如何将图章注释从图像导出到图像文件？

Question

如何将“图像中的图章注释”导出到图像文件？

我有一个包含图章注释的 pdf（实际上它是一个图像），我想将所有这些类型的图像导出到文件并获得 x/y 位置。

我是 pdf 新手。任何想法或代码将不胜感激。

[--- 编辑于 2019/08/08 ---]

    private void btnExtractAnnotaion_Click(object sender, EventArgs e)
    {
        PdfReader reader = new PdfReader(this.txtPdf.Text);
        PdfDictionary pageDict = reader.GetPageN(reader.NumberOfPages);
        PdfArray annotArray = pageDict.GetAsArray(PdfName.ANNOTS);
        PdfObject annot = null;
        Console.WriteLine("Annotation count:{0}", annotArray.Size);
        for (int i = 0; i < annotArray.Size; i++)
        {
            annot = annotArray.GetDirectObject(i);
            Console.WriteLine(annot.ToString());
            //curAnnot = annotArray.GetAsDict(i);
            //Console.WriteLine(curAnnot.ToString());
            bool btmp = annot.IsDictionary();
            if (btmp)
            {
                PdfDictionary pdfDic = ((PdfDictionary)annot);
                PdfName stamp = pdfDic.GetAsName(PdfName.SUBTYPE);
                if (stamp.Equals(PdfName.STAMP))
                {
                    //PdfObject img = pdfDic.GetDirectObject(PdfName.RECT);
                    // How Can I get the image(png, jpg...) of Stamp?
                }
            }

Answer 1

iText7 正是您想要使用的东西。 ;)

https://www.nuget.org/packages/itext7/

https://itextpdf.com/en/products/itext-7

这是您获得邮票的方式，具体取决于所使用的邮票技术：

using (PdfReader r = new PdfReader("input.pdf"))
using (PdfDocument doc = new PdfDocument(r))
{
    var annotations = doc.GetPage(1).GetAnnotations();
}

在其他情况下，这可以解决问题：

using (PdfReader r = new PdfReader("input.pdf"))
using (PdfDocument doc = new PdfDocument(r))
{
    var res = doc.GetFirstPage().GetResources();
}

除非你提供一个演示-pdf，否则我可以给你所有的帮助

Answer 2

@mkl @FastJack 感谢您的宝贵时间！通过这个回答

它解决了我的问题。以下是我的代码：

PdfReader reader = new PdfReader(this.txtPdf.Text);
PdfDictionary pageDict = reader.GetPageN(reader.NumberOfPages);
PdfArray annotArray = pageDict.GetAsArray(PdfName.ANNOTS);

//Console.WriteLine("Annotation count:{0}", annotArray.Size);
for (int i = 0; i < annotArray.Size; i++)
{
    PdfObject annot = annotArray.GetDirectObject(i);
    //Console.WriteLine(annot.ToString());
    bool btmp = annot.IsDictionary();
    if (btmp)
    {
        PdfDictionary pdfDic = ((PdfDictionary)annot);
        PdfName stamp = pdfDic.GetAsName(PdfName.SUBTYPE);
        if (stamp.Equals(PdfName.STAMP))
        {
            // rects are laid out [llx, lly, urx, ury]
            float x, y, width, height;
            PdfArray rect = pdfDic.GetAsArray(PdfName.RECT);
            x = rect.GetAsNumber(0).FloatValue;
            y = rect.GetAsNumber(1).FloatValue;
            width = rect.GetAsNumber(2).FloatValue - x;
            height = rect.GetAsNumber(3).FloatValue - y;

            PdfDictionary appearancesDic = pdfDic.GetAsDict(PdfName.AP);
            PdfStream normalAppearance = appearancesDic.GetAsStream(PdfName.N);
            PdfDictionary resourcesDic = ormalAppearance.GetAsDict(PdfName.RESOURCES);

            ImageRenderListener listener = new ImageRenderListener();
            PdfContentStreamProcessor processor = new PdfContentStreamProcessor(listener);
            processor.ProcessContent(
                ContentByteUtils.GetContentBytesFromContentObject(normalAppearance),                 resourcesDic);

            System.Drawing.Image drawingImage = listener.Images.First();
            //Image image = Image.GetInstance(drawingImage, drawingImage.RawFormat);
        }
    }
}

如何将图章注释从图像导出到图像文件？

How can I export the stamp annotation from image to an image file?

c#

image

itext

pdf-annotations