Rework gfx::Font by moving platform-specific code into inner classes....

gfx/platform_font_win.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 "gfx/font.h"
+#include "gfx/platform_font_win.h"
 
 #include <windows.h>
 #include <math.h>
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "base/win_util.h"
 #include "gfx/canvas_skia.h"
+#include "gfx/font.h"
 
-namespace gfx {
-
-// static
-Font::HFontRef* Font::base_font_ref_;
-
-// static
-Font::AdjustFontCallback Font::adjust_font_callback = NULL;
-Font::GetMinimumFontSizeCallback Font::get_minimum_font_size_callback = NULL;
+namespace {
 
 // If the tmWeight field of a TEXTMETRIC structure has a value >= this, the
 // font is bold.
-static const int kTextMetricWeightBold = 700;
+const int kTextMetricWeightBold = 700;
 
 // Returns either minimum font allowed for a current locale or
 // lf_height + size_delta value.
-static int AdjustFontSize(int lf_height, int size_delta) {
+int AdjustFontSize(int lf_height, int size_delta) {
   if (lf_height < 0) {
     lf_height -= size_delta;
   } else {
     lf_height += size_delta;
   }
   int min_font_size = 0;
-  if (Font::get_minimum_font_size_callback)
-    min_font_size = Font::get_minimum_font_size_callback();
+  if (gfx::PlatformFontWin::get_minimum_font_size_callback)
+    min_font_size = gfx::PlatformFontWin::get_minimum_font_size_callback();
   // Make sure lf_height is not smaller than allowed min font size for current
   // locale.
   if (abs(lf_height) < min_font_size) {
     return lf_height < 0 ? -min_font_size : min_font_size;
   } else {
     return lf_height;
   }
 }
 
-//
-// Font
-//
+}  // namespace
 
-Font::Font()
-    : font_ref_(GetBaseFontRef()) {
+namespace gfx {
+
+// static
+PlatformFontWin::HFontRef* PlatformFontWin::base_font_ref_;
+
+// static
+PlatformFontWin::AdjustFontCallback
+    PlatformFontWin::adjust_font_callback = NULL;
+PlatformFontWin::GetMinimumFontSizeCallback
+    PlatformFontWin::get_minimum_font_size_callback = NULL;
+
+////////////////////////////////////////////////////////////////////////////////
+// PlatformFontWin, public
+
+PlatformFontWin::PlatformFontWin() : font_ref_(GetBaseFontRef()) {
 }
 
-int Font::height() const {
+PlatformFontWin::PlatformFontWin(const Font& other) {
+  InitWithCopyOfHFONT(other.GetNativeFont());
+}
+
+PlatformFontWin::PlatformFontWin(NativeFont native_font) {
+  InitWithCopyOfHFONT(native_font);
+}
+
+PlatformFontWin::PlatformFontWin(const std::wstring& font_name,
+                                 int font_size) {
+  InitWithFontNameAndSize(font_name, font_size);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// PlatformFontWin, PlatformFont implementation:
+
+Font PlatformFontWin::DeriveFont(int size_delta, int style) const {
+  LOGFONT font_info;
+  GetObject(GetNativeFont(), sizeof(LOGFONT), &font_info);
+  font_info.lfHeight = AdjustFontSize(font_info.lfHeight, size_delta);
+  font_info.lfUnderline =
+      ((style & gfx::Font::UNDERLINED) == gfx::Font::UNDERLINED);
+  font_info.lfItalic = ((style & gfx::Font::ITALIC) == gfx::Font::ITALIC);
+  font_info.lfWeight = (style & gfx::Font::BOLD) ? FW_BOLD : FW_NORMAL;
+
+  HFONT hfont = CreateFontIndirect(&font_info);
+  return Font(new PlatformFontWin(CreateHFontRef(hfont)));
+}
+
+int PlatformFontWin::GetHeight() const {
   return font_ref_->height();
 }
 
-int Font::baseline() const {
+int PlatformFontWin::GetBaseline() const {
   return font_ref_->baseline();
 }
 
-int Font::ave_char_width() const {
+int PlatformFontWin::GetAverageCharacterWidth() const {
   return font_ref_->ave_char_width();
 }
 
-int Font::GetExpectedTextWidth(int length) const {
-  return length * std::min(font_ref_->dlu_base_x(), ave_char_width());
+int PlatformFontWin::GetStringWidth(const std::wstring& text) const {
+  int width = 0, height = 0;
+  CanvasSkia::SizeStringInt(text, Font(const_cast<PlatformFontWin*>(this)),
+                            &width, &height, gfx::Canvas::NO_ELLIPSIS);
+  return width;
 }
 
-int Font::style() const {
+int PlatformFontWin::GetExpectedTextWidth(int length) const {
+  return length * std::min(font_ref_->dlu_base_x(), GetAverageCharacterWidth());
+}
+
+int PlatformFontWin::GetStyle() const {
   return font_ref_->style();
 }
 
