Initial commit.

.gitignore

@@ -0,0 +1,3 @@
+*.o
+libschrift.a
+sftdemo

LICENSE

@@ -0,0 +1,16 @@
+ISC License
+
+© 2019, 2020 Thomas Oltmann
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+

Makefile

@@ -0,0 +1,32 @@
+# See LICENSE file for copyright and license details.
+
+.POSIX:
+
+include config.mk
+
+.PHONY: all clean install uninstall
+
+all: libschrift.a sftdemo
+
+libschrift.a: schrift.o
+	$(AR) rcs $@ $^
+sftdemo: sftdemo.o libschrift.a
+	$(LD) $(LDFLAGS) $< -o $@ -L. -lschrift
+sftdemo.o schrift.o: schrift.h
+sftdemo.o: arg.h
+
+clean:
+	rm -f *.o
+	rm -f libschrift.a
+	rm -f sftdemo
+
+install: all
+	mkdir -p "$(DESTDIR)$(PREFIX)/lib"
+	cp -f libschrift.a "$(DESTDIR)$(PREFIX)/lib"
+	mkdir -p "$(DESTDIR)$(PREFIX)/include"
+	cp -f schrift.h "$(DESTDIR)$(PREFIX)/include"
+
+uninstall:
+	rm -f "$(DESTDIR)$(PREFIX)/lib/libschrift.a"
+	rm -f "$(DESTDIR)$(PREFIX)/include/schrift.h"
+

README.md

@@ -0,0 +1,52 @@
+libschrift
+==========
+*libschrift* is a novel TTF font rendering library with focus
+on simplicity, correctness, and security.
+
+Goals
+-----
+- Be as suckless as possible.
+  See: <https://www.suckless.org/philosophy/>
+- Make correct (as in artifact-free, UTF-8 handling etc.)
+  font rendering easy-to-use.
+- Be reasonably secure, which especially means to not crash,
+  leak memory / resources or expose major security
+  vulnerabilities on corrupted / malicious / random input.
+
+Rationale
+---------
+Besides *libschrift*, there really are only two cross-platform
+open-source font rendering libraries available: *FreeType2* and
+*stb\_truetype*. *FreeType2* is a pretty stable implementation
+that supports most state-of-the-art features, but that also makes
+it incredibly bloated and frustrating to use. *stb\_truetype* is
+a lot better in this regard by virtue of keeping a much smaller
+scope, but it suffers from some annoying problems that can lead to
+visual artifacts. On top of that, it doesn't seem to be designed
+to be particularly secure, as its main use-case is working on
+trusted input files.
+
+Limitations
+-----------
+- Only Latin, Cyrillic and Greek writing systems will be fully
+  supported for now, as others would require significantly more
+  support for OpenType-specific features.
+- The only available text encoding is UTF-8.
+  See: <http://www.utf8everywhere.org>
+- Support for most TrueType (.ttf) and OpenType (.otf) fonts.
+  No bitmap or PostScript fonts (for now).
+- No hinting. Especially no auto-hinting like *FreeType2*.
+
+Progress
+--------
+Although most logic is already in-place and working, *libschrift*
+is not quite usable yet. Still missing are:
+
+- Better documentation. At least some more complete man pages.
+- Compound glyph support.
+- Correct handling of grapheme clusters?
+- Removal of TTF "parsing" stage.
+- No more bounds checking in big-endian 'get' functions - use
+  'pop' or ranges instead.
+- More rigorous bounds-checking everywhere.
+

