Re: deactivate "enter" signal on GtkButton

[Andrew Potter <agpotter gmail com>]

On Thu, Nov 7, 2013 at 7:06 PM, Mahesh Chaudhari
<mahesh chaudhari ymail com> wrote:
> On Thursday, 7 November 2013 10:46 AM, Andrew Potter <agpotter gmail com>
> wrote:
> On Thu, Nov 7, 2013 at 4:10 AM, Mahesh Chaudhari
> <mahesh chaudhari ymail com> wrote:
> > Also (unsuccessfully) tried :
> > void enter_button1(GtkWidget *widget, gpointer data)
> > {
> >    GtkStyle *style;
> >    style = gtk_widget_get_style(button1);
> >    style->bg[GTK_STATE_PRELIGHT] = style->bg[GTK_STATE_NORMAL];
> >    gtk_widget_set_style(button1, style);
> > }
>
> This may not have worked because the theme style may be being applied
> after you call this function.

Actually the reason is may be that your theme is not setting the
background color, but is instead setting a _background image_.

What I found is that on my installation, a background image was being
set for the default button image, the image being a gradient from top
to bottom of a darker shade of gray. On hover, this gradient was not
drawn.

The example program below prevents my global theme from setting any
background image by default by overwriting it with a completely
transparent image of my own. This may or may not be what you want.

The question becomes, "How do I set a theme selector to use a
different, possibly defined elsewhere, selector?" e.g. set
GtkButton:hover to look the same as the standard GtkButton, whatever
it is.

I don't know.

#include <gtk/gtk.h>

const gchar my_style[] = "GtkButton:hover,\
  GtkButton:prelight,                     \
  GtkButton                               \
  {                                       \
    background-image: -gtk-gradient(linear, center top, center bottom,
from(rgba(0,0,255,0)), to (rgba(0,0,255,0))); \
  }";

void on_realize(GtkWidget *widget, gpointer user_data) {
    GError *error = NULL;
    GdkScreen *screen = gtk_widget_get_screen(widget);
    GtkCssProvider *provider = gtk_css_provider_get_default();
    gtk_css_provider_load_from_data(provider, my_style,
G_N_ELEMENTS(my_style), &error);
    if (error) {
        fprintf(stderr, "Error loading CSS Theme: %s\n", error->message);
        g_error_free(error);
    } else {
        gtk_style_context_add_provider_for_screen(screen,
GTK_STYLE_PROVIDER(provider),
GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
    }
}

int main(int argc, char *argv[]) {
    gtk_init(&argc, &argv);
    GtkWidget *window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    GtkWidget *grid = gtk_grid_new();
    GtkWidget *button = gtk_button_new_with_label("Button!");

    gtk_container_add(GTK_CONTAINER(grid), gtk_label_new("Label 1"));
    gtk_container_add(GTK_CONTAINER(grid), button);
    gtk_container_add(GTK_CONTAINER(grid), gtk_label_new("Label 2"));
    gtk_container_add(GTK_CONTAINER(window), grid);
    g_signal_connect(window, "realize", G_CALLBACK(on_realize), NULL);
    g_signal_connect(window, "hide", G_CALLBACK(gtk_main_quit), NULL);

    gtk_widget_show_all(window);
    gtk_main();
    return 0;
}