From: Simon Tatham <anakin@pobox.com>
Date: Sun, 24 Apr 2016 06:30:20 +0000 (+0100)
Subject: Explicitly set RGB colourspace in icon.pl's use of convert.
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=6a8a53e7235a8621313b792b498ebb43452f9e38;p=sgt-puzzles.git

Explicitly set RGB colourspace in icon.pl's use of convert.

This is that annoying feature of up-to-date 'convert' in which
converting to or from a PNG file defaults to returning RGB values that
have been 'helpfully' gamma-corrected (or some such) from the exact
data stored in the source file to some nonsense you didn't want.

Usually the worst this causes is slightly washed-out looking graphics,
but in this case, since my entire aim was to squash the image into a
specific set of exact RGB values so as to turn it into a paletted
Windows icon file, it caused an actual build failure when the next
loop in icon.pl couldn't find the gamma-corrected values in its
expected palette map, and no wonder.
---

diff --git a/icons/icon.pl b/icons/icon.pl
index d0c5a8e..fcb1aa3 100755
--- a/icons/icon.pl
+++ b/icons/icon.pl
@@ -127,7 +127,7 @@ sub readicon {
     # point, to avoid having to do it ourselves (.BMP and hence
     # .ICO are bottom-up).
     my $data = [];
-    open IDATA, "convert -flip -depth 8 $filename rgba:- |";
+    open IDATA, "convert -set colorspace sRGB -flip -depth 8 $filename rgba:- |";
     push @$data, $rgb while (read IDATA,$rgb,4,0) == 4;
     close IDATA;
     # Check we have the right amount of data.