Preserve leading spaces on new lines in <pre> blocks#1866
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andersonhc merged 2 commits intoJun 17, 2026
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Fixes py-pdf#1063. The skip_leading_spaces default of Paragraph and ParagraphCollectorMixin.paragraph() was False, so an explicitly passed False got swallowed by the `or self._region.skip_leading_spaces` fallback whenever the region had skip_leading_spaces=True, which is how the HTML parser configures it. As a result, leading whitespace inside <pre> and <pre><code> blocks was dropped. The default is now None, and an explicit True or False always wins over the region default, resolved once when the paragraph is constructed. build_lines() and the bullet renderer use the paragraph's own resolved value instead of falling back to the region again. In html.py, _new_paragraph() now passes skip_leading_spaces=not self._pre_formatted, so preformatted blocks keep their leading whitespace while normal blocks behave as before. A regression test based on the issue's minimal example is added in test/html/.
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Thank you for the contribution.
I don't have any comment - the PR should be ready to be merged as soon as I fix the problems with the github actions workflow.
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@allcontributors please add @eugen-goebel for code |
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I've put up a pull request to add @eugen-goebel! 🎉 |
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Merged. Thank you @eugen-goebel |
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Thanks a lot for the review and the quick merge, and for adding me to the contributors list. This was my first contribution here and it was a really good experience. I will keep an eye out for more issues I can help with. |
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Fixes #1063.
Leading spaces on new lines inside
<pre>and<pre><code>blocks were dropped. The root cause is thatParagraphandParagraphCollectorMixin.paragraph()hadskip_leading_spacesdefaulting toFalse, and the effective value was computed asskip_leading_spaces or self._region.skip_leading_spaces. Since the HTML parser creates its text region withskip_leading_spaces=True, an explicitly passedFalsewas always swallowed by theor.Following @gmischler's plan from the issue thread:
fpdf/text_region.pythe default is nowNonein bothParagraph.__init__andparagraph(), and an explicitTrueorFalsealways wins over the region default. The value is resolved once when the paragraph is constructed, andbuild_lines()and the bullet renderer use the paragraph's own value instead of falling back to the region again. This is the part @dmail00 pointed out was still missing.fpdf/html.py_new_paragraph()now passesskip_leading_spaces=not self._pre_formatted, so preformatted blocks keep their leading whitespace while every other block behaves exactly as before.I added a regression test in
test/html/based on the minimal example from the issue. The existingtest_html_whitespace_handlingreference is unchanged, since its<pre>lines have no leading spaces.Checklist:
docs/folder — N/A (bugfix)CHANGELOG.mdBy submitting this pull request, I confirm that my contribution is made under the terms of the GNU LGPL 3.0 license.