有生成高质量的GIF缩略图的代码吗？

Question

RT

Answer 1

Image类下有GetThunmbnailImage方法.

Answer 2

GetThunmbnailImage只有一个重载  容易变型

Answer 3

参考    public void SplitTiffImage(string fileServerPath)
    {
        string currentMuilPageTiffName = Path.GetFileName(fileServerPath);
        Bitmap image = new Bitmap(fileServerPath);        try
        {
            Guid objGuid = image.FrameDimensionsList[0];
            FrameDimension objDimension = new FrameDimension(objGuid);            //Saves every frame as a separate file.
            System.Drawing.Imaging.Encoder enc = System.Drawing.Imaging.Encoder.Compression;
            int curFrame = 0;
            for (int i = 0; i < muilPageNum; i++)
            {
                image.SelectActiveFrame(objDimension, curFrame);
                EncoderParameters ep = new EncoderParameters(1);
                ep.Param[0] = new EncoderParameter(enc, (long)EncoderValue.CompressionLZW);
                ImageCodecInfo[] encoders = ImageCodecInfo.GetImageEncoders();
                for (int j = 0; j < encoders.Length; j++)
                {
                    if (encoders[j].MimeType == "image/gif")
                    {
                        info = encoders[j];
                    }
                }                //Save the master bitmap
                string onePageTiffName = string.Format("{0}{1}.GIF", currentMuilPageTiffName, i.ToString());
                string jpgFileName = onePageTiffName.Replace(".TIF", ".JPG");                createJpgFileString(jpgFileName, image.Width, image.Height);                string onePageTiffphyPath = "img_in/Img_OnePageTiff/" + onePageTiffName;
                string onePageTiffServerPath = Server.MapPath(onePageTiffphyPath);                image.Save(onePageTiffServerPath, info, ep);                curFrame++;
            }
            image.Dispose();
            System.GC.SuppressFinalize(image);
        }
        catch (Exception)
        {
            throw;
        }    }

Answer 4

给你一个自己写的用的缩略图生成方法，默认使用的最高质量配置。
取得 Image 保存成 gif 即可。        /// <summary>
        /// by vengair
        /// </summary>
        /// <param name="image"></param>
        /// <param name="percentage"></param>
        /// <returns></returns>
        private static Image GenerateThumbnailImage(Image image, int percentage)
        {
            Bitmap myBitmap = new Bitmap((int)(image.Width * percentage / 100), (int)(image.Height * percentage / 100));
            Graphics myGraphics = Graphics.FromImage(myBitmap);            // 绘制边框和背景
            myGraphics.FillRectangle(Brushes.Gray, new Rectangle(0, 0, myBitmap.Width, myBitmap.Height));
            myGraphics.FillRectangle(Brushes.White, new Rectangle(1, 1, myBitmap.Width - 2, myBitmap.Height - 2));            myGraphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
            myGraphics.SmoothingMode = SmoothingMode.HighQuality;
            myGraphics.DrawImage(image, new Rectangle(2, 2, myBitmap.Width - 4, myBitmap.Height - 4));
            myGraphics.Dispose();            return (Image)myBitmap;
        }

Answer 5

很简单，新建一个100*100的位图，然后把原图以100*50画在上面，保存为Gif格式即可~

Answer 6

Bitmap bmp = new Bitmap(100,100);
Bitmap bmpSrc = new Bitmap("C:\\src.Gif");
//得到等比压缩的宽高
int w = 100,h=100;
if (bmpSrc.Width>bmpSrc.Height)
{
    w = 100;
    h = bmpSrc.Height * 100 / bmpSrc.Width;
}
else
{
    h = 100;
    w = bmpSrc.Width * 100 / bmpSrc.Height;
}
Graphics g = Graphics.FromImage(bmp);
g.FillRectangle(new SolidBrush(Color.White),0,0,bmp.Width,bmp.Height);
g.DrawImage(bmpSrc,(100-w)/2,(100-h)/2,w,h);
g.Dispose();
bmp.Save("C:\\dest.Gif",ImageFormat.Gif);
bmp.Dispose();
bmpSrc.Dispose();

Answer 7

需要
using System.Drawing;
using System.Drawing.Imaging;

Answer 8

//忘记设质量了，加上Bitmap bmp = new Bitmap(100,100);
Bitmap bmpSrc = new Bitmap("C:\\src.Gif");
//得到等比压缩的宽高
int w = 100,h=100;
if (bmpSrc.Width>bmpSrc.Height)
{
    w = 100;
    h = bmpSrc.Height * 100 / bmpSrc.Width;
}
else
{
    h = 100;
    w = bmpSrc.Width * 100 / bmpSrc.Height;
}
Graphics g = Graphics.FromImage(bmp);
g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
g.FillRectangle(new SolidBrush(Color.White),0,0,bmp.Width,bmp.Height);
g.DrawImage(bmpSrc,(100-w)/2,(100-h)/2,w,h);
g.Dispose();
bmp.Save("C:\\dest.Gif",ImageFormat.Gif);
bmp.Dispose();
bmpSrc.Dispose();

Answer 9

viena太牛了你能回这么多层是因为三星还是利用csdn的bug?

Answer 10

好久不来CSDN
现在能连续回复那么多层了么？

Answer 11

.net生成的Gif损失很大，一般建议用jpg的