-NativeFont Font::nativeFont() const {
-  return hfont();
+const std::wstring& PlatformFontWin::GetFontName() const {
+  return font_ref_->font_name();
 }
 
-// static
-Font Font::CreateFont(HFONT font) {
-  DCHECK(font);
+int PlatformFontWin::GetFontSize() const {
   LOGFONT font_info;
-  GetObject(font, sizeof(LOGFONT), &font_info);
-  return Font(CreateHFontRef(CreateFontIndirect(&font_info)));
+  GetObject(font_ref_->hfont(), sizeof(LOGFONT), &font_info);
+  long lf_height = font_info.lfHeight;
+  HDC hdc = GetDC(NULL);
+  int device_caps = GetDeviceCaps(hdc, LOGPIXELSY);
+  int font_size = 0;
+  if (device_caps != 0) {
+    float font_size_float = -static_cast<float>(lf_height)*72/device_caps;
+    font_size = static_cast<int>(::ceil(font_size_float - 0.5));
+  }
+  ReleaseDC(NULL, hdc);
+  return font_size;
 }
 
-Font Font::CreateFont(const std::wstring& font_name, int font_size) {
+NativeFont PlatformFontWin::GetNativeFont() const {
+  return font_ref_->hfont();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Font, private:
+
+void PlatformFontWin::InitWithCopyOfHFONT(HFONT hfont) {
+  DCHECK(hfont);
+  LOGFONT font_info;
+  GetObject(hfont, sizeof(LOGFONT), &font_info);
+  font_ref_ = CreateHFontRef(CreateFontIndirect(&font_info));
+}
+
+void PlatformFontWin::InitWithFontNameAndSize(const std::wstring& font_name,
+                                              int font_size) {
   HDC hdc = GetDC(NULL);
   long lf_height = -MulDiv(font_size, GetDeviceCaps(hdc, LOGPIXELSY), 72);
   ReleaseDC(NULL, hdc);
   HFONT hf = ::CreateFont(lf_height, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-                    font_name.c_str());
-  return Font::CreateFont(hf);
+                          font_name.c_str());
+  font_ref_ = CreateHFontRef(hf);
 }
 
 // static
-Font::HFontRef* Font::GetBaseFontRef() {
+PlatformFontWin::HFontRef* PlatformFontWin::GetBaseFontRef() {
   if (base_font_ref_ == NULL) {
     NONCLIENTMETRICS metrics;
     win_util::GetNonClientMetrics(&metrics);
 
     if (adjust_font_callback)
       adjust_font_callback(&metrics.lfMessageFont);
     metrics.lfMessageFont.lfHeight =
         AdjustFontSize(metrics.lfMessageFont.lfHeight, 0);
     HFONT font = CreateFontIndirect(&metrics.lfMessageFont);
     DLOG_ASSERT(font);
-    base_font_ref_ = Font::CreateHFontRef(font);
+    base_font_ref_ = PlatformFontWin::CreateHFontRef(font);
     // base_font_ref_ is global, up the ref count so it's never deleted.
     base_font_ref_->AddRef();
   }
   return base_font_ref_;
 }
 
-const std::wstring& Font::FontName() const {
-  return font_ref_->font_name();
+PlatformFontWin::HFontRef* PlatformFontWin::CreateHFontRef(HFONT font) {
+  TEXTMETRIC font_metrics;
+  HDC screen_dc = GetDC(NULL);
+  HFONT previous_font = static_cast<HFONT>(SelectObject(screen_dc, font));
+  int last_map_mode = SetMapMode(screen_dc, MM_TEXT);
+  GetTextMetrics(screen_dc, &font_metrics);
+  // Yes, this is how Microsoft recommends calculating the dialog unit
+  // conversions.
+  SIZE ave_text_size;
+  GetTextExtentPoint32(screen_dc,
+                       L"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
+                       52, &ave_text_size);
+  const int dlu_base_x = (ave_text_size.cx / 26 + 1) / 2;
+  // To avoid the DC referencing font_handle_, select the previous font.
+  SelectObject(screen_dc, previous_font);
+  SetMapMode(screen_dc, last_map_mode);
+  ReleaseDC(NULL, screen_dc);
+
+  const int height = std::max(1, static_cast<int>(font_metrics.tmHeight));
+  const int baseline = std::max(1, static_cast<int>(font_metrics.tmAscent));
+  const int ave_char_width =
+      std::max(1, static_cast<int>(font_metrics.tmAveCharWidth));
+  int style = 0;
+  if (font_metrics.tmItalic)
+    style |= Font::ITALIC;
+  if (font_metrics.tmUnderlined)
+    style |= Font::UNDERLINED;
+  if (font_metrics.tmWeight >= kTextMetricWeightBold)
+    style |= Font::BOLD;
+
+  return new HFontRef(font, height, baseline, ave_char_width, style,
+                      dlu_base_x);
 }
 
