Handle gdk-pixbuf's dynamic format support better

If we use it, install an update script.

README.adoc

@@ -50,9 +50,9 @@ ExifTool, resvg (unstable API, needs to be requested explicitly)
  $ meson compile
 
 Considering the vast amount of dynamically-linked dependencies, do not attempt
-direct installations.  To test the program, help it find its custom thumbnailer:
+direct installations via `ninja install`.  To test the program:
 
- $ PATH=$(pwd):$PATH ./fiv
+ $ meson devenv fiv
 
 The lossless JPEG cropper is intended to be invoked from a context menu.
 

docs/fiv.html

@@ -94,6 +94,15 @@ rm -rf ~/.cache/thumbnails/wide-*
 
 <h2>Configuration</h2>
 
+<p>The few configuration options <i>fiv</i> has can be adjusted using
+<i>dconf-editor</i> or <i>gsettings</i>.
+
+<pre>
+gsettings list-recursively name.janouch.fiv
+</pre>
+
+<h3>Theming</h3>
+
 <p>The standard means to adjust the looks of the program is through GTK+ 3 CSS.
 As an example, to tightly pack browser items, put the following in your
 <i>~/.config/gtk-3.0/gtk.css</i>:

fiv-browser.c

@@ -1220,6 +1220,7 @@ fiv_browser_scroll_event(GtkWidget *widget, GdkEventScroll *event)
 	case GDK_SCROLL_SMOOTH:
 		// On GDK/Wayland, the mouse wheel will typically create 1.5 deltas,
 		// after dividing a 15 degree click angle from libinput by 10.
+		// (Noticed on Arch + Sway, cannot reproduce on Ubuntu 22.04.)
 		// On X11, as libinput(4) indicates, the delta will always be 1.0.
 		if ((delta += event->delta_y) <= -1)
 			set_item_size(self, self->item_size + 1);

fiv-update-desktop-files.in

@@ -0,0 +1,4 @@
+#!/bin/sh -e
+sed -i "s|^MimeType=.*|MimeType=$(
+	"${DESTDIR:+$DESTDIR/}"'@EXE@' --list-supported-media-types | tr '\n' ';'
+)|" "${DESTDIR:+$DESTDIR/}"'@DESKTOP@'

fiv-view.c

@@ -547,7 +547,9 @@ fiv_view_realize(GtkWidget *widget)
 	//
 	// If GTK+'s OpenGL integration fails to deliver, we need to use the window
 	// directly, sidestepping the toolkit entirely.
-	if (GDK_IS_X11_WINDOW(window))
+	GSettings *settings = g_settings_new(PROJECT_NS PROJECT_NAME);
+	if (GDK_IS_X11_WINDOW(window) &&
+		g_settings_get_boolean(settings, "native-view-window"))
 		gdk_window_ensure_native(window);
 #endif  // GDK_WINDOWING_X11
 

fiv.gschema.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<schemalist>
+	<schema path="/name/janouch/fiv/" id="name.janouch.fiv">
+		<key name='native-view-window' type='b'>
+			<default>true</default>
+			<summary>Use a native window for the view</summary>
+			<description>
+				On X11, using native GdkWindows enables use of 30-bit Visuals
+				(that is, 10 bits per channel), at the cost of disabling
+				double buffering.
+			</description>
+		</key>
+	</schema>
+</schemalist>

meson.build

@@ -70,10 +70,12 @@ endif
 
 # XXX: https://github.com/mesonbuild/meson/issues/825
 docdir = get_option('datadir') / 'doc' / meson.project_name()
+application_ns = 'name.janouch.'
 
