二、PDF加水印
我了解到的支持pdf加水印的工具有:
unidoc/unipdf pdfcpu1.unidoc/unipdf
unidoc平台开发的unipdf是一款用Go语言编写的PDF库,提供API和CLI使用模式,支持以下功能:
$ unipdf -h
...
Available Commands:
decrypt Decrypt PDF files
encrypt Encrypt PDF files
explode Explodes the input file into separate single page PDF files
extract Extract PDF resources
form PDF form operations
grayscale Convert PDF to grayscale
help Help about any command
info Output PDF information
merge Merge PDF files
optimize Optimize PDF files
passwd Change PDF passwords
rotate Rotate PDF file pages
search Search text in PDF files
split Split PDF files
version Output version information and exit
watermark Add watermark to PDF files
...
CLI模式添加水印
$ unipdf watermark in.pdf watermark.png -o out.pdf
Watermark successfully applied to in.pdf
Output file saved to out.pdf
使用API添加水印,可以直接参考unipdf github example
注意:unidoc的产品需要付费购买license使用
2.pdfcpu
pdfcpu 是一个用Go语言编写的PDF处理库，提供API和CLI模式使用
支持以下功能:
$ pdfcpu help
...
The commands are:
attachments list, add, remove, extract embedded file attachments
changeopw change owner password
changeupw change user password
decrypt remove password protection
encrypt set password protection
extract extract images, fonts, content, pages, metadata
fonts install, list supported fonts
grid rearrange pages or images for enhanced browsing experience
import import/convert images to PDF
info print file info
merge concatenate 2 or more PDFs
nup rearrange pages or images for reduced number of pages
optimize optimize PDF by getting rid of redundant page resources
pages insert, remove selected pages
paper print list of supported paper sizes
permissions list, set user access permissions
rotate rotate pages
split split multi-page PDF into several PDFs according to split span
stamp add, remove, update text, image or PDF stamps for selected pages
trim create trimmed version of selected pages
validate validate PDF against PDF 32000-1:2008 (PDF 1.7)
version print version
watermark add, remove, update text, image or PDF watermarks for selected pages
...
使用CLI工具以图片形式添加水印:
$ pdfcpu watermark add -mode image 'voucher_watermark.png' 's:1 abs, rot:0' in.pdf out.pdf
调用api添加水印
package main
import (
"github.com/pdfcpu/pdfcpu/pkg/api"
"github.com/pdfcpu/pdfcpu/pkg/pdfcpu"
)
func main() {
onTop := false
wm, _ := pdfcpu.ParseImageWatermarkDetails("watermark.png", "s:1 abs, rot:0", onTop)
api.AddWatermarksFile("in.pdf", "out.pdf", nil, wm, nil)
}
