From: glennrp <glennrp@git.imagemagick.org>
Date: Tue, 24 Sep 2013 00:38:27 +0000 (+0000)
Subject: Revised comments about interpretation of the -quality value in coders/png.c
X-Git-Tag: 7.0.1-0~3292
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ef804f5802b3d6517d516556b64fccc5843710b6;p=imagemagick

Revised comments about interpretation of the -quality value in coders/png.c
---

diff --git a/coders/png.c b/coders/png.c
index e191ed4ce..6b1401e74 100644
--- a/coders/png.c
+++ b/coders/png.c
@@ -10354,7 +10354,7 @@ static MagickBooleanType WriteOnePNGImage(MngInfo *mng_info,
 
      10's digit:
 
-        0: Use Z_HUFFMAN_ONLY strategy with the
+        0 or omitted: Use Z_HUFFMAN_ONLY strategy with the
            zlib default compression level
 
         1-9: the zlib compression level
@@ -10373,10 +10373,10 @@ static MagickBooleanType WriteOnePNGImage(MngInfo *mng_info,
              a MNG, othewise "none".  Did not work in IM-6.7.0-9
              and earlier because of a missing "else".
 
-        8:   Z_RLE strategy, all filters
+        8:   Z_RLE strategy (or Z_HUFFMAN_ONLY if quality < 10), all filters
              Unused prior to IM-6.7.0-10, was same as 6
 
-        9:   Z_RLE strategy, no PNG filters
+        9:   Z_RLE strategy (or Z_HUFFMAN_ONLY if quality < 10), no PNG filters
              Unused prior to IM-6.7.0-10, was same as 6
 
     Note that using the -quality option, not all combinations of