PdfiumViewer组件扩展(Pdfium.Net.Free)--注解

合集 - PdfiumViewer组件扩展(Pdfium.Net.Free)(16)

13.PdfiumViewer组件扩展(Pdfium.Net.Free)--注解2024-01-31

14.PdfiumViewer组件扩展(Pdfium.Net.Free)--可视化编辑pdf2024-04-07 15.什么是转换矩阵以及如何使用它2024-02-24 16.Pdfium.Net.Free 添加 bblanchon.PDFium nuget方式02-11

项目地址：

Pdfium.Net：https://github.com/1000374/Pdfium.Net

PdfiumViewer：https://github.com/1000374/PdfiumViewer

pdf的注解分很多类型，请查看以下枚举值：

public enum FpdfAnnotSubtypes
{
    //Unknown annotation.
    UNKNOWN = 0,
    //Text annotation type.
    TEXT = 1,
    //Link annotation type.
    LINK = 2,
    //Free text annotation type.
    FREETEXT = 3,
    //Line annotation type.
    LINE = 4,
    //Square annotatotion type.
    SQUARE = 5,
    //Circle annotation type.
    CIRCLE = 6,
    //Polygon annotation type.
    POLYGON = 7,
    //Plyline annotation type.
    POLYLINE = 8,
    //Highlight annotation type.
    HIGHLIGHT = 9,
    //Underline annotation type.
    UNDERLINE = 10,
    //Squiggle annotation type.
    SQUIGGLY = 11,
    //Strikeout annotation type.
    STRIKEOUT = 12,
    //Rubber stamp annotation type.
    STAMP = 13,
    //Caret annotation type.
    CARET = 14,
    //Ink annotation type.
    INK = 15,
    //Popup annotation type.
    POPUP = 16,
    //File attachment annotation type.
    FILEATTACHMENT = 17,
    //Sound annotation type.
    SOUND = 18,
    //Movie annotation type.
    MOVIE = 19,
    //Widget annotation type.
    WIDGET = 20,
    //Screen annotation type.
    SCREEN = 21,
    //Printer mark annotation type.
    PRINTERMARK = 22,
    //Trap network annotation type.
    TRAPNET = 23,
    //Watermark annotation type.
    WATERMARK = 24,
    THREED = 25,
    //Rich media annotation type
    RICHMEDIA = 26,
    XFAWIDGET = 27,
    REDACT = 28
 
}

可通过封装的方法获取常用的注解：

var pathPdf = "./Pdfium.NetTests/resources/annotation_highlight_long_content.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
{
    var page0 = doc.Pages[0];
    var links = page0.GetPageLinks();
}

也可通过以下方法自行遍历获取，此代码为示例代码、在pdf预览中很多交互未实现或者合并实现,比如填充（WIDGET）pdf等交互，感兴趣的可以自行研究

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var pathPdf = "./Pdfium.NetTests/resources/annotation_highlight_long_content.pdf";
using (var doc = PdfDocument.Load(new MemoryStream(File.ReadAllBytes(pathPdf))))
{
    var page0 = doc.Pages[0];
    var pageText0 = page0.PageText;
    var form = doc.PdfForm;
    var annotCount = page0.PageGetAnnotCount();
    for (int i = 0; i < annotCount; i++)
    {
        var annot = page0.PageGetAnnot(i);
        var subType = annot.Subtype;
        var rect = annot.Rect;
        //无用
        var flag = annot.Flags;
        var boo = annot.IsSupportedSubtype(subType);
        switch (subType)
        {
            case FpdfAnnotSubtypes.HIGHLIGHT:
                {
                    var higthLight = new AnnotData();
                    var keys = new string[] { FpdfAnnotationKeys.kAuthorKey, FpdfAnnotationKeys.kContents };
                    foreach (var key in keys)
                    {
                        var types = annot.GetValueType(key);
                        switch (types)
                        {
                            case FpdfObjectTypes.FPDF_OBJECT_STRING:
                                if (key.Equals(FpdfAnnotationKeys.kAuthorKey))
                                    higthLight.Author = annot.GetStringValue(key);
                                else
                                    higthLight.Content = annot.GetStringValue(key);
                                break;
                            case FpdfObjectTypes.FPDF_OBJECT_NUMBER:
                                if (annot.GetNumberValue(key, out float values))
                                {
                                    if (key.Equals(FpdfAnnotationKeys.kAuthorKey))
                                        higthLight.Author = values.ToString();
                                    else
                                        higthLight.Content = values.ToString();
                                }
                                break;
                        }
                    }
                    if (annot.GetColor(FpdfAnnotColorType.Color, out uint r, out uint g, out uint b, out uint a))
                        higthLight.BackColor = Color.FromArgb((int)a, (int)r, (int)g, (int)b);
                    var attcount = annot.AttachmentPointsCount;
                    for (int j = 0; j < (int)attcount; j++)
                    {
                        var quad_points = new FS_QUADPOINTSF();
                        if (annot.GetAttachmentPoints((ulong)j, quad_points))
                        {
 
