Adding code to calculate Underline Thickness from Font Metrics, this will be useful when Skia is us…

src/ports/SkFontHost_win_dw.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkTypes.h"
 #undef GetGlyphIndices
 
@@ skipping 856 matching lines @@
     fTypeface->fDWriteFontFace->GetMetrics(&dwfm);
 
     SkScalar upem = SkIntToScalar(dwfm.designUnitsPerEm);
     if (mx) {
         mx->fTop = -fRec.fTextSize * SkIntToScalar(dwfm.ascent) / upem;
         mx->fAscent = mx->fTop;
         mx->fDescent = fRec.fTextSize * SkIntToScalar(dwfm.descent) / upem;
         mx->fBottom = mx->fDescent;
         mx->fLeading = fRec.fTextSize * SkIntToScalar(dwfm.lineGap) / upem;
         mx->fXHeight = fRec.fTextSize * SkIntToScalar(dwfm.xHeight) / upem;
+        mx->fUnderlineThickness = fRec.fTextSize * SkIntToScalar(dwfm.underlinePosition) / upem;
+        mx->fUnderlinePosition = fRec.fTextSize * SkIntToScalar(dwfm.underlineThickness) / upem;
+
+        if(!mx->fUnderlineThickness)

[bungeman-skia, 2014/02/19 15:39:17]

Here and below: I don't believe that DirectWrite supports any font formats which
do not have this information, so there is no need for these checks.

[h.joshi, 2014/02/19 17:12:03]

Okey, Added these checks below as "face->underline_thickness" and
"face->underline_position" can be zero. Will make changes

On 2014/02/19 15:39:17, bungeman1 wrote:

+            mx->unsetFontMetricsFlag(SkPaint::FontMetrics::kUnderlineThinknessIsValid_FontMetricFlag);
+        else
+            mx->setFontMetricsFlag(SkPaint::FontMetrics::kUnderlineThinknessIsValid_FontMetricFlag);
+
+        if(!mx->fUnderlinePosition)
+            mx->unsetFontMetricsFlag(SkPaint::FontMetrics::kUnderlinePositionIsValid_FontMetricsflag);
+        else
+            mx->setFontMetricsFlag(SkPaint::FontMetrics::kUnderlinePositionIsValid_FontMetricsflag);
     }
 
     if (my) {
         my->fTop = -fRec.fTextSize * SkIntToScalar(dwfm.ascent) / upem;
         my->fAscent = my->fTop;
         my->fDescent = fRec.fTextSize * SkIntToScalar(dwfm.descent) / upem;
         my->fBottom = my->fDescent;
         my->fLeading = fRec.fTextSize * SkIntToScalar(dwfm.lineGap) / upem;
         my->fXHeight = fRec.fTextSize * SkIntToScalar(dwfm.xHeight) / upem;
+        my->fUnderlineThickness = fRec.fTextSize * SkIntToScalar(dwfm.underlinePosition) / upem;
+        my->fUnderlinePosition = fRec.fTextSize * SkIntToScalar(dwfm.underlineThickness) / upem;
+
+        if(!my->fUnderlineThickness)
+            my->unsetFontMetricsFlag(SkPaint::FontMetrics::kUnderlineThinknessIsValid_FontMetricFlag);
+        else
+            my->setFontMetricsFlag(SkPaint::FontMetrics::kUnderlineThinknessIsValid_FontMetricFlag);
+
+        if(!my->fUnderlinePosition)
+            my->unsetFontMetricsFlag(SkPaint::FontMetrics::kUnderlinePositionIsValid_FontMetricsflag);
+        else
+            my->setFontMetricsFlag(SkPaint::FontMetrics::kUnderlinePositionIsValid_FontMetricsflag);
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #include "SkColorPriv.h"
 
 static void bilevel_to_bw(const uint8_t* SK_RESTRICT src, const SkGlyph& glyph) {
     const int width = glyph.fWidth;
     const size_t dstRB = (width + 7) >> 3;
@@ skipping 1016 matching lines @@
         SK_TRACEHR(hr, "Could not get GetUserDefaultLocaleName.");
     } else {
         localeNameLen = getUserDefaultLocaleNameProc(localeNameStorage, LOCALE_NAME_MAX_LENGTH);
         if (localeNameLen) {
             localeName = localeNameStorage;
         };
     }
 
     return SkNEW_ARGS(SkFontMgr_DirectWrite, (sysFontCollection.get(), localeName, localeNameLen));
 }