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

src/ports/SkFontHost_win_dw.cpp

Index: src/ports/SkFontHost_win_dw.cpp
diff --git a/src/ports/SkFontHost_win_dw.cpp b/src/ports/SkFontHost_win_dw.cpp
index ce5e49b358c3a87f8d53f7d494a401aa6fa5c446..8c608bca5bd770610c2b0b88b9a15d36579f02a5 100644
--- a/src/ports/SkFontHost_win_dw.cpp
+++ b/src/ports/SkFontHost_win_dw.cpp
@@ -874,6 +874,18 @@ void SkScalerContext_DW::generateFontMetrics(SkPaint::FontMetrics* mx,
         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) {
@@ -883,6 +895,18 @@ void SkScalerContext_DW::generateFontMetrics(SkPaint::FontMetrics* mx,
         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);
     }
 }