[gtk/wip/chergert/spellcheck] textview: check spelling for visible region

[Christian Hergert <chergert src gnome org>]

commit bb7f114b2557b1723bd2f6af7ec2643473d13b10
Author: Christian Hergert <chergert redhat com>
Date:   Mon Mar 29 21:36:18 2021 -0700

    textview: check spelling for visible region

 gtk/gtktextview.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)
---
diff --git a/gtk/gtktextview.c b/gtk/gtktextview.c
index 33c40d3555..3350031f1c 100644
--- a/gtk/gtktextview.c
+++ b/gtk/gtktextview.c
@@ -42,6 +42,7 @@
 #include "gtktextiterprivate.h"
 #include "gtkimmulticontext.h"
 #include "gtkprivate.h"
+#include "gtktextbufferprivate.h"
 #include "gtktextutil.h"
 #include "gtkwidgetprivate.h"
 #include "gtkwindow.h"
@@ -8068,6 +8069,26 @@ gtk_text_view_drag_drop (GtkDropTarget *dest,
   return TRUE;
 }
 
+static void
+gtk_text_view_check_spelling (GtkTextView *text_view)
+{
+  GtkTextIter begin, end;
+  GdkRectangle visible;
+
+  g_assert (GTK_IS_TEXT_VIEW (text_view));
+
+  if (!_gtk_text_buffer_can_check_spelling (text_view->priv->buffer))
+    return;
+
+  gtk_text_view_get_visible_rect (text_view, &visible);
+  gtk_text_view_get_iter_at_location (text_view, &begin, visible.x, visible.y);
+  gtk_text_view_get_iter_at_location (text_view, &end,
+                                      visible.x + visible.width,
+                                      visible.y + visible.height);
+
+  _gtk_text_buffer_check_spelling (text_view->priv->buffer, &begin, &end);
+}
+
 static void
 gtk_text_view_set_hadjustment (GtkTextView   *text_view,
                                GtkAdjustment *adjustment)
@@ -8286,6 +8307,8 @@ gtk_text_view_value_changed (GtkAdjustment *adjustment,
 
   gtk_text_view_update_handles (text_view);
 
+  gtk_text_view_check_spelling (text_view);
+
   if (priv->anchored_children.length > 0)
     gtk_widget_queue_allocate (GTK_WIDGET (text_view));
   else