Implement rendering of 'dominant-baseline' property.

(bzr r14430.1.11)

4 files changed, 56 insertions, 39 deletions

diff --git a/src/libnrtype/FontInstance.cpp b/src/libnrtype/FontInstance.cpp
index 4578efe8f..79477d431 100644
--- a/src/libnrtype/FontInstance.cpp
+++ b/src/libnrtype/FontInstance.cpp
@@ -194,7 +194,7 @@ font_instance::font_instance(void) :
     _baselines[ SP_CSS_BASELINE_IDEOGRAPHIC      ] = -_descent;
     _baselines[ SP_CSS_BASELINE_HANGING          ] =  0.8 * _ascent;
     _baselines[ SP_CSS_BASELINE_MATHEMATICAL     ] =  0.8 * _xheight;
-    _baselines[ SP_CSS_BASELINE_CENTRAL          ] =  0.5;
+    _baselines[ SP_CSS_BASELINE_CENTRAL          ] =  0.5 - _descent;
     _baselines[ SP_CSS_BASELINE_MIDDLE           ] =  0.5 * _xheight;
     _baselines[ SP_CSS_BASELINE_TEXT_BEFORE_EDGE ] = -_descent;
     _baselines[ SP_CSS_BASELINE_TEXT_AFTER_EDGE  ] = _ascent;
@@ -710,7 +710,7 @@ void font_instance::FindFontMetrics() {
             _baselines[ SP_CSS_BASELINE_IDEOGRAPHIC      ] = -_descent;      // Recommendation
             _baselines[ SP_CSS_BASELINE_HANGING          ] = 0.8 * _ascent;  // Guess
             _baselines[ SP_CSS_BASELINE_MATHEMATICAL     ] = 0.8 * _xheight; // Guess
-            _baselines[ SP_CSS_BASELINE_CENTRAL          ] = 0.5;            // Definition
+            _baselines[ SP_CSS_BASELINE_CENTRAL          ] = 0.5 - _descent; // Definition
             _baselines[ SP_CSS_BASELINE_MIDDLE           ] = 0.5 * _xheight; // Definition
             _baselines[ SP_CSS_BASELINE_TEXT_BEFORE_EDGE ] = -_descent;      // Definition
             _baselines[ SP_CSS_BASELINE_TEXT_AFTER_EDGE  ] = _ascent;        // Definition
@@ -783,7 +783,7 @@ void font_instance::FindFontMetrics() {
             _baselines[ SP_CSS_BASELINE_IDEOGRAPHIC      ] = -_descent;      // Recommendation
             _baselines[ SP_CSS_BASELINE_HANGING          ] = 0.8 * _ascent;  // Guess
             _baselines[ SP_CSS_BASELINE_MATHEMATICAL     ] = 0.8 * _xheight; // Guess
-            _baselines[ SP_CSS_BASELINE_CENTRAL          ] = 0.5;            // Definition
+            _baselines[ SP_CSS_BASELINE_CENTRAL          ] = 0.5 - _descent; // Definition
             _baselines[ SP_CSS_BASELINE_MIDDLE           ] = 0.5 * _xheight; // Definition
             _baselines[ SP_CSS_BASELINE_TEXT_BEFORE_EDGE ] = -_descent;      // Definition
             _baselines[ SP_CSS_BASELINE_TEXT_AFTER_EDGE  ] = _ascent;        // Definition
@@ -803,9 +803,9 @@ void font_instance::FindFontMetrics() {
                 FT_Glyph_Get_CBox( aglyph, FT_GLYPH_BBOX_UNSCALED, &acbox );
                 double math = (acbox.yMin + acbox.yMax)/2.0/(double)theFace->units_per_EM;
                 _baselines[ SP_CSS_BASELINE_MATHEMATICAL ] = math;
-                std::cout << "Math baseline: - bbox: y_min: " << acbox.yMin
-                          << "  y_max: " << acbox.yMax
-                          << "  math: " << math << std::endl;
+                // std::cout << "Math baseline: - bbox: y_min: " << acbox.yMin
+                //           << "  y_max: " << acbox.yMax
+                //           << "  math: " << math << std::endl;
             }
 
