Text Rendering


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https://learnopengl.com/In-Practice/Text-Rendering

  • Rasterization: rendering a glyph to pixels
  • Shaping:
    • how to layout a sequence of glyphs on multiple lines
    • may not be straight-forward such as for latin languages

CoreText / CoreGraphics

Notes on Metal

Steps:

  1. Create CGContext
  2. Create MTLBuffer pointing to same memory
    1. Write to MTLBuffer with CGContext
  3. Create MTLTexture out of MTLBuffer
  • FreeType / Harfbuzz
  • FreeType for rasterization
  • Harfbuzz for shaping

Create a font with Harfbuzz

#include <hb-ft.h>
FT_New_Face(ft_library, font_path, index, &face);
FT_Set_Char_Size(face, 0, 1000, 0, 0);
hb_font_t *font = hb_ft_font_create(face);