Re: Help replacing GtkDrawingArea with GtkLayout

From: Joël Krähemann <joel weedlight ch>
To: richard rshann plus com
Cc: gtk-app-devel-list gnome org
Subject: Re: Help replacing GtkDrawingArea with GtkLayout
Date: Tue, 11 Mar 2014 21:14:53 +0100

On Tue, 2014-03-11 at 14:01 +0000, Richard Shann wrote:

On Tue, 2014-03-11 at 13:18 +0100, Joël Krähemann wrote:

On Tue, 2014-03-11 at 08:12 +0000, Richard Shann wrote:

On Tue, 2014-03-11 at 04:43 +0100, Joël Krähemann wrote:

On Mon, 2014-03-10 at 09:52 +0000, Richard Shann wrote:

On Mon, 2014-03-10 at 09:29 +0100, Joël Krähemann wrote:

On Mon, 2014-03-10 at 09:26 +0100, Joël Krähemann wrote:

On Sun, 2014-03-09 at 14:03 +0000, Richard Shann wrote:

From: Jo?l Kr?hemann <joel weedlight ch>
To: gtk-app-devel-list gnome org
Subject: Re: Help replacing GtkDrawingArea with GtkLayout
Message-ID: <1394327737 3369 3 camel debian>
Content-Type: text/plain; charset="us-ascii"

Hi,

Didn't before but may be check the following:

g_object_set(G_OBJECT(layout),
  "app-paintable\0", TRUE, 
  NULL);


Hmm, I hadn't noticed that property. It is presumably set ok since I can
draw and place widgets on the GtkLayout. It was the configure and scroll
events that I didn't receive.
BTW why do you have two NULL bytes at the end of the property name
(AFAIK only one is needed)?

Richard


Assumed you get annoyed by warnings, you can slightly disable it. It's
distribution depend what flags are per default on. For further reading:

http://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html

regards
Joël


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You should ask why I forget to add GDK_SCROLL_MASK


Well, I didn't ask because I already tried it. The GtkLayout didn't
receive that nor the configure signal even with setting
GDK_ALL_EVENTS_MASK. What *did* work is receiving the events on the
parent.
But I am still curious why you have two NULL bytes termination your
signal name strings, the extra one must surely get ignored...

Richard


gtk_widget_set_events (GTK_WIDGET (layout),
  GDK_EXPOSURE_MASK 
  | GDK_LEAVE_NOTIFY_MASK 
  | GDK_BUTTON_PRESS_MASK 
  | GDK_BUTTON_RELEASE_MASK 
  | GDK_POINTER_MOTION_MASK 
  | GDK_POINTER_MOTION_HINT_MASK 
  | GDK_SCROLL_MASK
  );

then you have to

g_signal_connect(G_OBJECT(layout), "scroll-event\0",
  G_CALLBACK(layout_callback), NULL);


gboolean
layout_callback(GtkWidget *widget, GdkEvent *event, gpointer user_data)
{
  /* do your thing */

  return(FALSE);
}

Is your code somewhere online? Are you using
gtk_widget_set_size_request()?


I gave a minimal example earlier in the thread:

https://mail.gnome.org/archives/gtk-app-devel-list/2014-March/msg00007.html


Richard

Much better! As someone told you before the widget is realized you have
to set the appropriate flags.


The widget is not realized before the flags are set. Indeed gtk_main()
has not even been called, so no signals have been emitted when the flags
are set.
Here is the code with the sequence altered as you suggest:

8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><
#include <gtk/gtk.h>
static gboolean
configure_event ()
{
    fprintf (stderr, "configure-event\n");
    gtk_main_quit ();
    return FALSE;
}

int main(int argc, char *argv[])
{
    GtkWidget *window;
    GtkWidget *layout;
    GtkWidget *label1;

    gtk_init (&argc, &argv);

    window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
   
    layout = gtk_layout_new (NULL, NULL);
    gtk_widget_add_events (layout, GDK_ALL_EVENTS_MASK);
    gtk_container_add (GTK_CONTAINER (window), layout);
   

    label1 = gtk_label_new ("label 1");

    gtk_layout_put (GTK_LAYOUT (layout), label1, 10, 50);
  

    gtk_widget_show_all (window);

    GdkWindow *win = gtk_widget_get_window(layout); 
    g_print("win is %p initial mask 0x%x\n", win, gdk_window_get_events
(win));
    gdk_window_set_events (win, gdk_window_get_events (win) |
GDK_STRUCTURE_MASK);
    g_print("After adding GDK_STRUCTURE_MASK mask 0x%x\n",
gdk_window_get_events (win));
    
    g_signal_connect (layout, "configure-event", G_CALLBACK
(configure_event), NULL);

    gtk_main ();

    return 0;
}

8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><8><

As you can verify, it makes no difference - it would be very bizarre if
it did.


layout = gtk_layout_new (NULL, NULL);

/* SET FLAGS HERE */

gtk_container_add (GTK_CONTAINER (window), layout);


and don't forget to add the missing parameters.


The parameters in the definition of the callback function
configure_event(void) are not missing, it is deliberately declared not
to have them. It is not a good idea to declare the callback with
parameters if they are not going to be used.

Richard


gboolean
configure_event(GtkWidget *widget, GdkEventConfigure *event, gpointer
user_data){
  /* YOUR CODE HERE */
}


Please consider the documentation of gtk_widget_set_app_paintable()
don't believe GtkLayout can do your job. You could try id with a
GtkDrawingArea with a cairo surface. I do some drawing in C take a look
at http://sourceforge.net/p/ags/code/HEAD/tree/src/ags/X/ags_editor.c

regards Joël

Follow-Ups:
- Re: Help replacing GtkDrawingArea with GtkLayout
  - From: Joël Krähemann

References:
- Re: Help replacing GtkDrawingArea with GtkLayout
  - From: Richard Shann
- Re: Help replacing GtkDrawingArea with GtkLayout
  - From: Joël Krähemann
- Re: Help replacing GtkDrawingArea with GtkLayout
  - From: Joël Krähemann
- Re: Help replacing GtkDrawingArea with GtkLayout
  - From: Richard Shann
- Re: Help replacing GtkDrawingArea with GtkLayout
  - From: Richard Shann

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