I hate font rendering

font-to-atlas/main.c

@@ -0,0 +1,107 @@
+#define _POSIX_C_SOURCE 200809l
+#define STB_TRUETYPE_IMPLEMENTATION
+#define STBTT_STATIC
+
+#include <sys/mman.h>
+
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <errno.h>
+#include <err.h>
+
+#include "stb_truetype.h"
+#include "ff.h"
+
+
+const int font_size = 32;
+
+
+void map_file(const unsigned char **str, int *size, const char *path)
+{
+	if (!path)
+		err(EXIT_FAILURE, "NULL filename");
+	FILE *fp = fopen(path, "r");
+	if (!fp)
+		err(EXIT_FAILURE, "Cannot open file %s", path);
+	*size = lseek(fileno(fp), 0, SEEK_END);
+	if (*size == (off_t)-1)
+		err(EXIT_FAILURE, "lseek failed");
+	*str = mmap(0, *size, PROT_READ, MAP_PRIVATE, fileno(fp), 0);
+	if (*str == (void*)-1)
+		err(EXIT_FAILURE, "mmap failed");
+	if (fclose(fp))
+		err(EXIT_FAILURE, "Error closing file");
+}
+
+
+int main(int argc, char *argv[])
+{
+	if (argc < 2)
+		return EXIT_FAILURE;
+	int len;
+	const unsigned char *map;
+	map_file(&map, &len, argv[1]);
+
+	stbtt_fontinfo font;
+	stbtt_InitFont(&font, map, stbtt_GetFontOffsetForIndex(map, 0));
+
+	// all this is to get the font bounding box in pixels
+	float font_scale = 1.0;
+	font_scale = stbtt_ScaleForPixelHeight(&font, font_size);
+	int ascent, descent, linegap;
+	stbtt_GetFontVMetrics(&font, &ascent, &descent, &linegap);
+	int x0,y0,x1,y1;
+	int bound_w, bound_h;
+	stbtt_GetFontBoundingBox(&font, &x0, &y0, &x1, &y1);
+
+	printf("font_scale: %f\n", font_scale);
+	printf("x0:%d y0:%d x1:%d y1:%d\n",x0,y0,x1,y1);
+
+	int baseline = font_scale * -y0;
+	bound_h = (baseline+font_scale*y1) - (baseline+font_scale*y0);
+	bound_w = (font_scale*x1) - (font_scale*x0);
+	baseline = bound_h - baseline;
+	unsigned char *bitmap = malloc(bound_h*bound_w);
+	if (!bitmap)
+		err(EXIT_FAILURE, "Cannot allocate bitmap");
+
+	printf("bounding h:%d w:%d\n", bound_h, bound_w);
+	printf("baseline: %d\n", baseline);
+
+	struct ff *image = ff_new(0, 0);
+
+	// get all ascii
+	int x = 0, y = 0, maxwidth = 64*bound_w;
+	for (unsigned int i = 0; i <= 0x7F; i++) {
+		int x0,y0,x1,y1,w,h,l,a, ox,oy;
+		int g = stbtt_FindGlyphIndex(&font, i);
+
+		stbtt_GetGlyphBitmapBoxSubpixel(&font, g, font_scale, font_scale, 0, 0, &x0, &y0, &x1, &y1);
+		w = x1 - x0;
+		h = y1 - y0;
+		//printf("%d\n", y0);
+		stbtt_GetGlyphHMetrics(&font, g, &a, &l);
+		stbtt_MakeGlyphBitmapSubpixel(&font, bitmap, w, h, w, font_scale, font_scale, 0, 0, g);
+		//printf("'%c' -> l*scale:%.0f, y0:%d\n", i, font_scale*l, bound_h+y0);
+		ox = font_scale*l;
+		oy = bound_h+y0;
+		ff_overlay_8r(&image, bitmap, x+ox, y+oy, w, h);
+
+		x += bound_w;
+		if (x >= maxwidth) y += bound_h;
+		x %= maxwidth;
+
+	}
+
+	FILE *fp = fopen("out.ff", "w");
+	if (fp) {
+		fwrite(image, 1, ff_bytes(image), fp);
+		fclose(fp);
+	}
+
+	free(bitmap);
+	ff_free(image);
+	munmap((void *)map, len);
+	return 0;
+}