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
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
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kb88凯时官网登录的版权所有",
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
run apt-get update && apt-get -y install libfontconfig1
如需要指定字体，请将字段文件进行拷贝(比如雅黑)
copy /xx/xxx/simhei.ttf /usr/share/fonts/simhei.ttf
