Skip to content

Allow null AnchorTable #482

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
JimBobSquarePants merged 1 commit into from
Nov 26, 2025
Merged

Allow null AnchorTable #482

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 9 additions & 1 deletion src/SixLabors.Fonts/Tables/AdvancedTypographic/AdvancedTypographicUtils.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -249,11 +249,19 @@ public static void ApplyAnchor(
FontMetrics fontMetrics,
GlyphPositioningCollection collection,
int index,
AnchorTable baseAnchor,
AnchorTable? baseAnchor,
MarkRecord markRecord,
int baseGlyphIndex,
Tag feature)
{
// baseAnchor may be null because OpenType MarkToBase allows NULL anchor offsets
// in BaseArray/BaseRecord. A NULL offset means "this base glyph has no anchor
// for this mark class", and the lookup must be ignored for this mark–base pair.
if (baseAnchor is null)
{
return;
}

GlyphShapingData baseData = collection[baseGlyphIndex];
AnchorXY baseXY = baseAnchor.GetAnchor(fontMetrics, baseData, collection);

Expand Down
10 changes: 5 additions & 5 deletions src/SixLabors.Fonts/Tables/AdvancedTypographic/GPos/LookupType4SubTable.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -71,10 +71,10 @@ public static LookupType4Format1SubTable Load(BigEndianBinaryReader reader, long
ushort markArrayOffset = reader.ReadOffset16();
ushort baseArrayOffset = reader.ReadOffset16();

var markCoverage = CoverageTable.Load(reader, offset + markCoverageOffset);
var baseCoverage = CoverageTable.Load(reader, offset + baseCoverageOffset);
var markArrayTable = new MarkArrayTable(reader, offset + markArrayOffset);
var baseArrayTable = new BaseArrayTable(reader, offset + baseArrayOffset, markClassCount);
CoverageTable markCoverage = CoverageTable.Load(reader, offset + markCoverageOffset);
CoverageTable baseCoverage = CoverageTable.Load(reader, offset + baseCoverageOffset);
MarkArrayTable markArrayTable = new(reader, offset + markArrayOffset);
BaseArrayTable baseArrayTable = new(reader, offset + baseArrayOffset, markClassCount);

return new LookupType4Format1SubTable(markCoverage, baseCoverage, markArrayTable, baseArrayTable, lookupFlags);
}
Expand Down Expand Up @@ -106,7 +106,7 @@ public override bool TryUpdatePosition(
while (--baseGlyphIndex >= 0)
{
GlyphShapingData data = collection[baseGlyphIndex];
if (!AdvancedTypographicUtils.IsMarkGlyph(fontMetrics, data.GlyphId, data) && !(data.LigatureComponent > 0))
if (!AdvancedTypographicUtils.IsMarkGlyph(fontMetrics, data.GlyphId, data) && data.LigatureComponent <= 0)
{
break;
}
Expand Down
Loading