2 files changed, 91 insertions, 1 deletions
diff --git a/bin/Makefile b/bin/Makefile
index c2bd7a09..c35e1c8f 100644
--- a/bin/Makefile
+++ b/bin/Makefile
@@ -135,7 +135,7 @@ $(HTMLS): html.sh style.sed hi scheme ttpre
 	sh html.sh $< man1/$(<:.sh=.1) > $@
 
 .h.html:
-	sh html.sh $< > $@
+	sh html.sh $< man3/$(<:.h=.3) > $@
 
 index.html: Makefile bin.7
 	sh html.sh Makefile bin.7 \
diff --git a/bin/man3/png.3 b/bin/man3/png.3
new file mode 100644
index 00000000..accffbd7
--- /dev/null
+++ b/bin/man3/png.3
@@ -0,0 +1,90 @@
+.Dd July 25, 2019
+.Dt PNG 3
+.Os
+.
+.Sh NAME
+.Nm png
+.Nd basic PNG output
+.
+.Sh SYNOPSIS
+.In png.h
+.
+.Ft void
+.Fo pngHead
+.Fa "FILE *file"
+.Fa "uint32_t width"
+.Fa "uint32_t height"
+.Fa "uint8_t depth"
+.Fa "uint8_t color"
+.Fc
+.
+.Ft void
+.Fn pngPalette "FILE *file" "const uint8_t *pal" "uint32_t len"
+.
+.Ft void
+.Fn pngData "FILE *file" "const uint8_t *data" "uint32_t len"
+.
+.Ft void
+.Fn pngTail "FILE *file"
+.
+.Sh DESCRIPTION
+The
+.Fn pngHead
+function
+writes the
+.Sy IHDR
+chunk to
+.Fa file .
+The
+.Fa color
+parameter can be one of
+.Dv PNGGrayscale ,
+.Dv PNGTruecolor
+optionally
+.Em or Ns 'ed
+with
+.Dv PNGAlpha ,
+or
+.Dv PNGIndexed .
+.
+.Pp
+The
+.Fn pngPalette
+function
+writes the
+.Sy PLTE
+chunk to
+.Fa file .
+.
+.Pp
+The
+.Fn pngData
+function
+writes the
+.Sy IDAT
+chunk to
+.Fa file
+without compression.
+The constants
+.Dv PNGNone ,
+.Dv PNGSub ,
+.Dv PNGUp ,
+.Dv PNGAverage ,
+.Dv PNGPaeth
+are defined
+for use in PNG data.
+.
+.Pp
+The
+.Fn pngTail
+function
+writes the
+.Sy IEND
+chunk to
+.Fa file .
+.
+.Sh ERRORS
+Any errors from writing to
+.Fa file
+are handled by calling
+.Xr err 3 .