master d98afc1: Fix display of :box face when overlay strings are around

[Eli Zaretskii]

branch: master
commit d98afc1019d9f177dd05042371dd8239b7901d47
Author: Eli Zaretskii <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    Fix display of :box face when overlay strings are around
    
    * src/xdisp.c (reset_box_start_end_flags): New function.
    (handle_face_prop): Only set the start_of_box_run_p flag, don't
    reset it.
    (pop_it): Set the face_box_p flag, if the popped face requires
    that, when continuing iteration over buffer text.
    (get_next_display_element, next_element_from_display_vector): Only
    set the end_of_box_run_p flag, never reset it here.
    (set_iterator_to_next): Don't reset the start_of_box_run_p and
    end_of_box_run_p flags here.  They are now reset as side effect of
    PRODUCE_GLYPHS.
    (append_space_for_newline): Restore the end_of_box_run_p flag
    after PRODUCE_GLYPHS where we previously didn't reset it.
    * src/dispextern.h (PRODUCE_GLYPHS): Call
    reset_box_start_end_flags after producing glyphs.
    (Bug#40124)
---
 src/dispextern.h |  3 +-
 src/xdisp.c      | 93 +++++++++++++++++++++++++++++++++++++++-----------------
 2 files changed, 67 insertions(+), 29 deletions(-)

diff --git a/src/dispextern.h b/src/dispextern.h
index 724aad4..08380f1 100644
--- a/src/dispextern.h
+++ b/src/dispextern.h
@@ -2782,7 +2782,8 @@ struct it
     else                                                \
       produce_glyphs ((IT));                            \
     if ((IT)->glyph_row != NULL)                        \
-      inhibit_free_realized_faces = true;              \
+      inhibit_free_realized_faces =true;               \
+    reset_box_start_end_flags ((IT));                  \
   } while (false)
 
 /* Bit-flags indicating what operation move_it_to should perform.  */
diff --git a/src/xdisp.c b/src/xdisp.c
index 3c594b5..04fc8aa 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -1020,6 +1020,7 @@ static Lisp_Object calc_line_height_property (struct it 
*, Lisp_Object,
 static void produce_special_glyphs (struct it *, enum display_element_type);
 static void show_mouse_face (Mouse_HLInfo *, enum draw_glyphs_face);
 static bool coords_in_mouse_face_p (struct window *, int, int);
+static void reset_box_start_end_flags (struct it *);
 
 
 
@@ -1435,6 +1436,29 @@ window_hscroll_limited (struct window *w, struct frame 
*f)
   return window_hscroll;
 }
 
+/* Reset the box-face start and end flags in the iterator.  This is
+   called after producing glyphs, such that we reset these flags only
+   after producing a glyph with the flag set.  */
+
+static void
+reset_box_start_end_flags (struct it *it)
+{
+  /* Don't reset if we've drawn the glyph in the display margins --
+     those don't count as "produced glyphs".  */
+  if (it->area == TEXT_AREA
+      /* Don't reset if we displayed a fringe bitmap.  */
+      && !(it->what == IT_IMAGE && it->image_id < 0))
+    {
+      /* Don't reset if the face is not a box face: that might mean we
+        are iterating some overlay or display string, and the first
+        character to have the box face is yet to be seen, when we pop
+        the iterator stack. */
+      if (it->face_box_p)
+       it->start_of_box_run_p = false;
+      it->end_of_box_run_p = false;
+    }
+}
+
 /* Return true if position CHARPOS is visible in window W.
    CHARPOS < 0 means return info about WINDOW_END position.
    If visible, set *X and *Y to pixel coordinates of top left corner.
@@ -4315,8 +4339,11 @@ handle_face_prop (struct it *it)
         this is the start of a run of characters with box face,
         i.e. this character has a shadow on the left side.  */
       it->face_id = new_face_id;
-      it->start_of_box_run_p = (new_face->box != FACE_NO_BOX
-                                && (old_face == NULL || !old_face->box));
+      /* Don't reset the start_of_box_run_p flag, only set it if
+        needed.  */
+      if (!(it->start_of_box_run_p && old_face && old_face->box))
+       it->start_of_box_run_p = (new_face->box != FACE_NO_BOX
+                                 && (old_face == NULL || !old_face->box));
       it->face_box_p = new_face->box != FACE_NO_BOX;
     }
 
