Prevent text decorations from overwriting surrounding areas on X

* src/xterm.c (x_draw_underwave): New parameter
`decoration_width'.
(x_draw_glyph_string): Constrain decoration width to current
text area.

1 files changed, 23 insertions, 10 deletions

diff --git a/src/xterm.c b/src/xterm.c
index e2b09938a27..cca57952ba0 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -3945,7 +3945,7 @@ x_get_scale_factor(Display *disp, int *scale_x, int *scale_y)
 
 */
 static void
-x_draw_underwave (struct glyph_string *s)
+x_draw_underwave (struct glyph_string *s, int decoration_width)
 {
   Display *display = FRAME_X_DISPLAY (s->f);
 
@@ -3958,7 +3958,7 @@ x_draw_underwave (struct glyph_string *s)
 
 #ifdef USE_CAIRO
   x_draw_horizontal_wave (s->f, s->gc, s->x, s->ybase - wave_height + 3,
-                          s->width, wave_height, wave_length);
+                          decoration_width, wave_height, wave_length);
 #else  /* not USE_CAIRO */
   int dx, dy, x0, y0, width, x1, y1, x2, y2, xmax, thickness = scale_y;;
   bool odd;
@@ -3968,7 +3968,7 @@ x_draw_underwave (struct glyph_string *s)
   dy = wave_height - 1;
   x0 = s->x;
   y0 = s->ybase + wave_height / 2 - scale_y;
-  width = s->width;
+  width = decoration_width;
   xmax = x0 + width;
 
   /* Find and set clipping rectangle */
@@ -4118,6 +4118,19 @@ x_draw_glyph_string (struct glyph_string *s)
 
   if (!s->for_overlaps)
     {
+      int area_x, area_y, area_width, area_height;
+      int area_max_x, decoration_width;
+
+      /* Prevent the underline from overwriting surrounding areas
+         and the fringe.  */
+      window_box (s->w, s->area, &area_x, &area_y,
+                  &area_width, &area_height);
+      area_max_x = area_x + area_width - 1;
+
+      decoration_width = s->width;
+      if (area_max_x < (s->x + decoration_width - 1))
+        decoration_width -= (s->x + decoration_width - 1) - area_max_x;
+
       /* Draw relief if not yet drawn.  */
       if (!relief_drawn_p && s->face->box != FACE_NO_BOX)
         x_draw_glyph_string_box (s);
@@ -4128,14 +4141,14 @@ x_draw_glyph_string (struct glyph_string *s)
           if (s->face->underline == FACE_UNDER_WAVE)
             {
               if (s->face->underline_defaulted_p)
-                x_draw_underwave (s);
+                x_draw_underwave (s, decoration_width);
               else
                 {
                   Display *display = FRAME_X_DISPLAY (s->f);
                   XGCValues xgcv;
                   XGetGCValues (display, s->gc, GCForeground, &xgcv);
                   XSetForeground (display, s->gc, s->face->underline_color);
-                  x_draw_underwave (s);
+                  x_draw_underwave (s, decoration_width);
                   XSetForeground (display, s->gc, xgcv.foreground);
                 }
             }
@@ -4225,7 +4238,7 @@ x_draw_glyph_string (struct glyph_string *s)
               y = s->ybase + position;
               if (s->face->underline_defaulted_p)
                 x_fill_rectangle (s->f, s->gc,
-                                s->x, y, s->width, thickness);
+                                  s->x, y, decoration_width, thickness);
               else
                 {
                   Display *display = FRAME_X_DISPLAY (s->f);
@@ -4233,7 +4246,7 @@ x_draw_glyph_string (struct glyph_string *s)
                   XGetGCValues (display, s->gc, GCForeground, &xgcv);
                   XSetForeground (display, s->gc, s->face->underline_color);
                   x_fill_rectangle (s->f, s->gc,
-                                  s->x, y, s->width, thickness);
+                                    s->x, y, decoration_width, thickness);
                   XSetForeground (display, s->gc, xgcv.foreground);
                 }
             }
@@ -4245,7 +4258,7 @@ x_draw_glyph_string (struct glyph_string *s)
 
           if (s->face->overline_color_defaulted_p)
             x_fill_rectangle (s->f, s->gc, s->x, s->y + dy,
-                            s->width, h);
+                              decoration_width, h);
           else
             {
               Display *display = FRAME_X_DISPLAY (s->f);
@@ -4253,7 +4266,7 @@ x_draw_glyph_string (struct glyph_string *s)
               XGetGCValues (display, s->gc, GCForeground, &xgcv);
               XSetForeground (display, s->gc, s->face->overline_color);
               x_fill_rectangle (s->f, s->gc, s->x, s->y + dy,
-                              s->width, h);
+                                decoration_width, h);
               XSetForeground (display, s->gc, xgcv.foreground);
             }
         }
@@ -4283,7 +4296,7 @@ x_draw_glyph_string (struct glyph_string *s)
               XGetGCValues (display, s->gc, GCForeground, &xgcv);
               XSetForeground (display, s->gc, s->face->strike_through_color);
               x_fill_rectangle (s->f, s->gc, s->x, glyph_y + dy,
-                              s->width, h);
+                                decoration_width, h);
               XSetForeground (display, s->gc, xgcv.foreground);
             }
         }