Merging Perspective Corrected Image With Transparent Background Template Image Using Pillow [pil, Python]

Problem: I have multiple book cover images. I made a template of 'book'-like template with a 3D perspective. And all I have to do now its take each of book cover images, correct a

Solution 1:

You don't really need to write any Python, you can just do it in the Terminal with ImageMagick using a "Perspective Transform" like this:

magick cover.png -virtual-pixel none -distort perspective "0,0 96,89 %w,0 325,63 %w,%h 326,522 0,%h 96,491" template.png +swap -flatten result.png

Looking at the parameters to the perspective transform, you can hopefully see there are 4 pairs of coordinates, one pair for each corner of the transform showing how the source location gets mapped in the output image.

So, the top-left corner of the cover (0,0) gets mapped to the top-left of the empty area in the template (96,89). The top right of the cover (width,0) gets mapped to the top-right of the empty area of the template (325,63). The bottom-right of the cover (width,height) gets mapped to the bottom-right of the empty area on the template (326,522). The bottom-left of the cover (0,height) gets mapped to the bottom-left corner of the empty area of the template (96,491).

If you are using the old v6 ImageMagick, replace magick with convert.

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Note that, if you really want to do it in Python, there is a Python binding called wandhere. I am not very experienced with wand but this seems to be equivalent:

#!/usr/bin/env python3from itertools import chain
from wand.color import Color
from wand.image import Image

with Image(filename='cover.png') as cover, Image(filename='template.png') as template:
    w, h = cover.size
    cover.virtual_pixel = 'transparent'
    source_points = (
        (0, 0),
        (w, 0),
        (w, h),
        (0, h)
    )
    destination_points = (
        (96, 89),
        (325, 63),
        (326, 522),
        (96, 491)
    )
    order = chain.from_iterable(zip(source_points, destination_points))
    arguments = list(chain.from_iterable(order))
    cover.distort('perspective', arguments)

    # Overlay cover onto template and save
    template.composite(cover,left=0,top=0)
    template.save(filename='result.png')

Keywords: Python, ImageMagick, wand, image processing, perspective transform, distort.