Re: [gtk-list] style usage

[Eric Harlow <linuxgeek yahoo com>]

Some more notes for you - just changing the style color after it's
been assigned to a widget causes the same behavior.  Comment out the
second gtk_widget_set_style and see for yourself. 

I don't think that directly modifying the style of a widget is good
practice.  You really should set the colors first, and then call
gtk_widget_set_style. 

Also, the second gtk_widget_set_style is trying to set the style of
the widget to the style it already has - and is ignored.  (See
gtkwidget.c, gtk_widget_set_style_internal ())

 -Eric

>     style->fg[GTK_STATE_NORMAL] = color;
>     gtk_widget_set_style( button, style );



---Robert Roebling <roebling@sun2.ruf.uni-freiburg.de> wrote:
>
> Hi,
> 
> I'm writing a C++ library with the GTK+ and
> I'd like to be able to set the foreground and
> background colour directly, not using resources.
> As I haven't managed to do this without segfaulting
> sooner or later, I have written a mini-program
> that reproduces the segv with GTK+ 1.0.6. What
> I do is to create a new style with 
>   gtk_style_copy()
> give it a new colour and assign it to a button.
> No problem.
> 
> But when I then reuse this style to change another
> colour of the style and assign the style to
> the button it will give a segv upon destruction
> of the button. I tried to use gtk_style_ref()
> but that didn't change anything. It is possble to
> do what I want by using gtk_style_copy() everytime,
> but I wonder if that is not a memory leak.
> 
> Also, in order to set the colour of the text of
> a button, I have to change the label's style as 
> well. As you can easily test with my program, it
> is possible without segfaulting to assign the
> same style to two widgets, the label and the
> button. Is that correct or do I have to fear
> memory garbage later on?
> 
>   Thanks and regards,
> 
>     Robert Roebling>
> 
> #include <gtk/gtk.h>
> 
> int main (int argc, char *argv[])
> {
>     GtkWidget     *window;
>     GtkWidget     *menu;
>     GtkWidget     *button;
>     GdkColor       color;
>     GdkColormap   *colormap;
>     GtkStyle      *style;
> 
>     gtk_init (&argc, &argv);
>     window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
>     gtk_window_set_title (GTK_WINDOW (window), "Style usage?");
> 
>     gtk_container_border_width (GTK_CONTAINER (window), 10);
>     gtk_widget_realize(window);
> 
>     /*
>        create simple button
>      */
>       
>     button = gtk_button_new_with_label( "Hallo" );
>     
>     gtk_container_add (GTK_CONTAINER (window), button );
>     
>     gtk_widget_realize( button );
>     gtk_widget_show( button );
>     
>     /*
>       create style by copying an existing one
>     */
>     
>     style = gtk_style_copy( gtk_widget_get_style( button ) );
> 
>     /*
>       create color and assign it to style's background
>     */
>         
>     color.red   = 40000;
>     color.green = 40000;
>     color.blue  = 40000;
>     colormap = gdk_window_get_colormap( button->window );
>     gdk_color_alloc( colormap, &color );
>     style->bg[GTK_STATE_NORMAL] = color;
>     
>     /*
>       assign style to button
>     */
>     
>     gtk_widget_set_style( button, style );
>     
>     /*
>       assign same color to style's foreground
>       if this is not done -> no SEGFAULT
>       if I do another gtk_style_copy(...) -> no SEGFAULT
>     */
>     
>     style->fg[GTK_STATE_NORMAL] = color;
>     gtk_widget_set_style( button, style );
>     
>     
>     gtk_widget_show (window);
>     
>     /*
>        destruction will produce SEGFAULT
>     */
>     
>     gtk_widget_destroy( window );
>     
>     return 0;
> }
> 
> 
> 

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