使用ReportLab(Python)的PDF文档中的PDF图像 [英] PDF image in PDF document using ReportLab (Python)
问题描述
我将matplotlib中的一些图表保存为pdf格式,因为它似乎提供了更好的质量。如何使用ReportLab将PDF图像包含到PDF文档中?便捷方法Image(filepath)不适用于此格式。
I saved some plots from matplotlib into a pdf format because it seems to offer a better quality. How do I include the PDF image into a PDF document using ReportLab? The convenience method Image(filepath) does not work for this format.
谢谢。
推荐答案
您可以将精彩的pdfrw软件包与reportlab一起使用,并使用它将matplotlib数字的文件对象直接传递给一个可流动的:
You can use the wonderful pdfrw package together with reportlab and use it to pass file-like objects of matplotlib figures directly into a flowable:
这个之前得到了回答,但我想在这里给出一个最小的例子,请看这里: https://stackoverflow.com/a/13870512 / 4497962
This was answered before, but I want to give a minimal example here, please also look here: https://stackoverflow.com/a/13870512/4497962
from io import BytesIO
import matplotlib.pyplot as plt
from pdfrw import PdfReader, PdfDict
from pdfrw.buildxobj import pagexobj
from pdfrw.toreportlab import makerl
from reportlab.platypus import Flowable
from reportlab.lib.enums import TA_JUSTIFY,TA_LEFT,TA_CENTER,TA_RIGHT
class PdfImage(Flowable):
"""
PdfImage wraps the first page from a PDF file as a Flowable
which can be included into a ReportLab Platypus document.
Based on the vectorpdf extension in rst2pdf (http://code.google.com/p/rst2pdf/)
This can be used from the place where you want to return your matplotlib image
as a Flowable:
img = BytesIO()
fig, ax = plt.subplots(figsize=(canvaswidth,canvaswidth))
ax.plot([1,2,3],[6,5,4],antialiased=True,linewidth=2,color='red',label='a curve')
fig.savefig(img,format='PDF')
return(PdfImage(img))
"""
def __init__(self, filename_or_object, width=None, height=None, kind='direct'):
# If using StringIO buffer, set pointer to begining
if hasattr(filename_or_object, 'read'):
filename_or_object.seek(0)
#print("read")
self.page = PdfReader(filename_or_object, decompress=False).pages[0]
self.xobj = pagexobj(self.page)
self.imageWidth = width
self.imageHeight = height
x1, y1, x2, y2 = self.xobj.BBox
self._w, self._h = x2 - x1, y2 - y1
if not self.imageWidth:
self.imageWidth = self._w
if not self.imageHeight:
self.imageHeight = self._h
self.__ratio = float(self.imageWidth)/self.imageHeight
if kind in ['direct','absolute'] or width==None or height==None:
self.drawWidth = width or self.imageWidth
self.drawHeight = height or self.imageHeight
elif kind in ['bound','proportional']:
factor = min(float(width)/self._w,float(height)/self._h)
self.drawWidth = self._w*factor
self.drawHeight = self._h*factor
def wrap(self, availableWidth, availableHeight):
"""
returns draw- width and height
convenience function to adapt your image
to the available Space that is available
"""
return self.drawWidth, self.drawHeight
def drawOn(self, canv, x, y, _sW=0):
"""
translates Bounding Box and scales the given canvas
"""
if _sW > 0 and hasattr(self, 'hAlign'):
a = self.hAlign
if a in ('CENTER', 'CENTRE', TA_CENTER):
x += 0.5*_sW
elif a in ('RIGHT', TA_RIGHT):
x += _sW
elif a not in ('LEFT', TA_LEFT):
raise ValueError("Bad hAlign value " + str(a))
#xobj_name = makerl(canv._doc, self.xobj)
xobj_name = makerl(canv, self.xobj)
xscale = self.drawWidth/self._w
yscale = self.drawHeight/self._h
x -= self.xobj.BBox[0] * xscale
y -= self.xobj.BBox[1] * yscale
canv.saveState()
canv.translate(x, y)
canv.scale(xscale, yscale)
canv.doForm(xobj_name)
canv.restoreState()
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