PNG: Export signatures.

nh2 · nh2 · commit a8838446d934 · 2022-11-14T17:33:41.000Z
They are useful for applications that just want to search for
these signatures, or implement PNG logic slighly differently.
diff --git a/src/Codec/Picture/Png/Internal/Type.hs b/src/Codec/Picture/Png/Internal/Type.hs
@@ -14,6 +14,8 @@ module Codec.Picture.Png.Internal.Type( PngIHdr( .. )
                              , APngFrameControl( .. )
                              , parsePalette 
                              , pngComputeCrc
+                             , pngSignature
+                             , iHDRSignature
                              , pLTESignature
                              , iDATSignature
                              , iENDSignature
