Adjust location of text in omnibox edit control for Metro.

chrome/browser/ui/views/omnibox/omnibox_view_win.cc

 // Copyright (c) 2012 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/views/omnibox/omnibox_view_win.h"
 
 #include <algorithm>
 #include <locale>
 #include <string>
 
@@ skipping 436 matching lines @@
       command_updater_(command_updater),
       popup_window_mode_(popup_window_mode),
       force_hidden_(false),
       tracking_click_(),
       tracking_double_click_(false),
       double_click_time_(0),
       can_discard_mousemove_(false),
       ignore_ime_messages_(false),
       delete_at_end_pressed_(false),
       font_(parent_view->font()),
+      font_x_height_(-1),
+      font_y_adjustment_(-1),
       possible_drag_(false),
       in_drag_(false),
       initiated_drag_(false),
       drop_highlight_position_(-1),
       ime_candidate_window_open_(false),
       background_color_(skia::SkColorToCOLORREF(LocationBarView::GetColor(
           ToolbarModel::NONE, LocationBarView::BACKGROUND))),
       security_level_(ToolbarModel::NONE),
       text_object_model_(NULL) {
   // Dummy call to a function exported by riched20.dll to ensure it sets up an
@@ skipping 17 matching lines @@
     keyboard_.CreateInstance(CLSID_TextInputPanel, NULL, CLSCTX_INPROC);
     if (keyboard_ != NULL)
       keyboard_->put_AttachedEditWindow(m_hWnd);
   }
 
   // NOTE: Do not use SetWordBreakProcEx() here, that is no longer supported as
   // of Rich Edit 2.0 onward.
   SendMessage(m_hWnd, EM_SETWORDBREAKPROC, 0,
               reinterpret_cast<LPARAM>(&WordBreakProc));
 
-  // Get the metrics for the font.
-  HDC hdc = ::GetDC(NULL);
-  HGDIOBJ old_font = SelectObject(hdc, font_.GetNativeFont());
-  TEXTMETRIC tm = {0};
-  GetTextMetrics(hdc, &tm);
-  const float kXHeightRatio = 0.7f;  // The ratio of a font's x-height to its
-                                     // cap height.  Sadly, Windows doesn't
-                                     // provide a true value for a font's
-                                     // x-height in its text metrics, so we
-                                     // approximate.
-  font_x_height_ = static_cast<int>((static_cast<float>(font_.GetBaseline() -
-      tm.tmInternalLeading) * kXHeightRatio) + 0.5);
-  // The distance from the top of the field to the desired baseline of the
-  // rendered text.
-  const int kTextBaseline = popup_window_mode_ ? 15 : 18;
-  font_y_adjustment_ = kTextBaseline - font_.GetBaseline();
-
-  // Get the number of twips per pixel, which we need below to offset our text
-  // by the desired number of pixels.
-  const long kTwipsPerPixel = kTwipsPerInch / GetDeviceCaps(hdc, LOGPIXELSY);
-  // It's unsafe to delete a DC with a non-stock object selected, so restore the
-  // original font.
-  SelectObject(hdc, old_font);
-  ::ReleaseDC(NULL, hdc);
-
-  // Set the default character style -- adjust to our desired baseline.
-  CHARFORMAT cf = {0};
-  cf.dwMask = CFM_OFFSET;
-  cf.yOffset = -font_y_adjustment_ * kTwipsPerPixel;
-  SetDefaultCharFormat(cf);
-
   SetBackgroundColor(background_color_);
 
   // By default RichEdit has a drop target. Revoke it so that we can install our
   // own. Revoke takes care of deleting the existing one.
   RevokeDragDrop(m_hWnd);
 
   // Register our drop target. RichEdit appears to invoke RevokeDropTarget when
   // done so that we don't have to explicitly.
   if (!popup_window_mode_) {
     scoped_refptr<EditDropTarget> drop_target = new EditDropTarget(this);
@@ skipping 1228 matching lines @@
   }
 }
 
 void OmniboxViewWin::OnPaint(HDC bogus_hdc) {
   // We need to paint over the top of the edit.  If we simply let the edit do
   // its default painting, then do ours into the window DC, the screen is
   // updated in between and we can get flicker.  To avoid this, we force the
   // edit to paint into a memory DC, which we also paint onto, then blit the
   // whole thing to the screen.
 
