GTK window motion animation?

Question

I want to move my GTK_WINDOW around the screen automatically. I currently have this in a draw / move cycle, but it is terribly volatile. I am very new to GTK programming (and generally to gui programming). What am I missing?

Answer 1

You did not say which way you want the window to follow. If the path is some simple time function, that is, if you have a way to figure out where you want the window to be at any given time, you can try the method shown in the following code. For a fairly simple menu in the example, it works fine on my Linux system and produces pretty smooth movement.

, , . , , , . ( g-timeout-add(), .)

. "HalfTime" timerEvent() , . 3 g_timeout_add() 0,003 333 (MPS). (, , 20, 30, 40 .. MPS, 3, g -timeout-add(), , , 30 , 33 MPS, , 333 MPS.) , MPS . , .

/* $Id: app12.c $
 Re: animating position of a top-level Gtk window
 jiw July 2011 -- Offered without warranty under GPL v3
 terms per http://www.gnu.org/licenses/gpl.html  */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <gtk/gtk.h>
typedef struct DATA { GTimer *timer; GtkWidget *window; int w, h; }
  DataStruct;

gboolean timerEvent(void *dataset) {
  enum { HalfTime=8, CycTime=2*HalfTime };
  gulong micros;
  DataStruct *data =dataset;
  double t = fabs(fmod (g_timer_elapsed (data->timer, &micros), CycTime));
  int x = (t*data->w)/HalfTime, y = (t*data->h)/HalfTime;
  gtk_window_move (GTK_WINDOW(data->window),
       t<HalfTime? x : 2*data->w-x, t<HalfTime? y : 2*data->h-y);
  return TRUE; /* Keep timeout running */
}

int main(int argc, char **argv) {
  GtkWidget *vbox, *b;
  GdkScreen *gds;
  DataStruct data;
  data.timer = g_timer_new();
  gtk_init (&argc, &argv);
  data.window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_default_size (GTK_WINDOW(data.window), 200, 150);
  g_signal_connect (G_OBJECT(data.window), "destroy",
            G_CALLBACK(gtk_main_quit), NULL);
  vbox = gtk_vbox_new (FALSE, 0);
  gtk_container_add (GTK_CONTAINER(data.window), vbox);
  b = gtk_button_new_with_label ("Click to Exit");
  gtk_box_pack_start (GTK_BOX(vbox), b, TRUE, TRUE, TRUE);
  g_signal_connect (b, "clicked", G_CALLBACK(gtk_main_quit), NULL);
  gtk_widget_show_all (data.window);

  gds = gdk_screen_get_default ();  /* Get pointer to screen  */
  data.w = gdk_screen_get_width (gds);  /* Find out screen width  */
  data.h = gdk_screen_get_height (gds); /* Find out screen height */
  printf ("Screen size = %d by %d\n", data.w, data.h); fflush(stdout);
  g_timeout_add(3, timerEvent, &data);  /* Create .003 sec timer   */
  gtk_main();
  return (0);
}