使用 C# 的 PDF 高亮注释

文本标记注释应以高亮、下划线、删除线或波浪（“波浪状”）下划线的形式出现在文档的文本中。打开时，它们应显示一个弹出窗口，包含相关注释的文本。

PDF 文档中的文本标记注释的属性可以使用 PDF 查看控件提供的属性窗口进行编辑。可以修改文本标记注释的颜色、不透明度、作者和主题。

可以使用 highlightSettings 属性获取或设置高亮注释的设置。highlightSettings 属性用于设置高亮注释的颜色、不透明度、作者、主题、修改日期和锁定状态属性。

也可以使用 strikethroughSettings 属性获取或设置删除线注释的设置。strikethroughSettings 属性用于设置删除线注释的颜色、不透明度、作者、主题、修改日期和锁定状态属性。

下一个功能是使用 underlineSettings 属性获取或设置下划线注释的设置。underlineSettings 属性用于设置下划线注释的颜色、不透明度、作者、主题、修改日期和锁定状态属性。

以下代码片段也适用于 Aspose.PDF.Drawing 库。

添加文本标记注释

为了向 PDF 文档添加文本标记注释，我们需要执行以下操作：

  1. 加载 PDF 文件 - 新建 Document 对象。
  2. 创建注释：
  3. 然后我们应该将所有注释添加到页面。
// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddTextMarkupAnnotations()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_Annotations();

    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "sample.pdf"))
    {
        // Create a TextFragmentAbsorber to find the text "PDF"
        var tfa = new Aspose.Pdf.Text.TextFragmentAbsorber("PDF");
        tfa.Visit(document.Pages[1]);

        // Create annotations for the found text fragments
        var highlightAnnotation = new Aspose.Pdf.Annotations.HighlightAnnotation(document.Pages[1], tfa.TextFragments[1].Rectangle)
        {
            Title = "Aspose User",
            Color = Aspose.Pdf.Color.LightGreen
        };

        var strikeOutAnnotation = new Aspose.Pdf.Annotations.StrikeOutAnnotation(document.Pages[1], tfa.TextFragments[2].Rectangle)
        {
            Title = "Aspose User",
            Color = Aspose.Pdf.Color.Blue
        };

        var squigglyAnnotation = new Aspose.Pdf.Annotations.SquigglyAnnotation(document.Pages[1], tfa.TextFragments[3].Rectangle)
        {
            Title = "Aspose User",
            Color = Aspose.Pdf.Color.Red
        };

        var underlineAnnotation = new Aspose.Pdf.Annotations.UnderlineAnnotation(document.Pages[1], tfa.TextFragments[4].Rectangle)
        {
            Title = "Aspose User",
            Color = Aspose.Pdf.Color.Violet
        };

        // Add annotations to the page
        document.Pages[1].Annotations.Add(highlightAnnotation);
        document.Pages[1].Annotations.Add(squigglyAnnotation);
        document.Pages[1].Annotations.Add(strikeOutAnnotation);
        document.Pages[1].Annotations.Add(underlineAnnotation);

        // Save PDF document
        document.Save(dataDir + "AddTextMarkupAnnotations_out.pdf");
    }
}

如果您想突出显示多行片段，您应该使用高级示例：

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddHighlightAnnotationAdvanced()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_Annotations();

    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "sample_mod.pdf"))
    {
        var page = document.Pages[1];
        var tfa = new TextFragmentAbsorber(@"Adobe\W+Acrobat\W+Reader", new TextSearchOptions(true));
        tfa.Visit(page);
        foreach (var textFragment in tfa.TextFragments)
        {
            var highlightAnnotation = HighLightTextFragment(page, textFragment, Color.Yellow);
            page.Annotations.Add(highlightAnnotation);
        }