+  // Font layout members should be set before we ever paint.
+  DCHECK_NE(font_x_height_, -1);
+  DCHECK_NE(font_y_adjustment_, -1);
+
   // Don't paint if not necessary.
   CRect paint_clip_rect;
   if (!GetUpdateRect(&paint_clip_rect, true))
     return;
 
   // Begin painting, and create a memory DC for the edit to paint into.
   CPaintDC paint_dc(m_hWnd);
   CDC memory_dc(CreateCompatibleDC(paint_dc));
   CRect rect;
   GetClientRect(&rect);
@@ skipping 122 matching lines @@
   //   * alt-space gets translated by the default WM_SYSCHAR handler to a
   //     WM_SYSCOMMAND to open the application context menu, so we need to allow
   //     it through.
   if (ch == VK_SPACE)
     SetMsgHandled(false);
 }
 
 void OmniboxViewWin::OnWindowPosChanging(WINDOWPOS* window_pos) {
   if (force_hidden_)
     window_pos->flags &= ~SWP_SHOWWINDOW;
+
+  // The first time this method is called is the earliest we know the
+  // dimensions of the view, which we must wait for so that we can
+  // calculate our font layout members, font_x_height_ and
+  // font_y_adjustment_.

[Peter Kasting, 2012/05/16 21:34:34]

Instead of doing this, pass in the expected height to the constructor. 
LocationBarView::Init() calculates this value as |height|.  This is simpler and
safer than waiting for OnWindowPosChanging().

+  if (font_x_height_ == -1) {
+    DCHECK_EQ(font_y_adjustment_, -1);
+
+    // Get the metrics for the font.
+    HDC hdc = ::GetDC(NULL);
+    HGDIOBJ old_font = SelectObject(hdc, font_.GetNativeFont());
+    TEXTMETRIC tm = {0};
+    GetTextMetrics(hdc, &tm);
+    int cap_height = font_.GetBaseline() - tm.tmInternalLeading;
+    const float kXHeightRatio = 0.7f;  // The ratio of a font's x-height to its
+    // cap height.  Sadly, Windows doesn't
+    // provide a true value for a font's
+    // x-height in its text metrics, so we
+    // approximate.
+    font_x_height_ = static_cast<int>(
+        (static_cast<float>(cap_height) * kXHeightRatio) + 0.5);
+
+    // We set font_y_adjustment_ so that the ascender of the font gets
+    // centered on the available height of the view.
+    DCHECK_GT(window_pos->cy, cap_height);
+    font_y_adjustment_ =
+        (window_pos->cy - cap_height) / 2 + cap_height - font_.GetBaseline();
+
+    // Get the number of twips per pixel, which we need below to offset our text
+    // by the desired number of pixels.
+    const long kTwipsPerPixel = kTwipsPerInch / GetDeviceCaps(hdc, LOGPIXELSY);
+    // It's unsafe to delete a DC with a non-stock object selected, so
+    // restore the original font.
+    SelectObject(hdc, old_font);
+    ::ReleaseDC(NULL, hdc);
+
+    // Set the default character style -- adjust to our desired baseline.
+    CHARFORMAT cf = {0};
+    cf.dwMask = CFM_OFFSET;
+    cf.yOffset = -font_y_adjustment_ * kTwipsPerPixel;
+    SetDefaultCharFormat(cf);
+
+    DCHECK_NE(font_x_height_, -1);
+    DCHECK_NE(font_y_adjustment_, -1);
+  }
+
   SetMsgHandled(true);
 }
 
 BOOL OmniboxViewWin::OnMouseWheel(UINT flags, short delta, CPoint point) {
   // Forward the mouse-wheel message to the window under the mouse.
   if (!ui::RerouteMouseWheel(m_hWnd, MAKEWPARAM(flags, delta),
                              MAKELPARAM(point.x, point.y)))
     SetMsgHandled(false);
   return 0;
 }
@@ skipping 759 matching lines @@
     bool popup_window_mode,
     LocationBarView* location_bar) {
   return new OmniboxViewWin(controller,
                             toolbar_model,
                             location_bar,
                             command_updater,
                             popup_window_mode,
                             location_bar);
 }
 #endif