From b88e8d999c52d0cdff3bb3283f85b500b7c0832e Mon Sep 17 00:00:00 2001
From: Vincenzo Mantova <xworld21@users.sf.net>
Date: Sun, 23 May 2021 19:04:07 +0100
Subject: [PATCH] eukleides: allow PostScript transparency

---
 pkgs/applications/science/math/eukleides/default.nix   |  8 ++++++--
 .../math/eukleides/gs-allowpstransparency.patch        | 10 ++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 pkgs/applications/science/math/eukleides/gs-allowpstransparency.patch

diff --git a/pkgs/applications/science/math/eukleides/default.nix b/pkgs/applications/science/math/eukleides/default.nix
index e96438b5b3e2..12226abdfca4 100644
--- a/pkgs/applications/science/math/eukleides/default.nix
+++ b/pkgs/applications/science/math/eukleides/default.nix
@@ -9,8 +9,12 @@ lib.fix (eukleides: stdenv.mkDerivation rec {
     sha256 = "0s8cyh75hdj89v6kpm3z24i48yzpkr8qf0cwxbs9ijxj1i38ki0q";
   };
 
-  # use $CC instead of hardcoded gcc
-  patches = [ ./use-CC.patch ];
+  patches = [
+    # use $CC instead of hardcoded gcc
+    ./use-CC.patch
+    # allow PostScript transparency in epstopdf call
+    ./gs-allowpstransparency.patch
+  ];
 
   nativeBuildInputs = [ bison flex texinfo makeWrapper ];
 
diff --git a/pkgs/applications/science/math/eukleides/gs-allowpstransparency.patch b/pkgs/applications/science/math/eukleides/gs-allowpstransparency.patch
new file mode 100644
index 000000000000..aa92e6cc9fa7
--- /dev/null
+++ b/pkgs/applications/science/math/eukleides/gs-allowpstransparency.patch
@@ -0,0 +1,10 @@
+--- a/bash/euktopdf
++++ b/bash/euktopdf
+@@ -55,6 +55,6 @@ do
+     exit 1
+   fi
+   dvips -q -E -o $base.eps $base.dvi &&
+-  epstopdf $base.eps &&
++  epstopdf --gsopt=-dALLOWPSTRANSPARENCY $base.eps &&
+   rm -f $base.{tex,log,dvi,eps}
+ done