[goocanvas] Motion event compression

["Felix Weilbach t-online de" <Felix Weilbach t-online de>]

I'm trying to deactivate motion compression on goocanvas, but it dosen't have any effect.

I'm using goocanvas2.

 

The code to deactivate event compression:

 

gdk_win_canvas = gtk_widget_get_window(canvas);

gdk_window_set_event_compression(gdk_win_canvas, FALSE);

 

At the end I include the code sample that I'm using. With the same sample with GtkDrawingArea instead of GooCanvas I get in 10 seconds

1400 motion events (drawing included and with a stylus). With goocanvas, I get just 600 motion events (drawing excluded and also with a stylus) in 10 seconds. If I turn on event compression in the sample with GtkDrawingArea, I get also 600 motion events in 10 seconds, it seems to me that the call to gdk_set_event_compression() has no effect on GooCanvas.

Can anyone tell me what I'm doing wrong?

 

Code Sample 1 with GooCanvas (When the button is released the counted motion events are shown, this is the GtkDrawingArea example from gtk3 documentation a little bit ugly modified to work with goocanvas):

 

Compile: gcc `pkg-config --cflags gtk+-3.0` -I/usr/include/goocanvas-2.0 -o goo-canvas goo-canvas.c `pkg-config --libs gtk+-3.0` -lgoocanvas-2.0 (on Ubuntu)

 

Source:

 

#include <gtk/gtk.h>

#include <goocanvas-2.0/goocanvas.h>

 

/* Surface to store current scribbles */

static cairo_surface_t *surface = NULL;

 

static int motion_cnt = 0;

 

static void

clear_surface (void)

{

  cairo_t *cr;

 

  cr = cairo_create (surface);

 

  cairo_set_source_rgb (cr, 1, 1, 1);

  cairo_paint (cr);

 

  cairo_destroy (cr);

}

 

/* Create a new surface of the appropriate size to store our scribbles */

static gboolean

configure_event_cb (GtkWidget         *widget,

                    GdkEventConfigure *event,

                    gpointer           data)

{

  if (surface)

    cairo_surface_destroy (surface);

 

  surface = gdk_window_create_similar_surface (gtk_widget_get_window (widget),

                                               CAIRO_CONTENT_COLOR,

                                               gtk_widget_get_allocated_width (widget),

                                               gtk_widget_get_allocated_height (widget));

 

  /* Initialize the surface to white */

  clear_surface ();

 

  /* We've handled the configure event, no need for further processing. */

  return TRUE;

}

 

/* Redraw the screen from the surface. Note that the ::draw

 * signal receives a ready-to-be-used cairo_t that is already

 * clipped to only draw the exposed areas of the widget

 */

static gboolean

draw_cb (GtkWidget *widget,

         cairo_t   *cr,

         gpointer   data)

{

  cairo_set_source_surface (cr, surface, 0, 0);

  cairo_paint (cr);

 

  return FALSE;

}

 

/* Draw a rectangle on the surface at the given position */

static void

draw_brush (GtkWidget *widget,

            gdouble    x,

            gdouble    y)

{

  cairo_t *cr;

 

  /* Paint to the surface, where we store our state */

  cr = cairo_create (surface);

 

  cairo_rectangle (cr, x - 3, y - 3, 6, 6);

  cairo_fill (cr);

 

  cairo_destroy (cr);

 

  /* Now invalidate the affected region of the drawing area. */

  gtk_widget_queue_draw_area (widget, x - 3, y - 3, 6, 6);

}

 

/* Handle button press events by either drawing a rectangle

 * or clearing the surface, depending on which button was pressed.

 * The ::button-press signal handler receives a GdkEventButton

 * struct which contains this information.

 */

static gboolean

button_press_event_cb (GtkWidget      *widget,

                       GdkEventButton *event,

                       gpointer        data)

{

  motion_cnt=0;

  /* paranoia check, in case we haven't gotten a configure event */

  if (surface == NULL)

    return FALSE;

 

  if (event->button == GDK_BUTTON_PRIMARY)

    {

      draw_brush (widget, event->x, event->y);

    }

  else if (event->button == GDK_BUTTON_SECONDARY)

    {

      clear_surface ();

      gtk_widget_queue_draw (widget);

    }

 

  /* We've handled the event, stop processing */

  return TRUE;

}

 

/* Handle motion events by continuing to draw if button 1 is

 * still held down. The ::motion-notify signal handler receives

 * a GdkEventMotion struct which contains this information.

