tools/libtxt/: text composition library (WIP)

tools/libtxt/Makefile

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+#
+# tools/libtxt/Makefile - Build the Antorcha tool
+#
+# Written 2012 by Werner Almesberger
+# Copyright 2012 Werner Almesberger
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+
+
+MAIN = libtxt.a
+
+CFLAGS = -g -Wall
+
+OBJS = font.o
+
+.PHONY:		all clean spotless
+
+all:		$(MAIN)
+
+$(MAIN):	$(OBJS)
+		$(CC) $(CFLAGS) -o $@ $(OBJS)
+
+clean:
+		rm -f $(OBJS)
+
+spotless:	clean
+		rm -f $(MAIN)

tools/libtxt/font.c

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+/*
+ * tools/libtxt/font.c - Font operations
+ *
+ * Written 2012 by Werner Almesberger
+ * Copyright 2012 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+
+#define _GNU_SOURCE /* for vasprintf */
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include "libtxt.h"
+
+
+static const char charset[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!?$%+-*/=@";
+
+
+#define	CHARS	(sizeof(charset)-1)
+
+
+struct sym {
+	int x, y;
+	int w, h;
+};
+
+struct font {
+	int w, h;
+	int span;	/* bytes per row */
+	struct sym sym[CHARS];
+	uint8_t *data;
+};
+
+
+static struct font font;
+
+
+static const char *alloc_sprintf(const char *fmt, ...)
+{
+	va_list ap;
+	char *tmp, *res;
+	int n;
+
+	va_start(ap, fmt);
+	n = vasprintf(&tmp, fmt, ap);
+	va_end(ap);
+	if (n < 0)
+		abort();
+	res = malloc(n+1);
+	if (!res)
+		abort();
+	memcpy(res, tmp, n+1);
+	return res;
+}
+
+
+static const char *read_font_file(FILE *file)
+{
+	int n;
+	unsigned v;
+	char c;
+	int bytes = 0;
+
+	free(font.data);
+	font.data = NULL;
+
+	n = fscanf(file, "#define %*[^_]_width %d\n", &font.w);
+	if (n < 0)
+		return alloc_sprintf("reading width: %s", strerror(errno));
+	if (n != 1)
+		return alloc_sprintf("width not found (%d)", n);
+
+	n = fscanf(file, "#define %*[^_]_height %d\n", &font.h);
+	if (n < 0)
+		return alloc_sprintf("reading height: %s", strerror(errno));
+	if (n != 1)
+		return alloc_sprintf("height not found");
+
+	n = fscanf(file, "%*[^{]{\n");
+	if (n < 0)
+		return alloc_sprintf("finding data: %s", strerror(errno));
+
+	while (1) {
+		n = fscanf(file, " 0x%x%c", &v, &c);
+		if (n < 0)
+			return alloc_sprintf("reading data: %s",
+			    strerror(errno));
+		if (n != 2)
+			return alloc_sprintf("data not found (%d)", n);
+
+		bytes++;
+		font.data = realloc(font.data, bytes);
+		if (!font.data)
+			abort();
+		font.data[bytes-1] = v;
+
+		if (c == ',')
+			continue;
+		if (c == '}')
+			break;
+		return alloc_sprintf("invalid data syntax");
+	}
+	font.span = (font.w+7) >> 3;
+	if (bytes != font.h*font.span)
+		return alloc_sprintf("%d bytes for %dx%d bitmap",
+		    bytes, font.h, font.w);
+	return NULL;
+}
+
+
+static void set_block(int *n, int xlast, int x, int y0, int y1)
+{
+	font.sym[*n].x = xlast+1;
+	font.sym[*n].y = y0;
+	font.sym[*n].w = x-xlast-1;
+	font.sym[*n].h = y1-y0+1;
+	(*n)++;
+}
+
+
+static void analyze_block(int *n, int y0, int y1)
+{
+	int x, y, last = -1;
+
+	for (x = 0; x != font.w; x++) {
+		for (y = y0; y <= y1; y++)
+			if (font.data[y*font.span+(x >> 3)] & (1 << (x & 7)))
