Develop Reference

Replacing a word with another word, and replacing an image with another image in a PDF file through python, is this possible?

I need to replace a K words with K other words for every PDF file I have within a certain path file location and on top of this I need to replace every logo with another logo. I have around 1000 PDF files, and so I do not want to use Adobe Acrobat and edit 1 file at a time. How can I start this?
Replacing words seems at least doable as long as there is a decent PDF reader one can access through Python ( Note I want to do this task in Python ), however replacing an image might be more difficult. I will most likely have to find the dimension of the current image and resize the image being used to replace the current image dynamically, whilst the program runs through these PDF files.
Hi, so I've written down some code regarding this:
from pikepdf import Pdf, PdfImage, Name
import os
import glob
from PIL import Image
import zlib
example = Pdf.open(r'...\Likelihood.pdf')
PagesWithImages = []
ImageCodesForPages = []
# Grab all the pages and all the images in every page.
for i in example.pages:
if len(list(i.images.keys())) >= 1:
PagesWithImages.append(i)
ImageCodesForPages.append(list(i.images.keys()))
pdfImages = []
for i,j in zip(PagesWithImages, ImageCodesForPages):
for x in j:
pdfImages.append(i.images[x])
# Replace every single page using random image, ensure that the dimensions remain the same?
for i in pdfImages:
pdfimage = PdfImage(i)
rawimage = pdfimage.obj
im = Image.open(r'...\panda.jpg')
pillowimage = pdfimage.as_pil_image()
print(pillowimage.height)
print(pillowimage.width)
im = im.resize((pillowimage.width, pillowimage.height))
im.show()
rawimage.write(zlib.compress(im.tobytes()), filter=Name("/FlateDecode"))
rawimage.ColorSpace = Name("/DeviceRGB")
So just one problem, it doesn't actually replace anything. If you're wondering why and how I wrote this code I actually got it from this documentation:
https://buildmedia.readthedocs.org/media/pdf/pikepdf/latest/pikepdf.pdf
Start at Page 53
I essentially put all the pdfImages into a list, as 1 page can have multiple images. In conjunction with this, the last for loop essentially tries to replace all these images whilst maintaining the same width and height size. Also note, the file path names I changed here and it definitely is not the issue.
Again Thank You

I have figured out what I was doing wrong. So for anyone that wants to actually replace an image with another image in place on a PDF file what you do is:
from pikepdf import Pdf, PdfImage, Name
from PIL import Image
import zlib
example = Pdf.open(filepath, allow_overwriting_input=True)
PagesWithImages = []
ImageCodesForPages = []
# Grab all the pages and all the images in every page.
for i in example.pages:
imagelists = list(i.images.keys())
if len(imagelists) >= 1:
for x in imagelists:
rawimage = i.images[x]
pdfimage = PdfImage(rawimage)
rawimage = pdfimage.obj
pillowimage = pdfimage.as_pil_image()
im = Image.open(imagePath)
im = im.resize((pillowimage.width, pillowimage.height))
rawimage.write(zlib.compress(im.tobytes()), filter=Name("/FlateDecode"))
rawimage.ColorSpace = Name("/DeviceRGB")
rawimage.Width, rawimage.Height = pillowimage.width, pillowimage.height
example.save()
Essentially, I changed the arguements in the first line, such that I specify that I can overwrite. In conjunction, I also added the last line which actually allows me to save.

Python/Opencv save multiple images to folder with different names

I am working on image processing, I have a folder with all of the images that needs to be processed, and I want to save all the processed images to another folder. How do I do that?
for img in glob.glob("Img/*.png"):
path = '/result'
image = cv2.imread(img)
angle, rotated = correct_skew(image)
print(angle)
cv2.imwrite(os.path.join(path , 'img.png'), rotated)
cv2.waitKey(1)
This code can read the image and process it, but I can't figure out how to save all the images with different names, like I want it to be img1.png, img2.png, etc.
Or is there anyway that I can save the images to another folder with the same names as before?

In order to save your processed images in a serial manner, you can use enumerate. When a loop is initiated using enumerate, a counter is also initiated. And each iteration yields an integer number.
In the following case i is the integer value which increments for each iteration. i is used as part of the file name to save the processed image
path = '/result'
for i, img in enumerate(glob.glob("Img/*.png"), 1):
image = cv2.imread(img)
angle, rotated = correct_skew(image)
print(angle)
cv2.imwrite(os.path.join(output_path, 'img_{}.png'.format(i)), rotated)

Save the last line as a variable wrapped in a string()
Then cv2.imwrite(variable)for the last line.
#My thought is to change the type to a string and then write the file as originally desired. When you save as a string you can change whatever type it is turning into inside the for statement.

Is there a way to speed up my python video creation script?

