imwayland: Pass cursor region via attributes

Use the new Pango attribute to communicate
the cursor region to the widgets.

Fixes: #5035

gtk/gtkimcontext.c

@@ -1005,3 +1005,50 @@ gtk_im_context_set_property (GObject      *obj,
       break;
     }
 }
+
+
+static PangoAttribute *
+attr_preedit_properties_copy (const PangoAttribute *attr)
+{
+  const PangoAttrInt *int_attr = (PangoAttrInt *)attr;
+
+  return gtk_im_context_preedit_attr_new (int_attr->value);
+}
+
+static void
+attr_preedit_properties_destroy (PangoAttribute *attr)
+{
+  PangoAttrInt *iattr = (PangoAttrInt *)attr;
+
+  g_slice_free (PangoAttrInt, iattr);
+}
+
+static gboolean
+attr_preedit_properties_equal (const PangoAttribute *attr1,
+                               const PangoAttribute *attr2)
+{
+  const PangoAttrInt *int_attr1 = (const PangoAttrInt *)attr1;
+  const PangoAttrInt *int_attr2 = (const PangoAttrInt *)attr2;
+
+  return (int_attr1->value == int_attr2->value);
+}
+
+PangoAttribute *
+gtk_im_context_preedit_attr_new (GtkIMContextPreeditProperties value)
+{
+  PangoAttrInt *result = g_slice_new (PangoAttrInt);
+    static PangoAttrClass klass = {
+    0,
+    attr_preedit_properties_copy,
+    attr_preedit_properties_destroy,
+    attr_preedit_properties_equal
+  };
+
+  if (!klass.type)
+    klass.type = pango_attr_type_register ("GtkIMContextPreeditProperties");
+
+  pango_attribute_init (&result->attr, &klass);
+  result->value = value;
+
+  return (PangoAttribute *)result;
+}

gtk/gtkimcontext.h

@@ -168,6 +168,16 @@ gboolean gtk_im_context_delete_surrounding  (GtkIMContext       *context,
 					     int                 offset,
 					     int                 n_chars);
 
+
+typedef enum
+{
+  GTK_IM_CONTEXT_PREEDIT_CURSOR,
+} GtkIMContextPreeditProperties;
+
+GDK_AVAILABLE_IN_4_8
+PangoAttribute *        gtk_im_context_preedit_attr_new (GtkIMContextPreeditProperties value);
+
+
 G_END_DECLS
 
 #endif /* __GTK_IM_CONTEXT_H__ */

gtk/gtkimcontextwayland.c

@@ -656,11 +656,10 @@ gtk_im_context_wayland_get_preedit_string (GtkIMContext   *context,
       if (context_wayland->current_preedit.cursor_begin
           != context_wayland->current_preedit.cursor_end)
         {
-          /* FIXME: Oh noes, how to highlight while taking into account user preferences? */
-          PangoAttribute *cursor = pango_attr_weight_new (PANGO_WEIGHT_BOLD);
-          cursor->start_index = context_wayland->current_preedit.cursor_begin;
-          cursor->end_index = context_wayland->current_preedit.cursor_end;
-          pango_attr_list_insert (*attrs, cursor);
+          attr = gtk_im_context_preedit_attr_new (GTK_IM_CONTEXT_PREEDIT_CURSOR);
+          attr->start_index = context_wayland->current_preedit.cursor_begin;
+          attr->end_index = context_wayland->current_preedit.cursor_end;
+          pango_attr_list_insert (*attrs, attr);
         }
     }
 }

gtk/gtktext.c

@@ -217,6 +217,8 @@ struct _GtkTextPrivate
 
   guint16       preedit_length;              /* length of preedit string, in bytes */
   guint16       preedit_cursor;              /* offset of cursor within preedit string, in chars */
+  guint16       preedit_highlight_start;
+  guint16       preedit_highlight_end;
 
   gint64        handle_place_time;
 
@@ -4234,6 +4236,32 @@ gtk_text_commit_cb (GtkIMContext *context,
     }
 }
 
+static void
+get_preedit_highlight (PangoAttrList *attrs,
+                       guint16       *start,
+                       guint16       *end)
+{
+  GSList *l, *list = pango_attr_list_get_attributes (attrs);
+
+  *start = *end = 0;
+
+  for (l = list; l; l = l->next)
+    {
+      PangoAttribute *attr = l->data;
+
+      if (pango_attr_type_get_name (attr->klass->type) == g_intern_static_string ("GtkIMContextPreeditProperties"))
+        {
+          *start = attr->start_index;
+          *end = attr->end_index;
+          break;
+        }
+    }
+
+  g_slist_free_full (list, (GDestroyNotify) pango_attribute_destroy);
+}
+
+static void update_selection_node (GtkText *self);
+
 static void
 gtk_text_preedit_changed_cb (GtkIMContext *context,
                              GtkText      *self)
@@ -4243,18 +4271,26 @@ gtk_text_preedit_changed_cb (GtkIMContext *context,
   if (priv->editable)
     {
       char *preedit_string;
+      PangoAttrList *preedit_attrs;
       int cursor_pos;
 