+				break;
+		if (y <= y1)
+			continue;
+		if (x != last+1)
+			set_block(n, last, x, y0, y1);
+		last = x;
+	}
+	if (x != last+1)
+		set_block(n, last, x, y0, y1);
+}
+
+
+static const char *analyze_font(void)
+{
+	int x, y, last = -1;
+	int n = 0;
+	
+	for (y = 0; y != font.h; y++) {
+		for (x = 0; x != font.span; x++)
+			if (font.data[y*font.span+x])
+				break;
+		if (x != font.span)
+			continue;
+		if (y != last+1)
+			analyze_block(&n, last+1, y-1);
+		last = y;
+	}
+	if (y != last+1)
+		analyze_block(&n, last+1, y-1);
+	if (n != CHARS)
+		return alloc_sprintf("found %d instead of %d characters",
+		    n, CHARS);
+	return NULL;
+}
+
+
+const char *load_font(const char *name)
+{
+	FILE *file;
+	const char *error;
+
+	file = fopen(name, "r");
+	if (!file)
+		return alloc_sprintf("%s: %s", name, strerror(errno));
+	error = read_font_file(file);
+	fclose(file);
+	if (error)
+		return error;
+
+	return analyze_font();
+}
+
+
+int draw_char(void *canvas, int width, int height, char c, int x, int y)
+{
+	uint8_t *p = canvas;
+	const char *cp;
+	const struct sym *sym;
+	int ix, iy, xt;
+
+	cp = strchr(charset, c);
+	if (!cp)
+		return 0;
+	sym = font.sym+(cp-charset);
+
+	for (ix = 0; ix != sym->w; ix++) {
+		if (x+ix >= width)
+			continue;
+		for (iy = 0; iy != sym->h; iy++) {
+			if (y+iy >= height)
+				continue;
+			xt = sym->x+ix;
+			if (font.data[(sym->y+iy)*font.span+(xt >> 3)] &
+			    (1 << (xt & 7))) {
+				xt = x+ix;
+				p[((y+iy)*width+xt) >> 3] |= 1 << (xt & 7);
+			}
+		}
+	}
+	return sym->w;
+}
+
+
+#define	W	64
+#define	H	20
+
+
+int main(int argc, char **argv)
+{
+	const char *error;
+	uint8_t canvas[W*H/8] = { 0 };
+	char *s;
+	int x, xo, y;
+
+	error = load_font(argv[1]);
+	if (error) {
+		fprintf(stderr, "%s\n", error);
+		return 1;
+	}
+	x = 0;
+	for (s = argv[2]; *s; s++) {
+		xo = draw_char(canvas, W, H, *s, x, 0);
+		if (xo)
+			x += xo+1;
+	}
+	for (y = 0; y != H; y++) {
+		for (x = 0; x != W; x++)
+			if (canvas[(y*W+x) >> 3] & (1 << (x & 7)))
+				putchar('#');
+			else
+				putchar('.');
+		putchar('\n');
+	}
+	return 0;
+}

tools/libtxt/libtxt.h

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+/*
+ * tools/libtxt/libtxt.h - Text processing functions
+ *
+ * Written 2012 by Werner Almesberger
+ * Copyright 2012 Werner Almesberger
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef LIBTXT_H
+#define LIBTXT_H
+
+struct edit {
+	enum edit_type {
+		edit_string,
+		edit_font,
+		edit_xoff,
+		edit_xpos,
+		edit_yoff,
+		edit_ypos,
+	} type;
+	union {
+		const char *s;
+		int n;
+	} u;
+	struct edit *next;
+};
+
+/*
+ * Markup:
+ *
+ * <FONT fontname>
+ * <IMG imagefile>
+ * <X+offset> <X-offset> <X=pos>
+ * <Y+offset> ...
+ *
+ * Empty lines are ignored. The newline of a line containing only markup is
+ * also ignored.
+ *
+ * Newline leaves one 
+ */
+
+const char *load_font(const char *name);
+int draw_char(void *canvas, int width, int height, char c, int x, int y);
+
+struct edit *text2edit(const char *s);
+char *edit2text(const struct edit *e);
+
+void *apply_edits(int width, int height, const struct edit *e);
+
+#endif /* !LIBTXT_H */