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

include/core/SkPaint.h

 
 
 /*
  * 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.
  */
 
 
@@ skipping 713 matching lines @@
         kUTF16_TextEncoding,    //!< the text parameters are UTF16
         kUTF32_TextEncoding,    //!< the text parameters are UTF32
         kGlyphID_TextEncoding   //!< the text parameters are glyph indices
     };
 
     TextEncoding getTextEncoding() const { return (TextEncoding)fTextEncoding; }
 
     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)
         SkScalar    fBottom;    //!< The greatest distance below the baseline for any glyph (will be >= 0)
         SkScalar    fLeading;   //!< The recommended distance to add between lines of text (will be >= 0)
         SkScalar    fAvgCharWidth;  //!< the average charactor width (>= 0)
         SkScalar    fMaxCharWidth;  //!< the max charactor width (>= 0)
         SkScalar    fXMin;      //!< The minimum bounding box x value for all glyphs
         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
         typeface/pointsize/etc. currently set in the paint.
         @param metrics      If not null, returns the font metrics for the
                             current typeface/pointsize/etc setting in this
                             paint.
         @param scale        If not 0, return width as if the canvas were scaled
                             by this value
         @param return the recommended spacing between lines
@@ skipping 322 matching lines @@
 #ifdef SK_BUILD_FOR_ANDROID
     SkPaintOptionsAndroid fPaintOptionsAndroid;
 
     // In order for the == operator to work properly this must be the last field
     // in the struct so that we can do a memcmp to this field's offset.
     uint32_t        fGenerationID;
 #endif
 };
 
 #endif