             // Find hanging baseline... assume it is at top of 'म'.
@@ -818,26 +818,26 @@ void font_instance::FindFontMetrics() {
                 FT_Glyph_Get_CBox( aglyph, FT_GLYPH_BBOX_UNSCALED, &acbox );
                 double hanging = (double)acbox.yMax/(double)theFace->units_per_EM;
                 _baselines[ SP_CSS_BASELINE_HANGING ] = hanging;
-                std::cout << "Hanging baseline:  प: " << hanging << std::endl;
+                // std::cout << "Hanging baseline:  प: " << hanging << std::endl;
             }
         }
 #endif
-        const gchar *family = pango_font_description_get_family(descr);
-        std::cout << "Font: " << (family?family:"null") << std::endl;
-        std::cout << "  ascent:      " << _ascent      << std::endl;
-        std::cout << "  descent:     " << _descent     << std::endl;
-        std::cout << "  x-height:    " << _xheight     << std::endl;
-        std::cout << "  max ascent:  " << _ascent_max  << std::endl;
-        std::cout << "  max descent: " << _descent_max << std::endl;
-        std::cout << " Baselines:" << std::endl;
-        std::cout << "  alphabetic:  " << _baselines[ SP_CSS_BASELINE_ALPHABETIC       ] << std::endl;
-        std::cout << "  ideographic: " << _baselines[ SP_CSS_BASELINE_IDEOGRAPHIC      ] << std::endl;
-        std::cout << "  hanging:     " << _baselines[ SP_CSS_BASELINE_HANGING          ] << std::endl;
-        std::cout << "  math:        " << _baselines[ SP_CSS_BASELINE_MATHEMATICAL     ] << std::endl;
-        std::cout << "  central:     " << _baselines[ SP_CSS_BASELINE_CENTRAL          ] << std::endl;
-        std::cout << "  middle:      " << _baselines[ SP_CSS_BASELINE_MIDDLE           ] << std::endl;
-        std::cout << "  text_before: " << _baselines[ SP_CSS_BASELINE_TEXT_BEFORE_EDGE ] << std::endl;
-        std::cout << "  text_after:  " << _baselines[ SP_CSS_BASELINE_TEXT_AFTER_EDGE  ] << std::endl;
+        // const gchar *family = pango_font_description_get_family(descr);
+        // std::cout << "Font: " << (family?family:"null") << std::endl;
+        // std::cout << "  ascent:      " << _ascent      << std::endl;
+        // std::cout << "  descent:     " << _descent     << std::endl;
+        // std::cout << "  x-height:    " << _xheight     << std::endl;
+        // std::cout << "  max ascent:  " << _ascent_max  << std::endl;
+        // std::cout << "  max descent: " << _descent_max << std::endl;
+        // std::cout << " Baselines:" << std::endl;
+        // std::cout << "  alphabetic:  " << _baselines[ SP_CSS_BASELINE_ALPHABETIC       ] << std::endl;
+        // std::cout << "  ideographic: " << _baselines[ SP_CSS_BASELINE_IDEOGRAPHIC      ] << std::endl;
+        // std::cout << "  hanging:     " << _baselines[ SP_CSS_BASELINE_HANGING          ] << std::endl;
+        // std::cout << "  math:        " << _baselines[ SP_CSS_BASELINE_MATHEMATICAL     ] << std::endl;
+        // std::cout << "  central:     " << _baselines[ SP_CSS_BASELINE_CENTRAL          ] << std::endl;
+        // std::cout << "  middle:      " << _baselines[ SP_CSS_BASELINE_MIDDLE           ] << std::endl;
+        // std::cout << "  text_before: " << _baselines[ SP_CSS_BASELINE_TEXT_BEFORE_EDGE ] << std::endl;
+        // std::cout << "  text_after:  " << _baselines[ SP_CSS_BASELINE_TEXT_AFTER_EDGE  ] << std::endl;
     }
 }
 
