text: font: add unifont backend

This adds a new Unifont font-backend based on the recently added Unifont
data. The backend is disabled by default for 2 reasons:
  - It takes about 5min to compile and needs >1GB of memory on an Intel
    Atom N450
  - License situation is unclear as it is GPL

Written-by: Ted Kotz <ted@kotz.us>
Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

COPYING

@@ -3,6 +3,7 @@
 This software was written by:
 	David Herrmann <dh.herrmann@googlemail.com>
 	Ran Benita <ran234@gmail.com>
+	Ted Kotz <ted@kotz.us>
 
 = Copyright Notice =
 
@@ -145,3 +146,10 @@ The "solarized" color palettes in vte.c are from:
 	LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 	OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 	THE SOFTWARE.
+
+The Unifont-Font is from http://unifoundry.com/unifont.html and licensed under
+the terms of the GNU GPL. So if you enable this font backend, then kmscon will
+also be released under the terms of the GNU GPL. Copyrights are:
+
+	Copyright 1998-2008 Roman Czyborra
+	Copyright 1998-2008 Paul Hardy

Makefile.am

@@ -146,6 +146,13 @@ libkmscon_core_la_SOURCES = \
 	src/text.c \
 	src/text_font.c
 
+if KMSCON_HAVE_UNIFONT
+libkmscon_core_la_SOURCES += \
+	src/text_font_unifont.h \
+	src/text_font_unifont.c \
+	src/text_font_unifont_data.c
+endif
+
 if KMSCON_HAVE_8X16
 libkmscon_core_la_SOURCES += \
 	src/text_font_8x16.c

configure.ac

@@ -130,6 +130,12 @@ AC_ARG_ENABLE([xkbcommon],
                               [disable xkbcommon keyboard backend])])
 AC_MSG_RESULT([ok])
 
+AC_MSG_CHECKING([whether to use static unifont backend])
+AC_ARG_ENABLE([unifont],
+              [AS_HELP_STRING([--enable-unifont],
+                              [enable static unifont font backend (GPL)])])
+AC_MSG_RESULT([ok])
+
 AC_MSG_CHECKING([whether to use static 8x16 font backend])
 AC_ARG_ENABLE([f8x16],
               [AS_HELP_STRING([--disable-f8x16],
@@ -403,9 +409,26 @@ AM_CONDITIONAL([UTERM_HAVE_XKBCOMMON], [test x$xkbcommon_enabled = xyes])
 
 #
 # Font backends
-# This checks for the 8x16, freetype2 and pango font backends and enables them
-# if requested and available.
+# This checks for the unifont, 8x16, freetype2 and pango font backends and
+# enables them if requested and available.
 #
+# Please note that the Unifont-data is GPL'ed and we compile this statically
+# into our application. I do not consider this a "derivative" but a lawyer may
+# disagree. So please make sure you enable this only if you use the GPL as
+# license for kmscon.
+#
+
+unifont_enabled=no
+if test x$enable_unifont = xyes ; then
+        unifont_enabled=yes
+fi
+
+if test x$unifont_enabled = xyes ; then
+        AC_DEFINE([KMSCON_HAVE_UNIFONT], [1],
+                  [Use static unifont backend])
+fi
+
+AM_CONDITIONAL([KMSCON_HAVE_UNIFONT], [test x$unifont_enabled = xyes])
 
 f8x16_enabled=no
 if test ! x$enable_f8x16 = xno ; then
@@ -537,6 +560,7 @@ AC_MSG_NOTICE([Build configuration:
 	    OpenGLES2: $gles2_enabled
 
   font backends:
+	      unifont: $unifont_enabled
 	         8x16: $f8x16_enabled
 	    freetype2: $freetype2_enabled
 	        pango: $pango_enabled

src/main.c

@@ -567,6 +567,7 @@ int main(int argc, char **argv)
 	if (ret)
 		goto err_out;
 
+	kmscon_font_unifont_load();
 	kmscon_font_8x16_load();
 	kmscon_font_pango_load();
 	kmscon_font_freetype2_load();
@@ -606,6 +607,7 @@ int main(int argc, char **argv)
 	kmscon_font_freetype2_unload();
 	kmscon_font_pango_unload();
 	kmscon_font_8x16_unload();
+	kmscon_font_unifont_unload();
 	conf_free(options, onum);
 	log_info("exiting");
 
@@ -617,6 +619,7 @@ err_unload:
 	kmscon_font_freetype2_unload();
 	kmscon_font_pango_unload();
 	kmscon_font_8x16_unload();
+	kmscon_font_unifont_unload();
 err_out:
 	conf_free(options, onum);
 	log_err("cannot initialize kmscon, errno %d: %s", ret, strerror(-ret));

src/text.h

@@ -180,6 +180,25 @@ void kmscon_text_abort(struct kmscon_text *txt);
 
