使用 C# 在 PDF 中格式化文本

以下代码片段也适用于 Aspose.PDF.Drawing 库。

如何在 PDF 中添加行缩进

Aspose.PDF for .NET 提供了 TextFormattingOptions 类中的 SubsequentLinesIndent 属性。可以在使用 TextFragment 和段落集合的 PDF 生成场景中指定行缩进。

请使用以下代码片段来使用该属性：

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

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        var page = document.Pages.Add();

        string textFragment = string.Concat(Enumerable.Repeat("A quick brown fox jumped over the lazy dog. ", 10));

        Aspose.Pdf.Text.TextFragment text = new Aspose.Pdf.Text.TextFragment(textFragment);

        // Initilize TextFormattingOptions for the text fragment and specify SubsequentLinesIndent value
        text.TextState.FormattingOptions = new Aspose.Pdf.Text.TextFormattingOptions()
        {
            SubsequentLinesIndent = 20
        };

        page.Paragraphs.Add(text);

        text = new Aspose.Pdf.Text.TextFragment("Line2");
        page.Paragraphs.Add(text);

        text = new Aspose.Pdf.Text.TextFragment("Line3");
        page.Paragraphs.Add(text);

        text = new Aspose.Pdf.Text.TextFragment("Line4");
        page.Paragraphs.Add(text);

        text = new Aspose.Pdf.Text.TextFragment("Line5");
        page.Paragraphs.Add(text);

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

如何添加文本边框

以下代码片段演示了如何使用 TextBuilder 添加文本边框，并设置 TextState 的 DrawTextRectangleBorder 属性：

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

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        // Get particular page
        var page = document.Pages.Add();
        // Create text fragment
        var textFragment = new Aspose.Pdf.Text.TextFragment("main text");
        textFragment.Position = new Aspose.Pdf.Text.Position(100, 600);
        // Set text properties
        textFragment.TextState.FontSize = 12;
        textFragment.TextState.Font = Aspose.Pdf.Text.FontRepository.FindFont("TimesNewRoman");
        textFragment.TextState.BackgroundColor = Aspose.Pdf.Color.LightGray;
        textFragment.TextState.ForegroundColor = Aspose.Pdf.Color.Red;
        // Set StrokingColor property for drawing border (stroking) around text rectangle
        textFragment.TextState.StrokingColor = Aspose.Pdf.Color.DarkRed;
        // Set DrawTextRectangleBorder property value to true
        textFragment.TextState.DrawTextRectangleBorder = true;
        var tb = new Aspose.Pdf.Text.TextBuilder(page);
        tb.AppendText(textFragment);

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

如何添加下划线文本

以下代码片段演示了如何在创建新 PDF 文件时添加下划线文本。

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

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        // Add age page to PDF document
        document.Pages.Add();
        // Create TextBuilder for first page
        var tb = new Aspose.Pdf.Text.TextBuilder(document.Pages[1]);
        // TextFragment with sample text
        var fragment = new Aspose.Pdf.Text.TextFragment("Test message");
        // Set the font for TextFragment
        fragment.TextState.Font = Aspose.Pdf.Text.FontRepository.FindFont("Arial");
        fragment.TextState.FontSize = 10;
        // Set the formatting of text as Underline
        fragment.TextState.Underline = true;
        // Specify the position where TextFragment needs to be placed
        fragment.Position = new Aspose.Pdf.Text.Position(10, 800);
        // Append TextFragment to PDF file
        tb.AppendText(fragment);

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

如何在添加文本周围添加边框

您可以控制添加文本的外观和感觉。下面的示例展示了如何通过在文本周围绘制矩形来添加边框。了解更多关于 PdfContentEditor 类的信息。

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void AddBorder()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_Text();
    
