Can anyone explain to me why the very small program beneath, demonstrating
a very basic form of rubberbanding, works excellent while compiled
with GTK1* but does not work correctly when compiled with GTK2*.
There seems to be a problem with reading the cursor movements, but whatever it
is, the program is useless when compiled with GTK2*.
I checked the incompatibles list on the GTK-site, but I could not find
a cause for this behaviour. Of course I did things like enable_depreciated
and a lot of other small changings of the program, but nothing seems to work.
I have written already a lot of rubber-banding functions/programs, using
different graphics libraries, so I am not a complete newby in this field.
As I have to use rubberbanding a lot in my programs and and I do not want
to go on using GTK1* , I am very anxious to find a solution!!
Thanks a lot for any help.
Kees de Jong, Delft, Holland.
#include <gtk/gtk.h>
#include <stdlib.h>
GtkWidget *window;
GtkWidget *fixed;
GtkWidget *drawing_area;
GdkGC *gc;
GdkColor *fore;
GdkColor *back;
gint ii;
GdkColor *newcolor(long red, long green, long blue)
{
GdkColor *c = (GdkColor *) g_malloc (sizeof (GdkColor));
c->red = red;
c->green = green;
c->blue = blue;
gdk_color_alloc(gdk_colormap_get_system(), c);
return (c);
}
void destroy (GtkWidget *widget, gpointer *data)
{
exit(0);
}
void cleararea(GtkWidget *drarea)
{
GdkDrawable *drawable;
drawable = drarea->window;
gdk_draw_rectangle (drawable,
drarea->style->white_gc,
TRUE,
0, 0,
drarea->allocation.width,
drarea->allocation.height);
}
gint drawareacb(GtkWidget *widget, GdkEventButton *event, gpointer data)
{
gint x0, y0;
gint x[2], y[2];
if(ii == 0)
{
cleararea(drawing_area);
ii=1;
}
gdk_window_get_pointer(drawing_area->window, &x0, &y0, NULL);
switch(event->type)
{
case GDK_BUTTON_PRESS:
x[0]=x0;
y[0]=y0;
gdk_draw_line(drawing_area->window, gc, 200, 400, x0, y0);
break;
case GDK_MOTION_NOTIFY:
x[1]=x0;
y[1]=y0;
gdk_draw_line(drawing_area->window, gc, 200, 400, x[0], y[0]);
gdk_draw_line(drawing_area->window, gc, 200, 400, x[1], y[1]);
x[0]=x[1];
y[0]=y[1];
break;
}
return(0);
}
void createinterface (char *title)
{
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title (GTK_WINDOW (window), title);
gtk_signal_connect (GTK_OBJECT (window), "destroy",
GTK_SIGNAL_FUNC (destroy), NULL);
fixed=gtk_fixed_new();
gtk_container_add(GTK_CONTAINER(window), fixed);
gtk_widget_show(fixed);
drawing_area=gtk_drawing_area_new();
gtk_widget_set_events(drawing_area, GDK_BUTTON_PRESS_MASK |
GDK_BUTTON_MOTION_MASK);
gtk_signal_connect(GTK_OBJECT (drawing_area), "motion_notify_event",
GTK_SIGNAL_FUNC (drawareacb), NULL);
gtk_signal_connect(GTK_OBJECT (drawing_area), "button_press_event",
GTK_SIGNAL_FUNC (drawareacb), NULL);
gtk_drawing_area_size(GTK_DRAWING_AREA (drawing_area), 800, 600);
gtk_fixed_put(GTK_FIXED(fixed), drawing_area, 0, 0);
gtk_widget_show (drawing_area);
gtk_widget_show (window);
gc = gdk_gc_new (drawing_area->window);
gdk_gc_set_foreground (gc, fore);
gdk_gc_set_background (gc, back);
gdk_gc_set_function(gc, GDK_XOR);
}
int main (int argc, char *argv[])
{
gtk_init (&argc, &argv);
ii=0;
fore=newcolor(0, 0, 0);
back=newcolor(65535, 65535, 65535);
fore->pixel=(back->pixel ^ fore->pixel);
createinterface("rubber");
gtk_main ();
exit (0);
}
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