tiny.filigree.ClusterMap

1pub const ClusterMap = struct {2    run: GlyphRun,34    pub fn byteOffsetToCluster(self: ClusterMap, byte_offset: usize) ?usize {5        if (byte_offset > std.math.maxInt(u32)) return null;6        const offset: u32 = @intCast(byte_offset);7        for (self.run.clusters, 0..) |cluster, i| {8            if (offset >= cluster.source.start and offset < cluster.source.end) return i;9        }10        return null;11    }1213    pub fn clusterSourceRange(self: ClusterMap, cluster_index: usize) ?SourceRange {14        if (cluster_index >= self.run.clusters.len) return null;15        return self.run.clusters[cluster_index].source;16    }1718    pub fn clusterGlyphSpan(self: ClusterMap, cluster_index: usize) ?GlyphSpan {19        if (cluster_index >= self.run.clusters.len) return null;20        return self.run.clusters[cluster_index].glyphs;21    }2223    pub fn glyphToCluster(self: ClusterMap, glyph_index: usize) ?usize {24        if (glyph_index >= self.run.glyphs.len) return null;25        return self.run.glyphs[glyph_index].cluster_index;26    }2728    pub fn clusterCaretStopCount(self: ClusterMap, cluster_index: usize) ?usize {29        if (cluster_index >= self.run.clusters.len) return null;30        return 2 + (self.clusterLigatureCaretCount(cluster_index) orelse return null);31    }3233    pub fn clusterCaretStop(self: ClusterMap, cluster_index: usize, caret_index: usize) ?u32 {34        if (cluster_index >= self.run.clusters.len) return null;35        const stop_count = self.clusterCaretStopCount(cluster_index) orelse return null;36        if (caret_index >= stop_count) return null;37        const source = self.run.clusters[cluster_index].source;38        if (caret_index == 0) return source.start;39        if (caret_index + 1 == stop_count) return source.end;40        const source_len = source.end - source.start;41        const interior_count = stop_count - 2;42        if (source_len == 0 or interior_count == 0) return null;43        const relative = (@as(u64, caret_index) * @as(u64, source_len)) / @as(u64, interior_count + 1);44        return source.start + @as(u32, @intCast(relative));45    }4647    pub fn clusterLigatureCaretCount(self: ClusterMap, cluster_index: usize) ?usize {48        if (cluster_index >= self.run.clusters.len) return null;49        const glyph = self.clusterSingleLigatureGlyph(cluster_index) orelse return 0;50        return glyph.ligature_caret_count;51    }5253    pub fn clusterLigatureCaret(self: ClusterMap, cluster_index: usize, caret_index: usize) ?LigatureCaret {54        if (cluster_index >= self.run.clusters.len) return null;55        const glyph = self.clusterSingleLigatureGlyph(cluster_index) orelse return null;56        if (caret_index >= glyph.ligature_caret_count) return null;57        return self.run.ligature_carets[@as(usize, @intCast(glyph.ligature_caret_start)) + caret_index];58    }5960    pub fn selectableAsUnitOnly(self: ClusterMap, cluster_index: usize) ?bool {61        if (cluster_index >= self.run.clusters.len) return null;62        const cluster = self.run.clusters[cluster_index];63        return cluster.codepoint_count > 1 or cluster.glyphs.end - cluster.glyphs.start > 1;64    }6566    pub fn breakRequiresReshaping(self: ClusterMap, cluster_index: usize) ?bool {67        if (cluster_index >= self.run.clusters.len) return null;68        return self.run.clusters[cluster_index].flags.unsafe_to_break;69    }7071    fn clusterSingleLigatureGlyph(self: ClusterMap, cluster_index: usize) ?ShapedGlyph {72        const cluster = self.run.clusters[cluster_index];73        if (cluster.glyphs.end <= cluster.glyphs.start) return null;74        if (cluster.glyphs.end - cluster.glyphs.start != 1) return null;75        const glyph_index: usize = @intCast(cluster.glyphs.start);76        if (glyph_index >= self.run.glyphs.len) return null;77        const glyph = self.run.glyphs[glyph_index];78        if (glyph.glyph_class != .ligature or glyph.ligature_caret_count == 0) return null;79        const caret_start: usize = @intCast(glyph.ligature_caret_start);80        const caret_count: usize = glyph.ligature_caret_count;81        if (caret_start > self.run.ligature_carets.len) return null;82        if (caret_count > self.run.ligature_carets.len - caret_start) return null;83        return glyph;84    }85};

1pub const ClusterMap = shape.ClusterMap;