在使用iText输出pdf表格文件时，有时存在较复杂的报表样式，需要支持在表格中画斜线，支持斜线表头，
iText在单元格中画斜线采用PdfContentByte的lineTo方法，斜线的坐标位置是采用相对于Document的绝对位置，
并不是相对于单元格的相对位置.

          

1. 创建一个iText Document 对象，pdf文档大小设置为A4，通过PdfWriter对象获取PdfContentByte 对象为 canvas，
下面是通过canvas去画图形

Document document = new Document();
PdfWriter writer = PdfWriter.getInstance(document, fos);
writer.setViewerPreferences(PdfWriter.PageModeUseThumbs);
document.setPageSize(PageSize.A4);
document.open();
PdfContentByte canvas = writer.getDirectContent();
              

2. 创建一个PdfPTable 对象，Pdf Table需要指定每列的宽度，pdf的宽度=像素宽*0.75, 指定Table的总宽度，总宽度是每列宽度之和，
设置Table相对于Document居左对齐。

PdfPTable table = new PdfPTable(widths);
table.setLockedWidth(true);
table.setTotalWidth(458 * PDF_PERCENT);
table.setHorizontalAlignment(Element.ALIGN_LEFT);
             

3. 画第一个单元格3个斜线，x1,y1,x2,y2,x3,y3为线的坐标终止位置，开始坐标为单元格开始位置，
LEFT=36，TOP=36，是PdfTable距离文档的左边距和上边距，而Pdf的y坐标位置是从底部开始计算的，所以第一个单元格的坐标位置是
document.getPageSize().getHeight() - TOP 与 LEFT, canvas.moveTo()单元格坐标位置，3条线分别lineTo()每个条线的终止坐标。

int x1 = 61, y1 = 77;
int x2 = 132, y2 = 76;
int x3 = 144, y3 = 31;
float top = document.getPageSize().getHeight() - TOP;
drawLine(canvas, LEFT, top, x1, y1);
drawLine(canvas, LEFT, top, x2, y2);
drawLine(canvas, LEFT, top, x3, y3);

canvas.saveState();
canvas.moveTo(left, top);
canvas.lineTo(left + x * PDF_PERCENT, top - y * PDF_PERCENT);
canvas.stroke();
canvas.restoreState();
             

4. 画表头斜线坐标比较容易确定，如果画表格中间单元格的斜线需要计算单元格的坐标位置，如下cellX=第一列宽 + 第二列宽，
cellY = 第一行高 * PDF_PERCENT

int cellX = (int) (widths[0] + widths[1]);
int cellY = (int) (77 * PDF_PERCENT);
int x = 201, y = 84;
drawLine(canvas, LEFT + cellX, top - cellY, x, y);
             

下面是输出pdf斜线完整的示例代码，使用的iText类库为：itextpdf-5.5.1.jar

import java.awt.Color;
import java.io.FileOutputStream;

import com.itextpdf.text.BaseColor;
import com.itextpdf.text.Document;
import com.itextpdf.text.Element;
import com.itextpdf.text.Font;
import com.itextpdf.text.PageSize;
import com.itextpdf.text.Paragraph;
import com.itextpdf.text.pdf.BaseFont;
import com.itextpdf.text.pdf.PdfContentByte;
import com.itextpdf.text.pdf.PdfPCell;
import com.itextpdf.text.pdf.PdfPTable;
import com.itextpdf.text.pdf.PdfWriter;

public class TestPdf {

	private static final float PDF_PERCENT = 0.75f;

	public static void main(String[] args) throws Exception {
		float[] widths = { 144 * PDF_PERCENT, 113 * PDF_PERCENT, 91 * PDF_PERCENT,
				110 * PDF_PERCENT };
		int TOP = 36, LEFT = 36;

		FileOutputStream fos = new FileOutputStream("D:/line.pdf");

		Document document = new Document();
		PdfWriter writer = PdfWriter.getInstance(document, fos);
		writer.setViewerPreferences(PdfWriter.PageModeUseThumbs);
		document.setPageSize(PageSize.A4);
		document.open();

