Re: GtkImageView

[muppet <scott asofyet org>]

On Dec 23, 2007, at 7:23 PM, Jeffrey Ratcliffe wrote:

> On 22/12/2007, muppet <scott asofyet org> wrote:
> > interactive.pl:  a quick transliteration of gtkimageview/tests/
> > interactive.c.  Note that the way this program uses the  
> > GtkImageTransp
> > values in the UI manager actions doesn't really play nicely with perl
> > syntax for enums, so there's a terrible, evil, horrible hack in its
> > place.  If you golf this down to more perlish code, using closures  
> > and
> > such, you can sidestep the problem.
>
> Do you mind my including this in an examples directory, attributing  
> you?
>
> I was getting:
>
> No anim!  Can't call method "set_sensitive" on an undefined value at
> ./examples/interactive.pl line 74.
>
> *** unhandled exception in callback:
> ***   FATAL: invalid enum GtkImageTransp value 1, expecting: color /
> GTK_IMAGE_TRANSP_COLOR, background / GTK_IMAGE_TRANSP_BACKGROUND, grid
> / GTK_IMAGE_TRANSP_GRID at ./examples/interactive.pl line 206.
> ***  ignoring at ./examples/interactive.pl line 602.
>
> which the attached patch fixes. But I don't see how to do it
> differently with a closure. I'd appreciate a hint.

Unfortunately, i misremembered GtkRadioActionEntry as having a closure  
slot in each item; it does not.  You're stuck with an integer value to  
distinguish them, and in this situation, the integer enumeration value  
is rather ideal.  For perl interoperability this kinda sucks, and  
you're left doing something like the evil hack i had.  Or, you could  
use random integers and switch instead on the $action->name, which you  
conveniently set to the enumeration string name / nick, which is also  
somewhat evil.

Earlier i'd had problems getting the idea of

    sub GTK_IMAGE_TRANSP_GRID { get_enum_value ('Gtk2::ImageTransp',  
'grid') }

working, and instead hardcoded it to the integer value; i figure out  
why that is.  You need to have the value table in  
gtkimageviewperl_gtk_image_transp_get_type() be "static" as well as  
"const".  Without this, the value table is on the stack, and the GType  
registry winds up pointing at stack garbage after the get_type  
function has returned, eventually causing SIGSEGV crashes.  Also, the  
g_intern_static_string() call isn't really necessary.  See enum.patch.




> I attempted to clean up the namespace with the second patch, but now
> the tests fail:

Now that everything is under the "Gtk2::ImageView" namespace, the  
"ignore" pattern in the call to Glib::CodeGen::write_boot() is  
ignoring all of the packages in the module, so nothing actually gets  
booted correctly.  You need to change that so that it ignores *only*  
the master package (which is needed to avoid an infinite loop at  
startup -- see the Glib::CodeGen manpage).

Attachment: boot.diff
Description: Binary data

Attachment: enum.patch
Description: Binary data

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