【www.bbyears.com--python】
Python提供了众多的PDF支持库，本文是在Python3环境下，试用了两个库来完成PDF的生成的功能。PyPDF对于读取PDF支持较好，但是没找到生成多层PDF的方法。Reportlab看起来更成熟，能够利用Canvas很方便的生成多层PDF，这样就能够实现图片扫描上来的内容也可以进行内容搜索的目标。
Reportlab
生成双层PDF
双层PDF应用PDF中的Canvas概念，先画文字，最后将图片画上去，这样就是两层的PDF。
importos
# import urllib2
importtime
fromreportlabimportplatypus
fromreportlab.lib.pagesizesimportletter
fromreportlab.lib.unitsimportinch
fromreportlab.platypusimportSimpleDocTemplate, Image
fromreportlab.pdfgenimportcanvas
image_file="./42.png"
# Use Canvas to generate pdf
c=canvas.Canvas('reportlab_canvas.pdf', pagesize=letter)
width, height=letter
c.setFillColorRGB(0,0.77,0.77)
# say hello (note after rotate the y coord needs to be negative!)
c.drawString(3*inch,3*inch,"Hello World")
c.drawImage(image_file,0,0)
c.showPage()
c.save()
PyPDF2
读取PDF
fromPyPDF2importPdfFileWriter, PdfFileReader
output=PdfFileWriter()
input1=PdfFileReader(open("jquery.pdf","rb"))
# print document info
print(input1.getDocumentInfo())
# print how many pages input1 has:
print("pdf_document.pdf has %d pages."%input1.getNumPages())
# print page content
page_content=input1.getPage(0).extractText()
print( page_content )
# add page 1 from input1 to output document, unchanged
output.addPage(input1.getPage(0))
# add page 2 from input1, but rotated clockwise 90 degrees
output.addPage(input1.getPage(1).rotateClockwise(90))
# finally, write "output" to document-output.pdf
outputStream=open("PyPDF2-output.pdf","wb")
output.write(outputStream)
word-wrap: break-word; margin: 5px 0px; color: rgb(0, 0, 0); font-family: " sans="" font-size:="" font-style:="" font-variant-ligatures:="" font-variant-caps:="" font-weight:="" letter-spacing:="" orphans:="" text-align:="" text-indent:="" text-transform:="" white-space:="" widows:="" word-spacing:="" -webkit-text-stroke-width:="">但是PyPDF获取PDF内容有很多问题，可以看这个问题列表。文档中也有说明。
| extractText(self) | ## | # Locate all text drawing commands, in the order they are provided in the | # content stream, and extract the text. This works well for some PDF | # files, but poorly for others, depending on the generator used. This will | # be refined in the future. Do not rely on the order of text coming out of | # this function, as it will change if this function is made more | # sophisticated. | #
| # Stability: Added in v1.7, will exist for all future v1.x releases. May | # be overhauled to provide more ordered text in the future. | # @return a unicode string object
以上就是本文的全部内容，希望对大家的学习有所帮助。