49 lines
1.4 KiB
Nix
49 lines
1.4 KiB
Nix
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{ pkgs ? import <nixpkgs> {} }:
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let
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crop_ppm = (pkgs.writers.writePython3Bin "crop_ppm" {libraries = [pkgs.python3Packages.opencv4];} ''
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import cv2
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import sys
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for path in sys.argv[1:]:
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img = cv2.imread(path)[30:-30, 30:]
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gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
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_, thresh = cv2.threshold(gray, 1, 255, cv2.THRESH_BINARY)
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contours, hierarchy = cv2.findContours(
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thresh,
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cv2.RETR_EXTERNAL,
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cv2.CHAIN_APPROX_SIMPLE
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)
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cnt = max(contours, key=cv2.contourArea)
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x, y, w, h = cv2.boundingRect(cnt)
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print(path, x, y, w, h)
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crop = img[y:y + h, x:x + w]
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cv2.imwrite(path, crop)
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'');
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in
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pkgs.mkShell {
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packages = [
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pkgs.poppler_utils
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pkgs.mupdf
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crop_ppm
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(pkgs.writers.writeDashBin "generate" ''
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set -x
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pwd=$(pwd)
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tmpdir=$(mktemp -d)
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cd "$tmpdir"
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[ $# -eq 1 ] || {
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echo Please provide one PDF file as argument. >&2
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exit 1
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}
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[ -f "$1" ] || {
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echo "$1" does not exist. >&2
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exit 1
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}
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basename=$(basename "$1" .pdf)
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${pkgs.poppler_utils}/bin/pdftoppm "$1" exploded
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${crop_ppm}/bin/crop_ppm exploded*.ppm
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${pkgs.imagemagick}/bin/convert exploded*.ppm "$pwd/cropped-$basename.pdf"
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${pkgs.mupdf}/bin/mutool poster -x 2 "$pwd/cropped-$basename.pdf" "$pwd/split-cropped-$basename.pdf"
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'')
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];
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}
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