如何在 C# 中新增和編輯 PDF 註解

using IronPdf;
using IronPdf.Annotations;

// Load an existing multi-page PDF
PdfDocument pdf = PdfDocument.FromFile("multipage.pdf");

// Create a clickable link on page 1 (index 0) that jumps to page 6 (index 5).
// Page indexes are zero-based. The default DestinationType (Page) fits the
// whole destination page in the viewer when the link is clicked.
LinkAnnotation link = new LinkAnnotation(pageIndex: 0, destinationPageIndex: 5)
{
    X = 72,        // points from the LEFT edge of the page (72 points = 1 inch)
    Y = 700,       // BOTTOM edge of the clickable area (PDF origin is bottom-left)
    Width = 200,
    Height = 20,
    Contents = "Go to Chapter 6"
};

// LinkAnnotation lives in the same collection as TextAnnotation
pdf.Annotations.Add(link);
pdf.SaveAs("internal-link.pdf");

using IronPdf;
using IronPdf.Annotations;

// Load an existing multi-page PDF
PdfDocument pdf = PdfDocument.FromFile("multipage.pdf");

// Create a clickable link on page 1 (index 0) that jumps to page 6 (index 5).
// Page indexes are zero-based. The default DestinationType (Page) fits the
// whole destination page in the viewer when the link is clicked.
LinkAnnotation link = new LinkAnnotation(pageIndex: 0, destinationPageIndex: 5)
{
    X = 72,        // points from the LEFT edge of the page (72 points = 1 inch)
    Y = 700,       // BOTTOM edge of the clickable area (PDF origin is bottom-left)
    Width = 200,
    Height = 20,
    Contents = "Go to Chapter 6"
};

// LinkAnnotation lives in the same collection as TextAnnotation
pdf.Annotations.Add(link);
pdf.SaveAs("internal-link.pdf");

using IronPdf;
using IronPdf.Annotations;
using IronPdf.Bookmarks;

PdfDocument pdf = PdfDocument.FromFile("multipage.pdf");

// 1. Scroll to a specific vertical position on the destination page (full width shown)
LinkAnnotation scrollLink = new LinkAnnotation(0, 2)
{
    X = 72, Y = 680, Width = 300, Height = 16,
    DestinationType = BookmarkDestinations.PageY,
    DestinationTop = 400        // scroll so y=400 sits at the top of the view
};
pdf.Annotations.Add(scrollLink);

// 2. Jump to a position AND set the zoom level
LinkAnnotation zoomLink = new LinkAnnotation(0, 3, "Zoom to figure")
{
    X = 72, Y = 650, Width = 200, Height = 16,
    DestinationType = BookmarkDestinations.PageZoom,
    DestinationLeft = 100,
    DestinationTop = 500,
    DestinationZoom = 150       // 150% zoom; use 0 to inherit the current zoom
};
pdf.Annotations.Add(zoomLink);

// 3. Fit a specific rectangle on the destination page
LinkAnnotation rectLink = new LinkAnnotation(0, 4)
{
    X = 72, Y = 620, Width = 200, Height = 16,
    DestinationType = BookmarkDestinations.PageRect,
    DestinationLeft = 50,
    DestinationBottom = 100,
    DestinationRight = 550,
    DestinationTop = 700
};
pdf.Annotations.Add(rectLink);

pdf.SaveAs("link-destinations.pdf");

using IronPdf;
using IronPdf.Annotations;
using IronPdf.Bookmarks;

PdfDocument pdf = PdfDocument.FromFile("multipage.pdf");

// 1. Scroll to a specific vertical position on the destination page (full width shown)
LinkAnnotation scrollLink = new LinkAnnotation(0, 2)
{
    X = 72, Y = 680, Width = 300, Height = 16,
    DestinationType = BookmarkDestinations.PageY,
    DestinationTop = 400        // scroll so y=400 sits at the top of the view
};
pdf.Annotations.Add(scrollLink);