diff --git a/src/libnrtype/Layout-TNG-Compute.cpp b/src/libnrtype/Layout-TNG-Compute.cpp
index 05cc638f7..2ae13efa6 100644
--- a/src/libnrtype/Layout-TNG-Compute.cpp
+++ b/src/libnrtype/Layout-TNG-Compute.cpp
@@ -692,10 +692,18 @@ static void dumpUnbrokenSpans(ParagraphInfo *para){
 
                         // y-coordinate is flipped between vertical and horizontal text... delta_y is common offset but applied with opposite sign
                         double delta_y = unbroken_span_glyph_info->geometry.y_offset * font_size_multiplier + unbroken_span.baseline_shift;
+                        SPCSSBaseline dominant_baseline = _flow._blockBaseline();
 
                         if (_block_progression == LEFT_TO_RIGHT || _block_progression == RIGHT_TO_LEFT) {
                             // Vertical text
 
+                            // Default dominant baseline is determined by overall block (i.e. <text>) 'text-orientation' value.
+                            if( _flow._blockTextOrientation() != SP_CSS_TEXT_ORIENTATION_SIDEWAYS ) {
+                                if( dominant_baseline == SP_CSS_BASELINE_AUTO ) dominant_baseline = SP_CSS_BASELINE_CENTRAL;
+                            } else {
+                                if( dominant_baseline == SP_CSS_BASELINE_AUTO ) dominant_baseline = SP_CSS_BASELINE_ALPHABETIC;
+                            }
+
                             new_glyph.y += delta_y;
 
                             // TODO: Should also check 'glyph_orientation_vertical' if 'text-orientation' is unset...
@@ -703,15 +711,10 @@ static void dumpUnbrokenSpans(ParagraphInfo *para){
                                 (new_span.text_orientation == SP_CSS_TEXT_ORIENTATION_MIXED &&
                                  para.pango_items[unbroken_span.pango_item_index].item->analysis.gravity == 0) ) {
 
-                                // Sideways orientation (Latin characters, CJK punctuation), 90deg rotation done at output stage.
+                                // Sideways orientation (Latin characters, CJK punctuation), 90deg rotation done at output stage. zzzzzzz
                                 new_glyph.orientation = ORIENTATION_SIDEWAYS;
 
-                                // Baseline is determined by overall block (i.e. <text>) 'text-orientation' value.
-                                if( _flow._blockTextOrientation() != SP_CSS_TEXT_ORIENTATION_SIDEWAYS ) {
-                                    // Baseline is center  (shift: alphabetic to center)
-                                    new_glyph.y += 0.5 * (new_span.line_height.descent - new_span.line_height.ascent);
-                                }
-
+                                new_glyph.y -= new_span.font_size * para.pango_items[unbroken_span.pango_item_index].font->GetBaselines()[ dominant_baseline ];
                                 new_glyph.width = new_span.font_size * para.pango_items[unbroken_span.pango_item_index].font->Advance(unbroken_span_glyph_info->glyph, false);
 
                             } else {
@@ -719,14 +722,10 @@ static void dumpUnbrokenSpans(ParagraphInfo *para){
 
                                 new_glyph.x +=  new_span.line_height.ascent;
 
