Check libpng directly into third_party/

third_party/libpng/contrib/testpngs/makepngs.sh

+#!/bin/sh
+#
+# Make a set of test PNG files, MAKEPNG is the name of the makepng executable
+# built from contrib/libtests/makepng.c
+
+# Copyright (c) 2015 John Cunningham Bowler
+
+# Last changed in libpng 1.7.0 [(PENDING RELEASE)]
+
+# This code is released under the libpng license.
+# For conditions of distribution and use, see the disclaimer
+# and license in png.h
+
+# The arguments say whether to build all the files or whether just to build the
+# ones that extend the code-coverage of libpng from the existing test files in
+# contrib/pngsuite.
+test -n "$MAKEPNG" || MAKEPNG=./makepng
+opts=
+
+mp(){
+   ${MAKEPNG} $opts $1 "$3" "$4" "$3-$4$2.png"
+}
+
+mpg(){
+   if test "$1" = "none"
+   then
+      mp "" "" "$2" "$3"
+   else
+      mp "--$1" "-$1" "$2" "$3"
+   fi
+}
+
+mptrans(){
+   if test "$1" = "none"
+   then
+      mp "--tRNS" "-tRNS" "$2" "$3"
+   else
+      mp "--tRNS --$1" "-$1-tRNS" "$2" "$3"
+   fi
+}
+
+case "$1" in
+   --small)
+      opts="--small";;&
+
+   --all|--small)
+      for g in none sRGB linear 1.8
+      do
+         for c in gray palette
+         do
+            for b in 1 2 4
+            do
+               mpg "$g" "$c" "$b"
+               mptrans "$g" "$c" "$b"
+            done
+         done
+
+         mpg "$g" palette 8
+         mptrans "$g" palette 8
+
+         for b in 8 16
+         do
+            for c in gray gray-alpha rgb rgb-alpha
+            do
+               mpg "$g" "$c" "$b"
+            done
+            for c in gray rgb
+            do
+               mptrans "$g" "$c" "$b"
+            done
+         done
+      done;;
+
+   --coverage)
+      # Comments below indicate cases known to be required and not duplicated
+      # in other (required) cases; the aim is to get a minimal set that gives
+      # the maxium code coverage.
+      mpg none gray-alpha 8 # required: code coverage, sRGB opaque component
+      mpg none palette 8 # required: basic palette read
+      mpg 1.8 gray 2 # required: tests gamma threshold code
+      mpg 1.8 palette 2 # required: code coverage
+      mpg 1.8 palette 4 # required: code coverage
+      mpg 1.8 palette 8 # error limits only
+      mpg linear palette 8 # error limits only
+      mpg linear rgb-alpha 16 # error limits only
+      mpg sRGB palette 1 # required: code coverage
+      mpg sRGB rgb-alpha 16 # required: code coverage: pngread.c:2422 untested
+      :;;
+
+   *)
+      echo "$0 $1: unknown argument, usage:" >&2
+      echo "  $0 [--all|--coverage|--small]" >&2
+      exit 1
+esac