Fix panic caused by oversized filter regions - #1079
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LaurenzV merged 3 commits intoAug 1, 2026
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The source pixmap of a filtered group is clamped to `max_bbox` in
`render_group`, but the filter `region` in `apply_inner` was derived
directly from the unclamped filter rect. When the filter region was
larger than the clamped buffer, `feComposite` with the `arithmetic`
operator panicked on a size mismatch, since it requires its inputs and
destination to have identical dimensions:
assertion failed: src1.height == src2.height && src1.height == dest.height
All intermediate filter images are expected to share the source's
dimensions, so clamp the region to the source bounds. This keeps every
buffer the same size and makes the affected SVG render correctly instead
of crashing (or being silently cleared).
This also fixes the `huge-region` test, whose reference image previously
captured the buggy behaviour where the filtered element disappeared; it
now renders the blurred shape correctly.
Fixes linebender#1021. Fixes linebender#1007.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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I just noticed there seem to be quite a few other issues related to filters, but this definitely is an improvement to before, so LGTM. |
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The source pixmap of a filtered group is clamped to
max_bboxinrender_group, but the filterregioninapply_innerwas derived directly from the unclamped filter rect. When the filter region was larger than the clamped buffer,feCompositewith thearithmeticoperator panicked on a size mismatch, since it requires its inputs and destination to have identical dimensions:All intermediate filter images are expected to share the source's dimensions, so clamp the region to the source bounds. This keeps every buffer the same size and makes the affected SVG render correctly instead of crashing (or being silently cleared).
This also fixes the
huge-regiontest, whose reference image previously captured the buggy behaviour where the filtered element disappeared; it now renders the blurred shape correctly.Fixes #1021. Fixes #1007.
Generated by Claude.
Note: I accidentally closed the original PR (#1061) by deleting my fork, which auto-closed it. This reopens the same change — the branch and commits are unchanged.