        // Save PDF document
        document.Save(dataDir + "AddHighlightAnnotationAdvanced_out.pdf");
    }
}

private static HighlightAnnotation HighLightTextFragment(Page page,
    Aspose.Pdf.Text.TextFragment textFragment, Aspose.Pdf.Color color)
{
    if (textFragment.Segments.Count == 1)
    {
        return new Aspose.Pdf.Annotations.HighlightAnnotation(page, textFragment.Segments[1].Rectangle)
        {
            Title = "Aspose User",
            Color = color,
            Modified = DateTime.Now,
            QuadPoints = new Aspose.Pdf.Point[]
            {
                new Aspose.Pdf.Point(textFragment.Segments[1].Rectangle.LLX, textFragment.Segments[1].Rectangle.URY),
                new Aspose.Pdf.Point(textFragment.Segments[1].Rectangle.URX, textFragment.Segments[1].Rectangle.URY),
                new Aspose.Pdf.Point(textFragment.Segments[1].Rectangle.LLX, textFragment.Segments[1].Rectangle.LLY),
                new Aspose.Pdf.Point(textFragment.Segments[1].Rectangle.URX, textFragment.Segments[1].Rectangle.LLY)
            }
        };
    }

    var offset = 0;
    var quadPoints = new Aspose.Pdf.Point[textFragment.Segments.Count * 4];
    foreach (Aspose.Pdf.Text.TextSegment segment in textFragment.Segments)
    {
        quadPoints[offset + 0] = new Aspose.Pdf.Point(segment.Rectangle.LLX, segment.Rectangle.URY);
        quadPoints[offset + 1] = new Aspose.Pdf.Point(segment.Rectangle.URX, segment.Rectangle.URY);
        quadPoints[offset + 2] = new Aspose.Pdf.Point(segment.Rectangle.LLX, segment.Rectangle.LLY);
        quadPoints[offset + 3] = new Aspose.Pdf.Point(segment.Rectangle.URX, segment.Rectangle.LLY);
        offset += 4;
    }

    var llx = quadPoints.Min(pt => pt.X);
    var lly = quadPoints.Min(pt => pt.Y);
    var urx = quadPoints.Max(pt => pt.X);
    var ury = quadPoints.Max(pt => pt.Y);
    return new Aspose.Pdf.Annotations.HighlightAnnotation(page, new Aspose.Pdf.Rectangle(llx, lly, urx, ury))
    {
        Title = "Aspose User",
        Color = color,
        Modified = DateTime.Now,
        QuadPoints = quadPoints
    };
}

private static void GetHighlightedText()
{
    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "sample_mod.pdf"))
    {
        var highlightAnnotations = document.Pages[1].Annotations
            .Where(a => a.AnnotationType == Aspose.Pdf.Annotations.AnnotationType.Highlight)
            .Cast<Aspose.Pdf.Annotations.HighlightAnnotation>();
        foreach (var ta in highlightAnnotations)
        {
            Console.WriteLine($"[{ta.GetMarkedText()}]");
        }
    }
}

获取文本标记注释

请尝试使用以下代码片段从 PDF 文档中获取文本标记注释。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void GetTextMarkupAnnotation()
{
    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "sample_mod.pdf"))
    {
        var textMarkupAnnotations = document.Pages[1].Annotations
            .Where(a => a.AnnotationType == Aspose.Pdf.Annotations.AnnotationType.Highlight
            || a.AnnotationType == Aspose.Pdf.Annotations.AnnotationType.Squiggly)
            .Cast<Aspose.Pdf.Annotations.TextMarkupAnnotation>();
        foreach (var ta in textMarkupAnnotations)
        {
            Console.WriteLine($"[{ta.AnnotationType} {ta.Rect}]");
        }
    }
}

删除文本标记注释

以下代码片段演示如何从 PDF 文件中删除文本标记注释。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void DeleteTextMarkupAnnotation()
{
    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "sample_mod.pdf"))
    {
        var textMarkupAnnotations = document.Pages[1].Annotations
            .Where(a => a.AnnotationType == Aspose.Pdf.Annotations.AnnotationType.Highlight
            ||a.AnnotationType == Aspose.Pdf.Annotations.AnnotationType.Squiggly)
            .Cast<Aspose.Pdf.Annotations.TextMarkupAnnotation>();
        foreach (var ta in textMarkupAnnotations)
        {
            document.Pages[1].Annotations.Delete(ta);
        }
        
        // Save PDF document
        document.Save(dataDir + "DeleteTextMarkupAnnotation_out.pdf");
    }
}
使用文本注释处理PDF 使用 C# 添加图形注释