(Gtk:4783): gtk-CRITICAL **: gtk_image_set_from_pixbuf: assertion 'GTK_IS_IMAGE (image)' failed

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1.00/5 (1 vote)

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This is my code:

#include <gtk/gtk.h>
#include <gdk-pixbuf/gdk-pixbuf.h>

void destroy(void) {
  gtk_main_quit();
}


int main()
{
    GdkPixbuf* buf;
    GdkPixbuf* buf2;
    GError* err = NULL;
    int a=0, i=0, j=0;

    GtkWidget* window;
    GtkWidget *image =0;


    gtk_init (NULL,NULL);
    window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
    buf = gdk_pixbuf_new_from_file("1.jpg", &err);
    buf2 = gdk_pixbuf_new_from_file("2.jpg", &err);


   for(i=0; i<10; i++)
   {


         if((i%2)==0)
     {

       gtk_image_set_from_pixbuf(GTK_IMAGE(image), buf);

            for(j=0; j<10000; j++)
            {}
          }else
          {

         gtk_image_set_from_pixbuf(GTK_IMAGE(image), buf2);
            for(j=0; j<10000; j++)
            {}
    }

  g_signal_connect(G_OBJECT (window), "destroy",
  G_CALLBACK (destroy), NULL);
  gtk_container_add(GTK_CONTAINER (window), image);
  gtk_widget_show_all(window);
  gtk_main();

    }

return 0;
}

And this is the result:

(gtk:4783): Gtk-CRITICAL **: gtk_image_set_from_pixbuf: assertion 'GTK_IS_IMAGE (image)' failed

(gtk:4783): Gtk-CRITICAL **: gtk_container_add: assertion 'GTK_IS_WIDGET (widget)' failed
^C

What I have tried:

What I am trying to do is : I have 2 images, and a loop that I want to show one image for odd numbers and other image for even numbers. But this simple task seems very hard to do! please help me to correcting my code...thank you!

Posted 12-Dec-17 7:13am

Member 13376650

Updated 13-Dec-17 3:16am

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Richard MacCutchan 12-Dec-17 13:59pm

Where does this message occur and what are the parameters that are causing it?

1 solution

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Jochen Arndt · Accepted Answer · 2017-12-13T03:16:00

I have not used GDK so far but the errors are quite clear.

Both are sourced by your image being NULL. You have to create a new empty GtkImage widget first:

C++

image = gtk_image_new();

Note also that you should check if loading from the files was successful:

C++

buf = gdk_pixbuf_new_from_file("1.jpg", &err);
if (NULL == buf)
{
    fprintf(stderr, "Loading image 1 failed with error %s\n", err->message);
    return 1;
}
buf2 = gdk_pixbuf_new_from_file("2.jpg", &err);
if (NULL == buf2)
{
    fprintf(stderr, "Loading image 2 failed with error %s\n", err->message);
    return 1;
}

You have not specified a full path to the image files. Then the current working directory is used. If that does not contain the image files, loading will fail.