                        }
                    }
 
                    var index = pageText0.GetCharIndexAtPos(rect.Left, rect.Top, Math.Abs(rect.Right - rect.Left), Math.Abs(rect.Top - rect.Bottom));
                    var fontName = pageText0.GetFontInfo(index, out FpdfFxfontFlags flags);
                    var fontSize = pageText0.GetFontSize(index);
                    higthLight.FontName = fontName;
                    higthLight.FontSize = fontSize;
 
                }
                break;
            case FpdfAnnotSubtypes.LINK:
                {
                    var flink = annot.GetLink();
                    var action = flink.GetAction();
                    var acType = action.GetActionType();
                    switch (acType)
                    {
                        case FpdfActionTypes.UNSUPPORTED:
                            {
                                var dest = doc.LinkGetDest(flink);
                                var targetPage = doc.DestGetDestPageIndex(dest);
                                var uri = doc.ActionGetURIPath(action);
                            }
                            break;
                        case FpdfActionTypes.GOTO:
                            {
                                var dest = doc.ActionGetDest(action);
                                var targetPage = doc.DestGetDestPageIndex(dest);
                                var uri = doc.ActionGetURIPath(action);
 
                            }
                            break;
                        case FpdfActionTypes.REMOTEGOTO:
                            break;
                        case FpdfActionTypes.URI:
                            {
                                var uri = doc.ActionGetURIPath(action);
 
                            }
                            break;
                        case FpdfActionTypes.LAUNCH:
                            {
                                var filePath = action.GetFilePath();
                                // new RectangleF(rect.Left, rect.Top, rect.Right - rect.Left, rect.Bottom - rect.Top)
                            }
                            break;
                        case FpdfActionTypes.EMBEDDEDGOTO:
                            {
                                var dest = doc.ActionGetDest(action);
                                var view = dest.GetDestView(out uint paraNum, out float paras);
                                var filePath = action.GetFilePath();
                            }
                            break;
                    }
                }
                break;
            case FpdfAnnotSubtypes.WIDGET:
                {
                    var formflag = form.AnnotGetFormFieldFlags(annot);
                    var formName = form.AnnotGetFormFieldName(annot);
                    var formValue = form.AnnotGetFormFieldValue(annot);
                    var fontsize = form.AnnotGetFontSize(annot);
                    var optionCount = form.AnnotGetOptionCount(annot);
                    for (int ni = 0; ni < optionCount; ni++)
                    {
                        var lable = form.AnnotGetOptionLabel(annot, ni);
                        var iselect = form.AnnotIsOptionSelected(annot, ni);
                    }
                }
                break;
            case FpdfAnnotSubtypes.POPUP:
                {
                    // Attempting to retrieve |annot|'s "IRT"-linked annotation would fail,
                    // since "IRT" is not a key in |annot|'s dictionary.
                    var kIRTKey = "IRT";
                    if (annot.HasKey(kIRTKey))
                    {
                        var linked = annot.GetLinkedAnnot(kIRTKey);
                    }
                    if (annot.HasKey(FpdfAnnotationKeys.kP))
                    {
                        var types = annot.GetValueType(FpdfAnnotationKeys.kP);
                        switch (types)
                        {
                            case FpdfObjectTypes.FPDF_OBJECT_STRING:
                                var strValue = annot.GetStringValue(FpdfAnnotationKeys.kP);
                                break;
                            case FpdfObjectTypes.FPDF_OBJECT_NUMBER:
                                var numValue = annot.GetNumberValue(FpdfAnnotationKeys.kP, out float values);
                                break;
                        }
                    }
                }
                break;
            case FpdfAnnotSubtypes.SQUARE:
                break;
        }
    }
 
}
  