翻译|使用教程|编辑:李显亮|2020-05-14 09:31:02.523|阅读 350 次
概述:在本系列教程中,将为开发者带来Aspose.PDF for .NET的一系列使用教程,例如进行文档间的转换,如何标记PDF文件,如何使用表单和图表等等。本文将在表格内添加HTML标签、在表格行之间插入分页符、将表格边框提取为图像。
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Aspose.PDF for .NET是一种高PDF处理和解析API,用于在跨平台应用程序中执行文档管理和操作任务。API可以轻松用于生成、修改、转换、渲染、保护和打印PDF文档,而无需使用Adobe Acrobat。此外,API还提供PDF压缩选项,表格创建和操作,图形和图像功能,广泛的超链接功能,印章和水印任务,扩展的安全控制和自定义字体处理。
在接下来的系列教程中,将为开发者带来Aspose.PDF for .NET的一系列使用教程,例如进行文档间的转换,如何标记PDF文件,如何使用表单和图表等等。本文将在表格内添加HTML标签、在表格行之间插入分页符、将表格边框提取为图像。
>>Aspose.PDF for .NET更新至最新版v20.5,欢迎下载体验。
使用PDF文档时,表格很重要。它们提供了用于以系统方式显示信息的强大功能。该Aspose.PDF.Generator命名空间包含同名的类Table,Cell并且Row它从头开始生成PDF文档时创建表提供的功能。
有时,可能会提出一个要求,即导入具有一些HTML标记的数据库内容,然后将其导入Table对象。导入内容时,应在PDF文档中相应地呈现HTML标记。
// The path to the documents directory. string dataDir = RunExamples.GetDataDir_AsposePdf_Tables(); DataTable dt = new DataTable("Employee"); dt.Columns.Add("data", System.Type.GetType("System.String")); DataRow dr = dt.NewRow(); dr[0] = "<li>Department of Emergency Medicine: 3400 Spruce Street Ground Silverstein Bldg Philadelphia PA 19104-4206</li>"; dt.Rows.Add(dr); dr = dt.NewRow(); dr[0] = "<li>Penn Observation Medicine Service: 3400 Spruce Street Ground Floor Donner Philadelphia PA 19104-4206</li>"; dt.Rows.Add(dr); dr = dt.NewRow(); dr[0] = "<li>UPHS/Presbyterian - Dept. of Emergency Medicine: 51 N. 39th Street . Philadelphia PA 19104-2640</li>"; dt.Rows.Add(dr); Document doc = new Document(); doc.Pages.Add(); // Initializes a new instance of the Table Aspose.Pdf.Table tableProvider = new Aspose.Pdf.Table(); //Set column widths of the table tableProvider.ColumnWidths = "400 50 "; // Set the table border color as LightGray tableProvider.Border = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, 0.5F, Aspose.Pdf.Color.FromRgb(System.Drawing.Color.LightGray)); // Set the border for table cells tableProvider.DefaultCellBorder = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, 0.5F, Aspose.Pdf.Color.FromRgb(System.Drawing.Color.LightGray)); Aspose.Pdf.MarginInfo margin = new Aspose.Pdf.MarginInfo(); margin.Top = 2.5F; margin.Left = 2.5F; margin.Bottom = 1.0F; tableProvider.DefaultCellPadding = margin; tableProvider.ImportDataTable(dt, false, 0, 0, 3, 1, true); doc.Pages[1].Paragraphs.Add(tableProvider); doc.Save(dataDir + "HTMLInsideTableCell_out.pdf");
作为默认行为,当在PDF文件中创建表格时,表格到达表格底边距时,表格会流向后续页面。但是,当为表添加一定数量的行时,我们可能需要强制插入分页符。以下代码段显示了为表添加10行时插入分页符的步骤。
// The path to the documents directory. string dataDir = RunExamples.GetDataDir_AsposePdf_Tables(); // Instantiate Document instance Document doc = new Document(); // Add page to pages collection of PDF file doc.Pages.Add(); // Create table instance Aspose.Pdf.Table tab = new Aspose.Pdf.Table(); // Set border style for table tab.Border = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, Aspose.Pdf.Color.Red); // Set default border style for table with border color as Red tab.DefaultCellBorder = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, Aspose.Pdf.Color.Red); // Specify table columsn widht tab.ColumnWidths = "100 100"; // Create a loop to add 200 rows for table for (int counter = 0; counter <= 200; counter++) { Aspose.Pdf.Row row = new Aspose.Pdf.Row(); tab.Rows.Add(row); Aspose.Pdf.Cell cell1 = new Aspose.Pdf.Cell(); cell1.Paragraphs.Add(new TextFragment("Cell " + counter + ", 0")); row.Cells.Add(cell1); Aspose.Pdf.Cell cell2 = new Aspose.Pdf.Cell(); cell2.Paragraphs.Add(new TextFragment("Cell " + counter + ", 1")); row.Cells.Add(cell2); // When 10 rows are added, render new row in new page if (counter % 10 == 0 && counter != 0) row.IsInNewPage = true; } // Add table to paragraphs collection of PDF file doc.Pages[1].Paragraphs.Add(tab); dataDir = dataDir + "InsertPageBreak_out.pdf"; // Save the PDF document doc.Save(dataDir);
页面边框是路径绘制操作。因此,Pdf-> Html处理逻辑仅执行绘图指令并将背景放在文本后面。因此,要重复此逻辑,您必须手动处理内容运算符并自己绘制图形。另外请注意,以下代码段可能不适用于各种PDF文件,但是如果您遇到任何问题,请随时与我们联系。此代码是为特定的PDF文件开发的。以下代码段显示了从PDF文档中提取表格边框作为Image的步骤。
// The path to the documents directory. string dataDir = RunExamples.GetDataDir_AsposePdf_Tables(); Document doc = new Document(dataDir + "input.pdf"); Stack graphicsState = new Stack(); System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap((int)doc.Pages[1].PageInfo.Width, (int)doc.Pages[1].PageInfo.Height); System.Drawing.Drawing2D.GraphicsPath graphicsPath = new System.Drawing.Drawing2D.GraphicsPath(); // Default ctm matrix value is 1,0,0,1,0,0 System.Drawing.Drawing2D.Matrix lastCTM = new System.Drawing.Drawing2D.Matrix(1, 0, 0, -1, 0, 0); // System.Drawing coordinate system is top left based, while pdf coordinate system is low left based, so we have to apply the inversion matrix System.Drawing.Drawing2D.Matrix inversionMatrix = new System.Drawing.Drawing2D.Matrix(1, 0, 0, -1, 0, (float)doc.Pages[1].PageInfo.Height); System.Drawing.PointF lastPoint = new System.Drawing.PointF(0, 0); System.Drawing.Color fillColor = System.Drawing.Color.FromArgb(0, 0, 0); System.Drawing.Color strokeColor = System.Drawing.Color.FromArgb(0, 0, 0); using (System.Drawing.Graphics gr = System.Drawing.Graphics.FromImage(bitmap)) { gr.SmoothingMode = SmoothingMode.HighQuality; graphicsState.Push(new System.Drawing.Drawing2D.Matrix(1, 0, 0, 1, 0, 0)); // Process all the contents commands foreach (Operator op in doc.Pages[1].Contents) { Aspose.Pdf.Operators.GSave opSaveState = op as Aspose.Pdf.Operators.GSave; Aspose.Pdf.Operators.GRestore opRestoreState = op as Aspose.Pdf.Operators.GRestore; Aspose.Pdf.Operators.ConcatenateMatrix opCtm = op as Aspose.Pdf.Operators.ConcatenateMatrix; Aspose.Pdf.Operators.MoveTo opMoveTo = op as Aspose.Pdf.Operators.MoveTo; Aspose.Pdf.Operators.LineTo opLineTo = op as Aspose.Pdf.Operators.LineTo; Aspose.Pdf.Operators.Re opRe = op as Aspose.Pdf.Operators.Re; Aspose.Pdf.Operators.EndPath opEndPath = op as Aspose.Pdf.Operators.EndPath; Aspose.Pdf.Operators.Stroke