How to start and stop GIF animated GtkImage in GTK+ - c

Question

I have a GTK+ application written in C that loads a matrix of animated GIF files. These GtkImages automatically run the animation when they are loaded and then stop when the animation is completed. How would I restart the animation of each GtkImage containing the GIF and are signals generated when the animation is complete?
Thank you.
EDIT :
Would the use of gdk_pixbuf_animation_get_iter() described here make this possible?
Full code is provided below.
/*
* Compile me with:
* gcc -o reels reels.c $(pkg-config --cflags --libs gtk+-2.0 gmodule-2.0)
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <time.h>
/* GTK */
#include <gdk/gdkx.h>
#include <gtk/gtk.h>
/**** prototypes ****/
static void destroy (GtkWidget*, gpointer);
GdkPixbuf *create_pixbuf(const gchar * filename);
GtkWidget *SetupWindow(gchar *data, const gchar *filename);
static void destroy (GtkWidget *window, gpointer data);
void btnSpin_clicked(GtkWidget *button, gpointer data);
void btnExit_clicked(GtkWidget *button, gpointer data);
/********************/
GtkWidget *images[3][5];
static void destroy (GtkWidget *window, gpointer data)
{
gtk_main_quit ();
}
void btnSpin_clicked(GtkWidget *button, gpointer data)
{
printf("Spin Button pressed.\n");
return;
}
void btnExit_clicked(GtkWidget *button, gpointer data)
{
gtk_main_quit();
return;
}
GtkWidget *SetupWindow(gchar *data, const gchar *filename)
{
GdkPixmap *background;
GdkPixbuf *pixbuf;
GdkScreen *ourscreen;
GdkColormap *colormap;
GtkStyle *style;
GdkColor fg;
GdkColor bg;
GError *error = NULL;
GdkRectangle *rect;
GtkWidget *window;
pixbuf = gdk_pixbuf_new_from_file (filename,&error);
if (error != NULL) {
if (error->domain == GDK_PIXBUF_ERROR) {
g_print ("Pixbuf Related Error:\n");
}
if (error->domain == G_FILE_ERROR) {
g_print ("File Error: Check file permissions and state:\n");
}
g_printerr ("%s\n", error[0].message);
}
gdk_pixbuf_render_pixmap_and_mask (pixbuf, &background, NULL, 0);
style = gtk_style_new ();
style->bg_pixmap[0] = background;
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
gtk_window_set_title (GTK_WINDOW (window), data);
// gtk_window_maximize(GTK_WINDOW(window));
gtk_window_set_modal (GTK_WINDOW (window),TRUE);
gtk_window_set_default_size(GTK_WINDOW(window),628,530);
gtk_widget_set_style (GTK_WIDGET(window), GTK_STYLE(style));
gtk_window_set_position(GTK_WINDOW(window),GTK_WIN_POS_CENTER_ALWAYS);
gtk_container_set_border_width(GTK_CONTAINER(window), 0);
//gtk_window_set_resizable(GTK_WINDOW(window), (gboolean) FALSE);
gtk_window_set_decorated( GTK_WINDOW(window), FALSE );
return(window);
}
int main (int argc, char *argv[])
{
GdkPixbufAnimation *animation;
GtkWidget *image;
int x,y;
GdkPixbuf *pixBuf;
GdkPixmap *pixMap;
gchar filename[20];
GtkWidget *btnSpin, *btnExit;
GtkWidget *frame; /* for absolute positionining of widgets */
GtkWidget *window;
int posx, posy;
gtk_init (&argc, &argv);
window = SetupWindow("Demo", "background.gif");
g_signal_connect (G_OBJECT (window), "destroy", G_CALLBACK (destroy), NULL);
frame = gtk_fixed_new();
gtk_container_add(GTK_CONTAINER(window), frame);
btnSpin = gtk_button_new_with_label("Spin");
gtk_widget_set_size_request(btnSpin, 80, 35);
gtk_fixed_put(GTK_FIXED(frame), btnSpin, 229, 485);
g_signal_connect(G_OBJECT( btnSpin ), "clicked", G_CALLBACK(btnSpin_clicked), NULL );
btnExit = gtk_button_new_with_label("Exit");
gtk_widget_set_size_request(btnExit, 80, 35);
gtk_fixed_put(GTK_FIXED(frame), btnExit, 320, 485);
g_signal_connect(G_OBJECT( btnExit ), "clicked", G_CALLBACK(btnExit_clicked), NULL );
/* setup animated gifs */
for( y = 0; y < 3; y++ )
{
posy = (y*120) + 20;
for( x = 0; x < 5; x++ )
{
posx = (x*120) + 20;
/* set each Image widget to spin GIF */
sprintf( filename,"%d-%d.gif", y+1,x+1 );
images[y][x] = gtk_image_new_from_file(filename);
gtk_fixed_put(GTK_FIXED(frame), images[y][x], posx, posy);
}
}
gtk_widget_show_all(window);
gtk_main ();
return 0;
}

Answer 1

After taking a look at the GtkImage source code, I am afraid there is no signal that is generated when the animation is completed. However, you should be able to restart the animation by calling gtk_image_set_from_file() or gtk_image_set_from_animation().
To completely solve your initial issue, I propose you create a subclass of GtkImage. It should behave exactly like GtkImage, except that animation_timeout should send a signal if delay < 0 around line 1315.
Information about creating a subclass of a GObject (note that GtkImage is a GObject) can be found here.

Answer 2

Based on user1202136's answer the following code snippets show the solution. I post this in case others find it useful.
The basic idea is to use GdkPixbufAnimation, gdk_pixbuf_animation_new_from_file and gtk_image_set_from_animation
The following code snippet(s) show how to do it.
GtkWidget *images[3][5];
GdkPixbufAnimation *animations[3][5];
/* Initial setup of animated gifs */
for( y = 0; y < 3; y++ )
{
for( x = 0; x < 5; x++ )
{
/* set each Image widget to spin GIF */
sprintf( filename,"%d-%d.gif", y+1,x+1 );
images[y][x] = gtk_image_new();
animations[y][x] = gdk_pixbuf_animation_new_from_file ( filename , &error);
gtk_image_set_from_animation (GTK_IMAGE(images[y][x]), animations[y][x]);
gtk_fixed_put(GTK_FIXED(frame), images[y][x], (x*120) + 20, (y*120) + 20);
}
}
/* now to restart the animations use the images and animations array already stored in memory,
no need to re-read the animations from disk so this happens quickly
*/
/* restart animated gifs */
for( y = 0; y < 3; y++ )
{
for( x = 0; x < 5; x++ )
{
gtk_image_set_from_animation(GTK_IMAGE(images[y][x]), animations[y][x]);
}
}