我使用PDFSharp创建一个PDF文件,但是当我将图像添加到PDF,文件大小上升显着,即使我将我的图像压缩为300x300像素和72dpi分辨率。当我创建一个没有图像的PDF格式,它是关于300KB这是伟大的,但第二个我在这个分辨率和尺寸添加一些图片,它上升到5MB。最多可以添加25张图片,这会使我的pdf变得荒谬。有没有人有什么建议?我已经把我的代码下面压缩我的图片:将图像添加到PDF大大增加了尺寸,即使图像为72dpi和300×300像素
//maxSize = 300x300 and mimetype can be either "image/png" or "image/jpg"
public static Bitmap CompressImage(Image currentImage, string mimeType, Size maxSize)
{
Bitmap myBitmap;
ImageCodecInfo myImageCodecInfo;
Encoder myEncoder;
EncoderParameter myEncoderParameter;
EncoderParameters myEncoderParameters;
MemoryStream stream = new MemoryStream();
// Create a Bitmap object based on a BMP file.
myBitmap = new Bitmap(currentImage);
if (currentImage.Width < maxSize.Width && currentImage.Height < maxSize.Height)
return myBitmap;
if (myBitmap.HorizontalResolution > 72.0f || myBitmap.VerticalResolution > 72.0f)
myBitmap.SetResolution(72.0f, 72.0f);
Size compressedImageSize = new Size();
compressedImageSize = ResizeToBound(new Size(myBitmap.Width, myBitmap.Height), maxSize);
Bitmap compressedBitmap = new Bitmap(myBitmap, compressedImageSize);
myBitmap.Dispose();
// Get an ImageCodecInfo object that represents the JPEG codec.
myImageCodecInfo = GetEncoderInfo(mimeType);
// for the Quality parameter category.
myEncoder = Encoder.Quality;
// EncoderParameter object in the array.
myEncoderParameters = new EncoderParameters(1);
// Save the bitmap as a JPEG file with quality level 75.
myEncoderParameter = new EncoderParameter(myEncoder, 75L);
myEncoderParameters.Param[0] = myEncoderParameter;
compressedBitmap.Save(stream, myImageCodecInfo, myEncoderParameters);
compressedBitmap.Dispose();
compressedBitmap = new Bitmap(stream);
return compressedBitmap;
}
这是GetEncoder辅助函数
public static ImageCodecInfo GetEncoderInfo(String mimeType)
{
mimeType = mimeType.ToLower();
if (mimeType.Contains("jpg"))
mimeType = mimeType.Replace("jpg", "jpeg");
int j;
ImageCodecInfo[] encoders;
encoders = ImageCodecInfo.GetImageEncoders();
for (j = 0; j < encoders.Length; ++j)
{
if (encoders[j].MimeType == mimeType)
return encoders[j];
}
return null;
}
这是ResizeToBound助手功能。
public static Size ResizeToBound(Size image, Size boundingBox)
{
double widthScale = 0, heightScale = 0;
if (image.Width != 0)
widthScale = (double)boundingBox.Width/(double)image.Width;
if (image.Height != 0)
heightScale = (double)boundingBox.Height/(double)image.Height;
double scale = Math.Min(widthScale, heightScale);
Size result = new Size((int)(image.Width * scale),
(int)(image.Height * scale));
return result;
}
如果你可以打一个比方PDF可用,您已经创建,我们可以看看,看看什么是真正被保存到PDF,什么占用的空间。这可能会让你朝正确的方向更快。 – 2014-11-09 13:55:37