[gtk/wip/chergert/textview-widgets] textview: add get_gutter() and set_gutter()

[Christian Hergert <chergert src gnome org>]

commit a6e6747de592fa07ed21161b861cb683b6fd63fb
Author: Christian Hergert <chergert redhat com>
Date:   Tue Sep 17 23:32:55 2019 -0700

    textview: add get_gutter() and set_gutter()
    
    This adds new functions to get/set a gutter (a widget in a border of the
    textview). It will always be allocated the full area of the border.
    
    Widgets like GtkSourceView can use this to set their gutters using real
    widgets instead of "renderers".

 gtk/gtktextview.c | 228 +++++++++++++++++++++++++++++++++++++++++++-----------
 gtk/gtktextview.h |   7 ++
 2 files changed, 190 insertions(+), 45 deletions(-)
---
diff --git a/gtk/gtktextview.c b/gtk/gtktextview.c
index 8e871e2201..4add47c6a0 100644
--- a/gtk/gtktextview.c
+++ b/gtk/gtktextview.c
@@ -224,6 +224,11 @@ struct _GtkTextViewPrivate
 
   GSList *children;
 
+  GtkWidget *bottom_gutter;
+  GtkWidget *left_gutter;
+  GtkWidget *right_gutter;
+  GtkWidget *top_gutter;
+
   GtkTextPendingScroll *pending_scroll;
 
   GtkGesture *drag_gesture;
@@ -671,7 +676,7 @@ static guint signals[LAST_SIGNAL] = { 0 };
 
 G_DEFINE_TYPE_WITH_CODE (GtkTextView, gtk_text_view, GTK_TYPE_CONTAINER,
                          G_ADD_PRIVATE (GtkTextView)
-                        G_IMPLEMENT_INTERFACE (GTK_TYPE_SCROLLABLE, NULL))
+                         G_IMPLEMENT_INTERFACE (GTK_TYPE_SCROLLABLE, NULL))
 
 static void
 add_move_binding (GtkBindingSet  *binding_set,
@@ -4201,24 +4206,27 @@ gtk_text_view_size_allocate (GtkWidget *widget,
   right_rect.x = text_rect.x + text_rect.width;
   bottom_rect.y = text_rect.y + text_rect.height;
 
-  text_window_size_allocate (priv->text_window,
-                             &text_rect);
+  text_window_size_allocate (priv->text_window, &text_rect);
 
   if (priv->left_window)
-    text_window_size_allocate (priv->left_window,
-                               &left_rect);
+    text_window_size_allocate (priv->left_window, &left_rect);
+  if (priv->left_gutter)
+    gtk_widget_size_allocate (priv->left_gutter, &left_rect, -1);
 
   if (priv->right_window)
-    text_window_size_allocate (priv->right_window,
-                               &right_rect);
+    text_window_size_allocate (priv->right_window, &right_rect);
+  if (priv->right_gutter)
+    gtk_widget_size_allocate (priv->right_gutter, &right_rect, -1);
 
   if (priv->top_window)
-    text_window_size_allocate (priv->top_window,
-                               &top_rect);
+    text_window_size_allocate (priv->top_window, &top_rect);
+  if (priv->top_gutter)
+    gtk_widget_size_allocate (priv->top_gutter, &top_rect, -1);
 
   if (priv->bottom_window)
-    text_window_size_allocate (priv->bottom_window,
-                               &bottom_rect);
+    text_window_size_allocate (priv->bottom_window, &bottom_rect);
+  if (priv->bottom_gutter)
+    gtk_widget_size_allocate (priv->bottom_gutter, &bottom_rect, -1);
 
   gtk_text_view_update_layout_width (text_view);
   
@@ -5500,7 +5508,8 @@ static void
 paint_border_window (GtkTextView     *text_view,
                      GtkSnapshot     *snapshot,
                      GtkTextWindow   *text_window,
-                     GtkStyleContext *context)
+                     GtkStyleContext *context,
+                     GtkWidget       *gutter)
 {
   gint x, y, w, h;
 
@@ -5517,6 +5526,9 @@ paint_border_window (GtkTextView     *text_view,
   gtk_snapshot_render_background (snapshot, context, x, y, w, h);
 
   gtk_style_context_restore (context);
+
+  if (gutter != NULL)
+    gtk_widget_snapshot_child (GTK_WIDGET (text_view), gutter, snapshot);
 }
 
 static void
@@ -5535,10 +5547,10 @@ gtk_text_view_snapshot (GtkWidget   *widget,
 
   draw_text (widget, snapshot); 
 
