Move font resize in a separate function

lib/font_renderer/font_renderer.cpp

@@ -14,8 +14,8 @@ public:
     // Conventional LUT values: (1./3., 2./9., 1./9.)
     // The values below are fine tuned as in the Elementary Plot library.
 
-    FontRendererImpl(bool hinting, bool kerning, float gamma_value) :
-        m_renderer(hinting, kerning),
+    FontRendererImpl(bool hinting, bool kerning, bool subpixel, float gamma_value) :
+        m_renderer(hinting, kerning, subpixel),
         m_gamma_lut(double(gamma_value)),
         m_blender(),
         m_lcd_lut(0.448, 0.184, 0.092)
@@ -38,7 +38,8 @@ private:
 FontRenderer *FontRendererNew(unsigned int flags, float gamma) {
     bool hinting = ((flags & FONT_RENDERER_HINTING) != 0);
     bool kerning = ((flags & FONT_RENDERER_KERNING) != 0);
-    return new FontRendererImpl(hinting, kerning, gamma);
+    bool subpixel = ((flags & FONT_RENDERER_SUBPIXEL) != 0);
+    return new FontRendererImpl(hinting, kerning, subpixel, gamma);
 }
 
 void FontRendererFree(FontRenderer *font_renderer) {
@@ -180,6 +181,7 @@ int FontRendererBakeFontBitmap(FontRenderer *font_renderer, int font_height,
 #else
     const int font_height_reduced = font_height;
 #endif
+    renderer_alpha.set_font_height(font_height_reduced);
     agg::int8u *cover_swap_buffer = new agg::int8u[pixels_width * subpixel_scale];
     for (int i = 0; i < num_chars; i++) {
         int codepoint = first_char + i;
@@ -194,7 +196,7 @@ int FontRendererBakeFontBitmap(FontRenderer *font_renderer, int font_height,
         const int y_baseline = y - pad_y - ascender_px;
 
         double x_next = x, y_next = y_baseline;
-        renderer_alpha.render_codepoint(ren_buf, font_height_reduced, text_color, x_next, y_next, codepoint, subpixel_scale);
+        renderer_alpha.render_codepoint(ren_buf, text_color, x_next, y_next, codepoint, subpixel_scale);
         int x_next_i = (subpixel_scale == 1 ? int(x_next + 1.0) : ceil_to_multiple(x_next + 0.5, subpixel_scale));
 
         // Below x and x_next_i will always be integer multiples of subpixel_scale.

lib/font_renderer/font_renderer.h

@@ -19,6 +19,7 @@ typedef struct FontRendererImpl FontRenderer;
 enum {
     FONT_RENDERER_HINTING  = 1 << 0,
     FONT_RENDERER_KERNING  = 1 << 1,
+    FONT_RENDERER_SUBPIXEL = 1 << 2,
 };
 
 typedef struct {

lib/font_renderer/font_renderer_alpha.h

@@ -26,6 +26,7 @@ class font_renderer_alpha
     // Font rendering options.
     bool m_hinting;
     bool m_kerning;
+    bool m_subpixel;
 
     bool m_font_loaded;
 
@@ -36,11 +37,12 @@ class font_renderer_alpha
 public:
     typedef agg::pixfmt_alpha8::color_type color_type;
 
-    font_renderer_alpha(bool hinting, bool kerning):
+    font_renderer_alpha(bool hinting, bool kerning, bool subpixel):
         m_feng(),
         m_fman(m_feng),
         m_hinting(hinting),
         m_kerning(kerning),
+        m_subpixel(subpixel),
         m_font_loaded(false),
         m_curves(m_fman.path_adaptor()),
         m_trans(m_curves, m_mtx)
@@ -74,21 +76,29 @@ public:
     bool load_font(const char *font_filename) {
         if(m_feng.load_font(font_filename, 0, agg::glyph_ren_outline)) {
             m_font_loaded = true;
+            m_feng.hinting(m_hinting);
         }
         return m_font_loaded;
     }
 
+    void set_font_height(double height) {
+        const double scale_x = 100.0;
+        m_feng.height(height);
+        if (m_subpixel) {
+            const int subpixel_scale = 3;
+            m_feng.width(height * scale_x * subpixel_scale);
+        } else {
+            m_feng.width(height * scale_x);
+        }
+    }
+
     template<class Rasterizer, class Scanline, class RenSolid>
     void draw_codepoint(Rasterizer& ras, Scanline& sl, 
         RenSolid& ren_solid, const color_type color,
-        int codepoint, double& x, double& y, double height, int subpixel_scale)
+        int codepoint, double& x, double& y, int subpixel_scale)
     {
         const double scale_x = 100;
 
-        m_feng.height(height);
-        m_feng.width(height * scale_x * subpixel_scale);
-        m_feng.hinting(m_hinting);
-
         // Represent the delta in x scaled by scale_x.
         double x_delta = 0;
         double start_x = x;
@@ -126,7 +136,6 @@ public:
     }
 
     void render_codepoint(agg::rendering_buffer& ren_buf,
-        const double text_size,
         const color_type text_color,
         double& x, double& y,
         int codepoint, int subpixel_scale)
@@ -141,6 +150,6 @@ public:
         agg::pixfmt_alpha8 pf(ren_buf);
         base_ren_type ren_base(pf);
         renderer_solid ren_solid(ren_base);
-        draw_codepoint(ras, sl, ren_solid, text_color, codepoint, x, y, text_size, subpixel_scale);
+        draw_codepoint(ras, sl, ren_solid, text_color, codepoint, x, y, subpixel_scale);
     }
 };

src/renderer.c

@@ -232,7 +232,7 @@ RenFont* ren_load_font(const char *filename, float size) {
   font->size = size;
 
   const float gamma = 1.5;
-  font->renderer = FontRendererNew(FONT_RENDERER_HINTING, gamma);
+  font->renderer = FontRendererNew(FONT_RENDERER_HINTING|FONT_RENDERER_SUBPIXEL, gamma);
   if (FontRendererLoadFont(font->renderer, filename)) {
     free(font);
     return NULL;