So I wrote a script that creates a video out of a series of images. I have the images stored in a folder called "TEMP". The part of the script that takes a very long time is the following:
from moviepy.editor import *
def createVideoFromImages(genre, audio):
#export name
timeStamp = str(time.time()).split(".")[0]
exportFolderName = f"./finished/{genre}{timeStamp}"
exportFileName = f"{exportFolderName}/video.mp4"
images = os.listdir("TEMP")
clips = [ImageClip(f"./TEMP/{m}").set_duration(10).crossfadein(1.0) for m in images]
concat_clip = concatenate_videoclips(clips, method="compose")
audio_duration = audio.duration
videoclip = concat_clip.set_duration(audio_duration)
exportClip = videoclip.set_audio(audio)
#create folder and save video there
os.mkdir(exportFolderName)
exportClip.write_videofile(exportFileName, fps=60, preset="ultrafast")
return exportFolderName
I tried a couple of things, like changing the concatenation of videoclips to method="chain" but that broke and I got a glitchy video, where only the first image was properly showing.
I also tried to add the preset="ultrafast" as I found somewhere online, but I find it to slow things down rather than speed things up.
I suspect the script to run this slow(it takes 8-9 hours for an ~300 second video) because it takes almost all the RAM of my computer.
Is there a way to speed up this script, preferrably with a minimal sacrifice of quality?

How to view real time mosaicing of large image?

I have built a code which will stitch 100X100 images approx. I want to view this stitiching process in real time. I am using pyvips to create large image. I am saving final image in .DZI format as it will take very less memory footprint to display.
Below code is copied just for testing purpose https://github.com/jcupitt/pyvips/issues/43.
#!/usr/bin/env python
import sys
import pyvips
# overlap joins by this many pixels
H_OVERLAP = 100
V_OVERLAP = 100
# number of images in mosaic
ACROSS = 40
DOWN = 40
if len(sys.argv) < 2 + ACROSS * DOWN:
print 'usage: %s output-image input1 input2 ..'
sys.exit(1)
def join_left_right(filenames):
images = [pyvips.Image.new_from_file(filename) for filename in filenames]
row = images[0]
for image in images[1:]:
row = row.merge(image, 'horizontal', H_OVERLAP - row.width, 0)
return row
def join_top_bottom(rows):
image = rows[0]
for row in rows[1:]:
image = image.merge(row, 'vertical', 0, V_OVERLAP - image.height)
return image
rows = []
for y in range(0, DOWN):
start = 2 + y * ACROSS
end = start + ACROSS
rows.append(join_left_right(sys.argv[start:end]))
image = join_top_bottom(rows)
image.write_to_file(sys.argv[1])
To run this code:
$ export VIPS_DISC_THRESHOLD=100
$ export VIPS_PROGRESS=1
$ export VIPS_CONCURRENCY=1
$ mkdir sample
$ for i in {1..1600}; do cp ~/pics/k2.jpg sample/$i.jpg; done
$ time ./mergeup.py x.dz sample/*.jpg
here cp ~/pics/k2.jpg will copy k2.jpg image 1600 times from pics folder, so change according to your image name and location.
I want to display this process in real time. Right now after creating final mosaiced image I am able to display. Just an idea,I am thinking to make a large image and display it, then insert smaller images. I don't know, how it can be done. I am confused as we also have to make pyramidal structure. So If we create large image first we have to replace each level images with the new images. Creating .DZI image is expensive, so I don't want to create it in every running loop. Replacing images may be a solution. Any suggestion folks??

I suppose you have two challenges: how to keep the pyramid up-to-date on the server, and how to keep it up-to-date on the client. The brute force method would be to constantly rebuild the DZI on the server, and periodically flush the tiles on the client (so they reload). For something like that you'll also need to add a cache bust to the tile URLs each time, or the browser will think it should just use its local copy (not realizing it has updated). Of course this brute force method is probably too slow (though it might be interesting to try!).
For a little more finesse, you'd want to make a pyramid that's exactly aligned with the sub images. That way when you change a single sub image, it's obvious which tiles need to be updated. You can do this with DZI if you have square sub images and you use a tile size that is some even fraction of the sub image size. Also no tile overlap. Of course you'll have to build your own DZI constructor, since the existing ones aren't primed to simply replace individual tiles. If you know which tiles you changed on the server, you can communicate that to the client (either via periodic polling or with something like web sockets) and then flush only those tiles (again with the cache busting).
Another solution you could experiment with would be to not attempt a pyramid, per se, but just a flat set of tiles at a reasonable resolution to allow the user to pan around the scene. This would greatly simplify your pyramid updating on the server, since all you would need to do would be replace a single image for each sub image. This could be loaded and shown in a custom (non-OpenSeadragon) fashion on the client, or you could even use OpenSeadragon's multi-image feature to take advantage of its panning and zooming, like here: http://www.letsfathom.com/ (each album cover is its own independent image object).

python PIL acces multiple images from a single image file

I have written a python script to Delta compress an image. The image file format is .tif which contains 8 images. When I use the normal code ...
org_Image = Image.open(image)
org_Data = org_Image.load()
... I can only access the first image. How do I go about accessing the other ones?

You use org_Image.seek(org_Image.tell() + 1) to get the next one.
In PIL seek moves you to a given frame, (with an IO_Error if it doesn't exist), and tell reports the current frame number.