Add desktop and icon files and install into the correct place

Remove 48x48 icon; use 256x256 icon only.
Remove icons from the executable.
No need to call gtk_window_set_default_icon_name() anymore.
Add desktop file.
Add install and uninstall Makefile targets.
Update USAGE.md with installation instructions.
Thanks to @szszoke for figuring this one out!

Fixes #2.

.gitignore

@@ -3,3 +3,4 @@
 .gdb_history
 alsa-scarlett-gui
 alsa-scarlett-gui-resources.c
+vu.b4.alsa-scarlett-gui.desktop

USAGE.md

@@ -71,6 +71,19 @@ To run:
 ./alsa-scarlett-gui
 ```
 
+You can install it into `/usr/local` (binary, desktop file, and icon)
+with:
+
+```
+sudo make install
+```
+
+And uninstall with:
+
+```
+sudo make uninstall
+```
+
 ## No interface connected
 
 If no interface is detected (usually because there isn’t one

src/Makefile

@@ -32,13 +32,14 @@ XML_OBJ := $(patsubst %.xml,%.c,$(XML_SRC))
 SRCS := $(sort $(wildcard *.c) $(XML_OBJ))
 OBJS := $(patsubst %.c,%.o,$(SRCS))
 TARGET := alsa-scarlett-gui
+DESKTOP_FILE := vu.b4.$(TARGET).desktop
 
 GLIB_COMPILE_RESOURCES := $(shell $(PKG_CONFIG) --variable=glib_compile_resources gio-2.0)
 
-all: $(TARGET)
+all: $(TARGET) $(DESKTOP_FILE)
 
 clean:
-	rm -f $(TARGET) $(OBJS) $(XML_OBJ)
+	rm -f $(TARGET) $(DESKTOP_FILE) $(OBJS) $(XML_OBJ)
 
 depclean:
 	rm -rf $(DEPDIR)
@@ -52,3 +53,28 @@ include $(wildcard $(DEPFILES))
 
 $(TARGET): $(OBJS)
 	cc ${LDFLAGS} -lm -o $(TARGET) $(OBJS)
+
+ifeq ($(PREFIX),)
+  PREFIX := /usr/local
+endif
+
+BINDIR := $(DESTDIR)$(PREFIX)/bin
+ICONTOP := $(DESTDIR)$(PREFIX)/share/icons/hicolor
+ICONDIR := $(ICONTOP)/256x256/apps
+DESKTOPDIR := $(DESTDIR)$(PREFIX)/share/applications
+
+$(DESKTOP_FILE): $(DESKTOP_FILE).template
+	sed 's_PREFIX_$(PREFIX)_' < $< > $@
+
+install: all
+	install -d $(BINDIR)
+	install -m 755 $(TARGET) $(BINDIR)
+	install -d $(ICONDIR)
+	install -m 644 img/$(TARGET).png $(ICONDIR)
+	install -d $(DESKTOPDIR)
+	install -m 644 $(DESKTOP_FILE) $(DESKTOPDIR)
+
+uninstall:
+	rm -f $(BINDIR)/$(TARGET)
+	rm -f $(ICONDIR)/$(TARGET).png
+	rm -f $(DESKTOPDIR)/$(DESKTOP_FILE)

src/alsa-scarlett-gui-resources.xml

@@ -4,12 +4,6 @@
     <file alias="alsa-scarlett-gui-logo.png">img/alsa-scarlett-gui-logo.png</file>
     <file alias="socket.svg">img/socket.svg</file>
   </gresource>
-  <gresource prefix="/vu/b4/alsa-scarlett-gui/icons/48x48/apps">
-    <file alias="alsa-scarlett-gui.png">img/alsa-scarlett-gui-48.png</file>
-  </gresource>
-  <gresource prefix="/vu/b4/alsa-scarlett-gui/icons/256x256/apps">
-    <file alias="alsa-scarlett-gui.png">img/alsa-scarlett-gui-256.png</file>
-  </gresource>
   <gresource prefix="/vu/b4/alsa-scarlett-gui">
     <file>alsa-scarlett-gui.css</file>
   </gresource>

src/main.c

@@ -30,7 +30,6 @@ static void load_css(void) {
 // gtk init
 
 static void startup(GtkApplication *app, gpointer user_data) {
-  gtk_window_set_default_icon_name("alsa-scarlett-gui");
   gtk_application_set_menubar(app, G_MENU_MODEL(create_app_menu(app)));
 
   alsa_inotify_init();

src/vu.b4.alsa-scarlett-gui.desktop.template

@@ -0,0 +1,9 @@
+[Desktop Entry]
+
+Encoding=UTF-8
+Value=1.5
+Type=Application
+Name=ALSA Scarlett Gen 2/3 Control Panel
+Icon=alsa-scarlett-gui
+Exec=PREFIX/bin/alsa-scarlett-gui
+Categories=GTK;AudioVideo;Audio;Mixer;