-int Font::FontSize() {
-  LOGFONT font_info;
-  GetObject(hfont(), sizeof(LOGFONT), &font_info);
-  long lf_height = font_info.lfHeight;
-  HDC hdc = GetDC(NULL);
-  int device_caps = GetDeviceCaps(hdc, LOGPIXELSY);
-  int font_size = 0;
-  if (device_caps != 0) {
-    float font_size_float = -static_cast<float>(lf_height)*72/device_caps;
-    font_size = static_cast<int>(::ceil(font_size_float - 0.5));
-  }
-  ReleaseDC(NULL, hdc);
-  return font_size;
+PlatformFontWin::PlatformFontWin(HFontRef* hfont_ref) : font_ref_(hfont_ref) {
 }
 
-Font::HFontRef::HFontRef(HFONT hfont,
+////////////////////////////////////////////////////////////////////////////////
+// PlatformFontWin::HFontRef:
+
+PlatformFontWin::HFontRef::HFontRef(HFONT hfont,
          int height,
          int baseline,
          int ave_char_width,
          int style,
          int dlu_base_x)
     : hfont_(hfont),
       height_(height),
       baseline_(baseline),
       ave_char_width_(ave_char_width),
       style_(style),
       dlu_base_x_(dlu_base_x) {
   DLOG_ASSERT(hfont);
 
   LOGFONT font_info;
   GetObject(hfont_, sizeof(LOGFONT), &font_info);
   font_name_ = std::wstring(font_info.lfFaceName);
 }
 
-Font::HFontRef::~HFontRef() {
+PlatformFontWin::HFontRef::~HFontRef() {
   DeleteObject(hfont_);
 }
 
-Font Font::DeriveFont(int size_delta, int style) const {
-  LOGFONT font_info;
-  GetObject(hfont(), sizeof(LOGFONT), &font_info);
-  font_info.lfHeight = AdjustFontSize(font_info.lfHeight, size_delta);
-  font_info.lfUnderline = ((style & UNDERLINED) == UNDERLINED);
-  font_info.lfItalic = ((style & ITALIC) == ITALIC);
-  font_info.lfWeight = (style & BOLD) ? FW_BOLD : FW_NORMAL;
+////////////////////////////////////////////////////////////////////////////////
+// PlatformFont, public:
 
-  HFONT hfont = CreateFontIndirect(&font_info);
-  return Font(CreateHFontRef(hfont));
+// static
+PlatformFont* PlatformFont::CreateDefault() {
+  return new PlatformFontWin;
 }
 
-int Font::GetStringWidth(const std::wstring& text) const {
-  int width = 0, height = 0;
-  CanvasSkia::SizeStringInt(text, *this, &width, &height,
-                            gfx::Canvas::NO_ELLIPSIS);
-  return width;
+// static
+PlatformFont* PlatformFont::CreateFromFont(const Font& other) {
+  return new PlatformFontWin(other);
 }
 
-Font::HFontRef* Font::CreateHFontRef(HFONT font) {
-  TEXTMETRIC font_metrics;
-  HDC screen_dc = GetDC(NULL);
-  HFONT previous_font = static_cast<HFONT>(SelectObject(screen_dc, font));
-  int last_map_mode = SetMapMode(screen_dc, MM_TEXT);
-  GetTextMetrics(screen_dc, &font_metrics);
-  // Yes, this is how Microsoft recommends calculating the dialog unit
-  // conversions.
-  SIZE ave_text_size;
-  GetTextExtentPoint32(screen_dc,
-                       L"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
-                       52, &ave_text_size);
-  const int dlu_base_x = (ave_text_size.cx / 26 + 1) / 2;
-  // To avoid the DC referencing font_handle_, select the previous font.
-  SelectObject(screen_dc, previous_font);
-  SetMapMode(screen_dc, last_map_mode);
-  ReleaseDC(NULL, screen_dc);
+// static
+PlatformFont* PlatformFont::CreateFromNativeFont(NativeFont native_font) {
+  return new PlatformFontWin(native_font);
+}
 
-  const int height = std::max(1, static_cast<int>(font_metrics.tmHeight));
-  const int baseline = std::max(1, static_cast<int>(font_metrics.tmAscent));
-  const int ave_char_width =
-      std::max(1, static_cast<int>(font_metrics.tmAveCharWidth));
-  int style = 0;
-  if (font_metrics.tmItalic) {
-    style |= Font::ITALIC;
-  }
-  if (font_metrics.tmUnderlined) {
-    style |= Font::UNDERLINED;
-  }
-  if (font_metrics.tmWeight >= kTextMetricWeightBold) {
-    style |= Font::BOLD;
-  }
-
-  return new HFontRef(font, height, baseline, ave_char_width, style,
-                      dlu_base_x);
+// static
+PlatformFont* PlatformFont::CreateFromNameAndSize(const std::wstring& font_name,
+                                                  int font_size) {
+  return new PlatformFontWin(font_name, font_size);
 }
 
 }  // namespace gfx