(glyph_rect): Determine the row and glyph more precisely.

1 files changed, 28 insertions, 11 deletions

diff --git a/src/w32term.c b/src/w32term.c
index 3c0e7c7deae..89b591cb0f3 100644
--- a/src/w32term.c
+++ b/src/w32term.c
@@ -7609,7 +7609,7 @@ glyph_rect (f, x, y, rect)
      RECT *rect;
 {
   Lisp_Object window;
-  int part, found = 0;
+  int part;
 
   window = window_from_coordinates (f, x, y, &part, 0);
   if (!NILP (window))
@@ -7619,27 +7619,44 @@ glyph_rect (f, x, y, rect)
       struct glyph_row *end = r + w->current_matrix->nrows - 1;
 
       frame_to_window_pixel_xy (w, &x, &y);
-      
-      for (; !found && r < end && r->enabled_p; ++r)
-        if (r->y + r->height >= y)
+
+      for (; r < end && r->enabled_p; ++r)
+        if (r->y <= y && r->y + r->height > y)
           {
+            /* Found the row at y.  */
             struct glyph *g = r->glyphs[TEXT_AREA];
             struct glyph *end = g + r->used[TEXT_AREA];
             int gx;
-              
-            for (gx = r->x; !found && g < end; gx += g->pixel_width, ++g)
-              if (gx + g->pixel_width >= x)
+
+            rect->top = WINDOW_TO_FRAME_PIXEL_Y (w, r->y);
+            rect->bottom = rect->top + r->height;
+
+            if (x < r->x)
+              {
+                /* x is to the left of the first glyph in the row.  */
+                rect->left = XINT (w->left);
+                rect->right = WINDOW_TO_FRAME_PIXEL_X (w, r->x);
+                return 1;
+              }
+
+            for (gx = r->x; g < end; gx += g->pixel_width, ++g)
+              if (gx <= x && gx + g->pixel_width > x)
                 {
+                  /* x is on a glyph.  */
                   rect->left = WINDOW_TO_FRAME_PIXEL_X (w, gx);
-                  rect->top = WINDOW_TO_FRAME_PIXEL_Y (w, r->y);
                   rect->right = rect->left + g->pixel_width;
-                  rect->bottom = rect->top + r->height;
-                  found = 1;
+                  return 1;
                 }
+
+            /* x is to the right of the last glyph in the row.  */
+            rect->left = WINDOW_TO_FRAME_PIXEL_X (w, gx);
+            rect->right = XINT (w->left) + XINT (w->width);
+            return 1;
           }
     }
 
-  return found;
+  /* The y is not on any row.  */
+  return 0;
 }
 
 /* Record the position of the mouse in last_mouse_glyph.  */