views/accelerator.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 "views/accelerator.h"

#if defined(OS_WIN)
#include <windows.h>
#elif defined(TOOLKIT_USES_GTK)
#include <gdk/gdk.h>
#endif

#include "base/i18n/rtl.h"
#include "base/logging.h"
#include "base/string_util.h"
#include "base/utf_string_conversions.h"
#include "grit/ui_strings.h"
#include "ui/base/l10n/l10n_util.h"

namespace views {

string16 Accelerator::GetShortcutText() const {
  int string_id = 0;
  switch(key_code_) {
    case ui::VKEY_TAB:
      string_id = IDS_APP_TAB_KEY;
      break;
    case ui::VKEY_RETURN:
      string_id = IDS_APP_ENTER_KEY;
      break;
    case ui::VKEY_ESCAPE:
      string_id = IDS_APP_ESC_KEY;
      break;
    case ui::VKEY_PRIOR:
      string_id = IDS_APP_PAGEUP_KEY;
      break;
    case ui::VKEY_NEXT:
      string_id = IDS_APP_PAGEDOWN_KEY;
      break;
    case ui::VKEY_END:
      string_id = IDS_APP_END_KEY;
      break;
    case ui::VKEY_HOME:
      string_id = IDS_APP_HOME_KEY;
      break;
    case ui::VKEY_INSERT:
      string_id = IDS_APP_INSERT_KEY;
      break;
    case ui::VKEY_DELETE:
      string_id = IDS_APP_DELETE_KEY;
      break;
    case ui::VKEY_LEFT:
      string_id = IDS_APP_LEFT_ARROW_KEY;
      break;
    case ui::VKEY_RIGHT:
      string_id = IDS_APP_RIGHT_ARROW_KEY;
      break;
    case ui::VKEY_BACK:
      string_id = IDS_APP_BACKSPACE_KEY;
      break;
    case ui::VKEY_F1:
      string_id = IDS_APP_F1_KEY;
      break;
    case ui::VKEY_F11:
      string_id = IDS_APP_F11_KEY;
      break;
    default:
      break;
  }

  string16 shortcut;
  if (!string_id) {
#if defined(OS_WIN)
    // Our fallback is to try translate the key code to a regular character
    // unless it is one of digits (VK_0 to VK_9). Some keyboard
    // layouts have characters other than digits assigned in
    // an unshifted mode (e.g. French AZERY layout has 'a with grave
    // accent' for '0'). For display in the menu (e.g. Ctrl-0 for the
    // default zoom level), we leave VK_[0-9] alone without translation.
    wchar_t key;
    if (key_code_ >= '0' && key_code_ <= '9')
      key = key_code_;
    else
      key = LOWORD(::MapVirtualKeyW(key_code_, MAPVK_VK_TO_CHAR));
    shortcut += key;
#elif defined(TOOLKIT_USES_GTK)
    const gchar* name = NULL;
    switch (key_code_) {
      case ui::VKEY_OEM_2:
        name = static_cast<const gchar*>("/");
        break;
      default:
        name = gdk_keyval_name(gdk_keyval_to_lower(key_code_));
        break;
    }
    if (name) {
      if (name[0] != 0 && name[1] == 0)
        shortcut += static_cast<string16::value_type>(g_ascii_toupper(name[0]));
      else
        shortcut += UTF8ToUTF16(name);
    }
#endif
  } else {
    shortcut = l10n_util::GetStringUTF16(string_id);
  }

  // Checking whether the character used for the accelerator is alphanumeric.
  // If it is not, then we need to adjust the string later on if the locale is
  // right-to-left. See below for more information of why such adjustment is
  // required.
  string16 shortcut_rtl;
  bool adjust_shortcut_for_rtl = false;
  if (base::i18n::IsRTL() && shortcut.length() == 1 &&
      !IsAsciiAlpha(shortcut[0]) && !IsAsciiDigit(shortcut[0])) {
    adjust_shortcut_for_rtl = true;
    shortcut_rtl.assign(shortcut);
  }

  if (IsShiftDown())
    shortcut = l10n_util::GetStringFUTF16(IDS_APP_SHIFT_MODIFIER, shortcut);

  // Note that we use 'else-if' in order to avoid using Ctrl+Alt as a shortcut.
  // See http://blogs.msdn.com/oldnewthing/archive/2004/03/29/101121.aspx for
  // more information.
  if (IsCtrlDown())
    shortcut = l10n_util::GetStringFUTF16(IDS_APP_CONTROL_MODIFIER, shortcut);
  else if (IsAltDown())
    shortcut = l10n_util::GetStringFUTF16(IDS_APP_ALT_MODIFIER, shortcut);

  // For some reason, menus in Windows ignore standard Unicode directionality
  // marks (such as LRE, PDF, etc.). On RTL locales, we use RTL menus and
  // therefore any text we draw for the menu items is drawn in an RTL context.
  // Thus, the text "Ctrl++" (which we currently use for the Zoom In option)
  // appears as "++Ctrl" in RTL because the Unicode BiDi algorithm puts
  // punctuations on the left when the context is right-to-left. Shortcuts that
  // do not end with a punctuation mark (such as "Ctrl+H" do not have this
  // problem).
  //
  // The only way to solve this problem is to adjust the string if the locale
  // is RTL so that it is drawn correnctly in an RTL context. Instead of
  // returning "Ctrl++" in the above example, we return "++Ctrl". This will
  // cause the text to appear as "Ctrl++" when Windows draws the string in an
  // RTL context because the punctunation no longer appears at the end of the
  // string.
  //
  // TODO(idana) bug# 1232732: this hack can be avoided if instead of using
  // views::Menu we use views::MenuItemView because the latter is a View
  // subclass and therefore it supports marking text as RTL or LTR using
  // standard Unicode directionality marks.
  if (adjust_shortcut_for_rtl) {
    int key_length = static_cast<int>(shortcut_rtl.length());
    DCHECK_GT(key_length, 0);
    shortcut_rtl.append(ASCIIToUTF16("+"));

    // Subtracting the size of the shortcut key and 1 for the '+' sign.
    shortcut_rtl.append(shortcut, 0, shortcut.length() - key_length - 1);
    shortcut.swap(shortcut_rtl);
  }

  return shortcut;
}

}  // namespace views