feat(linux): use fontconfig to locate fonts

Font paths are not guaranteed to be the same across
different linux systems, this commit introduces Fontconfig
support to locate the font files based on their font names.

see also: #136

configure.ac

@@ -107,6 +107,23 @@ else
 	want_font_engine=no
 fi
 
+# fontconfig
+want_fontconfig=yes
+AC_ARG_ENABLE(fontconfig, AC_HELP_STRING([--enable-fontconfig],
+[turn on fontconfig [[default=yes]]]), [want_fontconfig=$enableval])
+if test "$want_fontconfig" = yes; then
+	AC_CHECK_HEADERS([fontconfig/fontconfig.h], [
+		AC_CHECK_LIB([fontconfig], [FcInitLoadConfigAndFonts], [
+			want_fontconfig=yes
+			LCUI_LIBS="$LCUI_LIBS `pkg-config --libs fontconfig`"
+			CFLAGS="$CFLAGS `pkg-config --cflags-only-I fontconfig`"
+			AC_DEFINE_UNQUOTED([USE_FONTCONFIG], 1, [Define to 1 if you have Fontconfig.])
+		], [want_fontconfig=no])
+	], [want_fontconfig=no])
+else
+	want_fontconfig=no
+fi
+
 # 检测图形输出设备
 want_video_output=yes
 want_video_driver_x11=no
@@ -204,6 +221,7 @@ echo -e "Build with lcui-builder support .... : $enable_builder"
 echo -e "Build with libpng support .......... : $want_png"
 echo -e "Build with libjpeg support ......... : $want_jpeg"
 echo -e "Build with font-engine support ..... : $font_engine_name"
+echo -e "Build with fontconfig support ...... : $want_fontconfig"
 echo -e "Build with thread support .......... : $thread_name"
 echo -e "Build with video support ........... : $video_driver_name"
 echo

include/LCUI/config.h.in

@@ -3,6 +3,9 @@
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #undef HAVE_DLFCN_H
 
+/* Define to 1 if you have the <fontconfig/fontconfig.h> header file. */
+#undef HAVE_FONTCONFIG_FONTCONFIG_H
+
 /* Define to 1 if you have the <ft2build.h> header file. */
 #undef HAVE_FT2BUILD_H
 
@@ -144,6 +147,9 @@
 /* Define to 1 if you have the ANSI C header files. */
 #undef STDC_HEADERS
 
+/* Define to 1 if you have Fontconfig. */
+#undef USE_FONTCONFIG
+
 /* Define to 1 if you enabled LCUIBuilder function module. */
 #undef USE_LCUI_BUILDER
 

include/LCUI/font.h

@@ -35,5 +35,6 @@
 #include <LCUI/font/textstyle.h>
 #include <LCUI/font/textlayer.h>
 #include <LCUI/font/charset.h>
+#include <LCUI/font/fontconfig.h>
 
 #endif

include/LCUI/font/Makefile.am

@@ -1,5 +1,5 @@
 AUTOMAKE_OPTIONS=foreign
 
 # Headers to install
-pkginclude_HEADERS = fontlibrary.h textlayer.h textstyle.h charset.h
+pkginclude_HEADERS = fontlibrary.h fontconfig.h textlayer.h textstyle.h charset.h
 pkgincludedir=$(prefix)/include/LCUI/font

include/LCUI/font/fontconfig.h

@@ -0,0 +1,40 @@
+/* ***************************************************************************
+ * fontconfig.c -- The Fontconfig support module.
+ *
+ * Copyright (c) 2018, Liu Chao <lc-soft@live.cn> All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of LCUI nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef LCUI_FONTCONFIG_H
+#define LCUI_FONTCONFIG_H
+
+LCUI_BEGIN_HEADER
+
+char* Fontconfig_GetPath( char* name );
+
+LCUI_END_HEADER
+
+#endif

lcui.pc.in

@@ -7,5 +7,5 @@ Name: LCUI
 Description: A small C library for building user interfaces with C, XML and CSS. 
 Version: @PACKAGE_VERSION@
 Libs: -L${libdir} -lLCUI
-Libs.private: -lpthread -lfreetype -lpng -ljpeg -lX11 -lxml2
+Libs.private: -lpthread -lfreetype -lpng -ljpeg -lX11 -lxml2 -lfontconfig
 Cflags: -I${includedir}

