src/core/packages/fonts.sgl

1;;; Font rasterisation and font configuration.

2;;;

3;;; This is the half of foot's closure that has to reach OUTSIDE the store to

4;;; be useful, and it is the one place in this chain where "hermetic" and

5;;; "works on the user's desktop" pull against each other. Wayland does not:

6;;; a client and a compositor exchange a wire protocol over a socket and never

7;;; share a library, so version skew there is a non-issue. Fonts are

8;;; different -- a fontconfig built into the store looks for font FILES, and

9;;; the font files a user has are wherever their system put them.

10;;;

11;;; Nothing here solves that; it is recorded so the next reader does not

12;;; mistake a font-path gap for a foot defect. See the task note for the

13;;; measured runtime behaviour.

14(define-library (core packages fonts)

15 (import (sigil core)

16 (core build-environments)

17 (core packages compression)

18 (core packages xml)

19 (core packages graphics)

20 (core packages datastructures)

21 (core packages build-tools)

22 (core packages python)

23 (sigil env package)

24 (sigil build external))

25 (export freetype fontconfig fcft)

26 (begin

27 ;; freetype, with every optional backend OFF.

28 ;;

29 ;; The harfbuzz one is not a size decision, it is a CYCLE: harfbuzz builds

30 ;; against freetype and freetype can build against harfbuzz for

31 ;; auto-hinting. Distributions resolve it by building freetype twice.

32 ;; This channel does not need to, because nothing here does complex text

33 ;; shaping -- foot is configured without grapheme clustering, which is what

34 ;; would have pulled harfbuzz in through fcft.

35 (define freetype

36 (package

37 name: "freetype"

38 version: "2.13.3"

39 source: (external-source

40 location: "https://download.savannah.gnu.org/releases/freetype/freetype-2.13.3.tar.xz"

41 sha256: "0550350666d427c74daeb85d5ac7bb353acba5f76956395995311a9c6f063289")

42 buildenv: core-buildenv

43 dependencies: (list zlib)

44 phases: (list

45 (external-phase

46 kind: 'configure

47 args: (list "--prefix=${out}"

48 "--disable-shared"

49 "--enable-static"

50 "--with-zlib=yes"

51 "--with-bzip2=no"

52 "--with-png=no"

53 "--with-brotli=no"

54 "--with-harfbuzz=no"))

55 (external-phase kind: 'make)

56 (external-phase kind: 'install)

57 ;; fontconfig asks for `freetype2 >= 21.0.15` through

58 ;; PKG_CHECK_MODULES and fcft asks for it too, so the `.pc`

59 ;; is load-bearing rather than decorative. Note the version

60 ;; in that constraint is freetype's LIBTOOL version, not its

61 ;; release version -- 2.13.3 publishes 26.x -- which is why

62 ;; the check below asserts the file exists and does not try

63 ;; to be clever about its contents.

64 (external-phase

65 kind: 'run

66 args: (list "sh" "-c"

67 (string-append

68 "set -eu\n"

69 "d=\"$(dirname \"$PWD\")/install-root\"\n"

70 "test -f \"$d${out}/lib/pkgconfig/freetype2.pc\"\n"

71 "echo FREETYPE2-PC-PRESENT\n"))))))

72

73 ;; VERSION AND SOURCE, because both were forced and the reasoning matters.

74 ;;

75 ;; `www.freedesktop.org/software/fontconfig/release/` -- the URL every

76 ;; older recipe uses -- was unreachable from this host across three

77 ;; attempts spanning ten minutes. Upstream has moved distribution to

78 ;; the freedesktop GitLab generic package registry, which is where

79 ;; Alpine now points too, and that registry does NOT carry 2.15.0.

80 ;;

81 ;; So the choice was between 2.15.0 from a DISTRIBUTION MIRROR and

82 ;; 2.18.1 from the CANONICAL upstream host. Taking the canonical host

83 ;; keeps a real upstream release artifact on the critical path, which

84 ;; is the rule this channel is built on, and it is a current release

85 ;; rather than a two-year-old one.

86 ;;

87 ;; 2.18.1 SHIPS BOTH BUILD SYSTEMS, and this build deliberately uses

88 ;; the autotools one. Its meson.build pulls in Rust for the optional

89 ;; `fc-fontations` backend (meson.build:92, add_languages([rust]));

90 ;; configure.ac mentions Rust nowhere. Autotools therefore avoids

91 ;; introducing a whole second language toolchain to this channel for a

92 ;; feature foot does not use.

93 ;;

94 ;; fontconfig. Three build-time tools and two libraries, and the tool list

95 ;; is the interesting part:

96 ;;

97 ;; gperf -- configure.ac:216 RUNS it: `echo 'foo' | gperf -L ANSI-C`.