@@ -6457,7 +6484,16 @@ pop_it (struct it *it)
       it->object = p->u.stretch.object;
       break;
     case GET_FROM_BUFFER:
-      it->object = it->w->contents;
+      {
+       struct face *face = FACE_FROM_ID_OR_NULL (it->f, it->face_id);
+
+       /* Restore the face_box_p flag, since it could have been
+          overwritten by the face of the object that we just finished
+          displaying.  */
+       if (face)
+         it->face_box_p = face->box != FACE_NO_BOX;
+       it->object = it->w->contents;
+      }
       break;
     case GET_FROM_STRING:
       {
@@ -7586,9 +7622,8 @@ get_next_display_element (struct it *it)
                  /* If the box comes from face properties in a
                     display string, check faces in that string.  */
                  int string_face_id = face_after_it_pos (it);
-                 it->end_of_box_run_p
-                   = (FACE_FROM_ID (it->f, string_face_id)->box
-                      == FACE_NO_BOX);
+                 if (FACE_FROM_ID (it->f, string_face_id)->box == FACE_NO_BOX)
+                   it->end_of_box_run_p = true;
                }
              /* Otherwise, the box comes from the underlying face.
                 If this is the last string character displayed, check
@@ -7657,9 +7692,9 @@ get_next_display_element (struct it *it)
                                                       CHARPOS (pos), 0,
                                                       &ignore, face_id,
                                                       false, 0);
-                         it->end_of_box_run_p
-                           = (FACE_FROM_ID (it->f, next_face_id)->box
-                              == FACE_NO_BOX);
+                         if (FACE_FROM_ID (it->f, next_face_id)->box
+                             == FACE_NO_BOX)
+                           it->end_of_box_run_p = true;
                        }
                    }
                  else if (CHARPOS (pos) >= ZV)
@@ -7672,9 +7707,9 @@ get_next_display_element (struct it *it)
                                                 CHARPOS (pos)
                                                 + TEXT_PROP_DISTANCE_LIMIT,
                                                 false, -1, 0);
-                     it->end_of_box_run_p
-                       = (FACE_FROM_ID (it->f, next_face_id)->box
-                          == FACE_NO_BOX);
+                     if (FACE_FROM_ID (it->f, next_face_id)->box
+                         == FACE_NO_BOX)
+                       it->end_of_box_run_p = true;
                    }
                }
            }
@@ -7684,9 +7719,9 @@ get_next_display_element (struct it *it)
       else if (it->method != GET_FROM_DISPLAY_VECTOR)
        {
          int face_id = face_after_it_pos (it);
-         it->end_of_box_run_p
-           = (face_id != it->face_id
-              && FACE_FROM_ID (it->f, face_id)->box == FACE_NO_BOX);
+         if (face_id != it->face_id
+             && FACE_FROM_ID (it->f, face_id)->box == FACE_NO_BOX)
+           it->end_of_box_run_p = true;
        }
     }
   /* If we reached the end of the object we've been iterating (e.g., a
@@ -7723,10 +7758,6 @@ get_next_display_element (struct it *it)
 void
 set_iterator_to_next (struct it *it, bool reseat_p)
 {
-  /* Reset flags indicating start and end of a sequence of characters
-     with box.  Reset them at the start of this function because
-     moving the iterator to a new position might set them.  */
-  it->start_of_box_run_p = it->end_of_box_run_p = false;
 
   switch (it->method)
     {
@@ -8138,9 +8169,9 @@ next_element_from_display_vector (struct it *it)
            }
        }
       next_face = FACE_FROM_ID_OR_NULL (it->f, next_face_id);
-      it->end_of_box_run_p = (this_face && this_face->box != FACE_NO_BOX
-                             && (!next_face
-                                 || next_face->box == FACE_NO_BOX));
+      if (this_face && this_face->box != FACE_NO_BOX
+         && (!next_face || next_face->box == FACE_NO_BOX))
+       it->end_of_box_run_p = true;
       it->face_box_p = this_face && this_face->box != FACE_NO_BOX;
     }
   else
@@ -21485,6 +21516,8 @@ append_space_for_newline (struct it *it, bool 
default_face_p)
 
       const int indicator_column =
        fill_column_indicator_column (it, char_width);
+      int saved_end_of_box_run = it->end_of_box_run_p;
+      bool should_keep_end_of_box_run = false;
 
       if (it->current_x == indicator_column)
        {
@@ -21507,14 +21540,18 @@ append_space_for_newline (struct it *it, bool 
default_face_p)
             have the end_of_box_run_p flag set for it, so there's no
             need for the appended newline glyph to have that flag
             set.  */
-         if (it->glyph_row->reversed_p
-             /* But if the appended newline glyph goes all the way to
-                the end of the row, there will be no stretch glyph,
-                so leave the box flag set.  */
-             && saved_x + FRAME_COLUMN_WIDTH (it->f) < it->last_visible_x)
-           it->end_of_box_run_p = false;
+         if (!(it->glyph_row->reversed_p
+               /* But if the appended newline glyph goes all the way to
+                  the end of the row, there will be no stretch glyph,
+                  so leave the box flag set.  */
+               && saved_x + FRAME_COLUMN_WIDTH (it->f) < it->last_visible_x))
+           should_keep_end_of_box_run = true;
        }
       PRODUCE_GLYPHS (it);
+      /* Restore the end_of_box_run_p flag which was reset by
+        PRODUCE_GLYPHS.  */
+      if (should_keep_end_of_box_run)
+       it->end_of_box_run_p = saved_end_of_box_run;
 #ifdef HAVE_WINDOW_SYSTEM
       if (FRAME_WINDOW_P (it->f))
        {