Draggable region support for frameless app window on GTK.

chrome/browser/ui/gtk/extensions/shell_window_gtk.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/gtk/extensions/shell_window_gtk.h"
 
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/extensions/extension.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_view.h"
+#include "content/public/common/draggable_region.h"
 #include "ui/base/x/active_window_watcher_x.h"
 #include "ui/gfx/rect.h"
 
 ShellWindowGtk::ShellWindowGtk(Profile* profile,
                                const extensions::Extension* extension,
                                const GURL& url,
                                const ShellWindow::CreateParams& params)
     : ShellWindow(profile, extension, url),
       state_(GDK_WINDOW_STATE_WITHDRAWN),
       is_active_(!ui::ActiveWindowWatcherX::WMSupportsActivation()),
-      content_thinks_its_fullscreen_(false) {
+      content_thinks_its_fullscreen_(false),
+      frameless_(params.frame == ShellWindow::CreateParams::FRAME_NONE) {
   window_ = GTK_WINDOW(gtk_window_new(GTK_WINDOW_TOPLEVEL));
 
   gfx::NativeView native_view =
       web_contents()->GetView()->GetNativeView();
   gtk_container_add(GTK_CONTAINER(window_), native_view);
 
   gtk_window_set_default_size(
       window_, params.bounds.width(), params.bounds.height());
 
   // Hide titlebar when {frame: 'none'} specified on ShellWindow.
-  if (params.frame == ShellWindow::CreateParams::FRAME_NONE)
+  if (frameless_)
     gtk_window_set_decorated(window_, false);
 
   int min_width = params.minimum_size.width();
   int min_height = params.minimum_size.height();
   int max_width = params.maximum_size.width();
   int max_height = params.maximum_size.height();
   GdkGeometry hints;
   int hints_mask = 0;
   if (min_width || min_height) {
     hints.min_height = min_height;
@@ skipping 15 matching lines @@
 
   // TODO(mihaip): Mirror contents of <title> tag in window title
   gtk_window_set_title(window_, extension->name().c_str());
 
   g_signal_connect(window_, "delete-event",
                    G_CALLBACK(OnMainWindowDeleteEventThunk), this);
   g_signal_connect(window_, "configure-event",
                    G_CALLBACK(OnConfigureThunk), this);
   g_signal_connect(window_, "window-state-event",
                    G_CALLBACK(OnWindowStateThunk), this);
+  g_signal_connect(window_, "button-press-event",

[Evan Stade, 2012/08/07 23:20:58]

you only need to this if frameless.

+                   G_CALLBACK(OnButtonPressThunk), this);
 
   ui::ActiveWindowWatcherX::AddObserver(this);
 }
 
 ShellWindowGtk::~ShellWindowGtk() {
   ui::ActiveWindowWatcherX::RemoveObserver(this);
 }
 
 bool ShellWindowGtk::IsActive() const {
   return is_active_;
@@ skipping 125 matching lines @@
       !(state_ & GDK_WINDOW_STATE_FULLSCREEN)) {
     content_thinks_its_fullscreen_ = false;
     content::RenderViewHost* rvh = web_contents()->GetRenderViewHost();
     if (rvh)
       rvh->ExitFullscreen();
   }
 
   return FALSE;
 }
 
+gboolean ShellWindowGtk::OnButtonPress(GtkWidget* widget,
+                                       GdkEventButton * event) {

[Evan Stade, 2012/08/07 23:20:58]

no space before *

+  if (event->type == GDK_BUTTON_PRESS && event->button == 1) {
+    if (frameless_ && draggable_region_.Get() &&
+        draggable_region_.Get()->contains(event->x, event->y)) {
+      gtk_window_begin_move_drag(GTK_WINDOW(widget), event->button,
+                                 event->x_root, event->y_root, event->time);

[Evan Stade, 2012/08/07 23:20:58]

I think you actually want to return TRUE to indicate you've handled the press

+    }
+  }

[jeremya, 2012/08/08 04:38:37]

Is this sufficient? Do we get behaviour like maximising when double-clicking on
the draggable region, and a menu on right-click?

+
+  return FALSE;
+}
+
 void ShellWindowGtk::SetFullscreen(bool fullscreen) {
   content_thinks_its_fullscreen_ = fullscreen;
   if (fullscreen)
     gtk_window_fullscreen(window_);
   else
     gtk_window_unfullscreen(window_);
 }
 
 bool ShellWindowGtk::IsFullscreenOrPending() const {
   return content_thinks_its_fullscreen_;
 }
 
+void ShellWindowGtk::UpdateDraggableRegions(
+    const std::vector<content::DraggableRegion>& regions) {
+  // Draggable region is not supported for non-frameless window.
+  if (!frameless_)
+    return;
+
+  SkRegion* draggable_region = new SkRegion;
+
+  // By default, the whole window is draggable.
+  gfx::Rect bounds = GetBounds();
+  draggable_region->op(0, 0, bounds.right(), bounds.bottom(),
+                       SkRegion::kUnion_Op);
+
+  // Exclude those desinated as non-draggable.
+  for (std::vector<content::DraggableRegion>::const_iterator iter =
+           regions.begin();
+       iter != regions.end(); ++iter) {
+    const content::DraggableRegion& region = *iter;
+    draggable_region->op(region.bounds.x(),
+                         region.bounds.y(),
+                         region.bounds.right(),
+                         region.bounds.bottom(),
+                         SkRegion::kDifference_Op);
+  }
+
+  draggable_region_.Set(draggable_region);
+}
+
 // static
 ShellWindow* ShellWindow::CreateImpl(Profile* profile,
                                      const extensions::Extension* extension,
                                      const GURL& url,
                                      const ShellWindow::CreateParams& params) {
   return new ShellWindowGtk(profile, extension, url, params);
 }