lv_font_fmt_txt.h

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#ifndef LV_FONT_FMT_TXT_H
#define LV_FONT_FMT_TXT_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
/*********************
 *      INCLUDES
 *********************/
#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>
#include "lv_font.h"
 
/*********************
 *      DEFINES
 *********************/
 
/**********************
 *      TYPEDEFS
 **********************/
 
typedef struct {
#if LV_FONT_FMT_TXT_LARGE == 0
    uint32_t bitmap_index : 20;     
    uint32_t adv_w : 12;            
    uint8_t box_w;                  
    uint8_t box_h;                  
    int8_t ofs_x;                   
    int8_t ofs_y;                   
#else
    uint32_t bitmap_index;          
    uint32_t adv_w;                 
    uint16_t box_w;                 
    uint16_t box_h;                 
    int16_t ofs_x;                  
    int16_t ofs_y;                  
#endif
} lv_font_fmt_txt_glyph_dsc_t;
 
enum {
    LV_FONT_FMT_TXT_CMAP_FORMAT0_FULL,
    LV_FONT_FMT_TXT_CMAP_SPARSE_FULL,
    LV_FONT_FMT_TXT_CMAP_FORMAT0_TINY,
    LV_FONT_FMT_TXT_CMAP_SPARSE_TINY,
};
 
typedef uint8_t lv_font_fmt_txt_cmap_type_t;
 
typedef struct {
    uint32_t range_start;
 
    uint16_t range_length;
 
    uint16_t glyph_id_start;
 
    /*
    According the specification there are 4 formats:
        https://github.com/lvgl/lv_font_conv/blob/master/doc/font_spec.md
 
    For simplicity introduce "relative code point":
        rcp = codepoint - range_start
 
    and a search function:
        search a "value" in an "array" and returns the index of "value".
 
    Format 0 tiny
        unicode_list == NULL && glyph_id_ofs_list == NULL
        glyph_id = glyph_id_start + rcp
 
    Format 0 full
        unicode_list == NULL && glyph_id_ofs_list != NULL
        glyph_id = glyph_id_start + glyph_id_ofs_list[rcp]
 
    Sparse tiny
        unicode_list != NULL && glyph_id_ofs_list == NULL
        glyph_id = glyph_id_start + search(unicode_list, rcp)
 
    Sparse full
        unicode_list != NULL && glyph_id_ofs_list != NULL
        glyph_id = glyph_id_start + glyph_id_ofs_list[search(unicode_list, rcp)]
    */
 
    const uint16_t * unicode_list;
 
    const void * glyph_id_ofs_list;
 
    uint16_t list_length;
 
    lv_font_fmt_txt_cmap_type_t type;
} lv_font_fmt_txt_cmap_t;
 
typedef struct {
    /*To get a kern value of two code points:
       1. Get the `glyph_id_left` and `glyph_id_right` from `lv_font_fmt_txt_cmap_t
       2. for(i = 0; i < pair_cnt * 2; i += 2)
             if(gylph_ids[i] == glyph_id_left &&
                gylph_ids[i+1] == glyph_id_right)
                 return values[i / 2];
     */
    const void * glyph_ids;
    const int8_t * values;
    uint32_t pair_cnt   : 30;
    uint32_t glyph_ids_size : 2;    /*0: `glyph_ids` is stored as `uint8_t`; 1: as `uint16_t`*/
} lv_font_fmt_txt_kern_pair_t;
 
typedef struct {
    /*To get a kern value of two code points:
          1. Get the `glyph_id_left` and `glyph_id_right` from `lv_font_fmt_txt_cmap_t
          2. Get the class of the left and right glyphs as `left_class` and `right_class`
              left_class = left_class_mapping[glyph_id_left];
              right_class = right_class_mapping[glyph_id_right];
          3. value = class_pair_values[(left_class-1)*right_class_cnt + (right_class-1)]
        */
 
    const int8_t * class_pair_values;    /*left_class_cnt * right_class_cnt value*/
    const uint8_t * left_class_mapping;   /*Map the glyph_ids to classes: index -> glyph_id -> class_id*/
    const uint8_t * right_class_mapping;  /*Map the glyph_ids to classes: index -> glyph_id -> class_id*/
    uint8_t left_class_cnt;
    uint8_t right_class_cnt;
} lv_font_fmt_txt_kern_classes_t;
 
typedef enum {
    LV_FONT_FMT_TXT_PLAIN      = 0,
    LV_FONT_FMT_TXT_COMPRESSED = 1,
    LV_FONT_FMT_TXT_COMPRESSED_NO_PREFILTER = 1,
} lv_font_fmt_txt_bitmap_format_t;
 
typedef struct {
    uint32_t last_letter;
    uint32_t last_glyph_id;
} lv_font_fmt_txt_glyph_cache_t;
 
/*Describe store additional data for fonts*/
typedef struct {
    /*The bitmaps of all glyphs*/
    const uint8_t * glyph_bitmap;
 
    /*Describe the glyphs*/
    const lv_font_fmt_txt_glyph_dsc_t * glyph_dsc;
 
    /*Map the glyphs to Unicode characters.
     *Array of `lv_font_cmap_fmt_txt_t` variables*/
    const lv_font_fmt_txt_cmap_t * cmaps;
 
    const void * kern_dsc;
 
    /*Scale kern values in 12.4 format*/
    uint16_t kern_scale;
 
    /*Number of cmap tables*/
    uint16_t cmap_num       : 9;
 
    /*Bit per pixel: 1, 2, 3, 4, 8*/
    uint16_t bpp            : 4;
 
    /*Type of `kern_dsc`*/
    uint16_t kern_classes   : 1;
 
    /*
     * storage format of the bitmap
     * from `lv_font_fmt_txt_bitmap_format_t`
     */
    uint16_t bitmap_format  : 2;
 
    /*Cache the last letter and is glyph id*/
    lv_font_fmt_txt_glyph_cache_t * cache;
} lv_font_fmt_txt_dsc_t;
 
/**********************
 * GLOBAL PROTOTYPES
 **********************/
 
const uint8_t * lv_font_get_bitmap_fmt_txt(const lv_font_t * font, uint32_t letter);
 
bool lv_font_get_glyph_dsc_fmt_txt(const lv_font_t * font, lv_font_glyph_dsc_t * dsc_out, uint32_t unicode_letter,
                                   uint32_t unicode_letter_next);
 
void _lv_font_clean_up_fmt_txt(void);
 
/**********************
 *      MACROS
 **********************/
 
/**********************
 * ADD BUILT IN FONTS
 **********************/
 
#ifdef __cplusplus
} /*extern "C"*/
#endif
 
#endif /*LV_FONT_FMT_TXT_H*/