问题
I would like to use imagemagick Wand package to convert all pages of a pdf file into a single image file. I am having the following trouble though (see comments below which highlight problem)
import tempfile
from wand.image import Image
with file('my_pdf_with_5_pages.png') as f:
image = Image(file=f, format='png')
save_using_filename(image)
save_using_file(image)
def save_using_filename(image):
with tempfile.NamedTemporaryFile() as temp:
# this saves all pages, but a file for each page (so 3 files)
image.save(filename=temp.name)
def save_using_file(image):
with tempfile.NamedTemporaryFile() as temp:
# this only saves the first page as an image
image.save(file=temp)
My end goal it to be able to specify which pages are to be converted to one continual image. This is possible from the command line with a bit of
convert -append input.pdf[0-4]
but I am trying to work with python.
I see we can get slices by doing this:
[x for x in w.sequence[0:1]] # get page 1 and 2
now its a question of how to join these pages together.
回答1:
A slight simplification of @rikAtee's answer / addition of detecting the page count automatically by counting the length of the sequence:
def convert_pdf_to_png(blob):
pdf = Image(blob=blob)
pages = len(pdf.sequence)
image = Image(
width=pdf.width,
height=pdf.height * pages
)
for i in xrange(pages):
image.composite(
pdf.sequence[i],
top=pdf.height * i,
left=0
)
return image.make_blob('png')
I haven't noticed any memory link issues, although my PDFs only tend to be 2 or 3 pages.
回答2:
My solution:
from wand.image import Image
diag='yourpdf.pdf'
with(Image(filename=diag,resolution=200)) as source:
images=source.sequence
pages=len(images)
for i in range(pages):
Image(images[i]).save(filename=str(i)+'.png')
It works, and compared to other answers, it appears more flexible to some multi-page pdf files with variable size in different pages.
回答3:
note: this causes memory leak
I found a way. There is probably a better way, but it works.
class Preview(object):
def __init__(self, file):
self.image = Image(file=file)
def join_pages(self, page_count):
canvas = self.create_canvas(page_count=page_count)
for page_number in xrange(page_count):
canvas.composite(
self.image.sequence[page_number],
top=self.image.height*page_number,
left=0,
)
def create_canvas(self, page_count):
return Image(
width=self.pdf.width,
height=self.image.height*page_count,
)
preview = Preview(open('path/to/pdf')
preview.join_pages(3)
来源:https://stackoverflow.com/questions/23706661/imagemagick-wand-save-pdf-pages-as-images