 conf = configuration_data()
 conf.set_quoted('PROJECT_NAME', meson.project_name())
 conf.set_quoted('PROJECT_VERSION', meson.project_version())
+conf.set_quoted('PROJECT_NS', application_ns)
 conf.set_quoted('PROJECT_DOCDIR', get_option('prefix') / docdir)
 conf.set('HAVE_JPEG_QS', libjpegqs.found())
 conf.set('HAVE_LCMS2', lcms2.found())
@@ -103,6 +105,7 @@ tiff_tables = custom_target('tiff-tables.h',
 	capture : true,
 )
 
+desktops = ['fiv.desktop', 'fiv-browse.desktop']
 exe = executable('fiv', 'fiv.c', 'fiv-view.c', 'fiv-io.c', 'fiv-context-menu.c',
 	'fiv-browser.c', 'fiv-sidebar.c', 'fiv-thumbnail.c', 'xdg.c', resources,
 	install : true,
@@ -113,14 +116,13 @@ if gdkpixbuf.found()
 		dependencies : [dependencies, gdkpixbuf])
 endif
 
+desktops += 'fiv-jpegcrop.desktop'
 jpegcrop = executable('fiv-jpegcrop', 'fiv-jpegcrop.c',
 	install : true,
 	dependencies : [
 		dependency('gtk+-3.0'),
 		dependency('libturbojpeg'),
 	])
-install_data('fiv-jpegcrop.desktop',
-	install_dir : get_option('datadir') / 'applications')
 
 if get_option('tools').enabled()
 	# libjq 1.6 lacks a pkg-config file, and there is no release in sight.
@@ -135,26 +137,40 @@ if get_option('tools').enabled()
 	endforeach
 endif
 
-# XXX: With gdk-pixbuf, this even depends on currently installed modules.
-if meson.is_cross_build()
-	install_data('fiv.desktop',
+gsettings_schemas = ['fiv.gschema.xml']
+install_data(gsettings_schemas,
+	rename : [application_ns + gsettings_schemas[0]],
+	install_dir : get_option('datadir') / 'glib-2.0' / 'schemas')
+
+# For the purposes of development: make the program find its GSettings schemas.
+gnome.compile_schemas(depend_files : files(gsettings_schemas))
+
+if host_machine.system() != 'windows'
+	foreach desktop : desktops
+		install_data(desktop,
+			rename : application_ns + desktop,
 			install_dir : get_option('datadir') / 'applications')
-else
-	# XXX: The exe path may not contain spaces--quoting is a bitch in Meson.
-	desktop = custom_target('desktop',
-		output : 'fiv.desktop',
-		input : 'fiv.desktop',
-		command : ['sh', '-c', '''awk '/^MimeType=/ { $0 = "MimeType=";
-			while (((exe " --list-supported-media-types") | getline type) > 0)
-				$0 = $0 type ";" } 1' "exe=$1" "$2"''', 'sh', exe, '@INPUT@'],
-		capture : true,
-		install : true,
-		install_dir : get_option('datadir') / 'applications',
-	)
+	endforeach
+
+	# With gdk-pixbuf, fiv.desktop depends on currently installed modules;
+	# the package manager needs to be told to run this script as necessary.
+	dynamic_desktops = gdkpixbuf.found()
+
+	updater = configure_file(
+		input : 'fiv-update-desktop-files.in',
+		output : 'fiv-update-desktop-files',
+		configuration : {
+			'EXE' : get_option('prefix') / get_option('bindir') / exe.name(),
+			'DESKTOP' : get_option('prefix') / get_option('datadir') \
+				/ 'applications' / application_ns + 'fiv.desktop',
+		},
+		install : dynamic_desktops,
+		install_dir : get_option('bindir'))
+	if not meson.is_cross_build()
+		meson.add_install_script(updater, skip_if_destdir : dynamic_desktops)
+	endif
 endif
 
-install_data('fiv-browse.desktop',
-	install_dir : get_option('datadir') / 'applications')
 install_data('fiv.svg',
 	install_dir : get_option('datadir') / 'icons/hicolor/scalable/apps')
 install_subdir('docs', install_dir : docdir, strip_directory : true)