diff options
Diffstat (limited to 'gfx/harfbuzz/src/hb-repacker.hh')
| -rw-r--r-- | gfx/harfbuzz/src/hb-repacker.hh | 52 |
1 files changed, 50 insertions, 2 deletions
diff --git a/gfx/harfbuzz/src/hb-repacker.hh b/gfx/harfbuzz/src/hb-repacker.hh index e9cd376ad3..ed40f271cc 100644 --- a/gfx/harfbuzz/src/hb-repacker.hh +++ b/gfx/harfbuzz/src/hb-repacker.hh @@ -239,6 +239,54 @@ bool _try_isolating_subgraphs (const hb_vector_t<graph::overflow_record_t>& over } static inline +bool _resolve_shared_overflow(const hb_vector_t<graph::overflow_record_t>& overflows, + int overflow_index, + graph_t& sorted_graph) +{ + const graph::overflow_record_t& r = overflows[overflow_index]; + + // Find all of the parents in overflowing links that link to this + // same child node. We will then try duplicating the child node and + // re-assigning all of these parents to the duplicate. + hb_set_t parents; + parents.add(r.parent); + for (int i = overflow_index - 1; i >= 0; i--) { + const graph::overflow_record_t& r2 = overflows[i]; + if (r2.child == r.child) { + parents.add(r2.parent); + } + } + + unsigned result = sorted_graph.duplicate(&parents, r.child); + if (result == (unsigned) -1 && parents.get_population() > 2) { + // All links to the child are overflowing, so we can't include all + // in the duplication. Remove one parent from the duplication. + // Remove the lowest index parent, which will be the closest to the child. + parents.del(parents.get_min()); + result = sorted_graph.duplicate(&parents, r.child); + } + + if (result == (unsigned) -1) return result; + + if (parents.get_population() > 1) { + // If the duplicated node has more than one parent pre-emptively raise it's priority to the maximum. + // This will place it close to the parents. Node's with only one parent, don't need this as normal overflow + // resolution will raise priority if needed. + // + // Reasoning: most of the parents to this child are likely at the same layer in the graph. Duplicating + // the child will theoretically allow it to be placed closer to it's parents. However, due to the shortest + // distance sort by default it's placement will remain in the same layer, thus it will remain in roughly the + // same position (and distance from parents) as the original child node. The overflow resolution will attempt + // to move nodes closer, but only for non-shared nodes. Since this node is shared, it will simply be given + // further duplication which defeats the attempt to duplicate with multiple parents. To fix this we + // pre-emptively raise priority now which allows the duplicated node to pack into the same layer as it's parents. + sorted_graph.vertices_[result].give_max_priority(); + } + + return result; +} + +static inline bool _process_overflows (const hb_vector_t<graph::overflow_record_t>& overflows, hb_set_t& priority_bumped_parents, graph_t& sorted_graph) @@ -254,7 +302,7 @@ bool _process_overflows (const hb_vector_t<graph::overflow_record_t>& overflows, { // The child object is shared, we may be able to eliminate the overflow // by duplicating it. - if (sorted_graph.duplicate (r.parent, r.child) == (unsigned) -1) continue; + if (!_resolve_shared_overflow(overflows, i, sorted_graph)) continue; return true; } @@ -388,7 +436,7 @@ template<typename T> inline hb_blob_t* hb_resolve_overflows (const T& packed, hb_tag_t table_tag, - unsigned max_rounds = 20, + unsigned max_rounds = 32, bool recalculate_extensions = false) { graph_t sorted_graph (packed); if (sorted_graph.in_error ()) |