Turn FontMetrics into a class. Add maximum ascent/descent variables.

(bzr r14430.1.8)

4 files changed, 56 insertions, 19 deletions

diff --git a/src/libnrtype/Layout-TNG-Compute.cpp b/src/libnrtype/Layout-TNG-Compute.cpp
index 6b5697b10..2081b5a6d 100644
--- a/src/libnrtype/Layout-TNG-Compute.cpp
+++ b/src/libnrtype/Layout-TNG-Compute.cpp
@@ -482,7 +482,7 @@ static void dumpUnbrokenSpans(ParagraphInfo *para){
                 // Vertical text, use em box center as baseline
                 new_line.baseline_y += 0.5 * line_height.emSize();
             } else {
-                new_line.baseline_y += line_height.getAscent();
+                new_line.baseline_y += line_height.getTypoAscent();
             }
         }
 
diff --git a/src/libnrtype/Layout-TNG-OutIter.cpp b/src/libnrtype/Layout-TNG-OutIter.cpp
index c7275c24e..8c29b7dbc 100644
--- a/src/libnrtype/Layout-TNG-OutIter.cpp
+++ b/src/libnrtype/Layout-TNG-OutIter.cpp
@@ -120,7 +120,8 @@ Layout::iterator Layout::getNearestCursorPositionTo(double x, double y) const
     double best_y_range = DBL_MAX;
     double best_x_range = DBL_MAX;
     for (chunk_index = 0 ; chunk_index < _chunks.size() ; chunk_index++) {
-        FontMetrics line_height = {0.0, 0.0, 0.0};
+        FontMetrics line_height;
+        line_height *= 0.0; // Set all metrics to zero.
         double chunk_width = 0.0;
         for ( ; span_index < _spans.size() && _spans[span_index].in_chunk == chunk_index ; span_index++) {
             line_height.max(_spans[span_index].line_height);
diff --git a/src/libnrtype/Layout-TNG-Output.cpp b/src/libnrtype/Layout-TNG-Output.cpp
index 0bbf266c7..9557bc84c 100644
--- a/src/libnrtype/Layout-TNG-Output.cpp
+++ b/src/libnrtype/Layout-TNG-Output.cpp
@@ -93,10 +93,24 @@ void Layout::_clearOutputObjects()
     _path_fitted = NULL;
 }
 
+void Layout::FontMetrics::set(font_instance *font)
+{
+    if( font != NULL ) {
+        ascent      = font->GetTypoAscent();  
+        descent     = font->GetTypoDescent();
+        xheight     = font->GetXHeight();
+        ascent_max  = font->GetMaxAscent();
+        descent_max = font->GetMaxDescent();
+    }
+}
+
 void Layout::FontMetrics::max(FontMetrics const &other)
 {
-    if (other.ascent > ascent)  ascent  = other.ascent;
-    if (other.descent > descent) descent = other.descent;
+    if (other.ascent      > ascent      ) ascent      = other.ascent;
+    if (other.descent     > descent     ) descent     = other.descent;
+    if( other.xheight     > xheight     ) xheight     = other.xheight;
+    if( other.ascent_max  > ascent_max  ) ascent_max  = other.ascent_max;
+    if( other.descent_max > descent_max ) descent_max = other.descent_max;
 }
 
 void Layout::FontMetrics::computeEffective( const double &line_height_multiplier ) {
@@ -142,8 +156,8 @@ void Layout::show(DrawingGroup *in_arena, Geom::OptRect const &paintbox) const
         InputStreamTextSource const *text_source = static_cast<InputStreamTextSource const *>(_input_stream[_spans[span_index].in_input_stream_item]);
 
         text_source->style->text_decoration_data.tspan_width             =  _spans[span_index].width();
-        text_source->style->text_decoration_data.ascender                =  _spans[span_index].line_height.getAscent();
-        text_source->style->text_decoration_data.descender               =  _spans[span_index].line_height.getDescent();
+        text_source->style->text_decoration_data.ascender                =  _spans[span_index].line_height.getTypoAscent();
+        text_source->style->text_decoration_data.descender               =  _spans[span_index].line_height.getTypoDescent();
 
         if(!span_index ||
            (_chunks[_spans[span_index].in_chunk].in_line != _chunks[_spans[span_index-1].in_chunk].in_line)){
@@ -188,8 +202,8 @@ void Layout::show(DrawingGroup *in_arena, Geom::OptRect const &paintbox) const
                 // save the starting coordinates for the line - these are needed for figuring out dot/dash/wave phase
                 (void) nr_text->addComponent(_spans[span_index].font, _glyphs[glyph_index].glyph, glyph_matrix,
                     _glyphs[glyph_index].width,
-                    _spans[span_index].line_height.getAscent(),
-                    _spans[span_index].line_height.getDescent(),
+                    _spans[span_index].line_height.getTypoAscent(),
+                    _spans[span_index].line_height.getTypoDescent(),
                     glyph_matrix.translation()[Geom::X] - phase0
                 );
             }
diff --git a/src/libnrtype/Layout-TNG.h b/src/libnrtype/Layout-TNG.h
index c2895e05f..ccf4bbe43 100644
--- a/src/libnrtype/Layout-TNG.h
+++ b/src/libnrtype/Layout-TNG.h
@@ -622,20 +622,32 @@ public:
      *
      * It's useful for this to be public so that ScanlineMaker can use it.
      */
-    struct FontMetrics {
-
-        double ascent;
-        double descent;
-        double xheight;
+    class FontMetrics {
 
+    public:
+        FontMetrics() { reset(); }
+        
+        void reset() {
+            ascent      =  0.8;
+            descent     = -0.2;
+            xheight     =  0.5;
+            ascent_max  =  0.8;
+            descent_max =  0.2;
+        }            
+
+        inline void set( font_instance *font );
+        
         // CSS 2.1 dictates that font-size is based on em-size which is defined as ascent + descent
         inline double emSize() const {return ascent + descent;}
         // Alternatively name function for use 2.
         inline double lineSize() const { return ascent + descent; }
-        inline void setZero() {ascent = descent = xheight = 0.0;}
+        inline void setZero() {ascent = descent = xheight = ascent_max = descent_max = 0.0;}
 
         // For scaling for 'font-size'.
-        inline FontMetrics& operator*=(double x) {ascent *= x; descent *= x; xheight *= x; return *this;}
+        inline FontMetrics& operator*=(double x) {
+            ascent *= x; descent *= x; xheight *= x; ascent_max *= x; descent_max *= x;
+            return *this;
+        }
 
         /// Save the larger values of ascent and descent between this and other. Needed for laying
         /// out a line with mixed font-sizes, fonts, or line spacings.
@@ -644,10 +656,20 @@ public:
         /// Calculate the effective ascent and descent including half "leading".
         void computeEffective( const double &line_height );
 
-        inline double getAscent() const {return ascent; }
-        inline double getDescent() const {return descent; }
-        inline double getXheight() const {return xheight; }
-    };
+        inline double getTypoAscent()  const {return ascent; }
+        inline double getTypoDescent() const {return descent; }
+        inline double getXHeight()     const {return xheight; }
+        inline double getMaxAscent()   const {return ascent_max; }
+        inline double getMaxDescent()  const {return descent_max; }
+
+        // private:
+        double ascent;      // Typographic ascent.
+        double descent;     // Typographic descent.
+        double xheight;     // Height of 'x' measured from alphabetic baseline.
+        double ascent_max;  // Maximum ascent of all glyphs in font.
+        double descent_max; // Maximum descent of all glyphs in font.
+
+    }; // End FontMetrics
 
     /// see _enum_converter()
     struct EnumConversionItem {