    // Open PDF document
    using (var editor = new Aspose.Pdf.Facades.PdfContentEditor())
    {
        // Bind PDF document
        editor.BindPdf(dataDir + "AddBorder.pdf");
        var lineInfo = new Aspose.Pdf.Facades.LineInfo();
        lineInfo.LineWidth = 2;
        lineInfo.VerticeCoordinate = new float[] { 0, 0, 100, 100, 50, 100 };
        lineInfo.Visibility = true;
        // Add border
        editor.CreatePolygon(lineInfo, 1, new System.Drawing.Rectangle(0, 0, 0, 0), "");

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

如何添加换行符

TextFragment 不支持文本中的换行符。然而，为了添加带有换行符的文本，请使用带有 TextParagraph 的 TextFragment：

在 TextFragment 中使用 “\r\n” 或 Environment.NewLine，而不是单个 “\n”。
创建 TextParagraph 对象。它将添加带有行分割的文本。
使用 TextParagraph.AppendLine 添加 TextFragment。
使用 TextBuilder.AppendParagraph 添加 TextParagraph。

请使用以下代码片段。

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

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        var page = document.Pages.Add();

        // Initialize new TextFragment with text containing required newline markers
        var textFragment = new Aspose.Pdf.Text.TextFragment("Applicant Name: " + Environment.NewLine + " Joe Smoe");

        // Set text fragment properties if necessary
        textFragment.TextState.FontSize = 12;
        textFragment.TextState.Font = Aspose.Pdf.Text.FontRepository.FindFont("TimesNewRoman");
        textFragment.TextState.BackgroundColor = Aspose.Pdf.Color.LightGray;
        textFragment.TextState.ForegroundColor = Aspose.Pdf.Color.Red;

        // Create TextParagraph object
        var par = new Aspose.Pdf.Text.TextParagraph();

        // Add new TextFragment to paragraph
        par.AppendLine(textFragment);

        // Set paragraph position
        par.Position = new Aspose.Pdf.Text.Position(100, 600);

        // Create TextBuilder object
        var textBuilder = new Aspose.Pdf.Text.TextBuilder(page);
        // Add the TextParagraph using TextBuilder
        textBuilder.AppendParagraph(par);

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

如何添加删除线文本

TextState 类提供了设置放置在 PDF 文档中的 TextFragments 格式的能力。您可以使用此类将文本格式设置为粗体、斜体、下划线，并且从此版本开始，API 提供了将文本格式标记为删除线的能力。请尝试使用以下代码片段添加带有删除线格式的 TextFragment。

请使用完整的代码片段：

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

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        // Get particular page
        var page = document.Pages.Add();

        // Create text fragment
        var textFragment = new Aspose.Pdf.Text.TextFragment("main text");
        textFragment.Position = new Aspose.Pdf.Text.Position(100, 600);

        // Set text properties
        textFragment.TextState.FontSize = 12;
        textFragment.TextState.Font = Aspose.Pdf.Text.FontRepository.FindFont("TimesNewRoman");
        textFragment.TextState.BackgroundColor = Aspose.Pdf.Color.LightGray;
        textFragment.TextState.ForegroundColor = Aspose.Pdf.Color.Red;
        // Set StrikeOut property
        textFragment.TextState.StrikeOut = true;
        // Mark text as Bold
        textFragment.TextState.FontStyle = Aspose.Pdf.Text.FontStyles.Bold;

        // Create TextBuilder object
        var textBuilder = new Aspose.Pdf.Text.TextBuilder(page);
        // Append the text fragment to the PDF page
        textBuilder.AppendText(textFragment);

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

将渐变阴影应用于文本

文本格式化在 API 中得到了进一步增强，现在您可以在 PDF 文档中添加带有模式颜色空间的文本。Aspose.Pdf.Color 类通过引入新的 PatternColorSpace 属性得到了进一步增强，该属性可用于指定文本的阴影颜色。此新属性为文本添加不同的渐变阴影，例如轴向阴影、径向（类型 3）阴影，如以下代码片段所示：

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

    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "text_sample4.pdf"))
    {
        var absorber = new Aspose.Pdf.Text.TextFragmentAbsorber("Lorem ipsum");
        document.Pages.Accept(absorber);

        var textFragment = absorber.TextFragments[1];

