[Emacs-diffs] emacs-24 aa472a3: Fix the pixel coordinates returned by pos-visible-in-window-p. (Bug#19473)

[Eli Zaretskii]

branch: emacs-24
commit aa472a377134b7840fd7b9c97f948fb9440e6e9d
Author: Eli Zaretskii <address@hidden>
Commit: Eli Zaretskii <address@hidden>

    Fix the pixel coordinates returned by pos-visible-in-window-p.  (Bug#19473)
    
     src/xdisp.c (pos_visible_p): Fix up the X coordinate for
     right-to-left screen lines.
---
 src/ChangeLog |    5 +++++
 src/xdisp.c   |   23 +++++++++++++++++++----
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/ChangeLog b/src/ChangeLog
index 94f07c8..21303f2 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2014-12-30  Eli Zaretskii  <address@hidden>
+
+       * xdisp.c (pos_visible_p): Fix up the X coordinate for
+       right-to-left screen lines.  (Bug#19473)
+
 2014-12-28  Eli Zaretskii  <address@hidden>
 
        * w32proc.c (Fw32_get_codepage_charset): Doc fix.  (Bug#19458)
diff --git a/src/xdisp.c b/src/xdisp.c
index 173df5d..f0a851a 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -1403,6 +1403,7 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int 
*x, int *y,
   struct text_pos top;
   int visible_p = 0;
   struct buffer *old_buffer = NULL;
+  bool r2l = false;
 
   if (FRAME_INITIAL_P (XFRAME (WINDOW_FRAME (w))))
     return visible_p;
@@ -1688,6 +1689,8 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int 
*x, int *y,
          *rowh = max (0, (min (bottom_y, it.last_visible_y)
                           - max (top_y, window_top_y)));
          *vpos = it.vpos;
+         if (it.bidi_it.paragraph_dir == R2L)
+           r2l = true;
        }
     }
   else
@@ -1717,6 +1720,8 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int 
*x, int *y,
                           - max (it2.current_y,
                                  WINDOW_HEADER_LINE_HEIGHT (w))));
          *vpos = it2.vpos;
+         if (it2.bidi_it.paragraph_dir == R2L)
+           r2l = true;
        }
       else
        bidi_unshelve_cache (it2data, 1);
@@ -1726,10 +1731,20 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int 
*x, int *y,
   if (old_buffer)
     set_buffer_internal_1 (old_buffer);
 
-  if (visible_p && w->hscroll > 0)
-    *x -=
-      window_hscroll_limited (w, WINDOW_XFRAME (w))
-      * WINDOW_FRAME_COLUMN_WIDTH (w);
+  if (visible_p)
+    {
+      if (w->hscroll > 0)
+       *x -=
+         window_hscroll_limited (w, WINDOW_XFRAME (w))
+         * WINDOW_FRAME_COLUMN_WIDTH (w);
+      /* For lines in an R2L paragraph, we need to mirror the X pixel
+         coordinate wrt the text area.  For the reasons, see the
+         commentary in buffer_posn_from_coords and the explanation of
+         the geometry used by the move_it_* functions at the end of
+         the large commentart near the beginning of this file.  */
+      if (r2l)
+       *x = window_box_width (w, TEXT_AREA) - *x - 1;
+    }
 
 #if 0
   /* Debugging code.  */