opStroke = op as Aspose.Pdf.Operators.Stroke; Aspose.Pdf.Operators.Fill opFill = op as Aspose.Pdf.Operators.Fill; Aspose.Pdf.Operators.EOFill opEOFill = op as Aspose.Pdf.Operators.EOFill; Aspose.Pdf.Operators.SetRGBColor opRGBFillColor = op as Aspose.Pdf.Operators.SetRGBColor; Aspose.Pdf.Operators.SetRGBColorStroke opRGBStrokeColor = op as Aspose.Pdf.Operators.SetRGBColorStroke; if (opSaveState != null) { // Save previous state and push current state to the top of the stack graphicsState.Push(((System.Drawing.Drawing2D.Matrix)graphicsState.Peek()).Clone()); lastCTM = (System.Drawing.Drawing2D.Matrix)graphicsState.Peek(); } else if (opRestoreState != null) { // Throw away current state and restore previous one graphicsState.Pop(); lastCTM = (System.Drawing.Drawing2D.Matrix)graphicsState.Peek(); } else if (opCtm != null) { System.Drawing.Drawing2D.Matrix cm = new System.Drawing.Drawing2D.Matrix( (float)opCtm.Matrix.A, (float)opCtm.Matrix.B, (float)opCtm.Matrix.C, (float)opCtm.Matrix.D, (float)opCtm.Matrix.E, (float)opCtm.Matrix.F); // Multiply current matrix with the state matrix ((System.Drawing.Drawing2D.Matrix)graphicsState.Peek()).Multiply(cm); lastCTM = (System.Drawing.Drawing2D.Matrix)graphicsState.Peek(); } else if (opMoveTo != null) { lastPoint = new System.Drawing.PointF((float)opMoveTo.X, (float)opMoveTo.Y); } else if (opLineTo != null) { System.Drawing.PointF linePoint = new System.Drawing.PointF((float)opLineTo.X, (float)opLineTo.Y); graphicsPath.AddLine(lastPoint, linePoint); lastPoint = linePoint; } else if (opRe != null) { System.Drawing.RectangleF re = new System.Drawing.RectangleF((float)opRe.X, (float)opRe.Y, (float)opRe.Width, (float)opRe.Height); graphicsPath.AddRectangle(re); } else if (opEndPath != null) { graphicsPath = new System.Drawing.Drawing2D.GraphicsPath(); } else if (opRGBFillColor != null) { fillColor = opRGBFillColor.getColor(); } else if (opRGBStrokeColor != null) { strokeColor = opRGBStrokeColor.getColor(); } else if (opStroke != null) { graphicsPath.Transform(lastCTM); graphicsPath.Transform(inversionMatrix); gr.DrawPath(new System.Drawing.Pen(strokeColor), graphicsPath); graphicsPath = new System.Drawing.Drawing2D.GraphicsPath(); } else if (opFill != null) { graphicsPath.FillMode = FillMode.Winding; graphicsPath.Transform(lastCTM); graphicsPath.Transform(inversionMatrix); gr.FillPath(new System.Drawing.SolidBrush(fillColor), graphicsPath); graphicsPath = new System.Drawing.Drawing2D.GraphicsPath(); } else if (opEOFill != null) { graphicsPath.FillMode = FillMode.Alternate; graphicsPath.Transform(lastCTM); graphicsPath.Transform(inversionMatrix); gr.FillPath(new System.Drawing.SolidBrush(fillColor), graphicsPath); graphicsPath = new System.Drawing.Drawing2D.GraphicsPath(); } } } dataDir = dataDir + "ExtractBorder_out.png"; bitmap.Save(dataDir, ImageFormat.Png);
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