# websrc/pictools/MakeResources

# This is an 'include' makefile for 
# augmenting an .../images/... directory 
# with files made from soures 
# in a .../resources/... directory
# The only clever bits are those that know how to convert files 
# to transparent backgrounds while eliminating the "halo" effect. 
# See TRANSPARENTSURROUND and TRANSPARENTBACKGROUND, below.

# The Makefile has this form:
#	<set some variables>
#	include $(PICTOOLS)/MakeResources
#	<define build rules as required>

# $(PICTOOLS)/MakeVars is included below, 
# so the facilitites defined therein are available.
# In particular, this Makefile supports SUBDIRS 
# and the targets build and buildall. Upload is
# supported in that it causes build to happen.

#/---------------------------------------------------------\
#| Applicable Variables
#| The following variables are, or may be, defined:
#|
#| IMAGESDIR - defined herein as the directory 
#| into which files are built or copied.
#| The invoking Makefile may set this variable itself
#| to choose another directory as the destination.
#|
#| IMAGEDIRFILES - Names -- without directory - of files
#| to be built or copied into IMAGESDIR. 
#| The default is to copy a file. (Although usually
#| such files can simply reside directly in .../images/...)
#| If the file needs to be built, a rule to build it must be 
#| written. It should have the form:
#|    $(IMAGESDIR)/file: source file(s)
#|		commands to make the sources into $@
#|
#| BUILDFILES
#| Additional files to be created for the 'build' target.
#| There must also be rules for building these files.
#|
#| TRANSPARENTBACKGROUND
#| TRANSPARENTSURROUND
#| When an image is placed on a background, dithering 
#| usually leak colors between the background into the image.
#| Then when the image background is made transparent and
#| the image is placed on a background of another color, 
#| a halo appears around it. Similar artifacts occur when
#| anti-aliasing is applied to soften jagged lines.
#
#| This Makefile tool provides two halo reduction tricks.
#| Each makes the background transparent and the halo pixels
#| semi-transparent. When the image is laid over a new 
#| background its pixels will glimmer through.
#| The first trick, TRANSPARENTBACKGROUND, makes transparent
#| all instances of the background color. 
#| The second, TRANSPARENTSURROUND, makes transparent
#| only those background color pixels which form the edge
#| and adjacent pixels.
#|
#| The algorithm works best if the original background
#| is light, or even white. 
#|
#| The commands nobg and nosur are used. By default they 
#| treat all pixels within 5% (the default fuzzpct) of the 
#| transparent color as also being that color.
#\--------------------------------------------------------/

include $(PICTOOLS)/MakeVars

# get parallel directory ../.../images/...
ifndef IMAGESDIR
IMAGESDIR = $(subst /resources/,/images/,$(CURDIR)/.)
endif

_DESTFILES = $(IMAGEDIRFILES:%=$(IMAGESDIR)/%)\

_NOBGF =  $(foreach name,$(TRANSPARENTBACKGROUND),    \
               $(IMAGESDIR)/$(basename $(name)).png) 
_NOSURF = $(foreach name,$(TRANSPARENTSURROUND),    \
               $(IMAGESDIR)/$(basename $(name)).png) 


build: $(IMAGESDIR) transbuild $(_DESTFILES) $(BUILDFILES)
buildall: build subdirs 
upload: build
subdirs: 
	@for dir in $(SUBDIRS); do \
             $(MAKE) -C $$dir $(MAKECMDGOALS); \
	done

$(IMAGESDIR):
	mkdir -p $(IMAGESDIR)

# to get the dependencies we want, we build `tmake' and $(MAKE) it
# (perhaps this could be done with .SECONDEXPANSION)
transbuild:
	@tmak=Tmake.$$$$;						\
	echo transbuild:  $(_NOBGF) $(_NOSURF) > $$tmak;		\
	for name in $(TRANSPARENTBACKGROUND);				\
		do 	    						\
		echo $(IMAGESDIR)/$${name%.*}.png: $$name >>$$tmak;	\
		echo '	sh $(PICTOOLS)/nobg $$< $$@' >>$$tmak;		\
	done;								\
	for name in $(TRANSPARENTSURROUND);				\
		do 	    						\
		echo $(IMAGESDIR)/$${name%.*}.png: $$name >>$$tmak;	\
		echo '	sh $(PICTOOLS)/nosur $$< $$@' >>$$tmak;		\
	done;								\
	$(MAKE) -f $$tmak transbuild;					\
	rm $$tmak

$(IMAGESDIR)/%: %
	cp $< $@

####################################
# clean

.PHONY: clean
clean:
	rm -rf $(JUNKFILES)
	@for dir in $(SUBDIRS); do \
             $(MAKE) -C $$dir clean; \
	done