Re: float params of a gobject

[Christian Neumair <chris gnome-de org>]

Am Montag, den 10.07.2006, 12:45 -0300 schrieb Daniel Alonso:
> Hi, I'm trying to define a gobject class with a floating number
> property. In the init class procedure I define the property the
> following way:
>
>       param_spec = g_param_spec_float
>               ("width" /* name */,
>                _("Icon Width") /* nick */,
>                _("The width of the svg icon") /* blurb */,
>                G_MINFLOAT /* minimum */,
>                G_MAXFLOAT /* maximum */,
>                0.0 /* default_value */,
>                (GParamFlags)(G_PARAM_READABLE | G_PARAM_WRITABLE));
>       g_object_class_install_property (g_object_class,
>                                       PROP_WIDTH,
>                                       param_spec);
>
> This compiles fine, but when running the test program it raises a glib
> exception:
>
> (test:5073): GLib-GObject-CRITICAL **: g_param_spec_float: assertion
> `default_value >= minimum && default_value <= maximum' failed
>
> (test:5073): GLib-GObject-CRITICAL **: g_object_class_install_property:
> assertion `G_IS_PARAM_SPEC (pspec)' failed
>
> But default value 0.0 is equal G_MINFLOAT and lesser than G_MAXFLOAT,
> isn't it? 

> From the API docs [1]:

"The minimum positive value which can be held in a gfloat.

If you are interested in the smallest value which can be held in a
gfloat, use -G_MAX_FLOAT."

0.0 is not considered positive in this case, I think it works like:
G_MINFLOAT is the smalles floating number f that satisfies f > 0.

Since icons may only have a positive width, 1.0 might be a good default
value.

[1]
http://developer.gnome.org/doc/API/2.0/glib/glib-Limits-of-Basic-Types.html#G-MINFLOAT:CAPS";

-- 
Christian Neumair <chris gnome-de org>