84 lines
2.6 KiB
Nix
84 lines
2.6 KiB
Nix
{ lib, makeWrapper, tesseractBase, languages
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, runCommand, imagemagick
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# A list of languages like [ "eng" "spa" … ] or `null` for all available languages
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, enableLanguages ? null
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# A list of files or a directory containing files
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, tessdata ? (if enableLanguages == null then languages.all
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else map (lang: languages.${lang}) enableLanguages)
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# This argument is obsolete
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, enableLanguagesHash ? null
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}:
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let
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tesseractWithData = tesseractBase.overrideAttrs (_: {
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inherit tesseractBase tessdata;
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nativeBuildInputs = [ makeWrapper ];
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buildCommand = ''
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makeWrapper {$tesseractBase,$out}/bin/tesseract --set-default TESSDATA_PREFIX $out/share/tessdata
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# Recursively link include, share
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cp -rs --no-preserve=mode $tesseractBase/{include,share} $out
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cp -r --no-preserve=mode $tesseractBase/lib $out
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# Fixup the store paths in lib so that the tessdata from this derivation is used.
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if (( ''${#tesseractBase} != ''${#out} )); then
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echo "Can't replace store paths due to differing lengths"
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exit 1
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fi
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find $out/lib -type f -exec sed -i "s|$tesseractBase|$out|g" {} \;
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if [[ -d "$tessdata" ]]; then
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ln -s $tessdata/* $out/share/tessdata
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else
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for lang in $tessdata; do
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ln -s $lang $out/share/tessdata/''${lang#/nix/store*-}
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done
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fi
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if [[ ! -e $out/share/tessdata/eng.traineddata ]]; then
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# This is a bug in Tesseract's internal tessdata discovery mechanism
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echo "eng.traineddata must be present in tessdata for Tesseract to work"
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exit 1
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fi
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'';
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});
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passthru = { inherit tesseractBase languages tessdata; };
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# Only run test when all languages are available
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test = lib.optionalAttrs (enableLanguages == null) {
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tests.default = runCommand "tesseract-test-ocr" {
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buildInputs = [
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tesseractWithData
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imagemagick
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];
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} ''
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text="hello nix"
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convert -size 400x40 xc:white -font 'DejaVu-Sans' -pointsize 20 \
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-fill black -annotate +5+20 "$text" /tmp/test-img.png 2>/dev/null
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ocrResult=$(tesseract /tmp/test-img.png - | tr -d "\f")
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if [[ $ocrResult != $text ]]; then
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echo "OCR test failed"
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echo "expected: '$text'"
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echo "actual: '$ocrResult'"
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exit 1
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fi
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touch $out
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'';
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};
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tesseract = (if enableLanguages == [] then tesseractBase else tesseractWithData) // passthru // test;
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in
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if enableLanguagesHash == null then
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tesseract
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else
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lib.warn "Argument `enableLanguagesHash` is obsolete and can be removed."
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tesseract
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