Better text height estimation for AGG and... slightly better for Quartz.

Author: karwa

Sources/AGGRenderer/CPPAGGRenderer/CPPAGGRenderer.cpp

@@ -481,8 +481,9 @@ namespace CPPAGGRenderer{
     void get_text_size(const char *s, float size, float* outW, float* outH){
       font_width = font_height = size;
       m_contour.width(-font_weight*font_height*0.05);
-        float x = 0;
-        float y = 0;
+      float x = 0;
+      float maxY = 0;
+      float minY = 0;
       // set rotation of font engine to zero before calculating text width
       agg::trans_affine matrix;
       matrix *= agg::trans_affine_rotation(agg::deg2rad(0));
@@ -496,16 +497,16 @@ namespace CPPAGGRenderer{
           const agg::glyph_cache* glyph = m_fman.glyph(*s);
           if(glyph){
             x+=glyph->advance_x;
-            float height = glyph->bounds.y2 - glyph->bounds.y1;
-            y = max(y, height);
+            maxY = max(maxY, (float)glyph->bounds.y2);
+            minY = min(minY, (float)glyph->bounds.y1);
           }
           ++s;
         }
       }
         if (outW)
             *outW = x;
         if (outH)
-        *outH = y;
+          *outH = maxY - abs(minY);
     }
 
     unsigned save_image(const char *s, const char** errorDesc){

Sources/QuartzRenderer/QuartzRenderer.swift

@@ -43,6 +43,8 @@ public class QuartzRenderer: Renderer {
                               height: Int(imageSize.height))
             context.setFillColor(Color.white.cgColor)
             context.fill(rect)
+          self.context.setShouldSmoothFonts(false)
+//          context.setShouldAntialias(false)
         }
     }
 
@@ -64,6 +66,8 @@ public class QuartzRenderer: Renderer {
         self.context.setAllowsFontSmoothing(true)
         self.context.setShouldSmoothFonts(fontSmoothing)
         self.isExternalContext = false
+      self.context.setShouldSmoothFonts(false)
+//      context.setShouldAntialias(false)
     }
 
     /// Creates a renderer with the given external context and dimensions..
@@ -485,7 +489,8 @@ public class QuartzRenderer: Renderer {
         #endif
         let string = NSAttributedString(string: "\(text)", attributes: attributes)
         let size = string.size()
-        return Size(width: Float(size.width), height: Float(size.height))
+        // FIXME: 'size.height' is always too big and misaligns text.
+        return Size(width: Float(size.width), height: s)
     }
 
     enum WritePNGError: Error {