-                                // Baseline is determined by overall block (i.e. <text>) 'text-orientation' value.
-                                if( _flow._blockTextOrientation() == SP_CSS_TEXT_ORIENTATION_SIDEWAYS ) {
-                                    // Baseline is alphabetic .. sideways  (shift: left edge to alphabetic)
-                                    new_glyph.y -= new_span.line_height.descent;
-                                } else {
-                                    // Baseline is center  (shift: left edge to center)
-                                    new_glyph.y -= unbroken_span_glyph_info->geometry.width * 0.5 * font_size_multiplier;
-                                }
+                                // Glyph reference point is center  (shift: left edge to center glyph)
+                                new_glyph.y -= unbroken_span_glyph_info->geometry.width * 0.5 * font_size_multiplier;
+                                new_glyph.y -= new_span.font_size * (para.pango_items[unbroken_span.pango_item_index].font->GetBaselines()[ dominant_baseline ] -
+                                                                     para.pango_items[unbroken_span.pango_item_index].font->GetBaselines()[ SP_CSS_BASELINE_CENTRAL ] );
 
                                 new_glyph.width = new_span.font_size * para.pango_items[unbroken_span.pango_item_index].font->Advance(unbroken_span_glyph_info->glyph, true);
                                 if( new_glyph.width == 0 ) {
@@ -736,8 +735,12 @@ static void dumpUnbrokenSpans(ParagraphInfo *para){
                             }
                         } else {
                             // Horizontal text
-                            new_glyph.y -= delta_y;
 
+                            if( dominant_baseline == SP_CSS_BASELINE_AUTO ) dominant_baseline = SP_CSS_BASELINE_ALPHABETIC;
+
+                            new_glyph.y -= delta_y;
+                            new_glyph.y += new_span.font_size * para.pango_items[unbroken_span.pango_item_index].font->GetBaselines()[ dominant_baseline ];
+                            
                             new_glyph.width = unbroken_span_glyph_info->geometry.width * font_size_multiplier;
                             if ((new_glyph.width == 0) && (para.pango_items[unbroken_span.pango_item_index].font))
                                 new_glyph.width = new_span.font_size * para.pango_items[unbroken_span.pango_item_index].font->Advance(unbroken_span_glyph_info->glyph, false);
diff --git a/src/libnrtype/Layout-TNG-Input.cpp b/src/libnrtype/Layout-TNG-Input.cpp
index b66bbb5cd..6f5d4e5f8 100644
--- a/src/libnrtype/Layout-TNG-Input.cpp
+++ b/src/libnrtype/Layout-TNG-Input.cpp
@@ -151,6 +151,11 @@ SPCSSTextOrientation Layout::InputStreamTextSource::styleGetTextOrientation() co
   return ((SPCSSTextOrientation)style->text_orientation.computed);
 }
 
+SPCSSBaseline Layout::InputStreamTextSource::styleGetDominantBaseline() const
+{
+  return ((SPCSSBaseline)style->dominant_baseline.computed);
+}
+
 static Layout::Alignment text_anchor_to_alignment(unsigned anchor, Layout::Direction para_direction)
 {
     switch (anchor) {
diff --git a/src/libnrtype/Layout-TNG.h b/src/libnrtype/Layout-TNG.h
index c923cc0dc..97a05bde8 100644
--- a/src/libnrtype/Layout-TNG.h
+++ b/src/libnrtype/Layout-TNG.h
@@ -723,6 +723,7 @@ private:
         font_instance *styleGetFontInstance() const;
         Direction styleGetBlockProgression() const;
         SPCSSTextOrientation styleGetTextOrientation() const;
+        SPCSSBaseline styleGetDominantBaseline() const;
         Alignment styleGetAlignment(Direction para_direction, bool try_text_align) const;
     };
 
@@ -769,6 +770,14 @@ private:
             return SP_CSS_TEXT_ORIENTATION_MIXED;
         }
 
+    /** The overall text-orientation of the whole flow. */
+    inline  SPCSSBaseline _blockBaseline() const
+        {
+            if(!_input_stream.empty())
+                return static_cast<InputStreamTextSource*>(_input_stream.front())->styleGetDominantBaseline();
+            return SP_CSS_BASELINE_AUTO;
+        }
+
     /** so that LEFT_TO_RIGHT == RIGHT_TO_LEFT but != TOP_TO_BOTTOM */
     static bool _directions_are_orthogonal(Direction d1, Direction d2);