Make Combobox portable

views/controls/combobox/native_combobox_win.cc

+// Copyright (c) 2009 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/controls/combobox/native_combobox_win.h"
+
+#include "app/gfx/font.h"
+#include "app/l10n_util.h"
+#include "app/resource_bundle.h"
+#include "base/gfx/native_theme.h"
+#include "views/controls/combobox/combobox.h"
+#include "views/widget/widget.h"
+
+namespace views {
+
+// Limit how small a combobox can be.
+static const int kMinComboboxWidth = 148;
+
+// Add a couple extra pixels to the widths of comboboxes and combobox
+// dropdowns so that text isn't too crowded.
+static const int kComboboxExtraPaddingX = 6;
+
+////////////////////////////////////////////////////////////////////////////////
+// NativeComboboxWin, public:
+
+NativeComboboxWin::NativeComboboxWin(Combobox* combobox)
+    : combobox_(combobox),
+      content_width_(0) {
+}
+
+NativeComboboxWin::~NativeComboboxWin() {
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// NativeComboboxWin, NativeComboboxWrapper implementation:
+
+void NativeComboboxWin::UpdateFromModel() {
+  SendMessage(native_view(), CB_RESETCONTENT, 0, 0);
+  gfx::Font font = ResourceBundle::GetSharedInstance().GetFont(
+      ResourceBundle::BaseFont);
+  int max_width = 0;
+  int num_items = combobox_->model()->GetItemCount(combobox_);
+  for (int i = 0; i < num_items; ++i) {
+    const std::wstring& text = combobox_->model()->GetItemAt(combobox_, i);
+
+    // Inserting the Unicode formatting characters if necessary so that the
+    // text is displayed correctly in right-to-left UIs.
+    std::wstring localized_text;
+    const wchar_t* text_ptr = text.c_str();
+    if (l10n_util::AdjustStringForLocaleDirection(text, &localized_text))
+      text_ptr = localized_text.c_str();
+
+    SendMessage(native_view(), CB_ADDSTRING, 0,
+                reinterpret_cast<LPARAM>(text_ptr));
+    max_width = std::max(max_width, font.GetStringWidth(text));
+  }
+  content_width_ = max_width;
+
+  if (num_items > 0) {
+    SendMessage(native_view(), CB_SETCURSEL, combobox_->selected_item(), 0);
+
+    // Set the width for the drop down while accounting for the scrollbar and
+    // borders.
+    if (num_items > ComboBox_GetMinVisible(native_view()))
+      max_width += GetSystemMetrics(SM_CXVSCROLL);
+    // SM_CXEDGE would not be correct here, since the dropdown is flat, not 3D.
+    int kComboboxDropdownBorderSize = 1;
+    max_width += 2 * kComboboxDropdownBorderSize + kComboboxExtraPaddingX;
+    SendMessage(native_view(), CB_SETDROPPEDWIDTH, max_width, 0);
+  }
+}
+
+void NativeComboboxWin::UpdateSelectedItem() {
+  // Note that we use CB_SETCURSEL and not CB_SELECTSTRING because on RTL
+  // locales the strings we get from our ComboBox::Model might be augmented
+  // with Unicode directionality marks before we insert them into the combo box
+  // and therefore we can not assume that the string we get from
+  // ComboBox::Model can be safely searched for and selected (which is what
+  // CB_SELECTSTRING does).
+  SendMessage(native_view(), CB_SETCURSEL, combobox_->selected_item(), 0);
+}
+
+void NativeComboboxWin::UpdateEnabled() {
+  SetEnabled(combobox_->IsEnabled());
+}
+
+int NativeComboboxWin::GetSelectedItem() const {
+  LRESULT selected_item = SendMessage(native_view(), CB_GETCURSEL, 0, 0);
+  return selected_item != CB_ERR ? selected_item : -1;
+}
+
+bool NativeComboboxWin::IsDropdownOpen() const {
+  return SendMessage(native_view(), CB_GETDROPPEDSTATE, 0, 0) != 0;
+}
+
+gfx::Size NativeComboboxWin::GetPreferredSize() const {
+  COMBOBOXINFO cbi = { 0 };
+  cbi.cbSize = sizeof(cbi);
+  // Note: Don't use CB_GETCOMBOBOXINFO since that crashes on WOW64 systems
+  // when you have a global message hook installed.
+  GetComboBoxInfo(native_view(), &cbi);
+  gfx::Rect rect_item(cbi.rcItem);
+  gfx::Rect rect_button(cbi.rcButton);
+  gfx::Size border = gfx::NativeTheme::instance()->GetThemeBorderSize(
+      gfx::NativeTheme::MENULIST);
+
+  // The padding value of '3' is the xy offset from the corner of the control
+  // to the corner of rcItem.  It does not seem to be queryable from the theme.
+  // It is consistent on all versions of Windows from 2K to Vista, and is
+  // invariant with respect to the combobox border size.  We could conceivably
+  // get this number from rect_item.x, but it seems fragile to depend on
+  // position here, inside of the layout code.
+  const int kItemOffset = 3;
+  int item_to_button_distance = std::max(kItemOffset - border.width(), 0);
+
+  // The cx computation can be read as measuring from left to right.
+  int pref_width = std::max(kItemOffset + content_width_ +
+                                kComboboxExtraPaddingX +
+                                item_to_button_distance + rect_button.width() +
+                                 border.width(), kMinComboboxWidth);
+  // The two arguments to ::max below should be typically be equal.
+  int pref_height = std::max(rect_item.height() + 2 * kItemOffset,
+                             rect_button.height() + 2 * border.height());
+  return gfx::Size(pref_width, pref_height);
+}
+
+View* NativeComboboxWin::GetView() {
+  return this;
+}
+
+void NativeComboboxWin::SetFocus() {
+  Focus();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// NativeComboboxWin, NativeControlWin overrides:
+
+bool NativeComboboxWin::ProcessMessage(UINT message,
+                                       WPARAM w_param,
+                                       LPARAM l_param,
+                                       LRESULT* result) {
+  if (message == WM_COMMAND && HIWORD(w_param) == CBN_SELCHANGE) {
+    combobox_->SelectionChanged();
+    *result = 0;
+    return true;
+  }
+  return NativeControlWin::ProcessMessage(message, w_param, l_param, result);
+}
+
+void NativeComboboxWin::CreateNativeControl() {
+  DWORD flags = WS_CHILD | WS_CLIPSIBLINGS | WS_CLIPCHILDREN | CBS_DROPDOWNLIST;
+  HWND control_hwnd = ::CreateWindowEx(GetAdditionalExStyle(), L"COMBOBOX", L"",
+                                       flags, 0, 0, 100, 20, //width(), height(),
+                                       GetWidget()->GetNativeView(), NULL, NULL,
+                                       NULL);
+  NativeControlCreated(control_hwnd);
+}
+
+void NativeComboboxWin::NativeControlCreated(HWND native_control) {
+  NativeControlWin::NativeControlCreated(native_control);
+
+  UpdateFont();
+  UpdateFromModel();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// NativeComboboxWin, private:
+
+void NativeComboboxWin::UpdateFont() {
+  HFONT font = ResourceBundle::GetSharedInstance().
+      GetFont(ResourceBundle::BaseFont).hfont();
+  SendMessage(native_view(), WM_SETFONT, reinterpret_cast<WPARAM>(font), FALSE);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// NativeComboboxWrapper, public:
+
+// static
+NativeComboboxWrapper* NativeComboboxWrapper::CreateWrapper(
+    Combobox* combobox) {
+  return new NativeComboboxWin(combobox);
+}
+
+}  // namespace views