[英]Compress a Pdf using iTextSharp
我在網上發現了許多示例,其中之一:
var oldFile = @"C:\Users\XXX\Downloads\3921B2014901_2014_7346.pdf";
var newFile = @"C:\Users\XXX\Downloads\new\3921B2014901_2014_7346.pdf";
RandomAccessFileOrArray raf = new RandomAccessFileOrArray(oldFile);
PdfReader reader = new PdfReader(raf, null);
using (FileStream fs = new FileStream(newFile, FileMode.Create))
{
PdfStamper stamper = new PdfStamper(reader, fs, PdfWriter.VERSION_1_5);
PdfWriter writer = stamper.Writer;
writer.SetPdfVersion(PdfWriter.PDF_VERSION_1_5);
writer.CompressionLevel = PdfStream.BEST_COMPRESSION;
for (int i = 1; i <= reader.NumberOfPages; i++)
{
reader.SetPageContent(i, reader.GetPageContent(i), PdfStream.BEST_COMPRESSION, true);
}
stamper.SetFullCompression();
stamper.Close();
}
reader.Close();
raf.Close();
原始文件為2.75Mb,生成的新文件為2.77Mb。 為什么?
我嘗試了在線轉換器,它們將同一文件減少到500Kb。 如何獲得相同的結果?
protected void btnCompressPdf_click(object sender, EventArgs e)
{
string[] filename= Directory.GetFiles(input.Text, ".jpg");
string outputPath = MyDirectory;
if (!System.IO.Directory.Exists(MyDirectory))
System.IO.Directory.CreateDirectory(MyDirectory);
foreach (string filename in files)
{
ImageCollection images = new ImageCollection();
images.Add(filename);
String pdfName = Path.GetFileNameWithoutExtension(file);
for (int pageNumber = 0; pageNumber < images.Count; pageNumber++)
{
images[pageNumber].Save(MyDirectory + "\\" + pageNumber.ToString() + ".jpg");
}
string[] files1 = System.IO.Directory.GetFiles(MyDirectory, ".jpg");
iTextSharp.text.Document myDocument = new iTextSharp.text.Document(iTextSharp.text.PageSize.A4, 0, 0, 0, 0);
//PdfWriter.GetInstance(myDocument, new System.IO.FileStream(uxOutput.Text + "\\" + pdfName + ".pdf", System.IO.FileMode.Create));
PdfWriter writer = PdfWriter.GetInstance(myDocument, new System.IO.FileStream(Output.Text + "\\" + pdfName + ".pdf", System.IO.FileMode.Create));
writer.SetPdfVersion(PdfWriter.PDF_VERSION_1_5);
writer.CompressionLevel = PdfStream.BEST_COMPRESSION;
writer.SetFullCompression();
for (int i = 0; i <= files1.Length - 1; i++)
{
if (myDocument != null)
{
myDocument.Open();
AddImageToPDF(myDocument, MyDirectory + "\\" + (i).ToString() + ".jpg");
}
}
myDocument.Close();
myDocument = null;
System.IO.File.Delete(MyDirectory + "\\" + ".jpg");
}
}
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