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/**
* @file lv_font.h
*
*/
#ifndef LV_FONT_FMT_TXT_H
#define LV_FONT_FMT_TXT_H
#ifdef __cplusplus
extern "C" {
#endif
/*********************
* INCLUDES
*********************/
#ifdef LV_CONF_INCLUDE_SIMPLE
#include "lv_conf.h"
#else
#include "../../../lv_conf.h"
#endif
#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>
#include "lv_font.h"
/*********************
* DEFINES
*********************/
/**********************
* TYPEDEFS
**********************/
/** This describes a glyph. */
typedef struct
{
#if LV_FONT_FMT_TXT_LARGE == 0
uint32_t bitmap_index : 20; /**< Start index of the bitmap. A font can be max 1 MB. */
uint32_t adv_w :12; /**< Draw the next glyph after this width. 8.4 format (real_value * 16 is stored). */
#else
uint32_t bitmap_index; /**< Start index of the bitmap. A font can be max 4 GB. */
uint32_t adv_w; /**< Draw the next glyph after this width. 28.4 format (real_value * 16 is stored). */
#endif
uint8_t box_w; /**< Width of the glyph's bounding box*/
uint8_t box_h; /**< Height of the glyph's bounding box*/
int8_t ofs_x; /**< x offset of the bounding box*/
int8_t ofs_y; /**< y offset of the bounding box. Measured from the top of the line*/
}lv_font_fmt_txt_glyph_dsc_t;
/** Format of font character map. */
enum {
LV_FONT_FMT_TXT_CMAP_FORMAT0_TINY,
LV_FONT_FMT_TXT_CMAP_FORMAT0_FULL,
LV_FONT_FMT_TXT_CMAP_SPARSE_TINY,
LV_FONT_FMT_TXT_CMAP_SPARSE_FULL,
};
typedef uint8_t lv_font_fmt_txt_cmap_type_t;
/* Map codepoints to a `glyph_dsc`s
* Several formats are supported to optimize memory usage
* See https://github.com/littlevgl/lv_font_conv/blob/master/doc/font_spec.md
*/
typedef struct {
/** First Unicode character for this range */
uint32_t range_start;
/** Number of Unicode characters related to this range.
* Last Unicode character = range_start + range_length - 1*/
uint16_t range_length;
/** First glyph ID (array index of `glyph_dsc`) for this range */
uint16_t glyph_id_start;
/*
According the specification there are 4 formats:
https://github.com/littlevgl/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;
/** if(type == LV_FONT_FMT_TXT_CMAP_FORMAT0_...) it's `uint8_t *`
* if(type == LV_FONT_FMT_TXT_CMAP_SPARSE_...) it's `uint16_t *`
*/
const void * glyph_id_ofs_list;
/** Length of `unicode_list` and/or `glyph_id_ofs_list`*/
uint16_t list_length;
/** Type of this character map*/
lv_font_fmt_txt_cmap_type_t type;
}lv_font_fmt_txt_cmap_t;
/** A simple mapping of kern values from pairs*/
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 :24;
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;
/** More complex but more optimal class based kern value storage*/
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 + (righ_class-1)]
*/
const int8_t * class_pair_values; /*left_class_num * right_class_num 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;
/** Bitmap formats*/
typedef enum {
LV_FONT_FMT_TXT_PLAIN = 0,
LV_FONT_FMT_TXT_COMPRESSED = 1,
}lv_font_fmt_txt_bitmap_format_t;
/*Describe store additional data for fonts */
typedef struct {
/*The bitmaps os 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;
/* Store kerning values.
* Can be `lv_font_fmt_txt_kern_pair_t * or `lv_font_kern_classes_fmt_txt_t *`
* depending on `kern_classes`
*/
const void * kern_dsc;
/*Scale kern values in 12.4 format*/
uint16_t kern_scale;
/*Number of cmap tables*/
uint16_t cmap_num :10;
/*Bit per pixel: 1, 2, 3, 4*/
uint16_t bpp :3;
/*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*/
uint32_t last_letter;
uint32_t last_glyph_id;
}lv_font_fmt_txt_dsc_t;
/**********************
* GLOBAL PROTOTYPES
**********************/
/**
* Used as `get_glyph_bitmap` callback in LittelvGL's native font format if the font is uncompressed.
* @param font pointer to font
* @param unicode_letter an unicode letter which bitmap should be get
* @return pointer to the bitmap or NULL if not found
*/
const uint8_t * lv_font_get_bitmap_fmt_txt(const lv_font_t * font, uint32_t letter);
/**
* Used as `get_glyph_dsc` callback in LittelvGL's native font format if the font is uncompressed.
* @param font_p pointer to font
* @param dsc_out store the result descriptor here
* @param letter an UNICODE letter code
* @return true: descriptor is successfully loaded into `dsc_out`.
* false: the letter was not found, no data is loaded to `dsc_out`
*/
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);
/**********************
* MACROS
**********************/
/**********************
* ADD BUILT IN FONTS
**********************/
#ifdef __cplusplus
} /* extern "C" */
#endif
#endif /*LV_FONT_FMT_TXT_H*/
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