src/font/Makefile.am

@@ -2,4 +2,4 @@ SUBDIRS = in-core
 AUTOMAKE_OPTIONS=foreign
 AM_CFLAGS = -I$(abs_top_srcdir)/include $(CODE_COVERAGE_CFLAGS)
 noinst_LTLIBRARIES = libfont.la
-libfont_la_SOURCES = fontlibrary.c freetype.c charset.c textstyle.c textlayer.c in_core_font.c
+libfont_la_SOURCES = fontlibrary.c freetype.c fontconfig.c charset.c textstyle.c textlayer.c in_core_font.c

src/font/fontconfig.c

@@ -0,0 +1,71 @@
+/* ***************************************************************************
+ * fontconfig.c -- The Fontconfig support module.
+ *
+ * Copyright (c) 2018, Liu Chao <lc-soft@live.cn> All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   * Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of LCUI nor the names of its contributors may be used
+ *     to endorse or promote products derived from this software without
+ *     specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef LCUI_BUILD_IN_WIN32
+
+#include <LCUI/config.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fontconfig/fontconfig.h>
+
+char* Fontconfig_GetPath( char* name )
+{
+#ifdef USE_FONTCONFIG
+	FcConfig* config = FcInitLoadConfigAndFonts();
+	char* path = "";
+
+	FcPattern* pat = FcNameParse( (const FcChar8*)name );
+	FcConfigSubstitute( config, pat, FcMatchPattern );
+	FcDefaultSubstitute( pat );
+
+	FcResult result;
+	FcPattern* font = FcFontMatch( config, pat, &result );
+
+	if( font ) {
+		FcChar8* file = NULL;
+		if( FcPatternGetString( font, FC_FILE, 0, &file ) == FcResultMatch ) {
+			size_t path_len = strlen( (char*)file ) + 1;
+			path = (char*)malloc( path_len );
+			memset( path, '\0', path_len );
+			strncpy( path, (char*)file, path_len );
+		}
+		FcPatternDestroy( font );
+	}
+
+	FcPatternDestroy( pat );
+	FcConfigDestroy( config );
+
+	return path;
+#else
+	return NULL;
+#endif
+}
+
+#endif

src/font/fontlibrary.c

@@ -855,21 +855,22 @@ void LCUI_InitFontLibrary(void)
 		{ FONTDIR "msyh.ttc", "Microsoft YaHei", NULL }
 	};
 #else
-#define FONTDIR "/usr/share/fonts/"
-#define MAX_FONTFILE_NUM 4
+#define MAX_FONTFILE_NUM 3
 	struct {
 		const char *path;
 		const char *family;
 		const char *style;
 	} fonts[MAX_FONTFILE_NUM] = {
-		{ FONTDIR "truetype/ubuntu-font-family/Ubuntu-R.ttf", "Ubuntu",
-		NULL },
-		{ FONTDIR "opentype/noto/NotoSansCJK-Regular.ttc",
-		"Noto Sans CJK SC", NULL },
-		{ FONTDIR "opentype/noto/NotoSansCJK.ttc", "Noto Sans CJK SC",
-		NULL },
-		{ FONTDIR "truetype/wqy/wqy-microhei.ttc",
-		"WenQuanYi Micro Hei", NULL }
+		{
+			Fontconfig_GetPath( "Ubuntu" ),
+			"Ubuntu", NULL
+		}, {
+			Fontconfig_GetPath( "Noto Sans CJK SC" ),
+			"Noto Sans CJK SC", NULL
+		}, {
+			Fontconfig_GetPath( "WenQuanYi Micro Hei" ),
+			"WenQuanYi Micro Hei", NULL
+		}
 	};
 #endif
 
@@ -912,6 +913,11 @@ void LCUI_InitFontLibrary(void)
 			break;
 		}
 	}
+#ifndef LCUI_BUILD_IN_WIN32
+	for( i = 0; i < MAX_FONTFILE_NUM; ++i ) {
+		free( fonts[i].path );
+	}
+#endif
 }
 
 void LCUI_FreeFontLibrary(void)