Generate scaled icons of various sizes

Assembled into a barebones icon theme following the freedesktop.org
icon theme spec:

https://specifications.freedesktop.org/icon-theme-spec/icon-theme-spec-0.11.html

Makefile

@@ -0,0 +1,14 @@
+modules = icons
+
+.PHONY: $(modules) install clean all
+
+all: $(modules)
+
+install:
+	$(MAKE) $(foreach module,$(modules),-C $(module)) install
+
+clean:
+	$(MAKE) $(foreach module,$(modules),-C $(module)) clean
+
+$(modules):
+	$(MAKE) -C $@

icons/Makefile

@@ -0,0 +1,33 @@
+#!/usr/bin/env make
+# Requirements: Imagemagick
+
+prefix ?= /usr
+
+sizes = 16 24 32 48 64 72 96 128 256 512 1024
+theme = hicolor
+category = apps
+
+icons = $(foreach size,$(sizes),$(size)x$(size)/$(category)/nix-snowflake.png) \
+        scalable/$(category)/nix-snowflake.svg
+
+install_dest = $(DESTDIR)$(prefix)/share/icons/$(theme)
+
+all: $(icons)
+
+%/$(category)/nix-snowflake.png: ../logo/nix-snowflake.svg
+	@mkdir -p $(@D)
+	convert -background none -resize $* $< $@
+
+scalable/$(category)/nix-snowflake.svg: ../logo/nix-snowflake.svg
+	@mkdir -p $(@D)
+	cp $< $@
+
+$(install_dest)/%: %
+	install -D $< $@
+
+install: $(foreach icon,$(icons),$(install_dest)/$(icon))
+
+clean:
+	rm -f $(icons)
+
+.PHONY: all install clean