diff --git a/graphviz.mk b/graphviz.mk
index 6361b81..e00c47b 100644
--- a/graphviz.mk
+++ b/graphviz.mk
@@ -1,3 +1,8 @@
+# SPDX-License-Identifier: LGPL-3.0-or-later
+#
+# SPDX-FileCopyrightText: 2023 Glenn Y. Rolland <glenux@glenux.net>
+# Copyright © 2023 Glenn Y. Rolland <glenux@glenux.net>
+
 ##
 ## GRAPHVIZ MODULE
 ##
@@ -15,11 +20,18 @@ GRAPHVIZ_DEST_DIR ?=
 ## Find .dot graphs
 GRAPHVIZ_DOT := $(shell find $(GRAPHVIZ_SRC_DIR) \( -name '*.dot' ! -name '_*' \))
 GRAPHVIZ_DOT_SVG := $(patsubst $(GRAPHVIZ_SRC_DIR)/%.dot,$(GRAPHVIZ_DEST_DIR)/%.dot.svg,$(GRAPHVIZ_DOT))
+GRAPHVIZ_DOT_PNG := $(patsubst $(GRAPHVIZ_SRC_DIR)/%.dot,$(GRAPHVIZ_DEST_DIR)/%.dot.png,$(GRAPHVIZ_DOT))
+GRAPHVIZ_DOT_PDF := $(patsubst $(GRAPHVIZ_SRC_DIR)/%.dot,$(GRAPHVIZ_DEST_DIR)/%.dot.pdf,$(GRAPHVIZ_DOT))
 
 ## Find .circo graphs
 GRAPHVIZ_CIRCO := $(shell find $(GRAPHVIZ_SRC_DIR) \( -name '*.circo' ! -name '_*' \))
 GRAPHVIZ_CIRCO_SVG := $(patsubst $(GRAPHVIZ_SRC_DIR)/%.circo,$(GRAPHVIZ_DEST_DIR)/%.circo.svg,$(GRAPHVIZ_CIRCO))
+GRAPHVIZ_CIRCO_PNG := $(patsubst $(GRAPHVIZ_SRC_DIR)/%.circo,$(GRAPHVIZ_DEST_DIR)/%.circo.png,$(GRAPHVIZ_CIRCO))
+GRAPHVIZ_CIRCO_PDF := $(patsubst $(GRAPHVIZ_SRC_DIR)/%.circo,$(GRAPHVIZ_DEST_DIR)/%.circo.pdf,$(GRAPHVIZ_CIRCO))
+
 GRAPHVIZ_SVG := $(GRAPHVIZ_DOT_SVG) $(GRAPHVIZ_CIRCO_SVG)
+GRAPHVIZ_PNG := $(GRAPHVIZ_DOT_PNG) $(GRAPHVIZ_CIRCO_PNG)
+GRAPHVIZ_PDF := $(GRAPHVIZ_DOT_PDF) $(GRAPHVIZ_CIRCO_PDF)
 
 ##
 ## Prerequisistes (system packages)
@@ -40,21 +52,38 @@ $(GRAPHVIZ_DEST_DIR)/%.circo.svg: $(GRAPHVIZ_SRC_DIR)/%.circo | $(GRAPHVIZ_DEST_
 	circo -Tsvg $< > $@
 
 $(GRAPHVIZ_SVG): | $(GRAPHVIZ_DEST_DIR)
-	mkdir -p $(GRAPHVIZ_DEST_DIR)
 
+$(GRAPHVIZ_PDF): | $(GRAPHVIZ_DEST_DIR)
+
+$(GRAPHVIZ_PNG): | $(GRAPHVIZ_DEST_DIR)
+
+.PHONY: graphviz-build-dot-svg
 graphviz-build-dot-svg: $(GRAPHVIZ_DOT_SVG)
 
+.PHONY: graphviz-build-circo-svg
 graphviz-build-circo-svg: $(GRAPHVIZ_CIRCO_SVG)
 
+.PHONY: graphviz-build-svg
 graphviz-build-svg: graphviz-build-dot-svg graphviz-build-circo-svg
 
+.PHONY: graphviz-buil
 graphviz-build: graphviz-build-svg
 
 
 # Clean
 #
+.PHONY: graphviz-clean-svg
 graphviz-clean-svg:
 	rm -f $(GRAPHVIZ_SVG)
 
-graphviz-clean: graphviz-clean-svg
+.PHONY: graphviz-clean-pdf
+graphviz-clean-pdf:
+	rm -f $(GRAPHVIZ_PDF)
+
+.PHONY: graphviz-clean-png
+graphviz-clean-png:
+	rm -f $(GRAPHVIZ_PNG)
+
+.PHONY: graphviz-clean
+graphviz-clean: graphviz-clean-svg graphviz-clean-png graphviz-clean-pdf