Use customized RGBA-enabled tooltip window for tooltip on ChroemOS

views/widget/tooltip_window_gtk.cc

+// Copyright (c) 2010 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 "views/widget/tooltip_window_gtk.h"
+
+#include "base/utf_string_conversions.h"
+
+namespace views {
+
+TooltipWindowGtk::TooltipWindowGtk(GtkWidget* widget)
+    : host_(widget),
+      window_(NULL),
+      alignment_(NULL),
+      label_(NULL) {
+  Init();
+}
+
+TooltipWindowGtk::~TooltipWindowGtk() {
+  if (window_)
+    gtk_widget_destroy(window_);
+}
+
+void TooltipWindowGtk::SetTooltipText(const std::wstring& text) {
+  const std::string& utf8 = WideToUTF8(text);
+
+  gtk_label_set_text(label(), utf8.c_str());
+  // Setting the text in a label doesn't force recalculating wrap position.
+  // We force recalculating wrap position by resetting the max width.
+  gtk_label_set_max_width_chars(label(), 2999);
+  gtk_label_set_max_width_chars(label(), 3000);
+}
+
+void  TooltipWindowGtk::Init() {
+  // Creates and setup tooltip window.
+  window_ = gtk_window_new(GTK_WINDOW_POPUP);
+  gtk_window_set_type_hint(GTK_WINDOW(window_), GDK_WINDOW_TYPE_HINT_TOOLTIP);
+  gtk_widget_set_app_paintable(window_, TRUE);
+  gtk_window_set_resizable(GTK_WINDOW(window_), FALSE);
+  gtk_widget_set_name(window_, "gtk-tooltip");
+
+  GdkColormap* rgba_colormap =
+      gdk_screen_get_rgba_colormap(gdk_screen_get_default());
+  if (rgba_colormap)
+    gtk_widget_set_colormap(window_, rgba_colormap);
+
+  g_signal_connect(G_OBJECT(window_), "expose-event",
+                   G_CALLBACK(&OnPaintThunk), this);
+  g_signal_connect(G_OBJECT(window_), "style-set",
+                   G_CALLBACK(&OnStyleSetThunk), this);
+
+  alignment_ = gtk_alignment_new(0.5, 0.5, 1.0, 1.0);
+  gtk_container_add(GTK_CONTAINER(window_), alignment_);
+  gtk_widget_show(alignment_);
+
+  label_ = gtk_label_new("");
+  gtk_label_set_line_wrap(GTK_LABEL(label_), TRUE);
+  gtk_label_set_max_width_chars(GTK_LABEL(label_), 3000);
+  gtk_container_add(GTK_CONTAINER(alignment_), label_);
+  gtk_widget_show(label_);
+
+  // Associates the tooltip window with given widget
+  gtk_widget_set_tooltip_window(host_, GTK_WINDOW(window_));
+}
+
+// Paints our customized tooltip window.
+gboolean TooltipWindowGtk::OnPaint(GtkWidget* widget, GdkEventExpose* event) {
+  gtk_paint_flat_box(widget->style,
+      widget->window,
+      GTK_STATE_NORMAL,
+      GTK_SHADOW_OUT,
+      NULL,
+      widget,
+      "tooltip",
+      0, 0,
+      widget->allocation.width,
+      widget->allocation.height);
+
+  return FALSE;
+}
+
+// Style change handler.
+void TooltipWindowGtk::OnStyleSet(GtkWidget* widget,
+                                  GtkStyle* previous_style) {
+  gtk_alignment_set_padding(GTK_ALIGNMENT(alignment_),
+      widget->style->ythickness,
+      widget->style->ythickness,
+      widget->style->xthickness,
+      widget->style->xthickness);
+
+  gtk_widget_queue_draw(widget);
+}
+
+}  // namespace views