelFormat imgPixelFormat)
    {
        foreach (System.Drawing.Imaging.PixelFormat pf in indexedPixelFormats)
        {
            if (pf.Equals(imgPixelFormat)) return true;
        }

        return false;
    }



    public void ProcessRequest(HttpContext context)
    {
        string fn = context.Request.PhysicalPath;
        using (System.Drawing.Image img = System.Drawing.Image.FromFile(fn))
        {
            //如果原图片是索引像素格式之列的，则需要转换
            if (IsPixelFormatIndexed(img.PixelFormat))
            {
                Bitmap bmp = new Bitmap(img.Width, img.Height, PixelFormat.Format32bppArgb);
                using (Graphics g = Graphics.FromImage(bmp))
                {
                    g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                    g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                    g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
                    g.DrawImage(img, 0, 0);
                }
                Graphics gif = Graphics.FromImage(bmp);
                gif.DrawString("全局添加水印", new Font("宋体", 20), new SolidBrush(Color.Red), new PointF(20.0f, bmp.Height - 80.0f));
                gif.Dispose();
                context.Response.ContentType = "image/jpeg";
                bmp.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
                context.Response.End();
            }
            else //否则直接操作
            {
                Graphics gif = Graphics.FromImage(img);
                gif.DrawString("全局添加水印", new Font("宋体", 20), new SolidBrush(Color.Red), new PointF(20.0f, img.Height - 80.0f));
                gif.Dispose();
                context.Response.ContentType = "image/jpeg";
                img.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
                context.Response.End();
            }
        }



    #endregion
    }
}

咋回事啊，闷.请高手指点

[zftow110]

我也想知道如何给GIF动画加水印，做个记号关注

[redboy999]

做水印到时研究过,就是不带透明效果的那种,这个透明效果也是没做成功,我甚至把一张透明的图片整上去都不行,一同求解

[子夜__]

public static void CreateImageWaterMark(string imageFile, System.Drawing.Image waterImage)
{
    if (string.IsNullOrEmpty(imageFile) || !File.Exists(imageFile) || waterImage == null)
    {
        return;
    }

    System.Drawing.Image originalImage = System.Drawing.Image.FromFile(imageFile);

    if (originalImage.Width - 10 < waterImage.Width || originalImage.Height - 10 < waterImage.Height)
    {
        return;
    }

    Graphics graphics = Graphics.FromImage(originalImage);

    int x = originalImage.Width - waterImage.Width - 10;
    int y = originalImage.Height - waterImage.Height - 10;
    int width = waterImage.Width;
    int height = waterImage.Height;

    graphics.DrawImage(waterImage, new Rectangle(x, y, width, height), 0, 0, width, height, GraphicsUnit.Pixel);
    graphics.Dispose();

    MemoryStream stream = new MemoryStream();
    originalImage.Save(stream, ImageFormat.Jpeg);
    originalImage.Dispose();

    System.Drawing.Image imageWithWater = System.Drawing.Image.FromStream(stream);

    imageWithWater.Save(imageFile);
    imageWithWater.Dispose();
}
/// <summary>
/// 对一个指定的图片加上文字水印效果。
/// </summary>
/// <param name="imageFile">图片文件地址</param>
/// <param name="waterText">水印文字内容</param>
public static void CreateTextWaterMark(string imageFile, string waterText)
{
    if (string.IsNullOrEmpty(imageFile) || string.IsNullOrEmpty(waterText) || !File.Exists(imageFile))
    {
        return;
    }

    System.Drawing.Image originalImage = System.Drawing.Image.FromFile(imageFile);

    Graphics graphics = Graphics.FromImage(originalImage);

    graphics.SmoothingMode = SmoothingMode.HighQuality;
    graphics.TextRenderingHint = TextRenderingHint.ClearTypeGridFit;
    graphics.CompositingQuality = CompositingQuality.HighQuality;
    graphics.InterpolationMode = InterpolationMode.HighQualityBicubic;

    SolidBrush brush = new SolidBrush(Color.FromArgb(153, 255, 255, 255));
    Font waterTextFont = new Font("Arial", 16, FontStyle.Regular);
    SizeF waterTextSize = graphics.MeasureString(waterText, waterTextFont);

    float x = (float)originalImage.Width - waterTextSize.Width - 10F;
    float y = (float)originalImage.Height - waterTextSize.Height - 10F;

    graphics.DrawString(waterText, waterTextFont, brush, x, y);

    graphics.Dispose();
    brush.Dispose();

    MemoryStream stream = new MemoryStream();
    originalImage.Save(stream, ImageFormat.Jpeg);
    originalImage.Dispose();

    System.Drawing.Image imageWithWater = System.Drawing.Image.FromStream(stream);

    imageWithWater.Save(imageFile);
    imageWithWater.Dispose();
}

[寒叶gg]

楼上的代码没能解决我的问题。。

报错 ：无法从带有索引像素格式的图像创建 Graphics 对象。

[寒叶gg]

求帮忙啊