Re: Flickering with Socket and Plug

[René Hansen <rene hansen-audio de>]

Hey Eric,

> I looked at this a little more and can get the flicker. Testing on
> Ubuntu16.04 with GTK3.18 it works without flicker and on Ubuntu16.04
> with a jhbuild of GTK3.22 it does flicker. I tweaked your code a little
> so that I could test it a little easier.

Good, that you can reproduce it!

So what is your suggestion, how can we procceed with this issue? This is 
very likely a bug in GTK, right?

Many thanks for our effort!
René

On 27.09.2017 22:00, cecashon aol com wrote:
> Hi Rene,
>
> I looked at this a little more and can get the flicker. Testing on 
> Ubuntu16.04 with GTK3.18 it works without flicker and on Ubuntu16.04 
> with a jhbuild of GTK3.22 it does flicker. I tweaked your code a little 
> so that I could test it a little easier.
>
> Eric
>
>
> /*
>      gcc -Wall socket_plug1.c -o socket_plug1 `pkg-config --cflags 
> --libs gtk+-3.0`
>      Tested on Ubuntu16.04 and GTK3.18 and GTK3.22
>      Flickers with 3.22
> */
>
> #include <cairo.h>
> #include <gtk/gtkx.h>
>
> //cairo_surface_t * image = NULL;
> GdkPixbuf *image=NULL;
> static GTimer *timer=NULL;
> static guint timer_id=0;
>
> gboolean timeout(gpointer data)
> {
>    gtk_widget_queue_draw(GTK_WIDGET(data));
>    return TRUE;
> }
>
> gboolean draw_callback (GtkWidget *widget, cairo_t *cr, gpointer data)
> {
>    g_timer_start(timer);
>    gint width=gtk_widget_get_allocated_width(widget);
>    gint height=gtk_widget_get_allocated_height(widget);
>    gint rect_x=width/10;
>    gint rect_y=height/10;
>    gint i=0;
>    gint j=0;
>    gint move_x=0;
>    gint move_y=0;
>    static gint overlap=0;
>
>    //Set some limits to draw with.
>    if(rect_x>20&&rect_y>20)
>      {
>        GdkPixbuf *pixbuf=gdk_pixbuf_scale_simple(image, rect_x, rect_y, 
> GDK_INTERP_BILINEAR);
>        for(i=0;i<10;i++)
>          {
>            for(j=0;j<10;j++)
>              {
>                gdk_cairo_set_source_pixbuf(cr, pixbuf, move_x, move_y);
>                cairo_paint(cr);
>                move_x+=rect_x-overlap;
>              }
>            move_x=0;
>            move_y+=rect_y;
>          }
>        g_object_unref(pixbuf);
>
>        if(overlap==20) overlap=0;
>        else overlap++;
>      }
>    else
>      {
>        //Just draw white if below the limit.
>        cairo_set_source_rgb(cr, 1.0, 1.0, 1.0);
>        cairo_paint(cr);
>      }
>
>    g_print("Timer %f\n", g_timer_elapsed(timer, NULL));
>    return FALSE;
> }
> static void quit_program(GtkWidget *widget, gpointer data)
>    {
>      g_source_remove(timer_id);
>      gtk_main_quit();
>    }
> //-------------------------------------------------------------------------
> int main(int argc, char** argv)
> {
>    gtk_init (&argc, &argv);
>
>    //image = 
> cairo_image_surface_create_from_png("1200px-GTK+_logo.svg.png");
>    GError *error=NULL;
>    image = gdk_pixbuf_new_from_file("1200px-GTK+_logo.svg.png", &error);
>    if(error!=NULL) g_print("%s\n", error->message);
>
>    GtkWidget* window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
>    gtk_window_set_default_size(GTK_WINDOW(window), 400, 400);
>    g_signal_connect(window, "destroy", G_CALLBACK(quit_program), NULL);
>
>    timer=g_timer_new();
>
>    GtkWidget* socket = gtk_socket_new();
>    gtk_widget_set_hexpand(socket, TRUE);
>    gtk_widget_set_vexpand(socket, TRUE);
>    gtk_container_add(GTK_CONTAINER(window), socket);
>
>    Window socket_id = gtk_socket_get_id(GTK_SOCKET(socket));
>    GtkWidget* plug = gtk_plug_new(socket_id);
>    gtk_widget_set_hexpand(plug, TRUE);
>    gtk_widget_set_vexpand(plug, TRUE);
>
>    GtkWidget* drawing_area = gtk_drawing_area_new ();
>    gtk_widget_set_hexpand(drawing_area, TRUE);
>    gtk_widget_set_vexpand(drawing_area, TRUE);
>    gtk_container_add(GTK_CONTAINER(plug), drawing_area);
>    g_signal_connect (G_OBJECT (drawing_area), "draw", G_CALLBACK 
> (draw_callback), NULL);
>
>    timer_id=g_timeout_add(16, timeout, drawing_area);
>    gtk_widget_show_all(plug);
>    gtk_widget_show_all (window);
>
>    gtk_main ();
>    return 0;
> }