select region in GTK+

Да не должно быть сложного решения. Конечно, все зависит от того, какой виджет используется для отрисовки изображения, но в любом случае нужно просто повесит соответствующие обработчики на сигналы button_press_event, button_release_event, motion_notify.

Вот пример для GtkDrawingArea: В качестве pixmap может быть картинка.

#include <stdlib.h> #include <gtk/gtk.h>

static GdkPixmap *pixmap = NULL; static GdkPixmap *temp_pixmap = NULL;

static GdkRectangle rect; static GdkPoint point; static gboolean in_draw;

/* Create a new backing pixmap of the appropriate size */ static gint configure_event( GtkWidget *widget, GdkEventConfigure *event ) { if (pixmap) g_object_unref (pixmap); if (temp_pixmap) g_object_unref (temp_pixmap);

pixmap = gdk_pixmap_new (widget->window, widget->allocation.width, widget->allocation.height, -1); gdk_draw_rectangle (pixmap, widget->style->white_gc, TRUE, 0, 0, widget->allocation.width, widget->allocation.height);

temp_pixmap = gdk_pixmap_new (widget->window, widget->allocation.width, widget->allocation.height, -1); return TRUE; }

/* Redraw the screen from the backing pixmap */ static gint expose_event( GtkWidget *widget, GdkEventExpose *event ) { gdk_draw_drawable (temp_pixmap, widget->style->black_gc, pixmap, event->area.x, event->area.y, event->area.x, event->area.y, event->area.width, event->area.height);

if (in_draw) gdk_draw_rectangle (temp_pixmap, widget->style->black_gc, FALSE, rect.x, rect.y, rect.width, rect.height);

gdk_draw_drawable (widget->window, widget->style->fg_gc[GTK_WIDGET_STATE (widget)], temp_pixmap, event->area.x, event->area.y, event->area.x, event->area.y, event->area.width, event->area.height); return FALSE; }

static void update_area (GtkWidget *widget) { gtk_widget_queue_draw_area (widget, rect.x, rect.y, rect.width + 1, rect.height + 1); }

static gint button_press_event( GtkWidget *widget, GdkEventButton *event ) { if (event->button == 1 && pixmap != NULL) { rect.x = event->x; rect.y= event->y; rect.width = 0; rect.height = 0; point.x = rect.x; point.y = rect.y; in_draw = TRUE; update_area (widget); }

return TRUE; }

static gint button_release_event (GtkWidget *widget, GdkEventButton *event ) { if (event->button == 1 && pixmap != NULL) { in_draw = FALSE; update_area (widget); } g_message ("Selected region x=%d y=%d width=%d height=%d", rect.x, rect.y, rect.width, rect.height); return TRUE; }

#include <stdlib.h>
#include <gtk/gtk.h>

static GdkPixmap *pixmap = NULL;
static GdkPixmap *temp_pixmap = NULL;

static GdkRectangle rect;
static GdkPoint point;
static gboolean in_draw;

/* Create a new backing pixmap of the appropriate size */
static gint configure_event( GtkWidget         *widget,
                             GdkEventConfigure *event )
{
  if (pixmap)
    g_object_unref (pixmap);
  if (temp_pixmap)
    g_object_unref (temp_pixmap);
    

  pixmap = gdk_pixmap_new (widget->window,
			   widget->allocation.width,
			   widget->allocation.height,
			   -1);
  gdk_draw_rectangle (pixmap,
		      widget->style->white_gc,
		      TRUE,
		      0, 0,
		      widget->allocation.width,
		      widget->allocation.height);

  temp_pixmap = gdk_pixmap_new (widget->window,
			   widget->allocation.width,
			   widget->allocation.height,
			   -1);
  return TRUE;
}

/* Redraw the screen from the backing pixmap */
static gint expose_event( GtkWidget      *widget,
                          GdkEventExpose *event )
{
  gdk_draw_drawable (temp_pixmap,
		     widget->style->black_gc,
		     pixmap,
		     event->area.x, event->area.y,
		     event->area.x, event->area.y,
		     event->area.width, event->area.height);

  if (in_draw)
	gdk_draw_rectangle (temp_pixmap,
    			      widget->style->black_gc,
			      FALSE,
			      rect.x, rect.y,
			      rect.width, rect.height);

  
  gdk_draw_drawable (widget->window,
		     widget->style->fg_gc[GTK_WIDGET_STATE (widget)],
		     temp_pixmap,
		     event->area.x, event->area.y,
		     event->area.x, event->area.y,
		     event->area.width, event->area.height);
		     
