[gnome-utils] screenshot: Rewrite event handling in area selection

[Benjamin Otte <otte src gnome org>]

commit 772b9cc0774468ea21addb85ef843ee8dfef9e00
Author: Benjamin Otte <otte redhat com>
Date:   Fri Feb 4 03:44:16 2011 +0100

    screenshot: Rewrite event handling in area selection
    
    The previous code was handling X events directly. This breaks when GTK
    decides to use XI2 and no more regular events arrive.
    Instead we now use the window we create anyway to catch the events. At
    the window, they'll arrive properly preprocessed by GTK in the way we
    expect them.
    As a bonus, this code does not rely on X11 anymore, so we can stop
    including gdkx.h.

 gnome-screenshot/screenshot-utils.c |  216 +++++++++++++++--------------------
 1 files changed, 92 insertions(+), 124 deletions(-)
---
diff --git a/gnome-screenshot/screenshot-utils.c b/gnome-screenshot/screenshot-utils.c
index 0a44be9..bae3d25 100644
--- a/gnome-screenshot/screenshot-utils.c
+++ b/gnome-screenshot/screenshot-utils.c
@@ -21,7 +21,7 @@
 #include "config.h"
 #include "screenshot-utils.h"
 
-#include <gdk/gdkx.h>
+#include <gdk/gdkkeysyms.h>
 #include <gtk/gtk.h>
 #include <glib.h>
 #include <glib/gi18n.h>
@@ -252,46 +252,64 @@ screenshot_find_current_window ()
   return current_window;
 }
 
-static void
-select_area_button_press (XKeyEvent    *event,
-                          GdkRectangle *rect,
-                          GdkRectangle *draw_rect)
+typedef struct {
+  GdkRectangle  rect;
+  gboolean      button_pressed;
+  GtkWidget    *window;
+} select_area_filter_data;
+
+static gboolean
+select_area_button_press (GtkWidget               *window,
+                          GdkEventButton          *event,
+                          select_area_filter_data *data)
 {
-  rect->x = event->x_root;
-  rect->y = event->y_root;
+  if (data->button_pressed)
+    return TRUE;
+
+  data->button_pressed = TRUE;
+  data->rect.x = event->x_root;
+  data->rect.y = event->y_root;
 
-  draw_rect->x = rect->x;
-  draw_rect->y = rect->y;
-  draw_rect->width  = 0;
-  draw_rect->height = 0;
+  return TRUE;
 }
 
-static void
-select_area_update_rect (GtkWidget    *window,
-                         GdkRectangle *rect)
+static gboolean
+select_area_motion_notify (GtkWidget               *window,
+                           GdkEventMotion          *event,
+                           select_area_filter_data *data)
 {
-  if (rect->width <= 0 || rect->height <= 0)
+  GdkRectangle draw_rect;
+
+  if (!data->button_pressed)
+    return TRUE;
+
+  draw_rect.width = ABS (data->rect.x - event->x_root);
+  draw_rect.height = ABS (data->rect.y - event->y_root);
+  draw_rect.x = MIN (data->rect.x, event->x_root);
+  draw_rect.y = MIN (data->rect.y, event->y_root);
+
+  if (draw_rect.width <= 0 || draw_rect.height <= 0)
     {
-      gtk_widget_hide (window);
-      return;
+      gtk_window_move (GTK_WINDOW (window), -100, -100);
+      gtk_window_resize (GTK_WINDOW (window), 10, 10);
+      return TRUE;
     }
 
-  gtk_window_move (GTK_WINDOW (window), rect->x, rect->y);
-  gtk_window_resize (GTK_WINDOW (window), rect->width, rect->height);
-  gtk_widget_show (window);
-  
+  gtk_window_move (GTK_WINDOW (window), draw_rect.x, draw_rect.y);
+  gtk_window_resize (GTK_WINDOW (window), draw_rect.width, draw_rect.height);
+
   /* We (ab)use app-paintable to indicate if we have an RGBA window */
   if (!gtk_widget_get_app_paintable (window))
     {
       GdkWindow *gdkwindow = gtk_widget_get_window (window);
 