        // Create new color with pattern colorspace
        textFragment.TextState.ForegroundColor = new Aspose.Pdf.Color()
        {
            PatternColorSpace = new Aspose.Pdf.Drawing.GradientAxialShading(Aspose.Pdf.Color.Red, Aspose.Pdf.Color.Blue)
        };
        textFragment.TextState.Underline = true;

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

为了应用径向渐变，您可以在上述代码片段中将“PatternColorSpace”属性设置为“Aspose.Pdf.Drawing.GradientRadialShading(startingColor, endingColor)”。

如何将文本对齐到浮动内容

Aspose.PDF 支持为浮动框元素中的内容设置文本对齐。可以使用 Aspose.Pdf.FloatingBox 实例的对齐属性来实现，如以下代码示例所示。

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

    // Create PDF document
    using (var document = new Aspose.Pdf.Document())
    {
        var page = document.Pages.Add();

        // Create float box
        Aspose.Pdf.FloatingBox floatBox = new Aspose.Pdf.FloatingBox(100, 100);
        // Set settings to float box
        floatBox.VerticalAlignment = Aspose.Pdf.VerticalAlignment.Bottom;
        floatBox.HorizontalAlignment = Aspose.Pdf.HorizontalAlignment.Right;
        floatBox.Paragraphs.Add(new Aspose.Pdf.Text.TextFragment("FloatingBox_bottom"));
        floatBox.Border = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, Aspose.Pdf.Color.Blue);
        // Add float box
        page.Paragraphs.Add(floatBox);

        // Create float box
        Aspose.Pdf.FloatingBox floatBox1 = new Aspose.Pdf.FloatingBox(100, 100);
        // Set settings to float box
        floatBox1.VerticalAlignment = Aspose.Pdf.VerticalAlignment.Center;
        floatBox1.HorizontalAlignment = Aspose.Pdf.HorizontalAlignment.Right;
        floatBox1.Paragraphs.Add(new Aspose.Pdf.Text.TextFragment("FloatingBox_center"));
        floatBox1.Border = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, Aspose.Pdf.Color.Blue);
        // Add float box
        page.Paragraphs.Add(floatBox1);

        // Create float box
        Aspose.Pdf.FloatingBox floatBox2 = new Aspose.Pdf.FloatingBox(100, 100);
        // Set settings to float box
        floatBox2.VerticalAlignment = Aspose.Pdf.VerticalAlignment.Top;
        floatBox2.HorizontalAlignment = Aspose.Pdf.HorizontalAlignment.Right;
        floatBox2.Paragraphs.Add(new Aspose.Pdf.Text.TextFragment("FloatingBox_top"));
        floatBox2.Border = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, Aspose.Pdf.Color.Blue);
        // Add float box
        page.Paragraphs.Add(floatBox2);

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

如何从 PDF 文件中删除隐藏文本

首先，代码片段从文件创建一个 Document 对象。然后，它添加一个 TextFragmentAbsorber 来查找和编辑文本。接着，它检查隐藏文本并将其删除。最后，它保存更新后的文档。

此方法保持可见文本不变，并保留布局。

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

    // Open PDF document
    using (var document = new Aspose.Pdf.Document(dataDir + "HiddenText.pdf"))
    {
        var textAbsorber = new Aspose.Pdf.Text.TextFragmentAbsorber();

        // This option can be used to prevent other text fragments from moving after hidden text replacement
        textAbsorber.TextReplaceOptions = new Aspose.Pdf.Text.TextReplaceOptions(Aspose.Pdf.Text.TextReplaceOptions.ReplaceAdjustment.None);

        document.Pages.Accept(textAbsorber);

        // Remove hidden text
        foreach (var fragment in textAbsorber.TextFragments)
        {
            if (fragment.TextState.Invisible)
            {
                fragment.Text = "";
            }
        }

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

使用 C# 的 PDF 工具提示在PDF中替换文本