arg.h

@@ -0,0 +1,50 @@
+/*
+ * ISC-License
+ *
+ * Copyright 2004-2017 Christoph Lohmann <20h@r-36.net>
+ * Copyright 2017-2018 Laslo Hunhold <dev@frign.de>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#ifndef ARG_H
+#define ARG_H
+
+extern char *argv0;
+
+/* int main(int argc, char *argv[]) */
+#define ARGBEGIN for (argv0 = *argv, *argv ? (argc--, argv++) : ((void *)0);      \
+                      *argv && (*argv)[0] == '-' && (*argv)[1]; argc--, argv++) { \
+                 	int i_, argused_;                                         \
+                 	if ((*argv)[1] == '-' && !(*argv)[2]) {                   \
+                 		argc--, argv++;                                   \
+                 		break;                                            \
+                 	}                                                         \
+                 	for (i_ = 1, argused_ = 0; (*argv)[i_]; i_++) {           \
+                 		switch((*argv)[i_])
+#define ARGEND   		if (argused_) {                                   \
+                 			if ((*argv)[i_ + 1]) {                    \
+                 				break;                            \
+                 			} else {                                  \
+                 				argc--, argv++;                   \
+                 				break;                            \
+                 			}                                         \
+                 		}                                                 \
+                 	}                                                         \
+                 }
+#define ARGC()   ((*argv)[i_])
+#define ARGF_(x) (((*argv)[i_ + 1]) ? (argused_ = 1, &((*argv)[i_ + 1])) :        \
+                  (*(argv + 1))     ? (argused_ = 1, *(argv + 1))        : (x))
+#define EARGF(x) ARGF_(((x), exit(1), (char *)0))
+#define ARGF()   ARGF_((char *)0)
+
+#endif

config.mk

@@ -0,0 +1,15 @@
+# Customize below to fit your system
+
+# compiler and linker
+CC = cc
+LD = cc
+AR = ar
+
+# flags
+CPPFLAGS = -I./
+CFLAGS = -g -std=c99 -pedantic -Wall -Wextra
+LDFLAGS = -g
+
+# installation paths
+PREFIX = /usr/local
+

schrift.c

@@ -0,0 +1,160 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#include "schrift.h"
+
+/* So as it turns out, these first three naive macros are actually
+ * faster than any bit-tricks or specialized functions on amd64. */
+#define MIN(a, b) ((a) < (b) ? (a) : (b))
+#define MAX(a, b) ((a) > (b) ? (a) : (b))
+#define ABS(x) ((x) >= 0 ? (x) : -(x))
+
+struct SFT_Font
+{
+	uint8_t *memory;
+	size_t size;
+};
+
+struct SFT
+{
+	SFT_Font *font;
+	double xScale, yScale;
+};
+
+static inline uint8_t
+getu8(SFT_Font *font, size_t offset)
+{
+	assert(offset + 1 <= font->size);
+	return *(font->memory + offset);
+}
+
+static inline uint16_t
+getu16(SFT_Font *font, size_t offset)
+{
+	assert(offset + 2 <= font->size);
+	uint8_t *base = font->memory + offset;
+	uint16_t b1 = base[0], b0 = base[1]; 
+	return (uint16_t) (b1 << 8 | b0);
+}
+
+static inline int16_t
+geti16(SFT_Font *font, size_t offset)
+{
+	return (int16_t) getu16(font, offset);
+}
+
+static inline uint32_t
+getu32(SFT_Font *font, size_t offset)
+{
+	assert(offset + 4 <= font->size);
+	uint8_t *base = font->memory + offset;
+	uint32_t b3 = base[0], b2 = base[1], b1 = base[2], b0 = base[3]; 
+	return (uint32_t) (b3 << 24 | b2 << 16 | b1 << 8 | b0);
+}
+
+static int
+compare_tables(const void *a, const void *b)
+{
+	return memcmp(a, b, 4);
+}
+
+static size_t
+gettable(SFT_Font *font, char tag[4])
+{
+	uint16_t numTables = getu16(font, 4);
+	void *match = bsearch(tag, font->memory + 12, numTables, 16, compare_tables);
+	if (match == NULL) return 0;
+	size_t matchOffset = font->memory - (uint8_t *) match;
+	return getu32(font, matchOffset + 4);
+}
+
+static int
+readfile(SFT_Font *font, const char *filename)
+{
+	struct stat info;
+	if (stat(filename, &info) < 0) {
+		return -1;
+	}
+	font->size = info.st_size;
+	font->memory = malloc(font->size);
+	if (font->memory == NULL) {
+		return -1;
+	}
+	FILE *file = fopen(filename, "rb");
+	if (file == NULL) {
+		free(font->memory);
+		return -1;
+	}
+	/* TODO error handling here! */
+	fread(font->memory, 1, font->size, file);
+	fclose(file);
+	return 0;
+}
+
+SFT_Font *
+sft_loadfile(char const *filename)
+{
+	SFT_Font *font = calloc(1, sizeof(SFT_Font));
+	if (font == NULL) {
+		return NULL;
+	}
+	if (readfile(font, filename) < 0) {
+		free(font);
+		return NULL;
+	}
+	uint32_t scalerType = getu32(font, 0);
+	if (scalerType != 0x00010000 && scalerType != 0x74727565) {
+		free(font);
+		return NULL;
+	}
+	return font;
+}
+
+void
+sft_freefont(SFT_Font *font)
+{
+	if (font == NULL) return;
+	free(font->memory);
+	free(font);
+}
+
+SFT *
+sft_create(void)
+{
+	SFT *sft = calloc(1, sizeof(SFT));
+	if (sft == NULL) return NULL;
+	return sft;
+}
+
+void
+sft_destroy(SFT *sft)
+{
+	if (sft == NULL) return;
+	free(sft);
+}
+
+void
+sft_setstyle(SFT *sft, struct SFT_Style style)
+{
+	double sizeInPixels = 0.0;
+	switch (style.units) {
+	case 'd':
+		sizeInPixels = style.size * style.vdpi / 72.0;
+		break;
+	case 'x':
+	default:
+		sizeInPixels = style.size;
+		break;
+	}
+	const long unitsPerEm = 1000; /* FIXME */
+	double unitsToPixels = sizeInPixels / unitsPerEm;
+	double ratio = style.hdpi / style.vdpi;
+	sft->font = style.font;
+	sft->xScale = unitsToPixels * ratio;
+	sft->yScale = unitsToPixels;
+}
+

