[gravitypdf-bot]

Part of #603
Part of #552, part of #520

Problem

mPDF read border-radius on a table cell and never used it, so rounded table cards and cells came out square:

$mpdf = new \Mpdf\Mpdf(['mode' => 'c']);
$mpdf->WriteHTML('<table style="border-collapse: separate"><tr>
  <td style="border: 1mm solid #00f; border-radius: 3mm; background: #0f0">A</td>
</tr></table>');
$mpdf->Output('', 'S');

Rule	Browser	Before	After
td { border: 1mm solid #00f; border-radius: 3mm; background: #0f0 }, border-collapse: separate	rounded	square	rounded
td { border-radius: 50% } on a 60 × 10 mm cell	ellipse	square	ellipse, 30 × 5 mm radii
td { border: 3mm groove #36c; border-radius: 5mm }	rounded, two-tone	square, two-tone	rounded, two-tone
tr { background: #fcc }, td { border-radius: 5mm }	row colour clipped to the cell's corners	square	clipped
td { border-radius: 3mm }, border-collapse: collapse	square (CSS ignores it)	square	square, byte-identical

Fix

• Tag\Td reads the radius longhands with BorderRadius::parse(), in standard mode only, into $cell['border_radius']. Repeated header and footer rows copy it.
• Mpdf::roundedCellBox() gives the cell's border box (its slot less half the border-spacing on each side, which is the box a square cell's background already fills). It scales the radii by the table's shrink factor, resolves percentages against the box with BorderRadius::resolve(), and fits them with RoundedBox::fit(). It returns null under border-collapse: collapse, for simple tables, inside columns, and when every corner comes out square. In those cases nothing changes.
• Backgrounds. The cell's backgrounds are not painted where they are built. They are collected in tableBackgrounds and painted later. So roundedCellBox() counts each layer of the table's level, and once the cell is done clipRoundedCellBackgrounds() gives every entry added since a clip path round the rounded box. That covers the cell's colour, gradient and image, and the row's colour, gradient and image showing through it. A row gradient or image already had a square per-cell clip in the separated model, and the rounded one takes its place. PrintTableBackgrounds() now honours clippath on a plain colour too, as it already did for gradients and images. Doing it this way leaves the background-building code in _tableWrite() and TableHeaderFooter() untouched, and Draw every layer of a multiple background (#609) #723 rewrites that code.
• Border. paintRoundedCellBorder() strokes each side along the corners with RoundedBox::side(), as PaintImgBorder() does for a rounded image. dashed and dotted keep their dashes. double is drawn as two strokes, each a third of the border's width. groove, ridge, inset and outset take the two tones _tableRect() gives a square cell (ColorConverter::lighten() and darken()): one tone on the outer half of the top and left, the other on the inner half, and the other way round on the bottom and right. The tones change at the diagonal of each corner.
• RoundedBox::scale() divides radii by a shrink factor. imageBox() and roundedCellBox() both use it.

Decisions.

• Collapse. CSS says border-radius does not apply in the collapsing border model, on cells or on the table, so a collapsed cell is drawn exactly as before.
• Row backgrounds. Browsers paint a row's background in each cell's area, clipped to that cell's rounded corners, so this PR does the same.
• Columns. Inside <columns>, mPDF moves what was drawn by matching the first coordinate of each write. A curved path doesn't survive that, so cells stay square there. Block borders and image borders are also skipped in columns.
• Simple tables. simpleTables draws every cell with the table's border and ignores the cell's own border, so the cell's radius is ignored too.

Legacy mode

Under 'cssMode' => 'legacy', Td doesn't read the radius, so output is byte-identical to before. I checked a document of rounded cells in every border style: same bytes before and after. TableCellBorderRadiusTest::testTheLegacyModeKeepsTheCellSquare covers this.

Not in this PR

• border-radius on the table itself. The table's border is drawn per cell, one edge segment at a time (_tableRect() with 'table' corners in _tableWrite() and TableHeaderFooter()). Its background is painted per page segment. Rounding it means drawing the outer border as one path per page and clipping every background in the table to it. That is a separate change.
• The other parts of Draw border-radius, box-shadow and 3D border styles on every element, blur text-shadow, and draw outline #603: inline-element radius, shadows on cells, tables, inline elements and images, 3D styles on blocks and inline elements, text-shadow blur, and outline (Draw the outline of blocks, table cells, images and inline elements (#603) #727).
• Rounded image borders still draw double and the 3D styles as one solid line. paintRoundedCellBorder() could be shared with PaintImgBorder() when 3D styles on images are done.

Tests

tests/Mpdf/TableCellBorderRadiusTest.php reads the clip path and border strokes from the page stream:

• A length rounds every corner of the background by that much.
• The clip runs round the box a square background fills.
• A percentage is half of each side of the box.
• A corner longhand rounds that corner alone.
• A row background, and a gradient, are painted inside the rounded clip.
• The border ends each of its four sides in a curve. double and groove draw two strokes per side, and groove uses two colours.
• A side with no border isn't drawn.
• Each of these is byte-identical to the same cell without a radius: border-collapse: collapse, legacy mode, and border-radius: 0.
• Simple tables stay square.
• A repeated header row is rounded on every page.
• A nested table keeps its own clips.

With the src/ changes reverted, 10 of the 15 fail. The five that pass check that nothing changes.

tests/Snapshots/TableCellBorderRadiusSnapshotTest.php (fixture table-cell-border-radius) draws twelve cells, each under a caption saying what it should show: solid, 50% ellipse, 6mm 0, dashed, dotted, double, groove, ridge, inset, outset, a gradient, and a row background through a cell with none. It ends with a collapsed cell that stays square. Against the pre-fix src/ it fails (RMSE 0.07). No existing fixture changed.

Checks

• composer test: OK, 12748 tests, 31 skipped (none of them snapshots; --group snapshot: 219 tests OK)
• composer cs: clean
• PHPStan 2.x (--memory-limit=2G): 23 errors, all already on gravitypdf (Regenerate the PHPStan baseline for PHPStan 2.3, so the Lint job passes again #716 regenerates the baseline). None are new.

Expected conflicts: #723 (multiple backgrounds) touches PrintTableBackgrounds() and the cell background blocks. This PR adds one line before and one after each of those blocks, so any conflict should be small. #727 (outline) edits Tag/Td.php and Mpdf.php around cell painting. #721 and #710 touch Tag/Td.php and _tableWrite() elsewhere.

🤖 Generated with Claude Code