gp_font.h

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// SPDX-License-Identifier: LGPL-2.1-or-later
/*
 * Copyright (C) 2009-2024 Cyril Hrubis <metan@ucw.cz>
 */

#ifndef TEXT_GP_FONT_H
#define TEXT_GP_FONT_H
 
#include <stddef.h>
#include <stdint.h>
 
#define GP_FONT_NAME_MAX 64

typedef struct gp_glyph {
        uint8_t width;

        uint8_t height;

        int8_t bearing_x;

        int8_t bearing_y;

        uint8_t advance_x;

        uint8_t bitmap[];
} gp_glyph;

typedef enum gp_font_bitmap_format {
        GP_FONT_BITMAP_1BPP,
        GP_FONT_BITMAP_8BPP,
} gp_font_bitmap_format;

typedef enum gp_font_style {
        GP_FONT_REGULAR = 0x00,
        GP_FONT_MONO = 0x01,
        GP_FONT_BOLD = 0x02,
        GP_FONT_ITALIC = 0x04,
        GP_FONT_STYLE_MASK = 0x0f,
        GP_FONT_FALLBACK = 0x10,
} gp_font_style;
 
#define GP_FONT_STYLE(x) ((x) & GP_FONT_STYLE_MASK)
 
typedef uint32_t gp_glyph_offset;
#define GP_NOGLYPH UINT32_MAX

typedef struct gp_glyphs {
        void *glyphs;

        gp_glyph_offset *offsets;
        gp_glyph_offset offset;

        uint32_t min_glyph;
        uint32_t max_glyph;
} gp_glyphs;
 
typedef struct gp_font_face gp_font_face;

typedef struct gp_font_face_ops {
        gp_glyph *(*glyph_load)(const gp_font_face *self, uint32_t ch);
        void (*font_free)(gp_font_face *self);
} gp_font_face_ops;

struct gp_font_face {
        char family_name[GP_FONT_NAME_MAX];

        uint8_t style;

        uint8_t glyph_tables;

        uint16_t ascent;

        uint16_t descent;

        uint16_t max_glyph_width;

        uint16_t max_glyph_advance;

        uint16_t avg_glyph_advance;

        gp_font_bitmap_format glyph_bitmap_format;

        const gp_font_face_ops *ops;
        void *priv;

        gp_glyphs glyphs[];
};

typedef enum gp_font_ucode_block {
        GP_UCODE_LATIN_BASIC = 0x0001,
        GP_UCODE_LATIN_SUP = 0x0002,
        GP_UCODE_LATIN_EXT_A = 0x0004,
        GP_UCODE_GREEK = 0x0008,
        GP_UCODE_CYRILIC = 0x0010,
        GP_UCODE_PUNCTUATION = 0x0020,
        GP_UCODE_BOX = 0x0040,
        GP_UCODE_HIRAGANA= 0x0080,
        GP_UCODE_KATAKANA = 0x0100,
} gp_font_ucode_block;

typedef struct gp_font_family {
        const char *family_name;
        uint32_t ucode_blocks;
        const gp_font_face *const fonts[];
} gp_font_family;

static inline unsigned int gp_font_height(const gp_font_face *font)
{
        return font->ascent + font->descent;
}

static inline unsigned int gp_font_ascent(const gp_font_face *font)
{
        return font->ascent;
}

static inline unsigned int gp_font_descent(const gp_font_face *font)
{
        return font->descent;
}

static inline unsigned int gp_font_max_width(const gp_font_face *font)
{
        return font->max_glyph_width;
}

static inline unsigned int gp_font_max_advance_x(const gp_font_face *font)
{
        return font->max_glyph_advance;
}

static inline unsigned int gp_font_avg_advance_x(const gp_font_face *font)
{
        if (font->avg_glyph_advance)
                return font->avg_glyph_advance;
 
        /* For monospace bitmap fonts the avg == max */
        return font->max_glyph_advance;
}

static inline const char *gp_font_family_name(const gp_font_face *font)
{
        return font->family_name;
}

const char *gp_font_style_name(gp_font_style style);

gp_glyph *gp_glyph_get(const gp_font_face *font, uint32_t ch);

gp_font_face *gp_font_face_load(const char *path, uint32_t width, uint32_t height);

gp_font_face *gp_font_face_fc_load(const char *name, uint32_t width, uint32_t height);

void gp_font_face_free(gp_font_face *self);
 
#endif /* TEXT_GP_FONT_H */