-  paint_border_window (GTK_TEXT_VIEW (widget), snapshot, priv->left_window, context);
-  paint_border_window (GTK_TEXT_VIEW (widget), snapshot, priv->right_window, context);
-  paint_border_window (GTK_TEXT_VIEW (widget), snapshot, priv->top_window, context);
-  paint_border_window (GTK_TEXT_VIEW (widget), snapshot, priv->bottom_window, context);
+  paint_border_window (GTK_TEXT_VIEW (widget), snapshot, priv->left_window, context, priv->left_gutter);
+  paint_border_window (GTK_TEXT_VIEW (widget), snapshot, priv->right_window, context, priv->right_gutter);
+  paint_border_window (GTK_TEXT_VIEW (widget), snapshot, priv->top_window, context, priv->top_gutter);
+  paint_border_window (GTK_TEXT_VIEW (widget), snapshot, priv->bottom_window, context, priv->bottom_gutter);
 
   /* Propagate exposes to all unanchored children. 
    * Anchored children are handled in gtk_text_view_paint(). 
@@ -5601,6 +5613,31 @@ gtk_text_view_add (GtkContainer *container,
                                      0, 0);
 }
 
+static gboolean
+remove_gutter (GtkTextView *text_view,
+               GtkWidget   *child)
+{
+  GtkTextViewPrivate *priv = text_view->priv;
+  GtkWidget **gutterptr = NULL;
+
+  if (priv->left_gutter == child)
+    gutterptr = &priv->left_gutter;
+  else if (priv->right_gutter == child)
+    gutterptr = &priv->right_gutter;
+  else if (priv->top_gutter == child)
+    gutterptr = &priv->top_gutter;
+  else if (priv->bottom_gutter == child)
+    gutterptr = &priv->bottom_gutter;
+  else
+    return FALSE;
+
+  *gutterptr = NULL;
+  gtk_widget_unparent (child);
+  g_object_unref (child);
+
+  return TRUE;
+}
+
 static void
 gtk_text_view_remove (GtkContainer *container,
                       GtkWidget    *child)
@@ -5613,6 +5650,9 @@ gtk_text_view_remove (GtkContainer *container,
   text_view = GTK_TEXT_VIEW (container);
   priv = text_view->priv;
 
+  if (!remove_gutter (text_view, child))
+    return;
+
   vc = NULL;
   iter = priv->children;
 
@@ -9451,37 +9491,25 @@ static void
 gtk_text_view_measure_borders (GtkTextView *text_view,
                                GtkBorder   *border)
 {
-  GSList *tmp_list = text_view->priv->children;
-
-  border->top = 0;
-  border->left = 0;
-  border->right = 0;
-  border->bottom = 0;
-
-  while (tmp_list != NULL)
-    {
-      GtkTextViewChild *child = tmp_list->data;
-      GtkRequisition child_req;
-
-      tmp_list = tmp_list->next;
-
-      if (!(child->type == GTK_TEXT_WINDOW_LEFT ||
-            child->type == GTK_TEXT_WINDOW_RIGHT ||
-            child->type == GTK_TEXT_WINDOW_TOP ||
-            child->type == GTK_TEXT_WINDOW_BOTTOM))
-        continue;
+  GtkTextViewPrivate *priv = text_view->priv;
+  GtkRequisition left = {0};
+  GtkRequisition right = {0};
+  GtkRequisition top = {0};
+  GtkRequisition bottom = {0};
 
-      gtk_widget_get_preferred_size (child->widget, &child_req, NULL);
+  if (priv->left_gutter)
+    gtk_widget_get_preferred_size (priv->left_gutter, &left, NULL);
+  if (priv->right_gutter)
+    gtk_widget_get_preferred_size (priv->right_gutter, &right, NULL);
+  if (priv->top_gutter)
+    gtk_widget_get_preferred_size (priv->top_gutter, &top, NULL);
+  if (priv->bottom_gutter)
+    gtk_widget_get_preferred_size (priv->bottom_gutter, &bottom, NULL);
 
-      if (child->type == GTK_TEXT_WINDOW_LEFT)
-        border->left = MAX (border->left, child_req.width);
-      else if (child->type == GTK_TEXT_WINDOW_RIGHT)
-        border->right = MAX (border->right, child_req.width);
-      else if (child->type == GTK_TEXT_WINDOW_TOP)
-        border->top = MAX (border->top, child_req.height);
-      else if (child->type == GTK_TEXT_WINDOW_BOTTOM)
-        border->bottom = MAX (border->bottom, child_req.height);
-    }
+  border->top = top.height;
+  border->bottom = bottom.height;
+  border->left = left.width;
+  border->right = right.width;
 }
 
 static void
@@ -10126,3 +10154,113 @@ gtk_text_view_get_extra_menu (GtkTextView *text_view)
 
