Add outlining around glyphs

src/Font.cc

@@ -21,7 +21,7 @@ bool Initialize_FreeType()
     return true;
 }
 
-bool Font::load(const char * fname, int size)
+bool Font::load(const char * fname, int size, int outline_size)
 {
     if (!Initialize_FreeType())
     {
@@ -35,6 +35,8 @@ bool Font::load(const char * fname, int size)
 
     FT_Set_Pixel_Sizes(m_face, 0, size);
 
+    m_outline_size = outline_size;
+
     return preload_glyphs();
 }
 
@@ -82,7 +84,7 @@ std::shared_ptr<Glyph> Font::get_glyph(FT_ULong character)
         return it->second;
     }
     std::shared_ptr<Glyph> glyph = std::make_shared<Glyph>();
-    if (!glyph->load(m_face, character))
+    if (!glyph->load(ft_library_handle, m_face, character, m_outline_size))
     {
         glyph = nullptr;
     }

src/Font.h

@@ -8,7 +8,7 @@
 class Font
 {
 public:
-    bool load(const char * fname, int size);
+    bool load(const char * fname, int size, int outline_size);
     std::shared_ptr<Glyph> get_glyph(FT_ULong character);
     int get_advance() { return m_advance; }
     int get_line_height() { return m_line_height; }
@@ -22,6 +22,7 @@ protected:
     int m_advance;
     int m_line_height;
     int m_baseline_offset;
+    int m_outline_size;
 };
 
 #endif

src/Glyph.cc

@@ -1,17 +1,34 @@
 #include "Glyph.h"
+#include FT_STROKER_H
 
 #define round_up_26_6(val) (((val) + 63) >> 6u)
 
-bool Glyph::load(FT_Face face, FT_ULong char_code)
+bool Glyph::load(FT_Library library, FT_Face face, FT_ULong char_code, int outline_size)
 {
-    if (FT_Load_Char(face, char_code, FT_LOAD_RENDER) != 0)
-        return false;
+    FT_Glyph glyph;
+    FT_BitmapGlyph bitmap_glyph;
+
+    FT_UInt glyph_index = FT_Get_Char_Index(face, char_code);
+
+    /* Load the glyph to the face object */
+    FT_Load_Glyph(face, glyph_index, FT_LOAD_NO_BITMAP);
+    FT_Get_Glyph(face->glyph, &glyph);
+
+    if (outline_size > 0)
+    {
+        FT_Stroker stroker;
+        FT_Stroker_New(library, &stroker);
+        FT_Stroker_Set(stroker, outline_size, FT_STROKER_LINECAP_ROUND, FT_STROKER_LINEJOIN_ROUND, 0);
+        FT_Glyph_StrokeBorder(&glyph, stroker, false, true);
+    }
+    FT_Glyph_To_Bitmap(&glyph, FT_RENDER_MODE_NORMAL, nullptr, true);
+    bitmap_glyph = reinterpret_cast<FT_BitmapGlyph>(glyph);
 
     m_texture = glcxx::Texture::create();
     m_texture->bind(GL_TEXTURE_2D);
-    int width = face->glyph->bitmap.width;
+    int width = bitmap_glyph->bitmap.width;
     int rounded_width = glcxx::Texture::next_power_of_2(width);
-    int height = face->glyph->bitmap.rows;
+    int height = bitmap_glyph->bitmap.rows;
     int rounded_height = glcxx::Texture::next_power_of_2(height);
     m_advance = round_up_26_6(face->glyph->advance.x);
     uint8_t * texture = new uint8_t[rounded_width * rounded_height];
@@ -19,7 +36,7 @@ bool Glyph::load(FT_Face face, FT_ULong char_code)
     for (int i = 0; i < height; i++)
     {
         memcpy(&texture[rounded_width * i],
-               &face->glyph->bitmap.buffer[width * (height - i - 1)],
+               &bitmap_glyph->bitmap.buffer[width * (height - i - 1)],
                width);
     }
 
@@ -34,8 +51,8 @@ bool Glyph::load(FT_Face face, FT_ULong char_code)
     m_array = glcxx::Array::create();
     m_array->bind();
 
-    int left = face->glyph->bitmap_left;
-    int top = face->glyph->bitmap_top;
+    int left = bitmap_glyph->left;
+    int top = bitmap_glyph->top;
     float s_max = width / (float)rounded_width;
     float t_max = height / (float)rounded_height;
     m_buffer = glcxx::Buffer::create(GL_ARRAY_BUFFER, GL_STATIC_DRAW, {
@@ -48,5 +65,7 @@ bool Glyph::load(FT_Face face, FT_ULong char_code)
     glEnableVertexAttribArray(0);
     glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0);
 
+    FT_Done_Glyph(glyph);
+
     return true;
 }

src/Glyph.h

@@ -8,7 +8,7 @@
 class Glyph
 {
 public:
-    bool load(FT_Face face, FT_ULong char_code);
+    bool load(FT_Library library, FT_Face face, FT_ULong char_code, int outline_size);
     int get_advance() { return m_advance; }
     void render()
     {

src/main.cc

@@ -14,6 +14,7 @@ std::shared_ptr<RectShader> rect_shader;
 std::shared_ptr<glcxx::Array> rect_array;
 std::shared_ptr<glcxx::Buffer> rect_buffer;
 Font font;
+Font outlined_font;
 
 #define WIDTH   800
 #define HEIGHT  800
@@ -64,14 +65,20 @@ static void draw_string(int row)
 {
     static const char message[] = "Hello World! 0123456789_g*^#";
     float color = row / 9.0;
-    text_shader->set_color(color, color, color, 1.0);
     int x = 0;
     int y = font.get_line_height() * row + font.get_baseline_offset();
     for (size_t i = 0; i < sizeof(message) - 1; i++)
     {
-        auto g = font.get_glyph(message[i]);
+        auto g = outlined_font.get_glyph(message[i]);
         text_shader->set_position(x, y);
+        text_shader->set_color(1.0 - color, 1.0 - color, 1.0 - color, 1.0);
         g->render();
+
+        g = font.get_glyph(message[i]);
+        text_shader->set_position(x, y);
+        text_shader->set_color(color, color, color, 1.0);
+        g->render();
+
         x += g->get_advance();
     }
 }
@@ -148,7 +155,13 @@ int main(int argc, char *argv[])
         return 2;
     }
 
-    if (!font.load(argv[1], HEIGHT / 10 * 7 / 10))
+    if (!font.load(argv[1], HEIGHT / 10 * 7 / 10, 0))
+    {
+        fprintf(stderr, "Error loading font from %s\n", argv[1]);
+        return 2;
+    }
+
+    if (!outlined_font.load(argv[1], HEIGHT / 10 * 7 / 10, 128))
     {
         fprintf(stderr, "Error loading font from %s\n", argv[1]);
         return 2;