GTK3 resize attempt grows window exponentially - c

Question

I have a C GTK3 program that has a notebook with two images. I want to be able to grab the corner of the window and adjust the size of the image currently displayed. What I currently have is a program that once started, the window keeps growing until I kill it from the terminal using ctrl-c. I put a sleep call in the callback to slow it down, but it still grows. How do I stop the window from growing unless I "grab" a corner of the window and adjust it myself?
#include <stdio.h>
#include <gtk/gtk.h>
#include <gdk-pixbuf/gdk-pixbuf.h>
GtkWidget *notebook;
gboolean resize_image(GtkWidget *widget, GdkRectangle *allocation,
gpointer user_data)
{
int w,h, pagenum;
GdkPixbuf *pxbscaled;
GtkWidget *image;
GdkPixbuf *pixbuf;
pagenum = gtk_notebook_get_current_page (GTK_NOTEBOOK(notebook));
image = gtk_notebook_get_nth_page (GTK_NOTEBOOK(notebook), pagenum);
// GtkImageType image_type = gtk_image_get_storage_type
// (GTK_IMAGE(image));
pixbuf = gtk_image_get_pixbuf(GTK_IMAGE(image));
h = allocation->height;
w = (gdk_pixbuf_get_width(pixbuf) * h) / gdk_pixbuf_get_height(pixbuf);
pxbscaled = gdk_pixbuf_scale_simple(pixbuf, w, h, GDK_INTERP_BILINEAR);
printf("Allocation height %d width %d.\n", h, w);
gtk_image_set_from_pixbuf(GTK_IMAGE(image), pxbscaled);
g_object_unref (pxbscaled);
sleep(2);
return FALSE;
}
static gboolean delete( GtkWidget *widget,
GtkWidget *event,
gpointer data )
{
gtk_main_quit ();
return FALSE;
}
int main( int argc,
char *argv[] )
{
GtkWidget *window;
GtkWidget *button;
GtkWidget *table;
GtkWidget *label;
GtkWidget *image;
int i;
char bufferl[32];
gtk_init (&argc, &argv);
window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
// gtk_widget_set_size_request (GTK_WIDGET(window), 800, 480);
g_signal_connect (window, "delete-event",
G_CALLBACK (delete), NULL);
gtk_container_set_border_width (GTK_CONTAINER (window), 10);
table = gtk_grid_new ();
gtk_container_add (GTK_CONTAINER (window), table);
/* Create notebook, place position of tabs */
notebook = gtk_notebook_new ();
gtk_notebook_set_tab_pos (GTK_NOTEBOOK (notebook), GTK_POS_TOP);
gtk_grid_attach (GTK_GRID (table), notebook, 0, 6, 3, 3);
gtk_widget_show (notebook);
/* Append pages to the notebook */
for (i = 0; i < 2; i++) {
sprintf(bufferl, "Page %d", i + 1);
if (i == 0) {
image = gtk_image_new_from_file("image1.jpg");
} else {
image = gtk_image_new_from_file("image2.jpg");
}
gtk_widget_set_halign(image, GTK_ALIGN_START);
gtk_widget_set_valign(image, GTK_ALIGN_START);
g_signal_connect(window, "size-allocate",
G_CALLBACK(resize_image), NULL);
label = gtk_label_new (bufferl);
gtk_notebook_append_page (GTK_NOTEBOOK(notebook),
image, label);
}
/* Create a close button */
button = gtk_button_new_with_label ("close");
g_signal_connect (button, "clicked",
G_CALLBACK (delete), NULL);
gtk_grid_attach (GTK_GRID (table), button, 0, 10, 1, 1);
gtk_widget_show_all (window);
gtk_main ();
return 0;
}
A user will need to provide image1.jpg and image2.jpg. Edit out the sleep call will result in the program filling the screen extremely quickly.
EDIT: I have also asked this question on the gtk mailing list.

Answer 1

The window with the image was growing because I was applying the size of the window to the image. Hence the image got larger and thus made the window get larger. Which continued in an endless progression, the "size-allocate" signal was constantly being called.
I fixed it by limiting the allocation height in the call back, by multiplying it by 0.75.
Now I can expand and contract the window with ease and it does not grow out of control.
The image does get ugly quite quickly, but that is another problem.