doc: Use PNG images instead of SVG.

PNG images are supported by both the info and html engines.

* doc/ccwl.skb (Tutorial)[Workflow with multiple steps]: Use PNG
images instead of SVG.
* Makefile.am (CLEANFILES): Replace doc/*.svg with doc/*.png.
(%.svg): Delete rule.
(%.png): New rule.
* .gitignore: Replace doc/*.svg with doc/*.png.

4 files changed, 6 insertions, 8 deletions

diff --git a/.gitignore b/.gitignore
index efee198..d03af33 100644
--- a/.gitignore
+++ b/.gitignore
@@ -13,7 +13,7 @@ configure
 doc/*.cwl
 doc/*.html
 doc/*.info
-doc/*.svg
+doc/*.png
 doc/.dirstamp
 doc/stamp-vti
 pre-inst-env
diff --git a/Makefile.am b/Makefile.am
index ac921b5..e4c562a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -94,7 +94,7 @@ EXTRA_DIST +=			\
 
 include .depends
 
-CLEANFILES += doc/*.cwl doc/%.dot doc/*.svg
+CLEANFILES += doc/*.cwl doc/%.dot doc/*.png
 
 %.cwl: %.scm
 	$(CCWL_GEN)$(builddir)/pre-inst-env ccwl compile $< > $@
@@ -104,8 +104,8 @@ CLEANFILES += doc/*.cwl doc/%.dot doc/*.svg
 %.dot: %.cwl
 	$(CWLTOOL_GEN)$(CWLTOOL) --print-dot $< | $(SED) 's/file:[^#]*#//g' > $@
 
-%.svg: %.dot
-	$(DOT_GEN)$(DOT) -Tsvg -o$@ $<
+%.png: %.dot
+	$(DOT_GEN)$(DOT) -Tpng -o$@ $<
 
 # The info and html targets depend on the info-local and html-local
 # targets respectively. So, we use them to extend the info and html
diff --git a/doc/ccwl.skb b/doc/ccwl.skb
index 5fa7b40..b15f861 100644
--- a/doc/ccwl.skb
+++ b/doc/ccwl.skb
@@ -207,7 +207,7 @@ nothing to do with the Unix pipe. The inputs/outputs passed between
 steps are general CWL inputs/outputs. They need not be the standard
 stdin and stdout streams.])
 
-        (image :file "doc/decompress-compile-run.svg")
+        (image :file "doc/decompress-compile-run.png")
 
         (p [Writing this worklow to
 ,(file "decompress-compile-run.scm"), compiling and running it with
@@ -234,7 +234,7 @@ that are independent of each other. The workflow inputs coming into
 ,(code "tee"). The outputs of each step are collected together and
 unioned as the output of the ,(code "tee").])
 
-        (image :file "doc/checksum.svg")
+        (image :file "doc/checksum.png")
 
         (p [Writing this workflow to ,(file "checksum.scm"), compiling
 and running it with some file ,(file "hello.txt") gives us the
diff --git a/doc/skribilo.scm b/doc/skribilo.scm
index 4a5d0c1..22d31f9 100644
--- a/doc/skribilo.scm
+++ b/doc/skribilo.scm
@@ -129,8 +129,6 @@ and END are line numbers indexed from 1."
 (let ((html-engine (find-engine 'html)))
   (engine-custom-set! html-engine 'css "/style.css")
   (engine-custom-set! html-engine 'charset "UTF-8")
-  (engine-custom-set! html-engine 'image-format
-                      (list "svg" "png" "gif" "jpg" "jpeg"))
   (markup-writer 'abbr html-engine
                  #:options '(#:short #:long)
                  #:action (lambda (markup engine)