// 2. Jump to a position AND set the zoom level
LinkAnnotation zoomLink = new LinkAnnotation(0, 3, "Zoom to figure")
{
    X = 72, Y = 650, Width = 200, Height = 16,
    DestinationType = BookmarkDestinations.PageZoom,
    DestinationLeft = 100,
    DestinationTop = 500,
    DestinationZoom = 150       // 150% zoom; use 0 to inherit the current zoom
};
pdf.Annotations.Add(zoomLink);

// 3. Fit a specific rectangle on the destination page
LinkAnnotation rectLink = new LinkAnnotation(0, 4)
{
    X = 72, Y = 620, Width = 200, Height = 16,
    DestinationType = BookmarkDestinations.PageRect,
    DestinationLeft = 50,
    DestinationBottom = 100,
    DestinationRight = 550,
    DestinationTop = 700
};
pdf.Annotations.Add(rectLink);

pdf.SaveAs("link-destinations.pdf");

using IronPdf;
using IronPdf.Annotations;
using IronPdf.Bookmarks;
using System;
using System.Collections.Generic;

PdfDocument pdf = PdfDocument.FromFile("report-with-toc.pdf");

// Zero-based index of the page that holds the table-of-contents text
int tocPageIndex = 1;

// Map each TOC entry's leading text to the page index it should jump to
var tocEntries = new Dictionary<string, int>
{
    { "Introduction", 2 },
    { "Methodology",  4 },
    { "Results",      6 },
    { "Conclusion",   9 },
};

// Walk the text chunks on the TOC page and overlay a clickable link on each match
foreach (var chunk in pdf.Pages[tocPageIndex].TextChunks)
{
    string text = chunk.Contents.Trim();

    foreach (var entry in tocEntries)
    {
        if (!text.StartsWith(entry.Key)) continue;

        var box = chunk.BoundingBox;
        pdf.Annotations.Add(new LinkAnnotation(tocPageIndex, entry.Value)
        {
            X = (int)box.Left,
            Y = (int)box.Bottom,                       // Bottom, NOT Top (PDF origin is bottom-left)
            Width = (int)Math.Max(box.Width, 400),
            Height = (int)Math.Abs(box.Top - box.Bottom),
            DestinationType = BookmarkDestinations.PageY,
            DestinationTop = 792,                      // top of a US Letter page
            Hidden = true                              // invisible overlay on the existing TOC text
        });
        break;
    }
}

pdf.SaveAs("clickable-toc.pdf");

using IronPdf;
using IronPdf.Annotations;
using IronPdf.Bookmarks;
using System;
using System.Collections.Generic;

PdfDocument pdf = PdfDocument.FromFile("report-with-toc.pdf");

// Zero-based index of the page that holds the table-of-contents text
int tocPageIndex = 1;

// Map each TOC entry's leading text to the page index it should jump to
var tocEntries = new Dictionary<string, int>
{
    { "Introduction", 2 },
    { "Methodology",  4 },
    { "Results",      6 },
    { "Conclusion",   9 },
};

// Walk the text chunks on the TOC page and overlay a clickable link on each match
foreach (var chunk in pdf.Pages[tocPageIndex].TextChunks)
{
    string text = chunk.Contents.Trim();

    foreach (var entry in tocEntries)
    {
        if (!text.StartsWith(entry.Key)) continue;

        var box = chunk.BoundingBox;
        pdf.Annotations.Add(new LinkAnnotation(tocPageIndex, entry.Value)
        {
            X = (int)box.Left,
            Y = (int)box.Bottom,                       // Bottom, NOT Top (PDF origin is bottom-left)
            Width = (int)Math.Max(box.Width, 400),
            Height = (int)Math.Abs(box.Top - box.Bottom),
            DestinationType = BookmarkDestinations.PageY,
            DestinationTop = 792,                      // top of a US Letter page
            Hidden = true                              // invisible overlay on the existing TOC text
        });
        break;
    }
}

pdf.SaveAs("clickable-toc.pdf");