[gtksourceview] Do not assume that the border size equals gutter size

[Paolo Borelli <pborelli src gnome org>]

commit 71b738bf75a7660c15d22ea10eaba268cfec8db9
Author: Paolo Borelli <pborelli gnome org>
Date:   Mon Sep 14 20:47:11 2009 +0200

    Do not assume that the border size equals gutter size
    
    Be more careful in the logic that detects if gutter cell render changed
    size, by taking into accuont only the previous size of the gutter itself
    instead of assuming that it equals the size of the whole border.
    Fixes bug #589382.

 gtksourceview/gtksourcegutter.c |   33 ++++++++++++++++++++++++++++-----
 1 files changed, 28 insertions(+), 5 deletions(-)
---
diff --git a/gtksourceview/gtksourcegutter.c b/gtksourceview/gtksourcegutter.c
index 2e70f22..017d9fe 100644
--- a/gtksourceview/gtksourcegutter.c
+++ b/gtksourceview/gtksourcegutter.c
@@ -74,7 +74,7 @@ struct _GtkSourceGutterPrivate
 {
 	GtkSourceView *view;
 	GtkTextWindowType window_type;
-
+	gint size;
 	GList *renderers;
 	guint signals[LAST_EXTERNAL_SIGNAL];
 };
@@ -206,6 +206,8 @@ set_view (GtkSourceGutter *gutter,
 {
 	gutter->priv->view = view;
 
+	gutter->priv->size = -1;
+
 	g_object_weak_ref (G_OBJECT (view),
 	                   (GWeakNotify)view_notify,
 	                   gutter);
@@ -409,6 +411,8 @@ static void
 gtk_source_gutter_init (GtkSourceGutter *self)
 {
 	self->priv = GTK_SOURCE_GUTTER_GET_PRIVATE (self);
+
+	self->priv->size = -1;
 }
 
 static gint
@@ -682,7 +686,6 @@ gtk_source_gutter_queue_draw (GtkSourceGutter *gutter)
 	revalidate_size (gutter);
 }
 
-/* Callbacks */
 static gint
 calculate_size (GtkSourceGutter  *gutter,
                 Renderer         *renderer)
@@ -844,12 +847,32 @@ on_view_expose_event (GtkSourceView   *view,
 	text_view = GTK_TEXT_VIEW (view);
 	sizes = g_array_new (FALSE, FALSE, sizeof (gint));
 
+	/* This is fairly ugly, but we could not find a better way to
+	 * do it: renderers could have changed size and they do not have
+	 * a way to signal it. So on expose we revalidate the size and
+	 * requeue another expose.
+	 * To see if the size has changed we test the size of only the
+	 * gutter itself since the full border window size is not under
+	 * our control (see e.g bug #589382).
+	 * This also means that if the user manually forces the
+	 * border_window_size to a value smaller than the gutter, things
+	 * will not be drawn properly. */
 	size = calculate_sizes (gutter, sizes);
-
-	if (gtk_text_view_get_border_window_size (text_view, gutter->priv->window_type) != size)
+	if (gutter->priv->size != size)
 	{
+		gint border_size;
+
+		border_size = gtk_text_view_get_border_window_size (text_view, gutter->priv->window_type);
+
+		if (gutter->priv->size < 0)
+			border_size += size;
+		else
+			border_size = MAX (0, border_size - gutter->priv->size) + size;
+
+		gutter->priv->size = size;
+
 		/* Will trigger a new expose */
-		gtk_text_view_set_border_window_size (text_view, gutter->priv->window_type, size);
+		gtk_text_view_set_border_window_size (text_view, gutter->priv->window_type, border_size);
 	}
 	else
 	{