minor canvas API fix

[Tim Janik <timj gtk org>]

hi all,

jacob recently added a gulong property to the canvas, which is a pretty
bad idea, ulong/long properties are a porting nightmare, you need
to make sure to set and get them via:

g_object_set (object, "prop", (gulong) 5, NULL);
gulong v;
g_object_get (object, "prop", &v, NULL);

or they'll break on alpha and other sizeof(int)!=sizeof(long) platforms.

also, long/int/short/char is the wrong type in the first place for a
boolean propety. the estimated impact is pretty low, the property got
added just two weeks ago, so code already using it probably just
does g_object_set (canvas, "aa", 1, NULL); anyways (i couldn't find
code using it yet though, except for gnome_canvas_new_aa() which is
already broken for alpha).

so i intend to comit the following fix to gnome canvas:

Index: libgnomecanvas/ChangeLog
===================================================================
RCS file: /cvs/gnome/libgnomecanvas/libgnomecanvas/ChangeLog,v
retrieving revision 1.103
diff -u -u -r1.103 ChangeLog
--- libgnomecanvas/ChangeLog	2001/12/12 05:19:58	1.103
+++ libgnomecanvas/ChangeLog	2001/12/12 20:46:41
@@ -1,3 +1,10 @@
+Wed Dec 12 21:45:08 2001  Tim Janik  <timj gtk org>
+
+	* gnome-canvas.c (gnome_canvas_class_init): fix canvas::aa
+	property. it needs to be CONSTRUCT_ONLY because anti-aliased
+	can't be changed after construction. also, this property needs
+	to be boolean and not ulong.
+
 2001-12-12  Alexander Larsson  <alla lysator liu se>
 
 	* gnome-canvas-text.c (gnome_canvas_text_set_font_desc):
Index: libgnomecanvas/gnome-canvas.c
===================================================================
RCS file: /cvs/gnome/libgnomecanvas/libgnomecanvas/gnome-canvas.c,v
retrieving revision 1.140
diff -u -u -r1.140 gnome-canvas.c
--- libgnomecanvas/gnome-canvas.c	2001/12/06 22:51:35	1.140
+++ libgnomecanvas/gnome-canvas.c	2001/12/12 20:46:42
@@ -2036,8 +2036,7 @@
 {
 	switch (prop_id) {
 	case PROP_AA:
-		g_value_set_ulong (value,
-				   GNOME_CANVAS (object)->aa);
+		g_value_set_boolean (value, GNOME_CANVAS (object)->aa);
 		break;
 	default:
 		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -2053,7 +2052,7 @@
 {
 	switch (prop_id) {
 	case PROP_AA:
-		GNOME_CANVAS (object)->aa = g_value_get_ulong (value);
+		GNOME_CANVAS (object)->aa = g_value_get_boolean (value);
 		break;
 	default:
 		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -2102,11 +2101,11 @@
 
 	g_object_class_install_property (G_OBJECT_CLASS (object_class),
 					 PROP_AA,
-					 g_param_spec_ulong ("aa",
-							     _("Antialiased"),
-							     _("The antialiasing mode of the canvas."),
-							     0, 1, 0,
-							     G_PARAM_READWRITE | G_PARAM_CONSTRUCT));
+					 g_param_spec_boolean ("aa",
+							       _("Antialiased"),
+							       _("The antialiasing mode of the canvas."),
+							       FALSE,
+							       G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY));
 
 	canvas_signals[DRAW_BACKGROUND] =
 		g_signal_new ("draw_background",
@@ -2272,7 +2271,7 @@
 gnome_canvas_new_aa (void)
 {
 	return GTK_WIDGET (g_object_new (GNOME_TYPE_CANVAS,
-					 "aa", 1,
+					 "aa", TRUE,
 					 NULL));
 }

---
ciaoTJ