[gtk] fill in gap pixels in desktop notification corners

chrome/browser/ui/gtk/notifications/balloon_view_gtk.cc

 // Copyright (c) 2011 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/notifications/balloon_view_gtk.h"
 
 #include <gtk/gtk.h>
 
 #include <string>
 #include <vector>
@@ skipping 196 matching lines @@
   frame_container_ = gtk_window_new(GTK_WINDOW_POPUP);
 
   // Construct the options menu.
   options_menu_model_.reset(new NotificationOptionsMenuModel(balloon_));
   options_menu_.reset(new MenuGtk(this, options_menu_model_.get()));
 
   // Create a BalloonViewHost to host the HTML contents of this balloon.
   html_contents_.reset(new BalloonViewHost(balloon));
   html_contents_->Init();
   gfx::NativeView contents = html_contents_->native_view();
+  g_signal_connect_after(contents, "expose-event",
+                         G_CALLBACK(OnContentsExposeThunk), this);
 
   // Divide the frame vertically into the shelf and the content area.
   GtkWidget* vbox = gtk_vbox_new(0, 0);
   gtk_container_add(GTK_CONTAINER(frame_container_), vbox);
 
   shelf_ = gtk_hbox_new(0, 0);
   gtk_container_add(GTK_CONTAINER(vbox), shelf_);
 
   GtkWidget* alignment = gtk_alignment_new(0.0, 0.0, 1.0, 1.0);
   gtk_alignment_set_padding(
@@ skipping 154 matching lines @@
     gtk_widget_queue_draw(frame_container_);
   } else {
     NOTREACHED();
   }
 }
 
 void BalloonViewImpl::OnCloseButton(GtkWidget* widget) {
   Close(true);
 }
 
+// We draw black dots on the bottom left and right corners to fill in the
+// border. Otherwise, the border has a gap because the sharp corners of the
+// HTML view cut off the roundedness of the notification window.
+gboolean BalloonViewImpl::OnContentsExpose(GtkWidget* sender,
+                                           GdkEventExpose* event) {
+  cairo_t* cr = gdk_cairo_create(GDK_DRAWABLE(sender->window));
+  gdk_cairo_rectangle(cr, &event->area);
+  cairo_clip(cr);
+
+  // According to a discussion on a mailing list I found, these degenerate
+  // paths are the officially supported way to draw points in Cairo.
+  cairo_set_source_rgb(cr, 0, 0, 0);
+  cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
+  cairo_set_line_width(cr, 1.0);
+  cairo_move_to(cr, 0.5, sender->allocation.height - 0.5);
+  cairo_close_path(cr);
+  cairo_move_to(cr, sender->allocation.width - 0.5,
+                    sender->allocation.height - 0.5);
+  cairo_close_path(cr);
+  cairo_stroke(cr);
+  cairo_destroy(cr);
+
+  return FALSE;
+}
+
 gboolean BalloonViewImpl::OnExpose(GtkWidget* sender, GdkEventExpose* event) {
   cairo_t* cr = gdk_cairo_create(GDK_DRAWABLE(sender->window));
   gdk_cairo_rectangle(cr, &event->area);
   cairo_clip(cr);
 
   gfx::Size content_size = balloon_->content_size();
   gfx::Point offset = GetContentsOffset();
 
   // Draw a background color behind the shelf.
   cairo_set_source_rgb(cr, kShelfBackgroundColorR,
@@ skipping 17 matching lines @@
 
 void BalloonViewImpl::OnOptionsMenuButton(GtkWidget* widget) {
   options_menu_->PopupAsContext(gtk_get_current_event_time());
 }
 
 gboolean BalloonViewImpl::OnDestroy(GtkWidget* widget) {
   frame_container_ = NULL;
   Close(false);
   return FALSE;  // Propagate.
 }