[gtk/unmapped-text: 1/2] text: Defer most recomputation until we're mapped

[Matthias Clasen <matthiasc src gnome org>]

commit 91dcc7a6f4a61196662cabdd9236444ac09adc22
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Aug 23 15:09:45 2020 -0400

    text: Defer most recomputation until we're mapped
    
    It doesn't make sense to update scroll positions or
    im cursor locations while we're unmapped, and doing
    so causes us to do expensive text measuring.

 gtk/gtktext.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)
---
diff --git a/gtk/gtktext.c b/gtk/gtktext.c
index 7d7d3e37ab..c4300e9481 100644
--- a/gtk/gtktext.c
+++ b/gtk/gtktext.c
@@ -309,6 +309,7 @@ static void   gtk_text_dispose              (GObject      *object);
  */
 static void   gtk_text_realize              (GtkWidget        *widget);
 static void   gtk_text_unrealize            (GtkWidget        *widget);
+static void   gtk_text_map                  (GtkWidget        *widget);
 static void   gtk_text_unmap                (GtkWidget        *widget);
 static void   gtk_text_measure              (GtkWidget        *widget,
                                              GtkOrientation    orientation,
@@ -710,6 +711,7 @@ gtk_text_class_init (GtkTextClass *class)
   gobject_class->set_property = gtk_text_set_property;
   gobject_class->get_property = gtk_text_get_property;
 
+  widget_class->map = gtk_text_map;
   widget_class->unmap = gtk_text_unmap;
   widget_class->realize = gtk_text_realize;
   widget_class->unrealize = gtk_text_unrealize;
@@ -2131,6 +2133,16 @@ gtk_text_get_display_text (GtkText *self,
     }
 }
 
+static void
+gtk_text_map (GtkWidget *widget)
+{
+  GtkText *self = GTK_TEXT (widget);
+
+  GTK_WIDGET_CLASS (gtk_text_parent_class)->map (widget);
+
+  gtk_text_recompute (self);
+}
+
 static void
 gtk_text_unmap (GtkWidget *widget)
 {
@@ -3284,8 +3296,6 @@ static void
 gtk_text_root (GtkWidget *widget)
 {
   GTK_WIDGET_CLASS (gtk_text_parent_class)->root (widget);
-
-  gtk_text_recompute (GTK_TEXT (widget));
 }
 
 /* GtkEditable method implementations
@@ -4329,15 +4339,15 @@ static void
 gtk_text_recompute (GtkText *self)
 {
   gtk_text_reset_layout (self);
-  gtk_text_check_cursor_blink (self);
+  gtk_widget_queue_draw (GTK_WIDGET (self));
 
-  gtk_text_adjust_scroll (self);
+  if (!gtk_widget_get_mapped (GTK_WIDGET (self)))
+    return;
 
+  gtk_text_check_cursor_blink (self);
+  gtk_text_adjust_scroll (self);
   update_im_cursor_location (self);
-
   gtk_text_update_handles (self);
-
-  gtk_widget_queue_draw (GTK_WIDGET (self));
 }
 
 static PangoLayout *