   return priv->extra_menu;
 }
+
+static GtkWidget **
+get_gutter (GtkTextView       *text_view,
+            GtkTextWindowType  window_type)
+{
+  switch (window_type)
+    {
+    case GTK_TEXT_WINDOW_LEFT:
+      return &text_view->priv->left_gutter;
+
+    case GTK_TEXT_WINDOW_RIGHT:
+      return &text_view->priv->right_gutter;
+
+    case GTK_TEXT_WINDOW_TOP:
+      return &text_view->priv->top_gutter;
+
+    case GTK_TEXT_WINDOW_BOTTOM:
+      return &text_view->priv->bottom_gutter;
+
+    case GTK_TEXT_WINDOW_PRIVATE:
+    case GTK_TEXT_WINDOW_WIDGET:
+    case GTK_TEXT_WINDOW_TEXT:
+    default:
+      return NULL;
+    }
+}
+
+/**
+ * gtk_text_view_get_gutter:
+ * @text_view: a #GtkTextView
+ * @window_type: the window type of the gutter
+ *
+ * Gets a #GtkWidget that was previously set with gtk_text_view_set_gutter().
+ *
+ * @window_type must be one of %GTK_TEXT_WINDOW_LEFT, %GTK_TEXT_WINDOW_RIGHT,
+ * %GTK_TEXT_WINDOW_BOTTOM, or %GTK_TEXT_WINDOW_TOP.
+ *
+ * Returns: (transfer none): a #GtkWidget or %NULL
+ *
+ * Since: 4.0
+ */
+GtkWidget *
+gtk_text_view_get_gutter (GtkTextView       *text_view,
+                          GtkTextWindowType  window_type)
+{
+  g_return_val_if_fail (GTK_IS_TEXT_VIEW (text_view), NULL);
+  g_return_val_if_fail (window_type == GTK_TEXT_WINDOW_LEFT ||
+                        window_type == GTK_TEXT_WINDOW_RIGHT ||
+                        window_type == GTK_TEXT_WINDOW_TOP ||
+                        window_type == GTK_TEXT_WINDOW_BOTTOM,
+                        NULL);
+
+  return *get_gutter (text_view, window_type);
+}
+
+/**
+ * gtk_text_view_set_gutter:
+ * @text_view: a #GtkTextView
+ * @window_type: a #GtkTextWindowType
+ * @widget: (nullable): a #GtkWidget or %NULL
+ *
+ * Sets a widget as the gutter for @text_view.
+ *
+ * If @widget is %NULL, then the current gutter will be removed.
+ *
+ * If a widget was previously set for @window_type, it is removed
+ * before adding @widget.
+ *
+ * Since: 4.0
+ */
+void
+gtk_text_view_set_gutter (GtkTextView       *text_view,
+                          GtkTextWindowType  window_type,
+                          GtkWidget         *widget)
+{
+  GtkWidget **gutterptr = NULL;
+
+  g_return_if_fail (GTK_IS_TEXT_VIEW (text_view));
+  g_return_if_fail (!widget || GTK_IS_WIDGET (widget));
+  g_return_if_fail (window_type == GTK_TEXT_WINDOW_LEFT ||
+                    window_type == GTK_TEXT_WINDOW_RIGHT ||
+                    window_type == GTK_TEXT_WINDOW_TOP ||
+                    window_type == GTK_TEXT_WINDOW_BOTTOM);
+
+  gutterptr = get_gutter (text_view, window_type);
+
+  if (*gutterptr == widget)
+    return;
+
+  if (*gutterptr != NULL)
+    gtk_widget_destroy (*gutterptr);
+
+  g_return_if_fail (*gutterptr == NULL);
+
+  if (widget != NULL)
+    {
+      GtkCssNode *parent;
+
+      gtk_text_view_ensure_window (text_view, window_type);
+
+      *gutterptr = g_object_ref (widget);
+
+      parent = gtk_text_view_get_css_node (text_view, window_type);
+      gtk_css_node_set_parent (gtk_widget_get_css_node (widget), parent);
+
+      gtk_widget_set_parent (widget, GTK_WIDGET (text_view));
+    }
+
+  gtk_widget_queue_resize (GTK_WIDGET (text_view));
+}
diff --git a/gtk/gtktextview.h b/gtk/gtktextview.h
index 45d452caaf..117f0194e1 100644
--- a/gtk/gtktextview.h
+++ b/gtk/gtktextview.h
@@ -323,6 +323,13 @@ void gtk_text_view_add_child_in_window (GtkTextView          *text_view,
                                         /* window coordinates */
                                         gint                  xpos,
                                         gint                  ypos);
+GDK_AVAILABLE_IN_ALL
+GtkWidget *gtk_text_view_get_gutter    (GtkTextView          *text_view,
+                                        GtkTextWindowType     window_type);
+GDK_AVAILABLE_IN_ALL
+void       gtk_text_view_set_gutter    (GtkTextView          *text_view,
+                                        GtkTextWindowType     window_type,
+                                        GtkWidget            *widget);
 
 GDK_AVAILABLE_IN_ALL
 void gtk_text_view_move_child          (GtkTextView          *text_view,