Question

我想在asp.net中压缩图片，但我使用那些没有完全压缩文件的代码仍然非常庞大。我怎样才能进一步减小尺寸？

string directory = Server.MapPath("~/listingImages/" + date + filename);

// Create a bitmap of the conten t of the fileUpload control in memory
Bitmap originalBMP = new Bitmap(AsyncFileUpload1.FileContent);

// Calculate the new image dimensions
decimal origWidth = originalBMP.Width;
decimal origHeight = originalBMP.Height;
decimal sngRatio = origHeight / origWidth;
int newHeight = 300; //hight in pixels 
decimal newWidth_temp = newHeight / sngRatio;
int newWidth = Convert.ToInt16(newWidth_temp);

// Create a new bitmap which will hold the previous resized bitmap
Bitmap newBMP = new Bitmap(originalBMP, newWidth, newHeight);
// Create a graphic based on the new bitmap
Graphics oGraphics = Graphics.FromImage(newBMP);

// Set the properties for the new graphic file
oGraphics.SmoothingMode = SmoothingMode.AntiAlias; 
oGraphics.InterpolationMode = InterpolationMode.Bicubic;
// Draw the new graphic based on the resized bitmap
oGraphics.DrawImage(originalBMP, 0, 0, newWidth, newHeight);

// Save the new graphic file to the server
newBMP.Save(Server.MapPath("~/listingImages/" + date + filename));

Answer 1

尝试使用以下方法设置compressipn：

public static ImageCodecInfo GetEncoderInfo(String mimeType)
    {
        int j;
        ImageCodecInfo[] encoders;
        encoders = ImageCodecInfo.GetImageEncoders();
        for (j = 0; j < encoders.Length; ++j)
        {
            if (encoders[j].MimeType == mimeType)
                return encoders[j];
        } return null;
    }

EncoderParameters ep = new EncoderParameters(1);
ep.Param[0] = new EncoderParameter(Encoder.Quality, (long)70);
ImageCodecInfo ici = GetEncoderInfo("image/jpeg");

newBMP.Save(Server.MapPath("~/listingImages/" + date + filename), ici, ep);

点击此链接了解详情：https://msdn.microsoft.com/en-us/library/system.drawing.imaging.encoder.quality%28v=vs.110%29.aspx?f=255&MSPPError=-2147217396。

Answer 2

也许您应该指定image-format：

newBMP.Save(Server.MapPath("~/listingImages/" + date + filename), System.Drawing.Imaging.ImageFormat.Png);

压缩asp.net中的图片

2 个答案: