From 828b049e2d00b5da83a36ecfc92832a7cf99e220 Mon Sep 17 00:00:00 2001
From: Matthias Clasen <mclasen@redhat.com>
Date: Mon, 2 Aug 2021 01:47:07 -0400
Subject: itemize: Ignore width in horizontal context

Changes in width only need to break runs in
vertical context. Implementing this requires
some reorganization, since we need to compute
the resolved gravity for the next run before
determining the end of the run.

Fixes: #503
---
 pango/pango-context.c | 76 ++++++++++++++++++++++++++++-----------------------
 1 file changed, 42 insertions(+), 34 deletions(-)

diff --git a/pango/pango-context.c b/pango/pango-context.c
index 4f15dd61..67505d9d 100644
--- a/pango/pango-context.c
+++ b/pango/pango-context.c
@@ -872,8 +872,11 @@ update_end (ItemizeState *state)
     state->run_end = state->attr_end;
   if (state->script_end < state->run_end)
     state->run_end = state->script_end;
-  if (state->width_iter.end < state->run_end)
-    state->run_end = state->width_iter.end;
+  if (PANGO_GRAVITY_IS_VERTICAL (state->resolved_gravity))
+    {
+      if (state->width_iter.end < state->run_end)
+        state->run_end = state->width_iter.end;
+    }
   if (state->emoji_iter.end < state->run_end)
     state->run_end = state->emoji_iter.end;
 }
@@ -1000,6 +1003,38 @@ width_iter_fini (PangoWidthIter* iter)
 {
 }
 
+static void
+itemize_state_update_resolved_gravity (ItemizeState *state)
+{
+  if (state->changed & (FONT_CHANGED | SCRIPT_CHANGED | WIDTH_CHANGED))
+    {
+      /* Font-desc gravity overrides everything */
+      if (state->font_desc_gravity != PANGO_GRAVITY_AUTO)
+        {
+          state->resolved_gravity = state->font_desc_gravity;
+        }
+      else
+        {
+          PangoGravity gravity = state->gravity;
+          PangoGravityHint gravity_hint = state->gravity_hint;
+
+          if (G_LIKELY (gravity == PANGO_GRAVITY_AUTO))
+            gravity = state->context->resolved_gravity;
+
+          state->resolved_gravity = pango_gravity_get_for_script_and_width (state->script,
+                                                                            state->width_iter.upright,
+                                                                            gravity,
+                                                                            gravity_hint);
+        }
+
+      if (state->font_desc_gravity != state->resolved_gravity)
+        {
+          pango_font_description_set_gravity (state->font_desc, state->resolved_gravity);
+          state->changed |= FONT_CHANGED;
+        }
+    }
+}
+
 static void
 itemize_state_init (ItemizeState               *state,
                     PangoContext               *context,
@@ -1086,13 +1121,14 @@ itemize_state_init (ItemizeState               *state,
   if (state->emoji_iter.is_emoji)
     state->width_iter.end = MAX (state->width_iter.end, state->emoji_iter.end);
 
-  update_end (state);
-
   if (pango_font_description_get_set_fields (state->font_desc) & PANGO_FONT_MASK_GRAVITY)
     state->font_desc_gravity = pango_font_description_get_gravity (state->font_desc);
   else
     state->font_desc_gravity = PANGO_GRAVITY_AUTO;
 
+  itemize_state_update_resolved_gravity (state);
+  update_end (state);
+
   state->derived_lang = NULL;
   state->current_fonts = NULL;
   state->cache = NULL;
@@ -1143,6 +1179,8 @@ itemize_state_next (ItemizeState *state)
       state->changed |= WIDTH_CHANGED;
     }
 
+  /* Update resolved gravity before updating end */
+  itemize_state_update_resolved_gravity (state);
   update_end (state);
 
   return TRUE;
@@ -1404,36 +1442,6 @@ compute_derived_language (PangoLanguage *lang,
 static void
 itemize_state_update_for_new_run (ItemizeState *state)
 {
-  /* This block should be moved to update_attr_iterator, but I'm too lazy to
-   * do it right now */
-  if (state->changed & (FONT_CHANGED | SCRIPT_CHANGED | WIDTH_CHANGED))
-    {
-      /* Font-desc gravity overrides everything */
-      if (state->font_desc_gravity != PANGO_GRAVITY_AUTO)
-        {
-          state->resolved_gravity = state->font_desc_gravity;
-        }
-      else
-        {
-          PangoGravity gravity = state->gravity;
-          PangoGravityHint gravity_hint = state->gravity_hint;
-
-          if (G_LIKELY (gravity == PANGO_GRAVITY_AUTO))
-            gravity = state->context->resolved_gravity;
-
-          state->resolved_gravity = pango_gravity_get_for_script_and_width (state->script,
-                                                                            state->width_iter.upright,
-                                                                            gravity,
-                                                                            gravity_hint);
-        }
-
-      if (state->font_desc_gravity != state->resolved_gravity)
-        {
-          pango_font_description_set_gravity (state->font_desc, state->resolved_gravity);
-          state->changed |= FONT_CHANGED;
-        }
-    }
-
   if (state->changed & (SCRIPT_CHANGED | LANG_CHANGED))
     {
       PangoLanguage *old_derived_lang = state->derived_lang;
-- 
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