  return FALSE;
}

static void update_area (GtkWidget *widget)
{
  gtk_widget_queue_draw_area (widget, 
		      rect.x, rect.y,
		      rect.width + 1, rect.height + 1);
}

static gint button_press_event( GtkWidget      *widget,
                                GdkEventButton *event )
{
  if (event->button == 1 && pixmap != NULL)
    {
      rect.x = event->x; rect.y= event->y;
      rect.width = 0; rect.height = 0;
      point.x = rect.x; point.y = rect.y;
      in_draw = TRUE;
      
      update_area (widget);
    }

  return TRUE;
}

static gint button_release_event (GtkWidget      *widget,
                                GdkEventButton *event )
{
  if (event->button == 1 && pixmap != NULL)
    {
      in_draw = FALSE;
      update_area (widget);
    }
    
  g_message ("Selected region x=%d y=%d width=%d height=%d", rect.x, rect.y, rect.width, rect.height);
  return TRUE;
}

static gint motion_notify_event( GtkWidget *widget,
                                 GdkEventMotion *event )
{
  int x, y;
  GdkModifierType state;

  if (event->is_hint)
    gdk_window_get_pointer (event->window, &x, &y, &state);
  else
    {
      x = event->x;
      y = event->y;
      state = event->state;
    }
    
  if (in_draw && state & GDK_BUTTON1_MASK && pixmap)
   {
    in_draw = FALSE;
    update_area (widget);
    in_draw = TRUE;
    rect.width = abs (x - point.x);
    rect.height = abs (y - point.y);
    rect.x = MIN (x, point.x);
    rect.y = MIN (y, point.y);
    update_area (widget);    
   }
  
  return TRUE;
}

void quit ()
{
  exit (0);
}

int main( int   argc, 
          char *argv[] )
{
  GtkWidget *window;
  GtkWidget *drawing_area;
  GtkWidget *vbox;

  GtkWidget *button;

  gtk_init (&argc, &argv);
  
  in_draw = FALSE;

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);

  vbox = gtk_vbox_new (FALSE, 0);
  gtk_container_add (GTK_CONTAINER (window), vbox);
  gtk_widget_show (vbox);

  g_signal_connect (G_OBJECT (window), "destroy",
                    G_CALLBACK (quit), NULL);

  /* Create the drawing area */

  drawing_area = gtk_drawing_area_new ();
  gtk_widget_set_size_request (GTK_WIDGET (drawing_area), 200, 200);
  gtk_box_pack_start (GTK_BOX (vbox), drawing_area, TRUE, TRUE, 0);

  gtk_widget_show (drawing_area);

  /* Signals used to handle backing pixmap */

  g_signal_connect (G_OBJECT (drawing_area), "expose_event",
		    G_CALLBACK (expose_event), NULL);
  g_signal_connect (G_OBJECT (drawing_area),"configure_event",
		    G_CALLBACK (configure_event), NULL);

  /* Event signals */

  g_signal_connect (G_OBJECT (drawing_area), "motion_notify_event",
		    G_CALLBACK (motion_notify_event), NULL);
  g_signal_connect (G_OBJECT (drawing_area), "button_press_event",
		    G_CALLBACK (button_press_event), NULL);
  g_signal_connect (G_OBJECT (drawing_area), "button_release_event",
		    G_CALLBACK (button_release_event), NULL);

  gtk_widget_set_events (drawing_area, GDK_EXPOSURE_MASK
			 | GDK_LEAVE_NOTIFY_MASK
			 | GDK_BUTTON_PRESS_MASK
			 | GDK_BUTTON_RELEASE_MASK
			 | GDK_POINTER_MOTION_MASK
			 | GDK_POINTER_MOTION_HINT_MASK);

  /* .. And a quit button */
  button = gtk_button_new_with_label ("Quit");
  gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);

  g_signal_connect_swapped (G_OBJECT (button), "clicked",
			    G_CALLBACK (gtk_widget_destroy),
			    G_OBJECT (window));
  gtk_widget_show (button);

  gtk_widget_show (window);

  gtk_main ();

  return 0;
}

Достал уже этот форум. Сколько не пишу, никак нормально сообщение запостить не получается. То Preformatted забываешь, то сообщение слишком большое.

Спасибо большое. Сейчас попробую. Похоже, что это практически то, что мне нужно.