Re: How to use GdkColor?

[Aaron Kennedy <aaronk t131 aone net au>]

Erwin,

I think you'll find the following works...
Note that the variable "color1" is NO LONGER a pointer.  How can you
assign red, green and blue values to a pointer that hasn't been set to
point to any memory yet?
That's why it was crashing,
Aaron


#include <glib.h>
#include <gdk/gdk.h>
#include <gtk/gtk.h>


GtkWidget *drawingarea = NULL;


void destroy_window (GtkWidget *widget, gpointer client_data)
        {
        gtk_main_quit ();
        }


gint area_event (GtkWidget *widget, GdkEvent *event, gpointer *data)
        {
        gint x, y;
        GdkModifierType state;
        GdkColor color1;
        color1.red = 65;
        color1.green = 0;
        color1.blue = 0;
        gdk_gc_set_foreground (widget->style->fg_gc[1], &color1);

         /* Check if we've received a button pressed event */
        if (event->type == GDK_BUTTON_PRESS )
                {
                gdk_window_get_pointer (drawingarea->window, &x, &y,
&state);
                gdk_draw_rectangle
(drawingarea->window,widget->style->fg_gc[1],1,(gint)x,(gint)y,30,5);
                }
        return(0);
       }



gint main (gint argc, gchar *argv[])
        {
        GtkWidget *window, *window2;

        gtk_init (&argc,&argv);

        window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
        gtk_window_set_title (GTK_WINDOW(window), "Dessine-moi un
point");
        gtk_window_set_policy (GTK_WINDOW(window), TRUE, TRUE, TRUE);

        gtk_signal_connect (GTK_OBJECT(window), "delete_event",
                (GtkSignalFunc)destroy_window, (gpointer)window);
        gtk_signal_connect (GTK_OBJECT(window), "destroy",
                (GtkSignalFunc)destroy_window, (gpointer)window);


        window2 = gtk_window_new (GTK_WINDOW_TOPLEVEL);
        gtk_window_set_title (GTK_WINDOW(window2), "21 rectangles");
        gtk_window_set_policy (GTK_WINDOW(window2), TRUE, TRUE, TRUE);

        gtk_signal_connect (GTK_OBJECT(window2), "delete_event",
                (GtkSignalFunc)destroy_window, (gpointer)window2);
        gtk_signal_connect (GTK_OBJECT(window2), "destroy",
                (GtkSignalFunc)destroy_window, (gpointer)window2);


        drawingarea = gtk_drawing_area_new ();
        gtk_drawing_area_size (GTK_DRAWING_AREA(drawingarea), 300, 300);

        gtk_widget_set_events (drawingarea, GDK_BUTTON_PRESS_MASK |
                                        GDK_POINTER_MOTION_MASK |
                                        GDK_POINTER_MOTION_HINT_MASK);

        gtk_signal_connect (GTK_OBJECT(drawingarea), "event",
                (GtkSignalFunc)area_event, NULL);

        gtk_container_add (GTK_CONTAINER(window), drawingarea);

        gtk_widget_show (drawingarea);
        gtk_widget_show (window);

        gtk_main ();

        return(0);
       }



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