Retrieve font metrics from skia if DirectWrite is enabled for font metrics calculations in the chro…

ui/gfx/platform_font_win.cc

Index: ui/gfx/platform_font_win.cc
diff --git a/ui/gfx/platform_font_win.cc b/ui/gfx/platform_font_win.cc
index 6641935d2f9a93a4c9e6018f28a567cf1fd704cf..575149b9e205b072a288402cae5bdfb24662a2e3 100644
--- a/ui/gfx/platform_font_win.cc
+++ b/ui/gfx/platform_font_win.cc
@@ -20,6 +20,7 @@
 #include "base/win/scoped_hdc.h"
 #include "base/win/scoped_select_object.h"
 #include "base/win/win_util.h"
+#include "third_party/skia/include/core/SkTypeface.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/font_render_params.h"
@@ -82,7 +83,7 @@ PlatformFontWin::AdjustFontCallback
 PlatformFontWin::GetMinimumFontSizeCallback
     PlatformFontWin::get_minimum_font_size_callback = NULL;
 
-IDWriteFactory* PlatformFontWin::direct_write_factory_ = NULL;
+bool PlatformFontWin::use_skia_for_font_metrics_ = false;
 
 ////////////////////////////////////////////////////////////////////////////////
 // PlatformFontWin, public
@@ -250,10 +251,8 @@ PlatformFontWin::HFontRef* PlatformFontWin::GetBaseFontRef() {
 PlatformFontWin::HFontRef* PlatformFontWin::CreateHFontRef(HFONT font) {
   TEXTMETRIC font_metrics;
 
-  if (direct_write_factory_) {
-    base::win::ScopedGDIObject<HFONT> gdi_font(font);
-    font = ConvertGDIFontToDirectWriteFont(gdi_font);
-  }
+  if (use_skia_for_font_metrics_)
+    return CreateHFontRefFromSkia(font);
 
   {
     base::win::ScopedGetDC screen_dc(NULL);
@@ -318,40 +317,47 @@ Font PlatformFontWin::DeriveWithCorrectedSize(HFONT base_font) {
 }
 
 // static
-HFONT PlatformFontWin::ConvertGDIFontToDirectWriteFont(HFONT gdi_font) {
-  // This function uses  the DirectWrite Gdi interop interfaces to convert the
-  // gdi font passed in to a HFONT which is compatible with DirectWrite font
-  // metrics which could be different from GDI font metrics. This ensures that
-  // widgets like labels which use font metrics to calculate bounds have the
-  // same calculations as skia which uses DirectWrite.
-  DCHECK(direct_write_factory_);
-  base::win::ScopedComPtr<IDWriteGdiInterop> gdi_interop;
-  HRESULT hr = direct_write_factory_->GetGdiInterop(gdi_interop.Receive());
-  if (FAILED(hr)) {
-    CHECK(false);
-    return NULL;
-  }
-
-  base::win::ScopedGetDC screen_dc(NULL);
-  gfx::ScopedSetMapMode mode(screen_dc, MM_TEXT);
-
-  base::win::ScopedSelectObject scoped_font(screen_dc, gdi_font);
-
-  base::win::ScopedComPtr<IDWriteFontFace> font_face_gdi;
-  hr = gdi_interop->CreateFontFaceFromHdc(screen_dc, font_face_gdi.Receive());
-  if (FAILED(hr)) {
-    CHECK(false);
-    return NULL;
-  }
+PlatformFontWin::HFontRef* PlatformFontWin::CreateHFontRefFromSkia(
+    HFONT gdi_font) {
+  LOGFONT font_info = {0};
+  GetObject(gdi_font, sizeof(LOGFONT), &font_info);
+
+  int skia_style = SkTypeface::kNormal;
+  if (font_info.lfWeight >= FW_SEMIBOLD &&
+      font_info.lfWeight <= FW_ULTRABOLD) {
+    skia_style |= SkTypeface::kBold;
+  }
+  if (font_info.lfItalic)
+    skia_style |= SkTypeface::kItalic;
+
+  skia::RefPtr<SkTypeface> skia_face = skia::AdoptRef(
+      SkTypeface::CreateFromName(
+          base::SysWideToUTF8(font_info.lfFaceName).c_str(),
+                              static_cast<SkTypeface::Style>(skia_style)));
+  SkPaint paint;
+  paint.setAntiAlias(true);

[scottmg, 2014/11/01 00:39:15]

is there anywhere these can be tied back to where the rendering happens to make
sure they match?

[ananta, 2014/11/01 00:56:13]

Used the SystemParametersInfo function on the same lines as the
CachedFontRenderParams class in font_render_params_win.cc.

+  paint.setTypeface(skia_face.get());
+  SkPaint::FontMetrics skia_metrics;
+  paint.getFontMetrics(&skia_metrics);
+
+  const int height =

[scottmg, 2014/11/01 00:39:15]

are all the max(1, ...) necessary? I'm not familiar with cap_height, any
reference for these calculations you could comment here?

[ananta, 2014/11/01 00:56:13]

This is similar to the CreateHFontRef function which gets these values
from GDI. Added a comment to that effect. 

+      std::max<int>(1, std::ceil(fabs(skia_metrics.fAscent)) +
+                    std::ceil(skia_metrics.fDescent));
+  const int baseline = std::max<int>(1, std::ceil(fabs(skia_metrics.fAscent)));
+  const int cap_height = std::max<int>(1,
+      std::ceil(fabs(skia_metrics.fAscent)) - skia_metrics.fLeading);
+  const int ave_char_width = std::max<int>(1, skia_metrics.fAvgCharWidth);
+  const int font_size = std::max<int>(1, height - skia_metrics.fLeading);
 
-  LOGFONT dwrite_to_gdi_log_font = {0};
-  hr = gdi_interop->ConvertFontFaceToLOGFONT(font_face_gdi,
-                                             &dwrite_to_gdi_log_font);
-  if (FAILED(hr)) {
-    CHECK(false);
-    return NULL;
-  }
-  return CreateFontIndirect(&dwrite_to_gdi_log_font);
+  int style = 0;
+  if (skia_style & SkTypeface::kItalic)
+    style |= Font::ITALIC;
+  if (font_info.lfUnderline)
+    style |= Font::UNDERLINE;
+  if (font_info.lfWeight >= kTextMetricWeightBold)
+    style |= Font::BOLD;
+  return new HFontRef(gdi_font, font_size, height, baseline, cap_height,
+                      ave_char_width, style);
 }
 
 PlatformFontWin::PlatformFontWin(HFontRef* hfont_ref) : font_ref_(hfont_ref) {