[英]Set Author, Title, and Subject for PDF using Reportlab
How can you correctly set the Author, Title and Subject attributes for a PDF File using Reportlab?如何使用 Reportlab 正确设置 PDF 文件的作者、标题和主题属性? I have found the methods in the Reportlab User Guide on page 56, but I am not sure how to implement them correctly.我在第 56 页的Reportlab 用户指南中找到了这些方法,但我不确定如何正确实施它们。
Below in my PDF cropping and scaling script, I have added the annotations
method, but I don't know where to call them from, or if a whole new Canvas
object is needed.在我的 PDF 裁剪和缩放脚本的下方,我添加了annotations
方法,但我不知道从哪里调用它们,或者是否需要一个全新的Canvas
对象。 Please excuse the lengthy code, but only after line 113 is the doc
being created, above are mostly auxiliary methods, including the annotations
method on line 30.冗长的代码请见谅,不过是在113行之后才创建doc
,上面多为辅助方法,包括30行的annotations
方法。
# All the necessary parameters are accessible after line 92,
# but can of course be changed manually in the Code
# imports for the crop, rename to avoid conflict with reportlab Image import
from PIL import Image as imgPIL
from PIL import ImageChops, ImageOps, ImageFilter
import os.path, sys
# import for the PDF creation
import glob
from reportlab.lib.pagesizes import A4
from reportlab.lib import utils
from reportlab.platypus import Image, SimpleDocTemplate, Spacer
from reportlab.pdfgen import canvas
# get os path for Cropping
path = (os.path.dirname(os.path.abspath("cropPDF.py")))
dirs = os.listdir(path)
def trim(im, border="white"):
bg = imgPIL.new(im.mode, im.size, border)
diff = ImageChops.difference(im, bg)
bbox = diff.getbbox()
if bbox:
return im.crop(bbox)
def annotations(canvas):
canvas.setAuthor("the ReportLab Team")
canvas.setTitle("ReportLab PDF Generation User Guide")
canvas.setSubject("How to Generate PDF files using the ReportLab modules")
def findMaxWidth():
maxWidth = 0
for item in dirs:
try:
fullpath = os.path.join(path, item)
if os.path.isfile(fullpath):
im = imgPIL.open(fullpath)
maxWidth = max(maxWidth, im.size[0])
except:
pass
return maxWidth
def padImages(docHeight):
maxWidth = findMaxWidth()
for item in dirs:
try:
fullpath = os.path.join(path, item)
if os.path.isfile(fullpath):
im = imgPIL.open(fullpath)
f, e = os.path.splitext(fullpath)
width, height = im.size # get the image dimensions, the height is needed for the blank image
if not docHeight <= height: # to prevent oversized images from bein padded, such that they remain centered
image = imgPIL.new('RGB', (maxWidth, height),
(255, 255, 255)) # create a white image with the max width
image.paste(im, (0, 0)) # paste the original image overtop the blank one, flush on the left side
image.save(f + ".png", "PNG", quality=100)
except:
pass
def crop():
for item in dirs:
try:
fullpath = os.path.join(path, item)
if os.path.isfile(fullpath):
im = imgPIL.open(fullpath)
f, e = os.path.splitext(fullpath)
imCrop = trim(im, "white")
imCrop.save(f + ".png", "PNG", quality=100)
except:
pass
def add_page_number(canvas, doc):
canvas.saveState()
canvas.setFont('Times-Roman', numberFontSize)
page_number_text = "%d" % (doc.page)
canvas.drawCentredString(
pageNumberSpacing * mm,
pageNumberSpacing * mm,
page_number_text
)
canvas.restoreState()
#############################
executeCrop = True
executePad = True
outputName = "output.pdf" #The name of the file that will be created
fileAuthor = "Roman Stadler" #these 3 attributes are visible in the file info menu
fileTitle = ""
fileSubject = ""
margin = 0.5
imageWidthDefault = 550
spacerHeight = 7
scalingIfImageTooTall = 0.95 # larger than 95 can result in an empty page after the image
includePagenumbers = True
numberFontSize = 10
pageNumberSpacing = 5
############################
doc = SimpleDocTemplate(
outputName,
topMargin=margin * mm,
leftMargin=margin * mm,
rightMargin=margin * mm,
bottomMargin=margin * mm,
pagesize=A4
)
if executeCrop:
crop()
if executePad:
padImages(doc.height)
filelist = glob.glob("*.png") # Get a list of files in the current directory
filelist.sort()
story = [] # create the list of images for the PDF
for fn in filelist:
img = utils.ImageReader(fn)
img_width, img_height = img.getSize() # necessary for the aspect ratio
aspect = img_height / float(img_width)
documentHeight = doc.height
imageWidth = imageWidthDefault
imageHeight = imageWidth * aspect
if imageHeight > documentHeight:
imageHeight = documentHeight * scalingIfImageTooTall
imageWidth = imageHeight / aspect
img = Image(
fn,
width=imageWidth,
height=imageHeight
)
story.append(img)
space = Spacer(width=0, height=spacerHeight)
story.append(space)
if includePagenumbers and not len(filelist) == 0: # if pagenumbers are desired, or not
doc.build(
story,
onFirstPage=add_page_number,
onLaterPages=add_page_number,
)
elif not len(filelist) == 0:
doc.build(story)
else: # to prevent an empty PDF that can't be opened
print("no files found")
In the meantime, I have found another way, that does not use reportlab, but instead relies on PyPDF2:同时,我找到了另一种方法,它不使用 reportlab,而是依赖于 PyPDF2:
The following import is needed:需要以下导入:
# PyPDF2 for the metadata modification
from PyPDF2 import PdfFileReader, PdfFileWriter
Then the metadata can be edited like this:然后可以像这样编辑元数据:
author = "Roman Stadler"
title = "CropPDF"
subject = "Stackoverflow"
#rest of the script
#attemp the metadate edit
try:
file = open('output.pdf', 'rb+')
reader = PdfFileReader(file)
writer = PdfFileWriter()
writer.appendPagesFromReader(reader)
metadata = reader.getDocumentInfo()
writer.addMetadata(metadata)
writer.addMetadata({
'/Author': author,
'/Title': title,
'/Subject' : subject,
'/Producer' : "CropPDF",
'/Creator' : "CropPDF",
})
writer.write(file)
file.close()
except:
print("Error while editing metadata")
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