LibWeb: Bring CSS line-height closer to other engines

This patch makes a few changes to the way we calculate line-height: - `line-height: normal` is now resolved using metrics from the used font (specifically, round(A + D + lineGap)). - `line-height: calc(...)` is now resolved at style compute time. - `line-height` values are now absolutized at style compute time. As a consequence of the above, we no longer need to walk the DOM ancestor chain looking for line-heights during style computation. Instead, values are inherited, resolved and absolutized locally. This is not only much faster, but also makes our line-height metrics match those of other engines like Gecko and Blink.
2025-07-28 04:57:45 +00:00 · 2024-01-12 12:39:40 +01:00 · 2024-01-12 12:39:40 +01:00 · e7de5cb4d2
commit e7de5cb4d2
parent f0722671c3
385 changed files with 6889 additions and 6893 deletions
--- a/Tests/LibWeb/Layout/expected/flex/align-keywords-start-and-end.txt
+++ b/Tests/LibWeb/Layout/expected/flex/align-keywords-start-and-end.txt
@ -1,49 +1,49 @@
 Viewport <#document> at (0,0) content-size 800x600 children: not-inline
-  BlockContainer <html> at (1,1) content-size 798x284.40625 [BFC] children: not-inline
-    BlockContainer <body> at (10,10) content-size 780x266.40625 children: not-inline
+  BlockContainer <html> at (1,1) content-size 798x283 [BFC] children: not-inline
+    BlockContainer <body> at (10,10) content-size 780x265 children: not-inline
      Box <div.flex.row.align-start> at (11,11) content-size 500x200 flex-container(row) [FFC] children: not-inline
-        BlockContainer <div> at (12,12) content-size 136.5x17.46875 flex-item [BFC] children: inline
-          line 0 width: 136.5, height: 17.46875, bottom: 17.46875, baseline: 13.53125
-            frag 0 from TextNode start: 0, length: 18, rect: [12,12 136.5x17.46875]
+        BlockContainer <div> at (12,12) content-size 136.5x17 flex-item [BFC] children: inline
+          line 0 width: 136.5, height: 17, bottom: 17, baseline: 13.296875
+            frag 0 from TextNode start: 0, length: 18, rect: [12,12 136.5x17]
              "align-items: start"
          TextNode <#text>
-      Box <div.flex.align-end> at (11,213) content-size 500x19.46875 flex-container(row) [FFC] children: not-inline
-        BlockContainer <div> at (12,214) content-size 121.453125x17.46875 flex-item [BFC] children: inline
-          line 0 width: 121.453125, height: 17.46875, bottom: 17.46875, baseline: 13.53125
-            frag 0 from TextNode start: 0, length: 16, rect: [12,214 121.453125x17.46875]
+      Box <div.flex.align-end> at (11,213) content-size 500x19 flex-container(row) [FFC] children: not-inline
+        BlockContainer <div> at (12,214) content-size 121.453125x17 flex-item [BFC] children: inline
+          line 0 width: 121.453125, height: 17, bottom: 17, baseline: 13.296875
+            frag 0 from TextNode start: 0, length: 16, rect: [12,214 121.453125x17]
              "align-items: end"
          TextNode <#text>
-      BlockContainer <(anonymous)> at (10,233.46875) content-size 780x0 children: inline
+      BlockContainer <(anonymous)> at (10,233) content-size 780x0 children: inline
        TextNode <#text>
-      Box <div.flex.align-start> at (11,234.46875) content-size 500x19.46875 flex-container(row) [FFC] children: not-inline
-        BlockContainer <div> at (12,235.46875) content-size 136.5x17.46875 flex-item [BFC] children: inline
-          line 0 width: 136.5, height: 17.46875, bottom: 17.46875, baseline: 13.53125