       /* Shape the window to make only the outline visible */
-      if (rect->width > 2 && rect->height > 2)
+      if (draw_rect.width > 2 && draw_rect.height > 2)
         {
-          cairo_region_t *region, *region2;
+          cairo_region_t *region;
           cairo_rectangle_int_t region_rect = {
             0, 0,
-            rect->width - 2, rect->height - 2
+            draw_rect.width, draw_rect.height
           };
 
           region = cairo_region_create_rectangle (&region_rect);
@@ -299,56 +317,54 @@ select_area_update_rect (GtkWidget    *window,
           region_rect.y++;
           region_rect.width -= 2;
           region_rect.height -= 2;
-          region2 = cairo_region_create_rectangle (&region_rect);
-          cairo_region_subtract (region, region2);
+          cairo_region_subtract_rectangle (region, &region_rect);
 
           gdk_window_shape_combine_region (gdkwindow, region, 0, 0);
 
           cairo_region_destroy (region);
-          cairo_region_destroy (region2);
         }
       else
         gdk_window_shape_combine_region (gdkwindow, NULL, 0, 0);
     }
+
+  return TRUE;
 }
 
-static void
-select_area_button_release (XKeyEvent    *event,
-                            GdkRectangle *rect,
-                            GdkRectangle *draw_rect,
-                            GtkWidget    *window)
+static gboolean
+select_area_button_release (GtkWidget               *window,
+                            GdkEventButton          *event,
+                            select_area_filter_data *data)
 {
-  gtk_widget_hide (window);
+  if (!data->button_pressed)
+    return TRUE;
 
-  rect->width  = ABS (rect->x - event->x_root);
-  rect->height = ABS (rect->y - event->y_root);
+  data->rect.width  = ABS (data->rect.x - event->x_root);
+  data->rect.height = ABS (data->rect.y - event->y_root);
+  data->rect.x = MIN (data->rect.x, event->x_root);
+  data->rect.y = MIN (data->rect.y, event->y_root);
+  
+  gtk_main_quit ();
 
-  rect->x = MIN (rect->x, event->x_root);
-  rect->y = MIN (rect->y, event->y_root);
+  return TRUE;
 }
 
-static void
-select_area_motion_notify (XKeyEvent    *event,
-                           GdkRectangle *rect,
-                           GdkRectangle *draw_rect,
-                           GtkWidget    *window)
+static gboolean
+select_area_key_press (GtkWidget               *window,
+                       GdkEventKey             *event,
+                       select_area_filter_data *data)
 {
-  draw_rect->width  = ABS (rect->x - event->x_root);
-  draw_rect->height = ABS (rect->y - event->y_root);
-
-  draw_rect->x = MIN (rect->x, event->x_root);
-  draw_rect->y = MIN (rect->y, event->y_root);
-
-  select_area_update_rect (window, draw_rect);
+  if (event->keyval == GDK_KEY_Escape)
+    {
+      data->rect.x = 0;
+      data->rect.y = 0;
+      data->rect.width  = 0;
+      data->rect.height = 0;
+      gtk_main_quit ();
+    }
+ 
+  return TRUE;
 }
 
-typedef struct {
-  GdkRectangle  rect;
-  GdkRectangle  draw_rect;
-  gboolean      button_pressed;
-  GtkWidget    *window;
-} select_area_filter_data;
-
 static gboolean
 select_window_draw (GtkWidget *window, cairo_t *cr, gpointer unused)
 {
@@ -404,74 +420,37 @@ create_select_window (void)
 
   g_signal_connect (window, "draw", G_CALLBACK (select_window_draw), NULL);
 
+  gtk_window_move (GTK_WINDOW (window), -100, -100);
+  gtk_window_resize (GTK_WINDOW (window), 10, 10);
+  gtk_widget_show (window);
+  
   return window;
 }
 
