.net core利用PdfSharpCore操作PDF实例教程_Asp.net

前序

使用pdfsharpcore请注意使用xgraphics基类，与system.drawing 的graphics类似，xgraphics 提供xcolor（颜色）、xpen（画笔）、xbrush（画刷）、xfont(字体)、xpoint(位置)等对象。提供很多画线，矩形，圆，扇形，多边形，图，文本等方法。源码请查看https://github.com/ststeiger/pdfsharpcore/blob/master/pdfsharpcore/drawing/xgraphics.cs

1.设置pdf拥有者的密码，让pdf防篡改。

代码很简单设置pdfdocument.securitysettings.ownerpassword

            pdfdocument doc = pdfreader.open(@"a.pdf", pdfdocumentopenmode.modify);
            doc.securitysettings.ownerpassword = "123";
            var filepath = $"b.pdf";
            doc.save(filepath);

2.pdf添加页眉和页脚

（1）添加页码显示

xstringformats 指定文本的位置：详请查看https://github.com/ststeiger/pdfsharpcore/blob/master/pdfsharpcore/drawing/xstringformats.cs

xfont font = new xfont("simhei", 8);
            xbrush brush = xbrushes.black;
            pdfdocument doc = pdfreader.open(@"a.pdf", pdfdocumentopenmode.modify);
            for (int i = 0; i < doc.pages.count; i++)
            {
                pdfpage page = doc.pages[i];
                xrect layoutrectangle = new xrect(0, page.height - font.height, page.width, font.height);
                using (xgraphics gfx = xgraphics.frompdfpage(page))
                {
                    gfx.drawstring(
                        $"第{(i + 1).tostring()}页/共{doc.pages.count}页",
                        font,
                        brush,
                        layoutrectangle,
                        xstringformats.bottomleft);
                }
            }

（2）添加页眉

xfont font = new xfont("simhei", 8);
            xbrush brush = new xsolidbrush(xcolor.fromargb(128, 255, 0, 0));
            xpoint point = new xpoint(90, 20);
            pdfdocument doc = pdfreader.open(@"a.pdf", pdfdocumentopenmode.modify);
            for (int i = 0; i < doc.pages.count; i++)
            {
                var renderer = xgraphics.frompdfpage(doc.pages[i]);
                xsize pagesize = renderer.pagesize;
                renderer.drawstring("xxx有限公司", font, brush, point);
                xpen pen = new xpen(xbrushes.gray, 0.5f);
                renderer.drawline(pen, point.x, point.y, pagesize.width - point.x, point.y);
            }
            doc.save("b.pdf");

（3）添加页脚

xfont font = new xfont("simhei", 8);
            xbrush brush = new xsolidbrush(xcolor.fromargb(128, 255, 0, 0));
            pdfdocument doc = pdfreader.open(@"a.pdf", pdfdocumentopenmode.modify);
            for (int i = 0; i < doc.pages.count; i++)
            {
                var renderer = xgraphics.frompdfpage(doc.pages[i]);
                xsize pagesize = renderer.pagesize;
                xpoint point = new xpoint(90, pagesize.height-20);
                renderer.drawstring("xxx有限公司", font, brush, point);
                xpen pen = new xpen(xbrushes.gray, 0.5f);
                renderer.drawline(pen, point.x, point.y-10, pagesize.width - point.x, point.y-10);
            }
            doc.save("b.pdf");

3.pdf添加水印文字

xfont font = new xfont("simhei", 8);
            xbrush brush =new xsolidbrush(xcolor.fromargb(128, 255, 0, 0));
            pdfdocument doc = pdfreader.open(@"a.pdf", pdfdocumentopenmode.modify);
            for (int i = 0; i < doc.pages.count; i++)
            {
                xstringformat stringformat = new xstringformat();
                stringformat.alignment = xstringalignment.center;
                stringformat.linealignment = xlinealignment.center;
                pdfpage page = doc.pages[i];
                var gfx = xgraphics.frompdfpage(page, xpagedirection.downwards);
                gfx.drawstring(
                       $"xxx公司版权所有",
                       font,
                       brush,
                       new xpoint(500, 500),
                        stringformat);
            }
            doc.save("b.pdf");

4.pdf 添加图片

//第一步先加载pdf文件
            pdfdocument doc = pdfreader.open(@"a.pdf", pdfdocumentopenmode.modify);
            //导入图片（地址，文件流）
            var background = ximage.fromfile(@"qrcode.png");
            // var background = ximage.fromstream(()=> stream);
            //指定pdf 的页
            pdfpage page = doc.pages[0];
            var gfx = xgraphics.frompdfpage(page, xpagedirection.downwards);
            //写入指定位置
            gfx.drawimage(background, 20, 20, 250, 140);
            doc.save("b.pdf");

docker 模式，需要在 dockerfile 中添加如下配置