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A descendant can remove a text decoration it should only add to, because text-decoration is inherited instead of propagated #544
Description
Part of #520 (step 23). Changes existing output: needs a decision.
In CSS, text-decoration is not inherited. An ancestor's decoration propagates to its in-flow descendants and is drawn over their text whatever they set, and text-decoration: none on a descendant removes only the descendant's own. Decorations do not propagate into floats, positioned blocks, inline blocks or tables.
mPDF carries text-decoration as an inherited property (InlinePropertyConverter, whose comment notes CSS does not inherit it). Measured on gravitypdf at d660a410, PHP 8.5.4.
| Rules | Element | Browser | mPDF |
|---|---|---|---|
div{text-decoration:underline} |
<div><p> |
underlined | underlined |
div{text-decoration:underline} p{text-decoration:none} |
<div><p> |
underlined | not underlined |
div{text-decoration:underline} |
<div><table><tr><td> |
not underlined | not underlined |
vertical-align (super, sub) is carried to child blocks the same way, and CSS does not inherit it either.
Fix. Keep the decorations an element propagates as a set of their own, drawn over its descendants' text, and stop carrying text-decoration and vertical-align as inherited properties. This changes output where a document relies on text-decoration: none inside an underlined parent.
Tests. The rows above, a positioned block and a float inside an underlined block, and decorations from two ancestors combining.
Activity