Re: Setting/style-property enhancements

[Tim Janik <timj gtk org>]

On 1 Apr 2001, Owen Taylor wrote:

> 
> Here are some additions that I'd find useful for using the style
> properties mechanism for themes.
> 
> The intent here is to avoid having the 6 properties currently
> for the option-menu-tab - left/right/top/bottom/width/height
> by combining them into 2 properties - the border and the
> size.

am i missing something? i don't know what properties you refer to,
maybe you could outline what these are for?

> 	* gtk/gtkwidget.[ch] gtk/gtktypeutils.c gtk/gtk-boxed.defs:
> 	Add boxed type for GtkRequistion. Use it for ::size-request.

somewhere on my todo as well.

> 	* gtk/gtkstyle.[ch] gtk/gtktypeutils.c gtk/gtk-boxed.defs:
>         Add a new GtkBorder structure useful for geometry properties
> 	for widgets. Add corresponding GTK_TYPE_BORDER.

ok, i see you have:

+struct _GtkBorder
+{
+  gint left;
+  gint right;
+  gint top;
+  gint bottom;
+};

unless you want to deal with negative borders as well (not in the
style property parser, but if people start using that as widget
properties), this should probably have an own param_spec type
that does validation.

> 	* gtk/gtkwidget.c (gtk_widget_class_install_style_property):
> 	Support automatic parser selection like
> 	gtk_settings_install_property_parser().

erk, sure, forgot that. though, i'd prefer _gtk_rc_property_parser_from_type()
rather than _gtk_rc_property_select_parser(), don't you think?

> 	* gtk/gtksettings.c (_gtk_rc_property_select_parser): Export
> 	functionality for use by gtk_widget_class_install_style_property.
> 	Support GTK_TYPE_BORDER, GTK_TYPE_REQUISITION.
> 
> One thing I noticed here was that I wanted to make
> gtk_rc_parser_border() support '3' as equivalent to { 3, 3, 3, 3 },
> but couldn't.

why?

> And it doesn't look like gtk_rc_parse_color() supports the "#fffff"
> formats for similar reason.

well, the color parser is currently untested because i didn't know of
a color property to add and then test things for.

but, i think i know now what went wrong.
GtkSettingsValue -> GValue conversions are first attempted via gvalue
transforms, and only if that couldn't be done, parsers are invoked
with the code assuming a GString, that's a bit hosed and needs to be
fixed.
can you add a color or border property to some widget, so i can test
and fix parser invocation?
(you could get this to work with the current code even by adding
string->gdkcolor and int->gtkborder transforms, but that'd be
an ugly hack and shouldn't be done because those transforms aren't
usefull beyond rc parsing)

> Perhaps the parser functions should take GtkSettingsValue
> instead of GValue?

that doesn't make a whole lot of sense, a GtkSettingsValue is there
in the first place, what we want is to convert that into a GValue
that can be queried through the gtk_widget_style_property* functions,
not another GtkSettingsValue.
lemme just fix the parser code, so parsers always get precedence
over value transforms.

btw, i don't quite understand why you use goto's in your code:

+gboolean
+gtk_rc_property_parse_requisition  (const GParamSpec *pspec,
+                                   const GString    *gstring,
+                                   GValue           *property_value)
+{
+  GtkRequisition requisition;
+  GScanner *scanner;
+  gboolean success = FALSE;
+
+  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), FALSE);
+  g_return_val_if_fail (G_VALUE_HOLDS_BOXED (property_value), FALSE);
+
+  scanner = gtk_rc_scanner_new ();
+  g_scanner_input_text (scanner, gstring->str, gstring->len);
+
+  if (!get_braced_int (scanner, TRUE, FALSE, &requisition.width))
+    goto out;
+  if (!get_braced_int (scanner, FALSE, TRUE, &requisition.height))
+    goto out;
+
+  g_value_set_boxed (property_value, &requisition);
+  success = TRUE;
+
+ out:
+  g_scanner_destroy (scanner);
+
+  return success;
+}

i think:

gboolean
gtk_rc_property_parse_requisition  (const GParamSpec *pspec,
                                    const GString    *gstring,
                                    GValue           *property_value)
{
  GtkRequisition requisition;
  GScanner *scanner;
  gboolean success = FALSE;

  g_return_val_if_fail (G_IS_PARAM_SPEC (pspec), FALSE);
  g_return_val_if_fail (G_VALUE_HOLDS_BOXED (property_value), FALSE);

  scanner = gtk_rc_scanner_new ();
  g_scanner_input_text (scanner, gstring->str, gstring->len);

  if (get_braced_int (scanner, TRUE, FALSE, &requisition.width) &&
      get_braced_int (scanner, FALSE, TRUE, &requisition.height))
    {
      g_value_set_boxed (property_value, &requisition);
      success = TRUE;
    }
  g_scanner_destroy (scanner);

  return success;
}

doesn't read so bad, does it?

> 
> Regards, 
>                                    Owen
> 

---
ciaoTJ