98 ;; Absent, the substitution is empty, the two compile probes

99 ;; that follow test an empty snippet, the first succeeds, and

100 ;; configure concludes FC_GPERF_SIZE_T=size_t from a probe

101 ;; that measured nothing.

102 ;; python -- configure.ac:56 is AM_PATH_PYTHON([3]).

103 ;;

104 ;; Both are `build-inputs:` and not `dependencies:`, because neither is

105 ;; linked into the result and neither may contribute a store path to it.

106 (define fontconfig

107 (package

108 name: "fontconfig"

109 version: "2.18.1"

110 source: (external-source

111

                  location: "https://gitlab.freedesktop.org/api/v4/projects/890/packages/generic/fontconfig/2.18.1/fontconfig-2.18.1.tar.xz"

112 sha256: "2300f3dbfa7253b3a44f4feecdbc8dfa45dde5dc2cfb71fceaf31f394cb41031")

113 buildenv: core-buildenv

114 ;; ZLIB IS DECLARED HERE ALTHOUGH FONTCONFIG NEVER MENTIONS IT, AND THE

115 ;; REASON IS A PROPERTY OF THIS CHANNEL RATHER THAN OF FONTCONFIG.

116 ;;

117 ;; `dependency-pkgconfig` in (sigil build external) composes

118 ;; PKG_CONFIG_PATH from DIRECT dependencies only -- one

119 ;; `<dep>/lib/pkgconfig` entry each, with no transitive walk. freetype's

120 ;; generated `freetype2.pc` carries `Requires: zlib`, so pkg-config

121 ;; resolving `freetype2` must also resolve `zlib`, and without this line

122 ;; it cannot:

123 ;;

124 ;; checking for FREETYPE... no

125 ;; configure: error: Package requirements (freetype2 >= 21.0.15) were

126 ;; not met: Package 'zlib', required by 'freetype2', not found

127 ;;

128 ;; THE DIAGNOSTIC NAMES FREETYPE AND THE MISSING PACKAGE IS ZLIB, which

129 ;; is the part that costs the time.

130 ;;

131 ;; This is not a workaround. It is the same rule the builder applies to

132 ;; `${name}` interpolation -- a build that wants to reach a

133 ;; grand-dependency has to declare it -- and it is TRUE here: everything

134 ;; in this channel links statically, so zlib really is on fontconfig's

135 ;; link line and really is in its closure. Every consumer of a `.pc`

136 ;; with a `Requires:` chain inherits this.

137 dependencies: (list freetype expat zlib)

138 build-inputs: (list gperf python)

139 phases: (list

140 (external-phase

141 kind: 'configure

142 args: (list "--prefix=${out}"

143 "--disable-shared"

144 "--enable-static"

145 ;; The docs want docbook and would otherwise be

146 ;; a probe on what is installed.

147 "--disable-docs"

148 ;; Nothing in this channel reads a cache

149 ;; fontconfig would have to build at install

150 ;; time, and running fc-cache during a build

151 ;; would write outside the staged prefix.

152 "--disable-cache-build"

153 ;; NLS wants gettext, which is not in the seed

154 ;; and which nothing here reads.

155 "--disable-nls"))

156 (external-phase kind: 'make)

157 (external-phase kind: 'install)

158 (external-phase

159 kind: 'run

160 args: (list "sh" "-c"

161 (string-append

162 "set -eu\n"

163 "d=\"$(dirname \"$PWD\")/install-root\"\n"

164 "test -f \"$d${out}/lib/pkgconfig/fontconfig.pc\"\n"

165 ;; The config file is what a runtime consumer

166 ;; needs and what the font-path problem above is

167 ;; about; assert it landed so a missing one is

168 ;; found here rather than at first launch.

169 "test -f \"$d${out}/etc/fonts/fonts.conf\"\n"

170 "echo FONTCONFIG-PC-AND-CONF-PRESENT\n"))))))

171

172 ;; fcft: the glyph rasterisation and caching layer between foot and

173 ;; freetype/fontconfig. By the same author as foot, and foot's meson.build

174 ;; carries a `[wrap-git]` fallback for it -- which cannot resolve inside a

175 ;; sandbox, so a real package is required rather than optional.

176 ;;

177 ;; TEXT SHAPING IS OFF, AND THAT IS THE LARGEST SCOPE DECISION IN THIS

178 ;; CHAIN. `grapheme-shaping` and `run-shaping` each pull in harfbuzz, and

179 ;; run-shaping additionally pulls utf8proc. Turning both off removes two

180 ;; packages, and harfbuzz would additionally have re-opened the

181 ;; freetype/harfbuzz build cycle that `freetype` above is configured to

182 ;; avoid.