 /* modularized backends */
 
+#ifdef KMSCON_HAVE_UNIFONT
+
+int kmscon_font_unifont_load(void);
+void kmscon_font_unifont_unload(void);
+
+#else
+
+static inline int kmscon_font_unifont_load(void)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void kmscon_font_unifont_unload(void)
+{
+}
+
+#endif
+
+
 #ifdef KMSCON_HAVE_8X16
 
 int kmscon_font_8x16_load(void);

src/text_font_unifont.c

@@ -0,0 +1,145 @@
+/*
+ * kmscon - Fixed unifont font for font handling of text renderer
+ *
+ * Copyright (c) 2012 Ted Kotz <ted@kotz.us>
+ * Copyright (c) 2012 David Herrmann <dh.herrmann@googlemail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+/**
+ * SECTION:text_font_unifont.c
+ * @short_description: Fixed unifont font for font handling of text renderer
+ * @include: text.h
+ * 
+ * This is a fixed font renderer backend that supports just one font which is
+ * statically compiled into the file. This bitmap font has 8x16 and 16x16 
+ * glyphs. This can statically compile in any font defined as a unifont style
+ * hex format. This font is from the GNU unifont project available at: 
+ * http://unifoundry.com/unifont.html
+ *
+ * This file is heavily based on text_font_8x16.c
+ * 
+ */
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include "log.h"
+#include "text.h"
+#include "unicode.h"
+#include "uterm.h"
+
+#define LOG_SUBSYSTEM "text_font_unifont"
+
+/* array is generated and compiled externally */
+extern const struct kmscon_glyph kmscon_text_font_unifont_data_hex_glyphs[];
+extern size_t kmscon_text_font_unifont_data_hex_len;
+
+static int kmscon_font_unifont_init(struct kmscon_font *out,
+				    const struct kmscon_font_attr *attr)
+{
+	static const char name[] = "static-unifont";
+
+	log_debug("loading static unifont font");
+
+	memset(&out->attr, 0, sizeof(out->attr));
+	memcpy(out->attr.name, name, sizeof(name));
+	out->attr.bold = false;
+	out->attr.italic = false;
+	out->attr.width = 8;
+	out->attr.height = 16;
+	kmscon_font_attr_normalize(&out->attr);
+	out->baseline = 4;
+
+	return 0;
+}
+
+static void kmscon_font_unifont_destroy(struct kmscon_font *font)
+{
+	log_debug("unloading static unifont font");
+}
+
+static int kmscon_font_unifont_render(struct kmscon_font *font,
+				      kmscon_symbol_t sym,
+				      const struct kmscon_glyph **out)
+{
+	const uint32_t *val;
+	size_t len;
+
+	val = kmscon_symbol_get(&sym, &len);
+	if (len > 1 || *val >= kmscon_text_font_unifont_data_hex_len)
+		return -ERANGE;
+
+	*out = &kmscon_text_font_unifont_data_hex_glyphs[*val];
+
+	return 0;
+}
+
+static int kmscon_font_unifont_render_inval(struct kmscon_font *font,
+					    const struct kmscon_glyph **out)
+{
+	if (0xfffd < kmscon_text_font_unifont_data_hex_len)
+		*out = &kmscon_text_font_unifont_data_hex_glyphs[0xfffd];
+	else if ('?' < kmscon_text_font_unifont_data_hex_len)
+		*out = &kmscon_text_font_unifont_data_hex_glyphs['?'];
+	else
+		*out = &kmscon_text_font_unifont_data_hex_glyphs[0];
+
+	return 0;
+}
+
+static int kmscon_font_unifont_render_empty(struct kmscon_font *font,
+					    const struct kmscon_glyph **out)
+{
+	if (' ' < kmscon_text_font_unifont_data_hex_len) {
+		*out = &kmscon_text_font_unifont_data_hex_glyphs[' '];
+		return 0;
+	} else {
+		return kmscon_font_unifont_render_inval(font, out);
+	}
+}
+
+static const struct kmscon_font_ops kmscon_font_unifont_ops = {
+	.name = "unifont",
+	.init = kmscon_font_unifont_init,
+	.destroy = kmscon_font_unifont_destroy,
+	.render = kmscon_font_unifont_render,
+	.render_empty = kmscon_font_unifont_render_empty,
+	.render_inval = kmscon_font_unifont_render_inval,
+};
+
+int kmscon_font_unifont_load(void)
+{
+	int ret;
+
+	ret = kmscon_font_register(&kmscon_font_unifont_ops);
+	if (ret) {
+		log_error("cannot register unifont font");
+		return ret;
+	}
+
+	return 0;
+}
+
+void kmscon_font_unifont_unload(void)
+{
+	kmscon_font_unregister(kmscon_font_unifont_ops.name);
+}