LibPDF+LibGfx: Decode Mellor_ACTITC_10.pdf faster#26235
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nico merged 4 commits intoSerenityOS:masterfrom Oct 3, 2025
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LibPDF+LibGfx: Decode Mellor_ACTITC_10.pdf faster#26235nico merged 4 commits intoSerenityOS:masterfrom
nico merged 4 commits intoSerenityOS:masterfrom
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This avoids the performance costs of calling `set_pixel` (which includes a bunch of VERIFY) that valgrind measured as 5% on: `Build/lagom/bin/pdf --render out.png PDF/Mellor_ACTITC_10.pdf --page 4`
Makes JBIG2's composite_bilevel_image() drop from 25% to 18% in profiles.
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one small nit from my end
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I dropped the last commit in favor of #26239. |
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Thanks! I haven't profiled it, but the CCITT (and JBIG2) hashtable code is pretty inefficient. You put more efficient code in JPEGLoader (maybe that's even the same type of hashtable as in CCITT and JBIG2?), and Compress::CanonicalCodes is iirc more efficient still. (And https://www.hanshq.net/zip.html is still a bit nicer than CanonicalCodes – see e.g. #25005) |
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Related to #26082
This is mainly low-hanging fruits, but it still gives a nice perf improvement.
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