Java 添加和删除PDF图层的示例代码

com.spire.pdf.PdfDocument;
import com.spire.pdf.PdfPageBase;
import com.spire.pdf.graphics.PdfBrushes;
import com.spire.pdf.graphics.PdfCanvas;
import com.spire.pdf.graphics.PdfPen;
import com.spire.pdf.graphics.layer.PdfLayer;
import java.awt.geom.Point2D;
public class AddLayers {
 public static void main(String[] args) {
  //创建PDF文档
  PdfDocument pdf = new PdfDocument();
  //添加一页
  PdfPageBase page = pdf.getPages().add();

  //添加3个线条图层到PDF文档
  PdfLayer layer = pdf.getLayers().addLayer("red line1");
  PdfCanvas canvas1 = layer.createGraphics(pdf.getPages().get(0).getCanvas());
  canvas1.drawLine(new PdfPen(PdfBrushes.getRed(), 1), new Point2D.Float(50, 350), new Point2D.Float(200, 350));
  layer = pdf.getLayers().addLayer("blue line1");
  PdfCanvas canvas2 = layer.createGraphics(pdf.getPages().get(0).getCanvas());
  canvas2.drawLine(new PdfPen(PdfBrushes.getBlue(), 1), new Point2D.Float(50, 450), new Point2D.Float(200, 450));
  layer = pdf.getLayers().addLayer("green line1");
  PdfCanvas canvas3 = layer.createGraphics(pdf.getPages().get(0).getCanvas());
  canvas3.drawLine(new PdfPen(PdfBrushes.getGreen(), 1), new Point2D.Float(50,550), new Point2D.Float(200, 550));

  //保存结果文档
  pdf.saveToFile("output/addLayers.pdf");
  pdf.close();
 }
}

 com.spire.pdf.PdfDocument;
public class DeleteLayers {
 public static void main(String[] args) {
  //加载PDF文档
  PdfDocument pdf = new PdfDocument();
  pdf.loadFromFile("D:\\Desktop\\addLayers.pdf");

  //删除名为“red line1”的图层
  pdf.getLayers().removeLayer("red line1");

  //保存结果文档
  pdf.saveToFile("output/deleteLayer.pdf");
  pdf.close();
 }
}