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

include/core/SkPaint.h

Index: include/core/SkPaint.h
diff --git a/include/core/SkPaint.h b/include/core/SkPaint.h
index abb859950c5bb6a66aecccded690ca8cd6ae02a2..5b0addf126cd4bd82bd0625152edae0f576cea94 100644
--- a/include/core/SkPaint.h
+++ b/include/core/SkPaint.h
@@ -731,6 +731,15 @@ public:
     void setTextEncoding(TextEncoding encoding);
 
     struct FontMetrics {
+            /** Describes defined to identify which values are unknown, later can be

[bungeman-skia, 2014/02/17 19:10:06]

nit: this comment needs to be un-indented

This comment is difficult to parse, maybe something like "Flags which indicate
the confidence level of various metrics. A set flag indicates that the metric
may be trusted."

[h.joshi, 2014/02/18 05:48:48]

Okey, will make suggested changes

On 2014/02/17 19:10:06, bungeman1 wrote:

+                   used for other uses
+            */
+        enum FontMetricsFlags {
+            kUnderlineThinknessIsValid_FontMetricFlag = 0x01,
+            kUnderlinePositionIsValid_FontMetricsflag = 1 << 1,
+        };
+
+        uint32_t    fFontMetricsFlag;       //!< Bit field to identify which values are unknown
         SkScalar    fTop;       //!< The greatest distance above the baseline for any glyph (will be <= 0)
         SkScalar    fAscent;    //!< The recommended distance above the baseline (will be <= 0)
         SkScalar    fDescent;   //!< The recommended distance below the baseline (will be >= 0)
@@ -742,8 +751,17 @@ public:
         SkScalar    fXMax;      //!< The maximum bounding box x value for all glyphs
         SkScalar    fXHeight;   //!< The height of an 'x' in px, or 0 if no 'x' in face
         SkScalar    fCapHeight;  //!< The cap height (> 0), or 0 if cannot be determined.
+        SkScalar    fUnderlineThickness; //!< underline thickness, or 0 if cannot be determined
+        SkScalar    fUnderlinePosition; //!< underline position, or 0 if cannot be determined
     };
 
+   /** Method to get bit set for Font Metrics
+        @param fObject Pointer of FontMetrics object
+        @param bitSet  bit whose value we want to know is set or not
+        @param retrun true if FontMetrics bit i set false otherwise
+    */
+    bool isFontMetricsFlagSet(FontMetrics * fObject, FontMetrics::FontMetricsFlags bitSet) const;

[bungeman-skia, 2014/02/17 19:10:06]

This seems like a really odd public interface to have on SkPaint. At the very
least this seems like something that would go in the FontMetrics struct, since
you're passing a 'this' pointer (which should never be NULL) here anyway.

After putting it there, it really needs a different name, something more like
"check(FontMetricsFlag)" so that one can write something like
"fontMetrics.check(kUnderlineThinknessIsValid_FontMetricFlag)". Reed may have
other suggestions for a name.

[h.joshi, 2014/02/18 05:48:48]

Pls suggest should I move method inside FontMetrics?

On 2014/02/17 19:10:06, bungeman1 wrote:

+
     /** Return the recommend spacing between lines (which will be
         fDescent - fAscent + fLeading).
         If metrics is not null, return in it the font metrics for the