183 ;;

184 ;; WHAT IS LOST, said plainly rather than buried: without shaping, foot

185 ;; renders each grapheme cluster from a single font glyph. Combining

186 ;; sequences -- emoji built from ZWJ sequences, some scripts with complex

187 ;; joining behaviour -- will not compose. Latin, Cyrillic, Greek, CJK and

188 ;; box drawing are unaffected. Turn it back on by packaging harfbuzz and

189 ;; utf8proc and flipping these two options here and in `foot`.

190 ;;

191 ;; The SVG backend is left at its default, which uses the bundled nanosvg

192 ;; and therefore costs no package.

193 (define fcft

194 (package

195 name: "fcft"

196 version: "3.3.3"

197 source: (external-source

198 location: "https://codeberg.org/dnkl/fcft/releases/download/3.3.3/fcft-3.3.3.tar.gz"

199 sha256: "bb298772d625e7d917373d541456f34f1957a9e22b16f17f64158b2c3816563c")

200 buildenv: core-buildenv

201 ;; zlib is here for the reason spelled out on fontconfig above: it is

202 ;; reached through freetype2.pc's `Requires:` line, and this channel

203 ;; composes PKG_CONFIG_PATH from direct dependencies only.

204 dependencies: (list fontconfig freetype pixman tllist expat zlib)

205 build-inputs: (list meson samurai python)

206 phases: (list

207 (external-phase

208 kind: 'run

209 args: (list "sh" "-c"

210 (string-append

211 "set -eu\n"

212 "meson setup build"

213 " --prefix=${out}"

214 " --buildtype=plain"

215 " --default-library=static"

216 ;; `-Dprefer_static=true` MAKES MESON ASK

217 ;; PKG-CONFIG THE STATIC QUESTION, and without it

218 ;; a fully static link fails at the last step.

219 ;;

220 ;; A `.pc` file splits its link line: `Libs:` is

221 ;; what a SHARED consumer needs, `Libs.private:`

222 ;; and `Requires.private:` are the extra

223 ;; transitive libraries a STATIC consumer needs.

224 ;; fontconfig lists expat under

225 ;; `Requires.private:`, so a default

226 ;; `dependency('fontconfig')` emits no `-lexpat`

227 ;; -- correct for a shared link, fatal here:

228 ;;

229 ;; ld.lld: error: undefined symbol: XML_ErrorString

230 ;; >>> referenced by fcxml.c

231 ;; >>> fcxml.o in archive libfontconfig.a

232 ;;

233 ;; The symbol is missing from the LINK, not from

234 ;; the closure: expat is declared, built, and

235 ;; present. Only the query was the wrong one.

236 ;; This is the same `Requires.private:` line that

237 ;; had to be satisfied at CONFIGURE time; it bites

238 ;; twice, in two different ways, and fixing the

239 ;; first does not fix the second.

240 " -Dprefer_static=true"

241 " -Dgrapheme-shaping=disabled"

242 " -Drun-shaping=disabled"

243 " -Ddocs=disabled"

244 " -Dexamples=false"

245 " -Dtest-text-shaping=false\n"

246 "echo FCFT-CONFIGURED\n")))

247 (external-phase

248 kind: 'run

249 args: (list "sh" "-c"

250 (string-append

251 "set -eu\n"

252 "meson compile -C build\n"

253 "echo FCFT-COMPILED\n")))

254 (external-phase

255 kind: 'run

256 args: (list "sh" "-c"

257 (string-append

258 "set -eu\n"

259 "d=\"$(dirname \"$PWD\")/install-root\"\n"

260 "DESTDIR=\"$d\" meson install -C build --no-rebuild\n"

261 "test -f \"$d${out}/lib/pkgconfig/fcft.pc\"\n"

262 ;; foot pins fcft to >=3.3.1 <4.0.0, so the

263 ;; version pkg-config reports is load-bearing and

264 ;; is asserted rather than assumed.

265 ;; `--modversion` PRINTS a version; it does not

266 ;; CHECK one, and it exits 0 for any value. foot

267 ;; pins fcft to `>=3.3.1 <4.0.0`, so assert that

268 ;; range with the options that actually compare.

269 ;; Printing it as well keeps the value in the log.

270 "v=$(PKG_CONFIG_PATH=\"$d${out}/lib/pkgconfig\" pkg-config --modversion fcft)\n"

271 "echo \"FCFT-VERSION=[$v]\"\n"

272 "PKG_CONFIG_PATH=\"$d${out}/lib/pkgconfig\" pkg-config --atleast-version=3.3.1 fcft\n"

273 "PKG_CONFIG_PATH=\"$d${out}/lib/pkgconfig\" pkg-config --max-version=3.99.99 fcft\n"

274 "echo FCFT-INSTALLED\n"))))))))