diff --git a/tools/libtxt/edit.c b/tools/libtxt/edit.c
new file mode 100644
index 0000000..8f96684
--- /dev/null
+++ b/tools/libtxt/edit.c
@@ -0,0 +1,96 @@
+/*
+ * tools/libtxt/edit.c - Editing and rendering
+ *
+ * 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.
+ */
+
+
+#include <stdint.h>
+#include <stdlib.h>
+
+#include "libtxt.h"
+
+
+static int *do_edit(uint8_t *canvas, int width, int height,
+    const struct edit *e, const char **error)
+{
+	struct image *img;
+	struct font *font = NULL;
+	int x = 0, y = 0, max = 0;
+	int spc = 1;
+	const char *s;
+	int xo, yo;
+
+	while (e) {
+		switch (e->type) {
+		case edit_string:
+			for (s = e->u.s; *s; s++) {
+				xo = draw_char(canvas, width, height,
+				    font, *s, x, y);
+				yo = char_height(font, *s);
+				if (yo > max)
+					max = yo;
+				x += xo+spc;
+			}
+			break;
+		case edit_font:
+			free_font(font);
+			img = load_image(e->u.s, error);
+			if (!img)
+				return 0;
+			font = make_font(img, error);
+			if (!font)
+				goto fail;
+			break;
+		case edit_spc:
+			spc = e->u.n;
+			break;
+		case edit_xoff:
+			x += e->u.n;
+			break;
+		case edit_xpos:
+			x = e->u.n;
+			break;
+		case edit_yoff:
+			y += e->u.n;
+			break;
+		case edit_ypos:
+			y = e->u.n;
+			break;
+		case edit_nl:
+			x = 0;
+			y += max+1;
+			max = 0;
+			break;
+		default:
+			abort();
+		}
+		e = e->next;
+	}
+
+fail:
+	free_image(img);
+	free_font(font);
+	return 0;
+}
+
+
+void *apply_edits(int width, int height, const struct edit *e,
+    const char **error)
+{
+	uint8_t *canvas;
+
+	canvas = calloc(1, (width*height+7) >> 3);
+	if (!canvas)
+		abort();
+	if (do_edit(canvas, width, height, e, error))
+		return canvas;
+	free(canvas);
+	return NULL;
+}