java 添加和删除 pdf 图层-人生就是博尊龙凯时

图层使我们可以在pdf文档中选择性地隐藏或显示部分内容。spire.pdf for java支持添加线条、图片、文字、矩形等多种样式的图层到pdf文档，也支持从pdf文档中删除图层。本文将介绍如何使用spire.pdf for java添加和删除pdf图层。

添加图层

import 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();
    }
}

删除图层

import com.spire.pdf.pdfdocument;
public class deletelayers {
    public static void main(string[] args){
        //加载pdf文档
        pdfdocument pdf = new pdfdocument();
        pdf.loadfromfile("output/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();
    }
}