-            frag 0 from TextNode start: 0, length: 18, rect: [12,235.46875 136.5x17.46875]
+      Box <div.flex.align-start> at (11,234) content-size 500x19 flex-container(row) [FFC] children: not-inline
+        BlockContainer <div> at (12,235) content-size 136.5x17 flex-item [BFC] children: inline
+          line 0 width: 136.5, height: 17, bottom: 17, baseline: 13.296875
+            frag 0 from TextNode start: 0, length: 18, rect: [12,235 136.5x17]
              "align-items: start"
          TextNode <#text>
-      Box <div.flex.column.align-end> at (11,255.9375) content-size 500x19.46875 flex-container(column) [FFC] children: not-inline
-        BlockContainer <div> at (388.546875,256.9375) content-size 121.453125x17.46875 flex-item [BFC] children: inline
-          line 0 width: 121.453125, height: 17.46875, bottom: 17.46875, baseline: 13.53125
-            frag 0 from TextNode start: 0, length: 16, rect: [388.546875,256.9375 121.453125x17.46875]
+      Box <div.flex.column.align-end> at (11,255) content-size 500x19 flex-container(column) [FFC] children: not-inline
+        BlockContainer <div> at (388.546875,256) content-size 121.453125x17 flex-item [BFC] children: inline
+          line 0 width: 121.453125, height: 17, bottom: 17, baseline: 13.296875
+            frag 0 from TextNode start: 0, length: 16, rect: [388.546875,256 121.453125x17]
              "align-items: end"
          TextNode <#text>
-      BlockContainer <(anonymous)> at (10,276.40625) content-size 780x0 children: inline
+      BlockContainer <(anonymous)> at (10,275) content-size 780x0 children: inline
        TextNode <#text>

 ViewportPaintable (Viewport<#document>) [0,0 800x600]
-  PaintableWithLines (BlockContainer<HTML>) [0,0 800x286.40625]
-    PaintableWithLines (BlockContainer<BODY>) [9,9 782x268.40625]
+  PaintableWithLines (BlockContainer<HTML>) [0,0 800x285]
+    PaintableWithLines (BlockContainer<BODY>) [9,9 782x267]
      PaintableBox (Box<DIV>.flex.row.align-start) [10,10 502x202]
-        PaintableWithLines (BlockContainer<DIV>) [11,11 138.5x19.46875]
+        PaintableWithLines (BlockContainer<DIV>) [11,11 138.5x19]
          TextPaintable (TextNode<#text>)
-      PaintableBox (Box<DIV>.flex.align-end) [10,212 502x21.46875]
-        PaintableWithLines (BlockContainer<DIV>) [11,213 123.453125x19.46875]
+      PaintableBox (Box<DIV>.flex.align-end) [10,212 502x21]
+        PaintableWithLines (BlockContainer<DIV>) [11,213 123.453125x19]
          TextPaintable (TextNode<#text>)
-      PaintableWithLines (BlockContainer(anonymous)) [10,233.46875 780x0]
-      PaintableBox (Box<DIV>.flex.align-start) [10,233.46875 502x21.46875]
-        PaintableWithLines (BlockContainer<DIV>) [11,234.46875 138.5x19.46875]
+      PaintableWithLines (BlockContainer(anonymous)) [10,233 780x0]
+      PaintableBox (Box<DIV>.flex.align-start) [10,233 502x21]
+        PaintableWithLines (BlockContainer<DIV>) [11,234 138.5x19]
          TextPaintable (TextNode<#text>)
-      PaintableBox (Box<DIV>.flex.column.align-end) [10,254.9375 502x21.46875]
-        PaintableWithLines (BlockContainer<DIV>) [387.546875,255.9375 123.453125x19.46875]
+      PaintableBox (Box<DIV>.flex.column.align-end) [10,254 502x21]
+        PaintableWithLines (BlockContainer<DIV>) [387.546875,255 123.453125x19]
          TextPaintable (TextNode<#text>)
-      PaintableWithLines (BlockContainer(anonymous)) [10,276.40625 780x0]
+      PaintableWithLines (BlockContainer(anonymous)) [10,275 780x0]