textview: Track differences between ink and logical rects

This way, we can ensure that we queue redraws on the full ink rect. This
is particularly visible for squiggly underlines in spell checking.

https://bugzilla.gnome.org/show_bug.cgi?id=763741

3 files changed, 34 insertions, 6 deletions

diff --git a/gtk/gtktextbtree.c b/gtk/gtktextbtree.c
index 9e8d8386a8..2c995aaeff 100644
--- a/gtk/gtktextbtree.c
+++ b/gtk/gtktextbtree.c
@@ -2650,14 +2650,18 @@ redisplay_region (GtkTextBTree      *tree,
       else
         end_y = _gtk_text_btree_find_line_top (tree, end_line, view->view_id);
 
+      ld = _gtk_text_line_get_data (start_line, view->view_id);
+      if (ld)
+        start_y -= ld->top_ink;
+
       ld = _gtk_text_line_get_data (end_line, view->view_id);
       if (ld)
-        end_y += ld->height;
+        end_y += ld->height + ld->bottom_ink;
 
       if (cursors_only)
 	gtk_text_layout_cursors_changed (view->layout, start_y,
 					 end_y - start_y,
-					  end_y - start_y);
+					 end_y - start_y);
       else
 	gtk_text_layout_changed (view->layout, start_y,
 				 end_y - start_y,
@@ -3616,6 +3620,8 @@ _gtk_text_line_data_new (GtkTextLayout *layout,
   line_data->next = NULL;
   line_data->width = 0;
   line_data->height = 0;
+  line_data->top_ink = 0;
+  line_data->bottom_ink = 0;
   line_data->valid = FALSE;
 
   return line_data;
diff --git a/gtk/gtktextbtree.h b/gtk/gtktextbtree.h
index 0866218848..bea48419be 100644
--- a/gtk/gtktextbtree.h
+++ b/gtk/gtktextbtree.h
@@ -220,6 +220,8 @@ struct _GtkTextLineData {
   gpointer view_id;
   GtkTextLineData *next;
   gint height;
+  gint top_ink : 16;
+  gint bottom_ink : 16;
   signed int width : 24;
   guint valid : 8;		/* Actually a boolean */
 };
diff --git a/gtk/gtktextlayout.c b/gtk/gtktextlayout.c
index 6adcdc5ae7..6829d454c9 100644
--- a/gtk/gtktextlayout.c
+++ b/gtk/gtktextlayout.c
@@ -1041,23 +1041,31 @@ gtk_text_layout_validate_yrange (GtkTextLayout *layout,
       if (!line_data || !line_data->valid)
         {
           gint old_height, new_height;
+          gint top_ink, bottom_ink;
 	  
 	  old_height = line_data ? line_data->height : 0;
+          top_ink = line_data ? line_data->top_ink : 0;
+          bottom_ink = line_data ? line_data->bottom_ink : 0;
 
           _gtk_text_btree_validate_line (_gtk_text_buffer_get_btree (layout->buffer),
                                          line, layout);
           line_data = _gtk_text_line_get_data (line, layout);
 
 	  new_height = line_data ? line_data->height : 0;
+          if (line_data)
+            {
+              top_ink = MAX (top_ink, line_data->top_ink);
+              bottom_ink = MAX (bottom_ink, line_data->bottom_ink);
+            }
 
           delta_height += new_height - old_height;
           
           first_line = line;
-          first_line_y = -seen - new_height;
+          first_line_y = -seen - new_height - top_ink;
           if (!last_line)
             {
               last_line = line;
-              last_line_y = -seen;
+              last_line_y = -seen + bottom_ink;
             }
         }
 
@@ -1074,23 +1082,31 @@ gtk_text_layout_validate_yrange (GtkTextLayout *layout,
       if (!line_data || !line_data->valid)
         {
           gint old_height, new_height;
+          gint top_ink, bottom_ink;
 	  
 	  old_height = line_data ? line_data->height : 0;
+          top_ink = line_data ? line_data->top_ink : 0;
+          bottom_ink = line_data ? line_data->bottom_ink : 0;
 
           _gtk_text_btree_validate_line (_gtk_text_buffer_get_btree (layout->buffer),
                                          line, layout);
           line_data = _gtk_text_line_get_data (line, layout);
 	  new_height = line_data ? line_data->height : 0;
+          if (line_data)
+            {
+              top_ink = MAX (top_ink, line_data->top_ink);
+              bottom_ink = MAX (bottom_ink, line_data->bottom_ink);
+            }
 
           delta_height += new_height - old_height;
           
           if (!first_line)
             {
               first_line = line;
-              first_line_y = seen;
+              first_line_y = seen - top_ink;
             }
           last_line = line;
-          last_line_y = seen + new_height;
+          last_line_y = seen + new_height + bottom_ink;
         }
 
       seen += line_data ? line_data->height : 0;
@@ -1152,6 +1168,7 @@ gtk_text_layout_real_wrap (GtkTextLayout   *layout,
                            GtkTextLineData *line_data)
 {
   GtkTextLineDisplay *display;
+  PangoRectangle ink_rect, logical_rect;
 
   g_return_val_if_fail (GTK_IS_TEXT_LAYOUT (layout), NULL);
   g_return_val_if_fail (line != NULL, NULL);
@@ -1166,6 +1183,9 @@ gtk_text_layout_real_wrap (GtkTextLayout   *layout,
   line_data->width = display->width;
   line_data->height = display->height;
   line_data->valid = TRUE;
+  pango_layout_get_pixel_extents (display->layout, &ink_rect, &logical_rect);
+  line_data->top_ink = MAX (0, logical_rect.x - ink_rect.x);
+  line_data->bottom_ink = MAX (0, logical_rect.x + logical_rect.width - ink_rect.x - ink_rect.width);
   gtk_text_layout_free_line_display (layout, display);
 
   return line_data;