 */

static gboolean

motion_notify_event_cb (GtkWidget      *widget,

                        GdkEventMotion *event,

                        gpointer        data)

{

  int x, y;

  GdkModifierType state;

 

  g_print("motion\n");

  motion_cnt++;

  return TRUE;

}

 

static gboolean

button_release_event_cb (GtkWidget      *widget,

                       GdkEventButton *event,

                       gpointer        data)

{

  g_print("drawed %d points\n", motion_cnt);

  motion_cnt=0;

  return TRUE;

}

 

static void

close_window (void)

{

  if (surface)

    cairo_surface_destroy (surface);

}

 

static void

activate (GtkApplication *app,

          gpointer        user_data)

{

  GdkWindow *gdk_win_darea, *gdk_win_frame, *gdk_win_win;

  GtkWidget *window;

  GtkWidget *frame;

  //GtkWidget *drawing_area;

  GtkWidget *canvas;

 

  window = gtk_application_window_new (app);

  gtk_window_set_title (GTK_WINDOW (window), "Drawing Area");

 

  g_signal_connect (window, "destroy", G_CALLBACK (close_window), NULL);

 

  gtk_container_set_border_width (GTK_CONTAINER (window), 8);

 

  frame = gtk_frame_new (NULL);

  gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);

  gtk_container_add (GTK_CONTAINER (window), frame);

 

  canvas = goo_canvas_new();

  gtk_widget_set_size_request(canvas, 100, 100);

  goo_canvas_set_bounds (GOO_CANVAS (canvas), 0, 0, 1000, 1000);

  gtk_container_add(GTK_CONTAINER(frame), canvas);

 

  /* Event signals */

  g_signal_connect (canvas, "motion-notify-event",

                    G_CALLBACK (motion_notify_event_cb), NULL);

  g_signal_connect (canvas, "button-release-event",

                    G_CALLBACK (button_release_event_cb), NULL);

  g_signal_connect (canvas, "button-press-event",

                    G_CALLBACK (button_press_event_cb), NULL);

 

  /* Ask to receive events the drawing area doesn't normally

   * subscribe to. In particular, we need to ask for the

   * button press and motion notify events that want to handle.

   */

  gtk_widget_set_events (canvas, gtk_widget_get_events (canvas)

                      // | GDK_POINTER_MOTION_HINT_MASK

                         | GDK_LEAVE_NOTIFY_MASK

                         | GDK_BUTTON_PRESS_MASK

                         | GDK_BUTTON_RELEASE_MASK

                         | GDK_POINTER_MOTION_MASK);

 

  gtk_widget_show_all (window);

 

  gdk_win_darea = gtk_widget_get_window(canvas);

  gdk_window_set_event_compression(gdk_win_darea, FALSE);

 

  gdk_win_frame = gtk_widget_get_window(frame);

  gdk_window_set_event_compression(gdk_win_frame, FALSE);

 

  gdk_win_win = gtk_widget_get_window(window);

  gdk_window_set_event_compression(gdk_win_win, FALSE);

}

 

int

main (int    argc,

      char **argv)

{

  GtkApplication *app;

  int status;

 

  app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);

  g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);

  status = g_application_run (G_APPLICATION (app), argc, argv);

  g_object_unref (app);

 

  return status;

}

 

Code Sample 2 with GtkDrawingArea (This is nearly the GtkDrawingArea example from gtk3 documentation):

 

Compile: gcc `pkg-config --cflags gtk+-3.0` -o drawing-area drawing-area.c `pkg-config --libs gtk+-3.0` (on Ubuntu)

 

Source:

 

#include <gtk/gtk.h>

 

/* Surface to store current scribbles */

static cairo_surface_t *surface = NULL;

 

static int motion_cnt = 0;

 

static void

clear_surface (void)

{

  cairo_t *cr;

 

  cr = cairo_create (surface);

 

  cairo_set_source_rgb (cr, 1, 1, 1);

  cairo_paint (cr);

 

  cairo_destroy (cr);

}

 

/* Create a new surface of the appropriate size to store our scribbles */

static gboolean

configure_event_cb (GtkWidget         *widget,

                    GdkEventConfigure *event,

                    gpointer           data)

{

  if (surface)

    cairo_surface_destroy (surface);

 

  surface = gdk_window_create_similar_surface (gtk_widget_get_window (widget),

                                               CAIRO_CONTENT_COLOR,

                                               gtk_widget_get_allocated_width (widget),

                                               gtk_widget_get_allocated_height (widget));

 

  /* Initialize the surface to white */

  clear_surface ();

 

  /* We've handled the configure event, no need for further processing. */

  return TRUE;

}

 

/* Redraw the screen from the surface. Note that the ::draw

 * signal receives a ready-to-be-used cairo_t that is already

 * clipped to only draw the exposed areas of the widget

 */

static gboolean

draw_cb (GtkWidget *widget,

         cairo_t   *cr,

         gpointer   data)

{

  cairo_set_source_surface (cr, surface, 0, 0);

  cairo_paint (cr);

 

  return FALSE;

}

 

/* Draw a rectangle on the surface at the given position */

static void

draw_brush (GtkWidget *widget,

            gdouble    x,

            gdouble    y)

{

  cairo_t *cr;

 

  /* Paint to the surface, where we store our state */

  cr = cairo_create (surface);

 

  cairo_rectangle (cr, x - 3, y - 3, 6, 6);

  cairo_fill (cr);

 

  cairo_destroy (cr);

 

  /* Now invalidate the affected region of the drawing area. */

  gtk_widget_queue_draw_area (widget, x - 3, y - 3, 6, 6);

}

 

/* Handle button press events by either drawing a rectangle

 * or clearing the surface, depending on which button was pressed.

