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#include "basic/basic.h"
#include <os/os.h>
#include <client/font.h>
#include <assert.h>
#include <stb/stb_truetype.h>
#include <stb/stb_image.h>
#include <stb/stb_image_write.h>
#include <string.h>
#include <math.h>
f32
font_get_string32_cursor_xoff(Font *font, String32 *str, u32 cursor) {
f32 xoff = 0.0f;
u32 x = 0;
while (x < cursor) {
Glyph *glyph = font_get_glyph(font, str->codepoints[x]);
xoff += glyph->advance_width;
x++;
}
return xoff;
}
f32
font_get_string32_width(Font *font, String32 *str)
{
// @Todo: also consider left_side_bearing and kerning?
f32 width = 0.0f;
for (u64 i = 0; i < str->len; i++) {
Glyph *glyph = font_get_glyph(font, str->codepoints[i]);
width += glyph->advance_width;
}
return width;
}
f32
font_get_height(Font *font)
{
return font->y_advance;
}
Glyph *
font_get_glyph(Font *font, u32 codepoint)
{
assert(codepoint >= ' ' && codepoint <= '~');
i32 index = codepoint - ' ';
Glyph *glyph = &font->glyphs[index];
return glyph;
}
b32
font_init(Font *font, char *path, int font_size)
{
arena_init(&font->arena, MEBIBYTES(4));
size_t len;
u8 *ttf = (u8*)os_file_read_as_string(&font->arena, path, &len);
if (!ttf) {
arena_deinit(&font->arena);
return false;
}
// set font info
if (!stbtt_InitFont(&font->info, ttf, 0))
{
printf("stbtt_InitFont failed\n");
arena_deinit(&font->arena);
return false;
}
// set scale
f32 scale = stbtt_ScaleForPixelHeight(&font->info, font_size);
// get font vmetrics
i32 baseline, ascent, descent, line_gap;
stbtt_GetFontVMetrics(&font->info, &ascent, &descent, &line_gap);
baseline = scale * -descent;
ascent = scale * ascent;
descent = scale * descent;
line_gap = scale * line_gap;
font->scale = scale;
font->baseline = baseline;
font->y_advance = ascent - descent + line_gap;
// make glyphs
u32 glyph_count = '~' - ' ' + 1;
for (u32 it = 0; it < glyph_count; ++it)
{
Glyph *glyph = font->glyphs + it;
char c = it + ' ';
int bbx0, bby0, bbx1, bby1;
stbtt_GetCodepointBitmapBox(&font->info, c, scale, scale, &bbx0, &bby0, &bbx1, &bby1);
int width = bbx1 - bbx0;
int height = bby1 - bby0;
u8 *bitmap_correct = arena_push(&font->arena, width * height);
u32 arena_save_pos = font->arena.size_used;
u8 *bitmap_flipped = arena_push(&font->arena, width * height);
stbtt_MakeCodepointBitmap(&font->info, bitmap_flipped, width, height, width, scale, scale, c);
// @Speed: Adjust projection and don't execute this at all?
u8 *dest = bitmap_correct;
for (u32 y = 0; y < height; ++y)
{
u8 *src = bitmap_flipped + (height-1-y)*width;
for (u32 x = 0; x < width; ++x)
{
*dest++ = *src++;
}
}
i32 advance_width;
i32 left_side_bearing;
stbtt_GetCodepointHMetrics(&font->info, c, &advance_width, &left_side_bearing);
advance_width = scale * advance_width;
left_side_bearing = scale * left_side_bearing;
glyph->xoff = scale * bbx0 + left_side_bearing;
glyph->yoff = -bby1;
glyph->advance_width = advance_width;
glyph->bitmap.width = width;
glyph->bitmap.height = height;
glyph->bitmap.data.grayscale = bitmap_correct;
font->arena.size_used = arena_save_pos;
}
return true;
}
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