向现有PDF文件添加注释

在现有PDF文件中添加自由文本注释（facades）

PdfContentEditor 允许您在现有PDF文件中添加不同类型的注释。您可以使用相应的方法添加特定的注释。例如，在以下代码片段中，我们使用了 CreateFreeText 方法添加 FreeText 类型的注释。

任何类型的注释都可以以相同的方式添加到PDF文件中。首先，您需要创建一个类型为 PdfContentEditor 的对象，并使用 BindPdf 方法绑定输入PDF文件。其次，您必须创建一个矩形对象以指定注释的区域。

之后，您可以调用 CreateFreeText 方法添加 FreeText 注释，然后使用 Save 方法保存更新后的PDF文件。

以下代码片段向您展示如何在PDF文件中添加自由文本注释。

.NET Core 3.1

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

    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "input.pdf"))
    {
        // Instantiate PdfContentEditor object
        var editor = new Aspose.Pdf.Facades.PdfContentEditor(document);

        var tfa = new Aspose.Pdf.Text.TextFragmentAbsorber("PDF");
        tfa.Visit(document.Pages[1]);

        var rect = new System.Drawing.Rectangle
        {
            X = (int)tfa.TextFragments[1].Rectangle.LLX,
            Y = (int)tfa.TextFragments[1].Rectangle.URY + 5,
            Height = 18,
            Width = 100
        };

        // Add annotation
        editor.CreateFreeText(rect, "Free Text Demo", 1); // last param is a page number

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

.NET 8

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

    // Open PDF document
    using var document = new Aspose.Pdf.Document(dataDir + "input.pdf");

    // Instantiate PdfContentEditor object
    var editor = new Aspose.Pdf.Facades.PdfContentEditor(document);

    var tfa = new Aspose.Pdf.Text.TextFragmentAbsorber("PDF");
    tfa.Visit(document.Pages[1]);

    var rect = new System.Drawing.Rectangle
    {
        X = (int)tfa.TextFragments[1].Rectangle.LLX,
        Y = (int)tfa.TextFragments[1].Rectangle.URY + 5,
        Height = 18,
        Width = 100
    };

    // Add annotation
    editor.CreateFreeText(rect, "Free Text Demo", 1); // last param is a page number

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

在现有PDF文件中添加文本注释（facades）

在这个例子中，您也需要创建一个类型为 PdfContentEditor 的对象，并使用 BindPdf 方法绑定输入PDF文件。其次，您必须创建一个矩形对象以指定注释的区域。之后，您可以调用 CreateFreeText 方法添加自由文本注释，创建注释的标题，以及注释所在的页码。

.NET Core 3.1

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

    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "input.pdf"))
    {
        // Instantiate PdfContentEditor object
        var editor = new Aspose.Pdf.Facades.PdfContentEditor(document);

        var tfa = new Aspose.Pdf.Text.TextFragmentAbsorber("PDF");
        tfa.Visit(document.Pages[1]);

        var rect = new System.Drawing.Rectangle
        {
            X = (int)tfa.TextFragments[1].Rectangle.LLX,
            Y = (int)tfa.TextFragments[1].Rectangle.URY + 5,
            Height = 18,
            Width = 100
        };

        // Add annotation
        editor.CreateText(rect, "Aspose User", "PDF is a better format for modern documents", false, "Key", 1);

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

.NET 8

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

    // Open PDF document
    using var document = new Aspose.Pdf.Document(dataDir + "input.pdf");

    // Instantiate PdfContentEditor object
    var editor = new Aspose.Pdf.Facades.PdfContentEditor(document);

    var tfa = new Aspose.Pdf.Text.TextFragmentAbsorber("PDF");
    tfa.Visit(document.Pages[1]);

    var rect = new System.Drawing.Rectangle
    {
        X = (int)tfa.TextFragments[1].Rectangle.LLX,
        Y = (int)tfa.TextFragments[1].Rectangle.URY + 5,
        Height = 18,
        Width = 100
    };

    // Add annotation
    editor.CreateText(rect, "Aspose User", "PDF is a better format for modern documents", false, "Key", 1);

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

在现有PDF文件中添加线条注释（facades）

我们还指定了矩形、线条的起始和结束坐标、页码、注释框的厚度、样式和颜色、线条的虚线类型、线条的起始和结束类型。

.NET Core 3.1

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

    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "input.pdf"))
    {
        // Instantiate PdfContentEditor object
        var editor = new Aspose.Pdf.Facades.PdfContentEditor(document);

        // Create Line Annotation
        editor.CreateLine(
            new System.Drawing.Rectangle(550, 93, 562, 439),
            "Test",
            556, 99, 556, 443, 1, 2,
            System.Drawing.Color.Red,
            "dash",
            new int[] { 1, 0, 3 },
            new[] { "Open", "Open" });

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

.NET 8

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

    // Open PDF document
    using var document = new Aspose.Pdf.Document(dataDir + "input.pdf");

    // Instantiate PdfContentEditor object
    var editor = new Aspose.Pdf.Facades.PdfContentEditor(document);

    // Create Line Annotation
    editor.CreateLine(
        new System.Drawing.Rectangle(550, 93, 562, 439),
        "Test",
        556, 99, 556, 443, 1, 2,
        System.Drawing.Color.Red,
        "dash",
        new int[] { 1, 0, 3 },
        new[] { "Open", "Open" });

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