// 完毕:
using System;
using System.IO;
using System.Drawing;
using System.Linq;
using System.Collections.Generic;
using GrapeCity.Documents.Pdf;
using GrapeCity.Documents.Text;
using GrapeCity.Documents.Pdf.TextMap;
using GrapeCity.Documents.Pdf.Annotations;
using GrapeCity.Documents.Pdf.Structure;
using GrapeCity.Documents.Pdf.Recognition.Structure;
namespace DsPdfWeb.Demos
{
// Highlight paragraphs which have associated structure tags.
public class ReadTagsShowParas
{
public int CreatePDF(Stream stream)
{
var user = "DsPdfWeb Demo";
var doc = new GcPdfDocument();
using var s = File.OpenRead(Path.Combine("Resources", "PDFs", "C1Olap-QuickStart.pdf"));
doc.Load(s);
// 1st step - remove all but the first 5 pages from the loaded PDF,
// also removing tags that point to the removed pages:
void removeStructNodesForPage(StructElementCollection ses, Page p)
{
for (int i = ses.Count - 1; i >= 0; --i)
{
var se = ses[i];
if (se.DefaultPage == p)
ses.RemoveAt(i);
else
removeStructNodesForPage(se.Children, p);
}
}
for (int i = doc.Pages.Count - 1; i >= 5; --i)
{
removeStructNodesForPage(doc.StructTreeRoot.Children, doc.Pages[i]);
doc.Pages.RemoveAt(i);
}
// 2nd step - get the logical structure, highlight paragraphs
// and add sticky notes to them:
void highlightParagraphs(IReadOnlyList<Element> items)
{
var color = Color.FromArgb(64, Color.Magenta);
foreach (var e in items)
{
if (e.HasContentItems)
foreach (var i in e.ContentItems)
{
if (i is ContentItem ci)
{
var p = ci.GetParagraph();
if (p != null)
{
var rc = p.GetCoords().ToRect();
rc.Offset(rc.Width, 0);
rc.Size = new SizeF(16, 12);
var ta = new TextAnnotation()
{
UserName = user,
Rect = rc,
Page = ci.Page,
Contents = p.GetText(),
Color = Color.Yellow,
};
ci.Page.Graphics.DrawPolygon(p.GetCoords(), color, 1, null);
}
}
}
if (e.HasChildren)
highlightParagraphs(e.Children);
}
}
// Get the LogicalStructure and use it to highlight paragraphs:
LogicalStructure ls = doc.GetLogicalStructure();
highlightParagraphs(ls.Elements);
// Done:
doc.Save(stream);
return doc.Pages.Count;
}
}
}