C# 使用 itextsharp 将 Pdf 文件页面转换为图像
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Convert Pdf file pages to Images with itextsharp
提问by Prithvi Raj Nandiwal
I want to convert Pdf pages in Images using ItextSharp lib.
我想使用 ItextSharp lib 转换图像中的 Pdf 页面。
Have any idea how to convert each page in image file
知道如何转换图像文件中的每个页面
回答by Chris Haas
iText/iTextSharp can generate and/or modify existing PDFs but they do not perform any rendering which is what you are looking for. I would recommend checking out Ghostscriptor some other library that knows how to actually render a PDF.
iText/iTextSharp 可以生成和/或修改现有的 PDF，但它们不执行您正在寻找的任何渲染。我建议查看Ghostscript或其他一些知道如何实际呈现 PDF 的库。
回答by changcn
you can use ImageMagick convert pdf to image
您可以使用 ImageMagick 将 pdf 转换为图像
convert -density 300 "d:\1.pdf" -scale @1500000 "d:\a.jpg"
转换 -密度 300 "d:\1.pdf" -scale @1500000 "d:\a.jpg"
and split pdf can use itextsharp
和拆分pdf可以使用itextsharp
here is the code from others.
这是其他人的代码。
void SplitePDF(string filepath)
{
iTextSharp.text.pdf.PdfReader reader = null;
int currentPage = 1;
int pageCount = 0;
//string filepath_New = filepath + "\PDFDestination\";
System.Text.UTF8Encoding encoding = new System.Text.UTF8Encoding();
//byte[] arrayofPassword = encoding.GetBytes(ExistingFilePassword);
reader = new iTextSharp.text.pdf.PdfReader(filepath);
reader.RemoveUnusedObjects();
pageCount = reader.NumberOfPages;
string ext = System.IO.Path.GetExtension(filepath);
for (int i = 1; i <= pageCount; i++)
{
iTextSharp.text.pdf.PdfReader reader1 = new iTextSharp.text.pdf.PdfReader(filepath);
string outfile = filepath.Replace((System.IO.Path.GetFileName(filepath)), (System.IO.Path.GetFileName(filepath).Replace(".pdf", "") + "_" + i.ToString()) + ext);
reader1.RemoveUnusedObjects();
iTextSharp.text.Document doc = new iTextSharp.text.Document(reader.GetPageSizeWithRotation(currentPage));
iTextSharp.text.pdf.PdfCopy pdfCpy = new iTextSharp.text.pdf.PdfCopy(doc, new System.IO.FileStream(outfile, System.IO.FileMode.Create));
doc.Open();
for (int j = 1; j <= 1; j++)
{
iTextSharp.text.pdf.PdfImportedPage page = pdfCpy.GetImportedPage(reader1, currentPage);
pdfCpy.SetFullCompression();
pdfCpy.AddPage(page);
currentPage += 1;
}
doc.Close();
pdfCpy.Close();
reader1.Close();
reader.Close();
}
}
回答by Amer Sawan
You can use Ghostscriptto convert the PDF files into Images, I used the following parameters to convert the needed PDF into tiff image with multiple frames :
您可以使用Ghostscript将 PDF 文件转换为图像，我使用以下参数将所需的 PDF 转换为具有多帧的 tiff 图像：
gswin32c.exe -sDEVICE=tiff12nc -dBATCH -r200 -dNOPAUSE -sOutputFile=[Output].tiff [PDF FileName]
Also you can use the -q parameter for silent mode You can get more information about its output devices from here
您也可以将 -q 参数用于静默模式您可以从此处获取有关其输出设备的更多信息
After that I can easily load the tiff frames like the following
之后，我可以轻松加载如下所示的 tiff 帧
using (FileStream stream = new FileStream(@"C:\tEMP\image_$i.tiff", FileMode.Open, FileAccess.Read, FileShare.Read))
{
BitmapDecoder dec = BitmapDecoder.Create(stream, BitmapCreateOptions.IgnoreImageCache, BitmapCacheOption.None);
BitmapEncoder enc = BitmapEncoder.Create(dec.CodecInfo.ContainerFormat);
enc.Frames.Add(dec.Frames[frameIndex]);
}
回答by Reddy
you can extract Image from PDF and save as JPG here is the sample code you need Itext Sharp
您可以从 PDF 中提取图像并另存为 JPG，这里是您需要的示例代码 Itext Sharp
public IEnumerable<System.Drawing.Image> ExtractImagesFromPDF(string sourcePdf)
{
// NOTE: This will only get the first image it finds per page.
var pdf = new PdfReader(sourcePdf);
var raf = new RandomAccessFileOrArray(sourcePdf);
try
{
for (int pageNum = 1; pageNum <= pdf.NumberOfPages; pageNum++)
{
PdfDictionary pg = pdf.GetPageN(pageNum);
// recursively search pages, forms and groups for images.
PdfObject obj = ExtractImagesFromPDF_FindImageInPDFDictionary(pg);
if (obj != null)
{
int XrefIndex = Convert.ToInt32(((PRIndirectReference)obj).Number.ToString(CultureInfo.InvariantCulture));
PdfObject pdfObj = pdf.GetPdfObject(XrefIndex);
PdfStream pdfStrem = (PdfStream)pdfObj;
PdfImageObject pdfImage = new PdfImageObject((PRStream)pdfStrem);
System.Drawing.Image img = pdfImage.GetDrawingImage();
yield return img;
}
}
}
finally
{
pdf.Close();
raf.Close();
}
}
