Draggable region support for frameless app window on GTK.

chrome/browser/ui/gtk/gtk_window_util.cc

Index: chrome/browser/ui/gtk/gtk_window_util.cc
diff --git a/chrome/browser/ui/gtk/gtk_window_util.cc b/chrome/browser/ui/gtk/gtk_window_util.cc
index 91258b25cb3d64b93b42415c258699a5c44a3bc0..46605c213a902fa43faf5d3242f01d8b89444d1e 100644
--- a/chrome/browser/ui/gtk/gtk_window_util.cc
+++ b/chrome/browser/ui/gtk/gtk_window_util.cc
@@ -13,6 +13,12 @@ using content::WebContents;
 
 namespace gtk_window_util {
 
+// Keep track of the last click time and the last click position so we can
+// filter out extra GDK_BUTTON_PRESS events when a double click happens.
+static guint32 last_click_time;
+static int last_click_x;
+static int last_click_y;
+
 // Performs Cut/Copy/Paste operation on the |window|.
 // If the current render view is focused, then just call the specified |method|
 // against the current render view host, otherwise emit the specified |signal|
@@ -94,4 +100,77 @@ GdkCursorType GdkWindowEdgeToGdkCursorType(GdkWindowEdge edge) {
   return GDK_LAST_CURSOR;
 }
 
+bool BoundsMatchMonitorSize(GtkWindow* window, gfx::Rect bounds) {
+  // A screen can be composed of multiple monitors.
+  GdkScreen* screen = gtk_window_get_screen(window);
+  gint monitor_num = gdk_screen_get_monitor_at_window(screen,
+      gtk_widget_get_window(GTK_WIDGET(window)));
+
+  GdkRectangle monitor_size;
+  gdk_screen_get_monitor_geometry(screen, monitor_num, &monitor_size);
+  return bounds.size() == gfx::Size(monitor_size.width, monitor_size.height);
+}
+
+bool HandleTitleBarLeftMousePress(
+    GtkWindow* window,
+    const gfx::Rect& bounds,
+    GdkEventButton* event) {
+  // We want to start a move when the user single clicks, but not start a
+  // move when the user double clicks.  However, a double click sends the
+  // following GDK events: GDK_BUTTON_PRESS, GDK_BUTTON_RELEASE,
+  // GDK_BUTTON_PRESS, GDK_2BUTTON_PRESS, GDK_BUTTON_RELEASE.  If we
+  // start a gtk_window_begin_move_drag on the second GDK_BUTTON_PRESS,
+  // the call to gtk_window_maximize fails.  To work around this, we
+  // keep track of the last click and if it's going to be a double click,
+  // we don't call gtk_window_begin_move_drag.
+  DCHECK(event->type == GDK_BUTTON_PRESS);
+  DCHECK(event->button == 1);
+
+  static GtkSettings* settings = gtk_settings_get_default();
+  gint double_click_time = 250;
+  gint double_click_distance = 5;
+  g_object_get(G_OBJECT(settings),
+               "gtk-double-click-time", &double_click_time,
+               "gtk-double-click-distance", &double_click_distance,
+               NULL);
+
+  guint32 click_time = event->time - last_click_time;
+  int click_move_x = abs(event->x - last_click_x);
+  int click_move_y = abs(event->y - last_click_y);
+
+  last_click_time = event->time;
+  last_click_x = static_cast<int>(event->x);
+  last_click_y = static_cast<int>(event->y);
+
+  if (click_time > static_cast<guint32>(double_click_time) ||
+      click_move_x > double_click_distance ||
+      click_move_y > double_click_distance) {
+    // Ignore drag requests if the window is the size of the screen.
+    // We do this to avoid triggering fullscreen mode in metacity
+    // (without the --no-force-fullscreen flag) and in compiz (with
+    // Legacy Fullscreen Mode enabled).
+    if (!BoundsMatchMonitorSize(window, bounds)) {
+      gtk_window_begin_move_drag(window, event->button,
+                                 static_cast<gint>(event->x_root),
+                                 static_cast<gint>(event->y_root),
+                                 event->time);
+    }
+    return TRUE;
+  }
+  return FALSE;
+}
+
+void UnMaximize(GtkWindow* window,
+                const gfx::Rect& bounds,
+                const gfx::Rect& restored_bounds) {
+  gtk_window_unmaximize(window);
+
+  // It can happen that you end up with a window whose restore size is the same
+  // as the size of the screen, so unmaximizing it merely remaximizes it due to
+  // the same WM feature that SetWindowSize() works around.  We try to detect
+  // this and resize the window to work around the issue.
+  if (bounds.size() == restored_bounds.size())
+    gtk_window_resize(window, bounds.width(), bounds.height() - 1);
+}
+
 }  // namespace gtk_window_util