PDF管理控件Aspose.PDF for .Net使用教程（三十六）：在表格內(nèi)添加HTML標(biāo)簽和分頁符

Aspose.PDF for .NET是一種高PDF處理和解析API，用于在跨平臺(tái)應(yīng)用程序中執(zhí)行文檔管理和操作任務(wù)。API可以輕松用于生成、修改、轉(zhuǎn)換、渲染、保護(hù)和打印PDF文檔，而無需使用Adobe Acrobat。此外，API還提供PDF壓縮選項(xiàng)，表格創(chuàng)建和操作，圖形和圖像功能，廣泛的超鏈接功能，印章和水印任務(wù)，擴(kuò)展的安全控制和自定義字體處理。

在接下來的系列教程中，將為開發(fā)者帶來Aspose.PDF for .NET的一系列使用教程，例如進(jìn)行文檔間的轉(zhuǎn)換，如何標(biāo)記PDF文件，如何使用表單和圖表等等。本文將在表格內(nèi)添加HTML標(biāo)簽、在表格行之間插入分頁符、將表格邊框提取為圖像。

>>Aspose.PDF for .NET更新至最新版v20.5，歡迎下載體驗(yàn)。

使用PDF文檔時(shí)，表格很重要。它們提供了用于以系統(tǒng)方式顯示信息的強(qiáng)大功能。該Aspose.PDF.Generator命名空間包含同名的類Table，Cell并且Row它從頭開始生成PDF文檔時(shí)創(chuàng)建表提供的功能。

在表格內(nèi)添加HTML標(biāo)簽

有時(shí)，可能會(huì)提出一個(gè)要求，即導(dǎo)入具有一些HTML標(biāo)記的數(shù)據(jù)庫(kù)內(nèi)容，然后將其導(dǎo)入Table對(duì)象。導(dǎo)入內(nèi)容時(shí)，應(yīng)在PDF文檔中相應(yīng)地呈現(xiàn)HTML標(biāo)記。

// 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");

在表格行之間插入分頁符

作為默認(rèn)行為，當(dāng)在PDF文件中創(chuàng)建表格時(shí)，表格到達(dá)表格底邊距時(shí)，表格會(huì)流向后續(xù)頁面。但是，當(dāng)為表添加一定數(shù)量的行時(shí)，我們可能需要強(qiáng)制插入分頁符。以下代碼段顯示了為表添加10行時(shí)插入分頁符的步驟。

// 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);

將表格邊框提取為圖像

頁面邊框是路徑繪制操作。因此，Pdf-> Html處理邏輯僅執(zhí)行繪圖指令并將背景放在文本后面。因此，要重復(fù)此邏輯，您必須手動(dòng)處理內(nèi)容運(yùn)算符并自己繪制圖形。另外請(qǐng)注意，以下代碼段可能不適用于各種PDF文件，但是如果您遇到任何問題，請(qǐng)隨時(shí)與我們聯(lián)系。此代碼是為特定的PDF文件開發(fā)的。以下代碼段顯示了從PDF文檔中提取表格邊框作為Image的步驟。

// 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);