Re: How can I modify the background colour of a Button?

[James Su <suzhe turbolinux com cn>]

Thank you very much. But if I set the button relief to none, then the 
background will not be set. Is it a bug of gtk?

Regards
James Su

Dave Smith wrote:

> On Monday 01 September 2003 03:19, James Su wrote:
>  
>
> > I have tried both gtk_widget_modify_bg and gtk_widget_modify_base on the
> > button and its child, but all have no effect.
> >    
>
> Attached is the "Hello World" example (from gtk+-2.x.x/examples/helloworld), 
> modified to change the button's background and text colors.
>
> Dave Smith
>
> ------------------------------------------------------------------------
>
>
> #include <stdlib.h>       /* Needed for "exit" */
> #include <gtk/gtk.h>
>
> /* This is a callback function. The data arguments are ignored
> * in this example. More on callbacks below. */
> void hello( GtkWidget *widget,
>            gpointer   data )
> {
>    g_print ("Hello World\n");
> }
>
> gint delete_event( GtkWidget *widget,
>                   GdkEvent  *event,
>                    gpointer   data )
> {
>    /* If you return FALSE in the "delete_event" signal handler,
>     * GTK will emit the "destroy" signal. Returning TRUE means
>     * you don't want the window to be destroyed.
>     * This is useful for popping up 'are you sure you want to quit?'
>     * type dialogs. */
>
>    g_print ("delete event occurred\n");
>
>    /* Change TRUE to FALSE and the main window will be destroyed with
>     * a "delete_event". */
>
>    return TRUE;
> }
>
> /* Another callback */
> void destroy( GtkWidget *widget,
>              gpointer   data )
> {
>    gtk_main_quit ();
> }
>
> int main( int   argc,
>          char *argv[] )
> {
>    /* GtkWidget is the storage type for widgets */
>    GtkWidget *window;
>    GtkWidget *button;
>    
>    /* This is called in all GTK applications. Arguments are parsed
>     * from the command line and are returned to the application. */
>    gtk_init (&argc, &argv);
>    
>    /* create a new window */
>    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
>    
>    /* When the window is given the "delete_event" signal (this is given
>     * by the window manager, usually by the "close" option, or on the
>     * titlebar), we ask it to call the delete_event () function
>     * as defined above. The data passed to the callback
>     * function is NULL and is ignored in the callback function. */
>    g_signal_connect (G_OBJECT (window), "delete_event",
>                       G_CALLBACK (delete_event), NULL);
>    
>    /* Here we connect the "destroy" event to a signal handler.  
>     * This event occurs when we call gtk_widget_destroy() on the window,
>     * or if we return FALSE in the "delete_event" callback. */
>    g_signal_connect (G_OBJECT (window), "destroy",
>                       G_CALLBACK (destroy), NULL);
>    
>    /* Sets the border width of the window. */
>    gtk_container_set_border_width (GTK_CONTAINER (window), 10);
>    
>    /* Creates a new button with the label "Hello World". */
>    button = gtk_button_new_with_label ("Hello World");
>    
>    /* When the button receives the "clicked" signal, it will call the
>     * function hello() passing it NULL as its argument.  The hello()
>     * function is defined above. */
>    g_signal_connect (G_OBJECT (button), "clicked",
>                       G_CALLBACK (hello), NULL);
>    
>    /* This will cause the window to be destroyed by calling
>     * gtk_widget_destroy(window) when "clicked".  Again, the destroy
>     * signal could come from here, or the window manager. */
>    g_signal_connect_swapped (G_OBJECT (button), "clicked",
>                               G_CALLBACK (gtk_widget_destroy),
>                              G_OBJECT (window));
>    
>    /* This packs the button into the window (a gtk container). */
>    gtk_container_add (GTK_CONTAINER (window), button);
>
> /* New code to change the color of a button*/
>    GdkColor color;
>
>    /* Define the color for the button's background */
>    color.red = 65535;
>    color.blue = 0;
>    color.green = 65535;
>    /* Change the color of the button's background */
>    gtk_widget_modify_bg ( button, GTK_STATE_NORMAL, &color );
>
>    /* Get the pointer to the child widget */
>    GtkWidget *child_label;
>    child_label = gtk_bin_get_child (GTK_BIN (button) );
>    if (! child_label)
>    {
>      g_print ( "Label widget not defined\n" );
>      exit (1);
>    }
>
>    /* Define the color for the label's text */
>    color.red = 0;
>    color.blue = 65535;
>    color.green = 0;
>    gtk_widget_modify_fg ( child_label, GTK_STATE_NORMAL, &color );
> /* End of new code */
>    
>    /* The final step is to display this newly created widget. */
>    gtk_widget_show (button);
>    
>    /* and the window */
>    gtk_widget_show (window);
>    
>    /* All GTK applications must have a gtk_main(). Control ends here
>     * and waits for an event to occur (like a key press or
>     * mouse event). */
>    gtk_main ();
>    
>    return 0;
> }
>