       gtk_text_obscure_mouse_cursor (self);
 
       gtk_im_context_get_preedit_string (priv->im_context,
-                                         &preedit_string, NULL,
+                                         &preedit_string,
+                                         &preedit_attrs,
                                          &cursor_pos);
       g_signal_emit (self, signals[PREEDIT_CHANGED], 0, preedit_string);
       priv->preedit_length = strlen (preedit_string);
       cursor_pos = CLAMP (cursor_pos, 0, g_utf8_strlen (preedit_string, -1));
       priv->preedit_cursor = cursor_pos;
+      if (priv->preedit_length > 0)
+        get_preedit_highlight (preedit_attrs, &priv->preedit_highlight_start, &priv->preedit_highlight_end);
+
+      update_selection_node (self);
+
       g_free (preedit_string);
+      pango_attr_list_unref (preedit_attrs);
 
       gtk_text_recompute (self);
       update_placeholder_visibility (self);
@@ -4329,6 +4365,35 @@ gtk_text_enter_text (GtkText    *self,
   priv->need_im_reset = old_need_im_reset;
 }
 
+static void
+update_selection_node (GtkText *self)
+{
+  GtkTextPrivate *priv = gtk_text_get_instance_private (self);
+
+  if ((priv->current_pos != priv->selection_bound) ||
+      (priv->preedit_length > 0 && priv->preedit_highlight_start != priv->preedit_highlight_end))
+    {
+      if (!priv->selection_node)
+        {
+          GtkCssNode *widget_node = gtk_widget_get_css_node (GTK_WIDGET (self));
+
+          priv->selection_node = gtk_css_node_new ();
+          gtk_css_node_set_name (priv->selection_node, g_quark_from_static_string ("selection"));
+          gtk_css_node_set_parent (priv->selection_node, widget_node);
+          gtk_css_node_set_state (priv->selection_node, gtk_css_node_get_state (widget_node));
+          g_object_unref (priv->selection_node);
+        }
+    }
+  else
+    {
+      if (priv->selection_node)
+        {
+          gtk_css_node_set_parent (priv->selection_node, NULL);
+          priv->selection_node = NULL;
+        }
+    }
+}
+
 /* All changes to priv->current_pos and priv->selection_bound
  * should go through this function.
  */
@@ -4362,27 +4427,7 @@ gtk_text_set_positions (GtkText *self,
 
   g_object_thaw_notify (G_OBJECT (self));
 
-  if (priv->current_pos != priv->selection_bound)
-    {
-      if (!priv->selection_node)
-        {
-          GtkCssNode *widget_node = gtk_widget_get_css_node (GTK_WIDGET (self));
-
-          priv->selection_node = gtk_css_node_new ();
-          gtk_css_node_set_name (priv->selection_node, g_quark_from_static_string ("selection"));
-          gtk_css_node_set_parent (priv->selection_node, widget_node);
-          gtk_css_node_set_state (priv->selection_node, gtk_css_node_get_state (widget_node));
-          g_object_unref (priv->selection_node);
-        }
-    }
-  else
-    {
-      if (priv->selection_node)
-        {
-          gtk_css_node_set_parent (priv->selection_node, NULL);
-          priv->selection_node = NULL;
-        }
-    }
+  update_selection_node (self);
 
   if (changed)
     {
@@ -4595,6 +4640,8 @@ gtk_text_draw_text (GtkText     *self,
   GtkStyleContext *context;
   PangoLayout *layout;
   int x, y;
+  int start_index, end_index;
+  const char *text;
 
   /* Nothing to display at all */
   if (gtk_text_get_display_mode (self) == DISPLAY_BLANK)
@@ -4602,6 +4649,7 @@ gtk_text_draw_text (GtkText     *self,
 
   context = gtk_widget_get_style_context (widget);
   layout = gtk_text_ensure_layout (self, TRUE);
+  text = pango_layout_get_text (layout);
 
   gtk_text_get_layout_offsets (self, &x, &y);
 
@@ -4609,9 +4657,23 @@ gtk_text_draw_text (GtkText     *self,
 
   if (priv->selection_bound != priv->current_pos)
     {
-      const char *text = pango_layout_get_text (layout);
-      int start_index = g_utf8_offset_to_pointer (text, priv->selection_bound) - text;
-      int end_index = g_utf8_offset_to_pointer (text, priv->current_pos) - text;
+      start_index = g_utf8_offset_to_pointer (text, priv->selection_bound) - text;
+      end_index = g_utf8_offset_to_pointer (text, priv->current_pos) - text;
+    }
+  else if (priv->preedit_length > 0)
+    {
+      start_index = end_index = g_utf8_offset_to_pointer (text, priv->selection_bound) - text;
+      start_index += priv->preedit_highlight_start;
+      end_index += priv->preedit_highlight_end;
+    }
+  else
+    {
+      start_index = 0;
+      end_index = 0;
+    }
+
+  if (start_index != end_index)
+    {
       cairo_region_t *clip;
       cairo_rectangle_int_t clip_extents;
       int range[2];