-static GdkFilterReturn
-select_area_filter (GdkXEvent *gdk_xevent,
-                    GdkEvent  *event,
-                    gpointer   user_data)
-{
-  select_area_filter_data *data = user_data;
-  XEvent *xevent = (XEvent *) gdk_xevent;
-
-  switch (xevent->type)
-    {
-    case ButtonPress:
-      if (!data->button_pressed)
-        {
-          select_area_button_press (&xevent->xkey,
-                                    &data->rect, &data->draw_rect);
-          data->button_pressed = TRUE;
-        }
-      return GDK_FILTER_REMOVE;
-    case ButtonRelease:
-      if (data->button_pressed)
-      {
-        select_area_button_release (&xevent->xkey,
-                                    &data->rect, &data->draw_rect,
-                                    data->window);
-        gtk_main_quit ();
-      }
-      return GDK_FILTER_REMOVE;
-    case MotionNotify:
-      if (data->button_pressed)
-        select_area_motion_notify (&xevent->xkey,
-                                   &data->rect, &data->draw_rect,
-                                   data->window);
-      return GDK_FILTER_REMOVE;
-    case KeyPress:
-      if (xevent->xkey.keycode == XKeysymToKeycode (GDK_DISPLAY_XDISPLAY (gdk_display_get_default ()), XK_Escape))
-        {
-          data->rect.x = 0;
-          data->rect.y = 0;
-          data->rect.width  = 0;
-          data->rect.height = 0;
-          gtk_main_quit ();
-          return GDK_FILTER_REMOVE;
-        }
-      break;
-    default:
-      break;
-    }
- 
-  return GDK_FILTER_CONTINUE;
-}
-
 gboolean
 screenshot_select_area (int *px,
                         int *py,
                         int *pwidth,
                         int *pheight)
 {
-  GdkWindow               *root;
   GdkCursor               *cursor;
   select_area_filter_data  data;
 
-  root = gdk_get_default_root_window ();
+  data.rect.x = 0;
+  data.rect.y = 0;
+  data.rect.width  = 0;
+  data.rect.height = 0;
+  data.button_pressed = FALSE;
+  data.window = create_select_window();
+
+  g_signal_connect (data.window, "key-press-event", G_CALLBACK (select_area_key_press), &data);
+  g_signal_connect (data.window, "button-press-event", G_CALLBACK (select_area_button_press), &data);
+  g_signal_connect (data.window, "button-release-event", G_CALLBACK (select_area_button_release), &data);
+  g_signal_connect (data.window, "motion-notify-event", G_CALLBACK (select_area_motion_notify), &data);
+
   cursor = gdk_cursor_new (GDK_CROSSHAIR);
 
-  if (gdk_pointer_grab (root, FALSE,
+  if (gdk_pointer_grab (gtk_widget_get_window (data.window), FALSE,
                         GDK_POINTER_MOTION_MASK|GDK_BUTTON_PRESS_MASK|GDK_BUTTON_RELEASE_MASK,
                         NULL, cursor,
                         GDK_CURRENT_TIME) != GDK_GRAB_SUCCESS)
@@ -480,32 +459,21 @@ screenshot_select_area (int *px,
       return FALSE;
     }
 
-  if (gdk_keyboard_grab (root, FALSE, GDK_CURRENT_TIME) != GDK_GRAB_SUCCESS)
+  if (gdk_keyboard_grab (gtk_widget_get_window (data.window), FALSE, GDK_CURRENT_TIME) != GDK_GRAB_SUCCESS)
     {
       gdk_pointer_ungrab (GDK_CURRENT_TIME);
       gdk_cursor_unref (cursor);
       return FALSE;
     }
 
-  gdk_window_add_filter (root, (GdkFilterFunc) select_area_filter, &data);
-
   gdk_flush ();
 
-  data.rect.x = 0;
-  data.rect.y = 0;
-  data.rect.width  = 0;
-  data.rect.height = 0;
-  data.button_pressed = FALSE;
-  data.window = create_select_window();
-
   gtk_main ();
 
-  gdk_window_remove_filter (root, (GdkFilterFunc) select_area_filter, &data);
-
-  gtk_widget_destroy (data.window);
-
   gdk_keyboard_ungrab (GDK_CURRENT_TIME);
   gdk_pointer_ungrab (GDK_CURRENT_TIME);
+
+  gtk_widget_destroy (data.window);
   gdk_cursor_unref (cursor);
 
   *px = data.rect.x;