ra8_glyph_atlas.h

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#pragma once
 
#ifdef __cplusplus
extern "C" {
#endif
 
#include <stdint.h>
 
#include "ra8_err.h"
#include "ra8_keycache.h"

typedef struct {
  uint32_t glyph_id; 
  uint16_t face_id;  
  uint16_t size_px;  
  uint16_t mode;     
  uint16_t reserved; 
} ra8_glyph_key_t;
 
/* The key is compared/hashed byte-wise over sizeof(ra8_glyph_key_t); guard the
 * padding-free layout at compile time so an accidental field change cannot
 * introduce indeterminate padding bytes into the comparison. */
static_assert(sizeof(ra8_glyph_key_t) == sizeof(uint32_t) + sizeof(uint16_t) + sizeof(uint16_t) +
                                           sizeof(uint16_t) + sizeof(uint16_t),
              "ra8_glyph_key_t must be padding-free for byte-wise key comparison");

typedef struct {
  uint16_t w; 
  uint16_t h; 
} ra8_glyph_dims_t;

typedef struct {
  const uint8_t* bitmap; 
  uint16_t       width;  
  uint16_t       height; 
} ra8_glyph_t;

typedef ra8_err_t (*ra8_glyph_render_fn)(void*                  ctx,
                                         const ra8_glyph_key_t* key,
                                         uint8_t*               cell,
                                         uint32_t               cell_bytes,
                                         uint16_t*              out_w,
                                         uint16_t*              out_h);

typedef struct {
  uint8_t*             cell_mem;     
  uint32_t             cell_bytes;   
  uint32_t             cell_count;   
  ra8_keycache_cell_t* meta;         
  ra8_glyph_key_t*     keys;         
  ra8_glyph_dims_t*    dims;         
  int32_t*             buckets;      
  uint32_t             bucket_count; 
  ra8_glyph_render_fn  render;       
  void*                render_ctx;   
} ra8_glyph_atlas_cfg_t;

typedef struct {
  ra8_keycache_t      kc;         
  ra8_glyph_render_fn render;     
  void*               render_ctx; 
} ra8_glyph_atlas_t;

[[nodiscard]] ra8_err_t ra8_glyph_atlas_init(ra8_glyph_atlas_t*           atlas,
                                             const ra8_glyph_atlas_cfg_t* cfg);

[[nodiscard]] ra8_err_t
ra8_glyph_atlas_get(ra8_glyph_atlas_t* atlas, const ra8_glyph_key_t* key, ra8_glyph_t* out_glyph);

[[nodiscard]] ra8_err_t ra8_glyph_atlas_put(ra8_glyph_atlas_t* atlas, const uint8_t* bitmap);

[[nodiscard]] ra8_err_t ra8_glyph_atlas_stats(const ra8_glyph_atlas_t* atlas,
                                              uint32_t*                out_hits,
                                              uint32_t*                out_misses,
                                              uint32_t*                out_evictions);
 
#ifdef __cplusplus
}
#endif