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

src/ports/SkFontHost_win.cpp

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkAdvancedTypefaceMetrics.h"
 #include "SkBase64.h"
@@ skipping 1043 matching lines @@
     if (0 == ret) {
         return;
     }
 
     if (mx) {
         mx->fTop = SkIntToScalar(-otm.otmrcFontBox.left);
         mx->fAscent = SkIntToScalar(-otm.otmAscent);
         mx->fDescent = SkIntToScalar(-otm.otmDescent);
         mx->fBottom = SkIntToScalar(otm.otmrcFontBox.right);
         mx->fLeading = SkIntToScalar(otm.otmLineGap);
+        mx->fUnderlineThickness = SkIntToScalar(otm.otmsUnderscoreSize);
+        mx->fUnderlinePosition = SkIntToScalar(otm.otmsUnderscorePosition);
+
+        if(!mx->fUnderlineThickness)

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

If we get here, we're only dealing with fonts which will have this information,
so these checks don't make sense, and we should just set that we trust these two
values. (Same below.) Note that the fonts which do not have this information
have already been dealt with above, and we are zeroing the entire FontMetrics
struct, so those already state not to trust these values (which is good since
they're just 0).

[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) {
 #ifndef SK_GDI_ALWAYS_USE_TEXTMETRICS_FOR_FONT_METRICS
         my->fTop = SkIntToScalar(-otm.otmrcFontBox.top);
         my->fAscent = SkIntToScalar(-otm.otmAscent);
         my->fDescent = SkIntToScalar(-otm.otmDescent);
         my->fBottom = SkIntToScalar(-otm.otmrcFontBox.bottom);
         my->fLeading = SkIntToScalar(otm.otmLineGap);
         my->fAvgCharWidth = SkIntToScalar(otm.otmTextMetrics.tmAveCharWidth);
         my->fMaxCharWidth = SkIntToScalar(otm.otmTextMetrics.tmMaxCharWidth);
         my->fXMin = SkIntToScalar(otm.otmrcFontBox.left);
         my->fXMax = SkIntToScalar(otm.otmrcFontBox.right);
+        my->fUnderlineThickness = SkIntToScalar(otm.otmsUnderscoreSize);
+        my->fUnderlinePosition = SkIntToScalar(otm.otmsUnderscorePosition);
+
+        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);
 #endif
         my->fXHeight = SkIntToScalar(otm.otmsXHeight);
 
         GLYPHMETRICS gm;
         sk_bzero(&gm, sizeof(gm));
         DWORD len = GetGlyphOutlineW(fDDC, 'x', GGO_METRICS, &gm, 0, 0, &gMat2Identity);
         if (len != GDI_ERROR && gm.gmBlackBoxY > 0) {
             my->fXHeight = SkIntToScalar(gm.gmBlackBoxY);
         }
     }
@@ skipping 1542 matching lines @@
 
 private:
     SkTDArray<ENUMLOGFONTEX> fLogFontArray;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkFontMgr* SkFontMgr_New_GDI() {
     return SkNEW(SkFontMgrGDI);
 }