add thumbnail build support

Makefile

@@ -30,11 +30,13 @@ OUT_DIR 		= build
 SRC_DIRS 		= de en script style
 SRC_FLS 		= 
 
-# SOURCE FILES:
+# RESOURCE FILES:
 # all RESOURCE_FLS and all files in the RESOURCE_DIRS will be copied to OUT_DIR
 RESOURCE_DIRS 	= resources 
 RESOURCE_FLS	= 
-
+# THUMBNAILS:
+# if set, thumbnails for all resource files will be generated and placed in THUMB_OUT_DIR (relative to OUT_DIR)
+THUMB_OUT_DIR 	= thumbs
 
 # MULTI-LANG SOURCE FILES:
 # the files in COMMON_DIR will be built for all LANGS:
@@ -103,6 +105,15 @@ ML_OUT_DIRS		= $(foreach lang, $(LANGS), $(patsubst $(_COMMON_DIR)/%, $(ML_OUT_D
 ML_OUT_FLS 		= $(foreach lang, $(LANGS), $(patsubst $(_COMMON_DIR)/%, $(ML_OUT_DIR)/$(lang)/%, $(_ML_SRC_FLS)))
 endif
 
+ifdef THUMB_OUT_DIR
+_THUMB_FOR_TYPES = png gif jpg jpeg webp pdf 
+_THUMB_TYPE 	= jpg
+# files for which to generate thumbnails
+_THUMB_FLS 		= $(filter $(foreach type, $(_THUMB_FOR_TYPES), %.$(type)), $(_RES_FLS))
+THUMB_OUT_FLS 	= $(addsuffix .jpg, $(basename $(patsubst $(PROJECT_DIR)/%, $(OUT_DIR)/$(THUMB_OUT_DIR)/%, $(_THUMB_FLS))))
+THUMB_OUT_DIRS	= $(sort $(dir $(THUMB_OUT_FLS)))  # sort for removing duplicates
+endif
+
 # needed for creating them
 _DEP_DIRS 		= $(sort $(patsubst $(OUT_DIR)/%, $(DEP_DIR)/%, $(OUT_DIRS) $(ML_OUT_DIRS)))
 # needed for reading
@@ -112,7 +123,8 @@ _DEP_FLS 		= $(shell find $(DEP_DIR) -type f -name '*.d' 2>/dev/null)
 FMT_VAR_SRC		="Variable '\e[1;34m%s\e[0m': \e[0;33m%s\e[0m\n"
 FMT_VAR_OUT		="Variable '\e[1;34m%s\e[0m': \e[0;35m%s\e[0m\n"
 FMT_DIR			="\e[1;34mMaking directory\e[0m: \e[0;35m%s\e[0m\n"
-FMT_OUT_HTML	="\e[1;34mBuilding html\e[0m \e[1;33m%s\e[0m at \e[1;35m%s\e[0m\n"
+FMT_OUT_HTML	="\e[1;34mBuilding html\e[0m: \e[1;33m%s\e[0m at \e[1;35m%s\e[0m\n"
+FMT_OUT_THUMB	="\e[1;34mBuilding thumbnail\e[0m: \e[1;33m%s\e[0m at \e[1;35m%s\e[0m\n"
 FMT_OUT_OTHER	="\e[1;34mBuilding\e[0m: \e[1;33m%s\e[0m at \e[1;35m%s\e[0m\n"
 
 FMT_OUT_ML_HTML="\e[1;34mBuilding html\e[0m in lang \e[1;34m%s\e[0m: \e[1;33m%s\e[0m at \e[1;35m%s\e[0m\n"
@@ -127,10 +139,11 @@ FMT_OUT_ML_OTHER="\e[1;34mBuilding\e[0m in lang \e[1;34m%s\e[0m: \e[1;33m%s\e[0m
 # include all the dependency makefiles
 include $(_DEP_FLS)
 
-all: normal multilang resources
+all: normal multilang resources thumbnails
 normal:	$(OUT_FLS)
 multilang: $(ML_OUT_FLS)
 resources: $(RES_OUT_FLS)
+thumbnails: $(THUMB_OUT_FLS)
 
 print:
 	@printf $(FMT_VAR_SRC) "PROJECT_DIR" 	"$(PROJECT_DIR)"
@@ -145,10 +158,16 @@ ifdef COMMON_DIR
 	@printf $(FMT_VAR_OUT) "ML_OUT_FLS" 	"$(ML_OUT_FLS)"
 endif
 	@printf $(FMT_VAR_SRC) "_DEP_FLS" 		"$(_DEP_FLS)"
+ifdef THUMB_OUT_DIR
+	@printf $(FMT_VAR_SRC) "THUMB_OUT_DIR" 	"$(THUMB_OUT_DIR)"
+	@printf $(FMT_VAR_OUT) "_THUMB_FLS" 	"$(_THUMB_FLS)"
+	@printf $(FMT_VAR_OUT) "THUMB_OUT_FLS"  "$(THUMB_OUT_FLS)"
+	@printf $(FMT_VAR_OUT) "THUMB_OUT_DIRS" "$(THUMB_OUT_DIRS)"
+endif
 	@# @printf $(FMT_VAR_SRC) "y" 		"$(y)"
 
 # DIRECTORIES
-$(sort $(ML_OUT_DIRS) $(_DEP_DIRS) $(RES_OUT_DIRS) $(OUT_DIRS)):
+$(sort $(ML_OUT_DIRS) $(_DEP_DIRS) $(RES_OUT_DIRS) $(OUT_DIRS) $(THUMB_OUT_DIRS)):
 	@printf $(FMT_DIR) "$@"
 	@mkdir -p $@
 
@@ -171,6 +190,22 @@ $(foreach out_dir, $(ML_OUT_LANG_DIRS), $(out_dir)/%): $(_COMMON_DIR)/% | $(ML_O
 	cp $< $@
 endif
 
+# THUMBNAILS
+$(OUT_DIR)/$(THUMB_OUT_DIR)/%.jpg: | $(THUMB_OUT_DIRS)
+	@fulltarget="$@"; \
+	target="$(patsubst $(OUT_DIR)/$(THUMB_OUT_DIR)/%.jpg,%,$@)"; \
+	sources=($(_THUMB_FLS)); \
+	source=$$(printf  "%s\n" $${sources[@]} | grep "$$target"'\.'); \
+	printf $(FMT_OUT_THUMB) "$$source" "$$fulltarget"; \
+	if [ "$${source##*.}" = "pdf" ]; then \
+		pdftoppm -f 1 -singlefile -jpeg -r 50 "$$source" "$${fulltarget%.*}"; \
+	else \
+		magick "$$source" -thumbnail '100x100>' "$@"; \
+	fi; \
+
+
+
+
 #
 # (NORMAL/RE-)SOURCE RULES
 #