doc: Port from Doxygen to gtk-doc

Split the introduction into separate chapters, add filler documentation
for async functions, fix mismatched function arguments.

doc/meson.build

@@ -1,17 +1,67 @@
-cdata = configuration_data()
-cdata.set('SRCDIR', join_paths(meson.source_root(), 'libfprint'))
-cdata.set('BUILDDIR', join_paths(meson.build_root(), 'doc'))
+subdir('xml')
 
-cfg = configure_file(input: 'doxygen.cfg.in',
-                     output: 'doxygen.cfg',
-                     configuration: cdata,
-                     install: false)
+private_headers = [
+  'config.h',
 
-doxygen = find_program('doxygen')
-datadir = join_paths(get_option('datadir'), 'doc', 'libfprint-devel')
-custom_target('docs',
-              input: cfg,
-              output: 'html',
-              command: [ doxygen, '@INPUT@' ],
-              install: true,
-              install_dir: datadir)
+  'aeslib.h',
+  'assembling.h',
+  'fp_internal.h',
+
+  # Drivers
+  'aes1660.h',
+  'aes2501.h',
+  'aes2550.h',
+  'aes2660.h',
+  'aes3k.h',
+  'aesx660.h',
+  'driver_ids.h',
+  'elan.h',
+  'upeksonly.h',
+  'upektc.h',
+  'upektc_img.h',
+  'vfs0050.h',
+  'vfs301_proto_fragments.h',
+  'vfs301_proto.h',
+  'vfs5011_proto.h',
+
+  # NBIS
+  'morph.h',
+  'sunrast.h',
+  'bozorth.h',
+  'defs.h',
+  'log.h',
+  'bz_array.h',
+  'lfs.h',
+]
+
+html_images = [
+]
+
+content_files = [
+  'intro.xml'
+]
+
+expand_content_files = content_files
+
+glib_prefix = dependency('glib-2.0').get_pkgconfig_variable('prefix')
+glib_docpath = join_paths(glib_prefix, 'share', 'gtk-doc', 'html')
+docpath = join_paths(get_option('datadir'), 'gtk-doc', 'html')
+
+gnome.gtkdoc('libfprint',
+             main_xml: 'libfprint-docs.xml',
+             src_dir: join_paths(meson.source_root(), 'libfprint'),
+             dependencies: libfprint_dep,
+             content_files: content_files,
+             expand_content_files: expand_content_files,
+             scan_args: [
+               '--rebuild-types',
+               '--ignore-decorators=API_EXPORTED',
+               '--ignore-headers=' + ' '.join(private_headers),
+             ],
+             fixxref_args: [
+               '--html-dir=@0@'.format(docpath),
+               '--extra-dir=@0@'.format(join_paths(glib_docpath, 'glib')),
+               '--extra-dir=@0@'.format(join_paths(glib_docpath, 'gobject')),
+             ],
+             html_assets: html_images,
+             install: true)