Ignore embedding level when collapsing a single line

Author: thomasp85

NEWS.md

@@ -1,5 +1,8 @@
 # textshaping (development version)
 
+* Fixed a bug in bidi embedding arrangement when shaping a single line
+  (ggplot2#6497)
+
 # textshaping 1.0.1
 
 * Fixed a bug where hard line breaks where ignored if the line consisted of

src/string_shape.cpp

@@ -588,9 +588,9 @@ EmbedInfo HarfBuzzShaper::shape_single_line(const char* string, FontSettings& fo
 
   rearrange_embeddings(final_embeddings);
 
-  // Combined all embeddings into one
+  // Combine all embeddings into one
   for (auto iter = std::next(final_embeddings.begin()); iter != final_embeddings.end(); ++iter) {
-    final_embeddings.front().add(*iter);
+    final_embeddings.front().add(*iter, false);
   }
   return final_embeddings.front();
 }

src/string_shape.h

@@ -79,11 +79,11 @@ struct EmbedInfo {
   size_t embedding_level;
   int32_t full_width;
   bool terminates_paragraph;
-  void add(const EmbedInfo& other) {
-    if (embedding_level != other.embedding_level) {
+  void add(const EmbedInfo& other, bool check = true) {
+    if (check && embedding_level != other.embedding_level) {
       cpp11::stop("Unable to merge embeddings of different levels");
     }
-    if (terminates_paragraph) {
+    if (check && terminates_paragraph) {
       cpp11::stop("Can't combine embeddings past termination point");
     }
     glyph_id.insert(glyph_id.end(), other.glyph_id.begin(), other.glyph_id.end());