		PdfContentByte canvas = writer.getDirectContent();
		float top = document.getPageSize().getHeight() - TOP;

		PdfPTable table = new PdfPTable(widths);
		table.setLockedWidth(true);
		table.setTotalWidth(458 * PDF_PERCENT);
		table.setHorizontalAlignment(Element.ALIGN_LEFT);

		PdfPCell pdfCell = new PdfPCell();
		final String text = "                              AB\n\n\n CD";
		setBorderColor(pdfCell);
		pdfCell.setMinimumHeight(77 * PDF_PERCENT);
		pdfCell.setPhrase(new Paragraph(text, getPdfChineseFont()));
		table.addCell(pdfCell);

		// draw cell line
		int x1 = 61, y1 = 77;
		int x2 = 132, y2 = 76;
		int x3 = 144, y3 = 31;
		drawLine(canvas, LEFT, top, x1, y1);
		drawLine(canvas, LEFT, top, x2, y2);
		drawLine(canvas, LEFT, top, x3, y3);

		pdfCell = new PdfPCell();
		setBorderColor(pdfCell);
		pdfCell.setMinimumHeight(77 * PDF_PERCENT);
		table.addCell(pdfCell);

		pdfCell = new PdfPCell();
		setBorderColor(pdfCell);
		pdfCell.setMinimumHeight(77 * PDF_PERCENT);
		table.addCell(pdfCell);

		pdfCell = new PdfPCell();
		setBorderColor(pdfCell);
		pdfCell.setMinimumHeight(77 * PDF_PERCENT);
		table.addCell(pdfCell);

		pdfCell = new PdfPCell();
		setBorderColor(pdfCell);
		pdfCell.setMinimumHeight(83 * PDF_PERCENT);
		table.addCell(pdfCell);

		pdfCell = new PdfPCell();
		setBorderColor(pdfCell);
		pdfCell.setMinimumHeight(83 * PDF_PERCENT);
		table.addCell(pdfCell);

		pdfCell = new PdfPCell();
		setBorderColor(pdfCell);
		pdfCell.setColspan(2);
		pdfCell.setMinimumHeight(83 * PDF_PERCENT);
		table.addCell(pdfCell);
		setBorderColor(pdfCell);

		int cellX = (int) (widths[0] + widths[1]);
		int cellY = (int) (77 * PDF_PERCENT);
		int x = 201, y = 84;
		drawLine(canvas, LEFT + cellX, top - cellY, x, y);

		document.add(table);
		document.close();
	}

	// draw cell line
	private static void drawLine(PdfContentByte canvas, float left, float top, int x, int y) {
		canvas.saveState();
		canvas.moveTo(left, top);
		canvas.lineTo(left + x * PDF_PERCENT, top - y * PDF_PERCENT);
		canvas.stroke();
		canvas.restoreState();
	}

	// 设置边框样式
	public static void setBorderColor(PdfPCell pdfCell) {
		Color rgbColor = Color.BLACK;
		BaseColor baseColor = new BaseColor(rgbColor.getRed(), rgbColor.getGreen(), rgbColor
				.getBlue());

		pdfCell.setBorderWidthTop(0.1f);
		pdfCell.setBorderWidthBottom(0.1f);
		pdfCell.setBorderWidthLeft(0.1f);
		pdfCell.setBorderWidthRight(0.1f);
		pdfCell.setBorderColorBottom(baseColor);
		pdfCell.setBorderColorLeft(baseColor);
		pdfCell.setBorderColorRight(baseColor);
		pdfCell.setBorderColorTop(baseColor);
	}

	public static Font getPdfChineseFont() throws Exception {
		BaseFont bfChinese = BaseFont.createFont("STSongStd-Light", "UniGB-UCS2-H",
				BaseFont.NOT_EMBEDDED);
		Font fontChinese = new Font(bfChinese, 12, Font.NORMAL);
		return fontChinese;
	}
}