 * The ::button-press signal handler receives a GdkEventButton

 * struct which contains this information.

 */

static gboolean

button_press_event_cb (GtkWidget      *widget,

                       GdkEventButton *event,

                       gpointer        data)

{

  /* paranoia check, in case we haven't gotten a configure event */

  if (surface == NULL)

    return FALSE;

 

  if (event->button == GDK_BUTTON_PRIMARY)

    {

      draw_brush (widget, event->x, event->y);

    }

  else if (event->button == GDK_BUTTON_SECONDARY)

    {

      clear_surface ();

      gtk_widget_queue_draw (widget);

    }

 

  /* We've handled the event, stop processing */

  return TRUE;

}

 

/* Handle motion events by continuing to draw if button 1 is

 * still held down. The ::motion-notify signal handler receives

 * a GdkEventMotion struct which contains this information.

 */

static gboolean

motion_notify_event_cb (GtkWidget      *widget,

                        GdkEventMotion *event,

                        gpointer        data)

{

  int x, y;

  GdkModifierType state;

 

  /* paranoia check, in case we haven't gotten a configure event */

  if (surface == NULL)

    return FALSE;

 

  if (event->is_hint) {

    gdk_window_get_device_position (event->window, event->device, &x, &y, &state);

  }

  else {

      x = event->x;

      y = event->y;

      state = event->state;

    }

 

  if (event->state & GDK_BUTTON1_MASK) {

    motion_cnt++;

    g_print("motion\n");

    draw_brush (widget, event->x, event->y);

  }

 

  /* We've handled it, stop processing */

  return TRUE;

}

 

static gboolean

button_release_event_cb (GtkWidget      *widget,

                       GdkEventButton *event,

                       gpointer        data)

{

  g_print("drawed %d points\n", motion_cnt);

  motion_cnt=0;

  return TRUE;

}

 

static void

close_window (void)

{

  if (surface)

    cairo_surface_destroy (surface);

}

 

static void

activate (GtkApplication *app,

          gpointer        user_data)

{

  GdkWindow *gdk_win_darea, *gdk_win_frame, *gdk_win_win;

  GtkWidget *window;

  GtkWidget *frame;

  GtkWidget *drawing_area;

 

  window = gtk_application_window_new (app);

  gtk_window_set_title (GTK_WINDOW (window), "Drawing Area");

 

  g_signal_connect (window, "destroy", G_CALLBACK (close_window), NULL);

 

  gtk_container_set_border_width (GTK_CONTAINER (window), 8);

 

  frame = gtk_frame_new (NULL);

  gtk_frame_set_shadow_type (GTK_FRAME (frame), GTK_SHADOW_IN);

  gtk_container_add (GTK_CONTAINER (window), frame);

 

  drawing_area = gtk_drawing_area_new ();

  /* set a minimum size */

  gtk_widget_set_size_request (drawing_area, 100, 100);

 

  gtk_container_add (GTK_CONTAINER (frame), drawing_area);

 

  /* Signals used to handle the backing surface */

  g_signal_connect (drawing_area, "draw",

                    G_CALLBACK (draw_cb), NULL);

  g_signal_connect (drawing_area,"configure-event",

                    G_CALLBACK (configure_event_cb), NULL);

 

  /* Event signals */

  g_signal_connect (drawing_area, "motion-notify-event",

                    G_CALLBACK (motion_notify_event_cb), NULL);

  g_signal_connect (drawing_area, "button-release-event",

                    G_CALLBACK (button_release_event_cb), NULL);

  g_signal_connect (drawing_area, "button-press-event",

                    G_CALLBACK (button_press_event_cb), NULL);

 

  /* Ask to receive events the drawing area doesn't normally

   * subscribe to. In particular, we need to ask for the

   * button press and motion notify events that want to handle.

   */

  gtk_widget_set_events (drawing_area, gtk_widget_get_events (drawing_area)

                         // | GDK_POINTER_MOTION_HINT_MASK

                         | GDK_LEAVE_NOTIFY_MASK

                                     | GDK_BUTTON_PRESS_MASK

                         | GDK_BUTTON_RELEASE_MASK

                                     | GDK_POINTER_MOTION_MASK);

 

  gtk_widget_show_all (window);

 

  gdk_win_darea = gtk_widget_get_window(drawing_area);

  gdk_window_set_event_compression(gdk_win_darea, FALSE);

  /*gdk_win_frame = gtk_widget_get_window(frame);

  gdk_window_set_event_compression(gdk_win_frame, FALSE);

  gdk_win_win = gtk_widget_get_window(window);

  gdk_window_set_event_compression(gdk_win_win, FALSE);*/

}

 

int

main (int    argc,

      char **argv)

{

  GtkApplication *app;

  int status;

 

  app = gtk_application_new ("org.gtk.example", G_APPLICATION_FLAGS_NONE);

  g_signal_connect (app, "activate", G_CALLBACK (activate), NULL);

  status = g_application_run (G_APPLICATION (app), argc, argv);

  g_object_unref (app);

 

  return status;

}

 

 



 

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