Re: gtk_widget_queue_resize() forgetting allocation

[Stephen Bach <9sjb qlink queensu ca>]

No one has any insight here?  It seems to me that a call to
gtk_widget_size_request() should be followed by a gtk_widget_size_allocate()
when generated by a gtk_widget_queue_resize(), especially if the program goes
idle.

Is there something about the size negotiation process that I'm
misunderstanding?

Thanks

On Sun, Sep 19, 2004 at 12:02:48PM -0400, Stephen Bach wrote:
> Hello,
> 
> I've run into an issue in a program I'm writing where sometimes a call to
> gtk_widget_queue_resize() ends in a request rather than an allocate.  I've
> put together a short test case (tested in GTK+ 2.4.4) which keeps the spirit
> of the program intact (see below).
> 
> First, a little context -- connecting to the toplevel window's
> configure-event to queue a resize on one of its grandchildren probably seems
> unconventional and even redundant, but it's a requirement of my program (not
> this test case) because the request function of that grandchild optimizes
> itself to the window's width (i.e. the grandchild needs more information than
> just the size requests of its children).  In the real program the change in
> the window's width is passed on and then the queue_resize is made.
> 
> All of that is beside the point.  Here is the problem: _sometimes_ when the
> window is resized, there is no allocation of the grandchild label after a
> request.  If the window is resized again, _then_ the allocation happens
> (usually followed by another unfulfilled size request).
> 
> One thing that's kind-of strange is that if the label is added directly to
> the scrolledwindow (without being added to the vbox, which then gets put into
> the scrolledwindow), everything works as it should -- every size request is
> followed by a size allocate.  I also tried using a table instead of a vbox,
> but the result is the same.
> 
> Insight welcome.
> 
> Thanks,
> 
> Stephen
> 
> =========
> 
> #include <gtk/gtk.h>
> 
> static void
> allocate_callback(GtkWidget *label, GtkAllocation *allocation, gpointer data) {
> 	g_print("(allocate)");
> }
> 
> static void
> request_callback(GtkWidget *label, GtkRequisition *requisition, gpointer data) {
> 	g_print("(request)");
> }
> 
> static gboolean
> configure_callback(GtkWidget* window, GdkEventConfigure* event, gpointer data) {
> 	GtkWidget* label = data;
> 
> 	/* Only queue resize if the width is changed */
> 	if (event->width != window->allocation.width)
> 		gtk_widget_queue_resize(label);
> 
> 	return FALSE;
> }
> 
> int
> main(int argc, char* argv[]) {
> 
> 	GtkWidget* window;
> 	GtkWidget* scrolled_window;
> 	GtkWidget* vbox;
> 	GtkWidget* label;
> 
> 	gtk_init (&argc, &argv);
> 
> 	window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
> 	scrolled_window = gtk_scrolled_window_new(NULL, NULL);
> 	vbox = gtk_vbox_new(FALSE, 0);
> 	label = gtk_label_new("Testing");
> 
> 	g_signal_connect(G_OBJECT(label), "size-allocate",
> 	                 G_CALLBACK(allocate_callback), NULL);
> 	g_signal_connect(G_OBJECT(label), "size-request",
> 	                 G_CALLBACK(request_callback), NULL);
> 	g_signal_connect(G_OBJECT(window), "configure-event",
> 	                 G_CALLBACK(configure_callback), label);
> 
> 	gtk_scrolled_window_set_policy(
> 		GTK_SCROLLED_WINDOW(scrolled_window),
> 		GTK_POLICY_NEVER,
> 		GTK_POLICY_ALWAYS);
> 
> 	gtk_box_pack_start(GTK_BOX(vbox), label, FALSE, FALSE, 0);
> 	gtk_scrolled_window_add_with_viewport(
> 		GTK_SCROLLED_WINDOW(scrolled_window), vbox);
> 	gtk_container_add(GTK_CONTAINER(window), scrolled_window);
> 
> 	gtk_widget_show(label);
> 	gtk_widget_show(vbox);
> 	gtk_widget_show(scrolled_window);
> 	gtk_widget_show(window);
> 
> 	gtk_main();
> 
> 	return 0;
> }
> 
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