schrift.h

@@ -0,0 +1,47 @@
+/* This file is part of libschrift.
+ *
+ * © 2019, 2020 Thomas Oltmann
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#ifndef SCHRIFT_H
+#define SCHRIFT_H 1
+
+struct SFT_Font;
+struct SFT;
+
+typedef struct SFT_Font SFT_Font;
+typedef struct SFT SFT;
+
+struct SFT_Style
+{
+	SFT_Font *font;
+	double hdpi, vdpi, size;
+	char units;
+};
+
+SFT_Font *sft_loadfile(char const *filename);
+void sft_freefont(SFT_Font *font);
+
+SFT *sft_create(void);
+void sft_destroy(SFT *sft);
+void sft_clear(SFT *sft);
+void sft_setstyle(SFT *sft, struct SFT_Style style);
+double sft_linegap(SFT *sft);
+void *sft_image(SFT *sft, int bounds[4]);
+
+void sft_boundstring(SFT *sft, double x, double y, const char *str, int bounds[4]);
+void sft_drawstring(SFT *sft, double x, double y, const char *str);
+
+#endif
+

sftdemo.c

@@ -0,0 +1,77 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <schrift.h>
+
+#include "arg.h"
+
+char *argv0;
+
+static void
+die(const char *msg)
+{
+	fprintf(stderr, "%s\n", msg);
+	exit(1);
+}
+
+static void
+usage(void)
+{
+	fprintf(stderr,
+		"usage: %s [-f font file] [-h hdpi] [-v vdpi] "
+		"[-d size in pt] [-x size in px]\n", argv0);
+}
+
+int
+main(int argc, char *argv[])
+{
+	const char *filename;
+	SFT_Font *font;
+	struct SFT_Style style;
+	SFT *sft;
+
+	filename = "resources/Ubuntu-R.ttf";
+	style.hdpi = 96.0;
+	style.vdpi = 96.0;
+	style.size = 64.0;
+	style.units = 'x';
+
+	ARGBEGIN {
+	case 'f':
+		filename = EARGF(usage());
+		break;
+	case 'h':
+		style.hdpi = atof(EARGF(usage()));
+		break;
+	case 'v':
+		style.vdpi = atof(EARGF(usage()));
+		break;
+	case 'd':
+		style.size = atof(EARGF(usage()));
+		style.units = 'd';
+		break;
+	case 'x':
+		style.size = atof(EARGF(usage()));
+		style.units = 'x';
+		break;
+	default:
+		usage();
+		exit(1);
+	} ARGEND
+	if (argc) {
+		usage();
+		exit(1);
+	}
+
+	if ((font = sft_loadfile(filename)) == NULL)
+		die("Can't load font file.");
+	if ((sft = sft_create()) == NULL)
+		die("Can't create schrift context.");
+	style.font = font;
+	sft_setstyle(sft, style);
+
+	sft_destroy(sft);
+	sft_freefont(font);
+	return 0;
+}
+