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#include "memory.h"
#include "plat.h"
#include "render.h"
#include "stb_rect_pack.h"
#include "stb_truetype.h"
#include <math.h>
typedef struct {
Bitmap bmp;
stbtt_bakedchar glyphs[max_glyphset];
} Glyph_Set;
struct Font {
const void* data;
Heap* heap;
stbtt_fontinfo info;
Glyph_Set* sets[max_glyphset];
int size, height;
};
int font_height(Font* f) {
return f->height;
}
static const char* utf8_to_codepoint(
const char* p,
unsigned* dst
) {
unsigned res, n;
switch (*p & 0xf0) {
case 0xf0 : res = *p & 0x07; n = 3; break;
case 0xe0 : res = *p & 0x0f; n = 2; break;
case 0xd0 :
case 0xc0 : res = *p & 0x1f; n = 1; break;
default : res = *p; n = 0; break;
}
while (n--) {
res = (res << 6) | (*(++p) & 0x3f);
}
*dst = res;
return p + 1;
}
static Glyph_Set* load_glyph_set(
Font* font,
int idx
) {
Glyph_Set* gs;
Bitmap* bmp;
int r, i;
int ascent, descent, linegap, scaled_ascent;
float s;
gs = heap_alloc(font->heap, sizeof *gs);
bmp = &gs->bmp;
bmp->w = 512;
bmp->h = 512;
retry:
bmp->pixels = heap_alloc(
font->heap,
bmp->w * bmp->h * 4
);
s =
stbtt_ScaleForMappingEmToPixels(&font->info, 1) /
stbtt_ScaleForPixelHeight(&font->info, 1);
r = stbtt_BakeFontBitmap(
font->data,
0,
font->size * s,
(unsigned char*)bmp->pixels,
bmp->w,
bmp->h,
idx * 256,
256,
gs->glyphs
);
if (r <= 0) {
bmp->w *= 2;
bmp->h *= 2;
heap_free(font->heap, bmp->pixels);
goto retry;
}
stbtt_GetFontVMetrics(&font->info, &ascent, &descent, &linegap);
s = stbtt_ScaleForMappingEmToPixels(&font->info, font->size);
scaled_ascent = (int)(ascent * s + 0.5f);
for (i = 0; i < 256; i++) {
gs->glyphs[i].yoff += scaled_ascent;
gs->glyphs[i].xadvance = (float)floor(gs->glyphs[i].xadvance);
}
for (i = bmp->w * bmp->h - 1; i >= 0; i--) {
unsigned char n = ((unsigned char*)bmp->pixels)[i];
bmp->pixels[i].r = 255;
bmp->pixels[i].g = 255;
bmp->pixels[i].b = 255;
bmp->pixels[i].a = n;
}
return gs;
}
static Glyph_Set* get_glyph_set(
Font* font,
int codepoint
) {
int idx = (codepoint >> 8) % max_glyphset;
if (!font->sets[idx]) {
font->sets[idx] = load_glyph_set(font, idx);
}
return font->sets[idx];
}
void init_font(
Font* font,
Heap* heap,
const unsigned char* raw,
int size
) {
int r, i;
int ascent, descent, linegap;
float scale;
font->heap = heap;
font->data = raw;
font->size = size;
stbtt_bakedchar* g;
for (i = 0; i < max_glyphset; i++)
font->sets[i] = 0;
r = stbtt_InitFont(&font->info, font->data, 0);
if (!r) {
print("Invalid font.\n");
pbreak(error_font);
}
stbtt_GetFontVMetrics(
&font->info,
&ascent,
&descent,
&linegap
);
scale = stbtt_ScaleForMappingEmToPixels(
&font->info,
size
);
font->height = (int)(
(ascent - descent + linegap) *
scale + 0.5f
);
g = get_glyph_set(font, '\n')->glyphs;
g['\t'].x1 = g['\t'].x0;
g['\n'].x1 = g['\n'].x0;
}
Font* new_font(
Heap* h,
const unsigned char* raw,
int size
) {
Font* f;
f = heap_alloc(h, sizeof *f);
init_font(f, h, raw, size);
return f;
}
Rectangle text_rect(
Font* font,
const char* text
) {
const char* p = text;
unsigned codepoint;
int x = 0;
Glyph_Set* gs;
stbtt_bakedchar* g;
Rectangle re = { 0 }, r;
while (*p) {
p = utf8_to_codepoint(p, &codepoint);
gs = get_glyph_set(font, codepoint);
g = &gs->glyphs[codepoint & 0xff];
r.x = x + (int)g->xoff;
r.y = (int)g->yoff;
r.w = (int)g->x1 - g->x0;
r.h = (int)g->y1 - g->y0;
rect_merge(&re, &r);
x += (int)g->xadvance;
}
return re;
}
#define rf(expr) \
const char* p = text; \
unsigned codepoint; \
Glyph_Set* gs; \
stbtt_bakedchar* g; \
Rectangle r; \
while (*p) { \
p = utf8_to_codepoint(p, &codepoint); \
gs = get_glyph_set(font, codepoint); \
g = &gs->glyphs[codepoint & 0xff]; \
r.x = (int)g->x0; \
r.y = (int)g->y0; \
r.w = (int)g->x1 - g->x0; \
r.h = (int)g->y1 - g->y0; \
expr; \
x += (int)g->xadvance; \
}
void rfont_text(
Font* font,
int x,
int y,
const char* text
) {
rf(render_bitmap(
&gs->bmp,
x + (int)g->xoff,
y + (int)g->yoff,
&r
));
}
void rfont_text_col(
Font* font,
int x,
int y,
const char* text,
Colour colour
) {
rf(render_bitmap_col(
&gs->bmp,
x + (int)g->xoff,
y + (int)g->yoff,
&r,
colour
));
}
#undef rf
#define STB_RECT_PACK_IMPLEMENTATION
#define STB_TRUETYPE_IMPLEMENTATION
#include "stb_rect_pack.h"
#include "stb_truetype.h"
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