views: Draw underline in menu bar for accelerators.

atom/browser/ui/views/submenu_button.cc

@@ -0,0 +1,77 @@
+// Copyright (c) 2014 GitHub, Inc. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/ui/views/submenu_button.h"
+
+#include "base/strings/string_util.h"
+#include "base/strings/utf_string_conversions.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/text_utils.h"
+
+namespace atom {
+
+namespace {
+
+// Filter out the "&" in menu label.
+base::string16 FilterAccecelator(const base::string16& label) {
+  base::string16 out;
+  base::RemoveChars(label, base::ASCIIToUTF16("&").c_str(), &out);
+  return out;
+}
+
+}  // namespace
+
+SubmenuButton::SubmenuButton(views::ButtonListener* listener,
+                             const base::string16& title,
+                             views::MenuButtonListener* menu_button_listener)
+    : views::MenuButton(listener, FilterAccecelator(title),
+                        menu_button_listener, false),
+      underline_start_(-1),
+      underline_end_(-1),
+      text_width_(0),
+      text_height_(0),
+      underline_color_(SK_ColorBLACK) {
+  GetUnderlinePosition(title, &underline_start_, &underline_end_);
+  gfx::Canvas::SizeStringInt(text(), font_list(), &text_width_,
+                             &text_height_, 0, 0);
+}
+
+SubmenuButton::~SubmenuButton() {
+}
+
+void SubmenuButton::SetUnderlineColor(SkColor color) {
+  underline_color_ = color;
+}
+
+void SubmenuButton::OnPaint(gfx::Canvas* canvas) {
+  views::MenuButton::OnPaint(canvas);
+
+  if (underline_start_ != underline_end_) {
+    int padding = (width() - text_width_) / 2;
+    int underline_height = (height() + text_height_) / 2 - 2;
+    canvas->DrawLine(gfx::Point(underline_start_ + padding, underline_height),
+                     gfx::Point(underline_end_ + padding, underline_height),
+                     underline_color_);
+  }
+}
+
+void SubmenuButton::GetUnderlinePosition(
+    const base::string16& text, int* start, int* end) {
+  int pos, span;
+  gfx::RemoveAcceleratorChar(text, '&', &pos, &span);
+  if (pos > -1 && span != 0) {
+    GetCharacterPosition(text, pos, start);
+    GetCharacterPosition(text, pos + span, end);
+  }
+}
+
+void SubmenuButton::GetCharacterPosition(
+    const base::string16& text, int index, int* pos) {
+  int width, height;
+  gfx::Canvas::SizeStringInt(text.substr(0, index), font_list(), &width,
+                             &height, 0, 0);
+  *pos = width;
+}
+
+}  // namespace atom