From 93afebdb303b46215d8bf67c1f9e8d75f79be988 Mon Sep 17 00:00:00 2001
From: Slava Pestov <slava@slava-pestovs-macbook-pro.local>
Date: Sun, 1 Feb 2009 20:32:00 -0600
Subject: [PATCH] colors: add an opaque? word and a transparent color

---
 basis/colors/colors.factor        | 5 ++++-
 basis/colors/hsv/hsv-tests.factor | 2 ++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/basis/colors/colors.factor b/basis/colors/colors.factor
index 89f2dd1cd4..5a4e2134d5 100644
--- a/basis/colors/colors.factor
+++ b/basis/colors/colors.factor
@@ -1,7 +1,7 @@
 ! Copyright (C) 2003, 2009 Slava Pestov.
 ! Copyright (C) 2008 Eduardo Cavazos.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: kernel accessors combinators ;
+USING: kernel accessors combinators math ;
 IN: colors
 
 TUPLE: color ;
@@ -21,6 +21,9 @@ M: color blue>> ( color -- blue ) >rgba blue>> ;
 : >rgba-components ( object -- r g b a )
     >rgba { [ red>> ] [ green>> ] [ blue>> ] [ alpha>> ] } cleave ; inline
 
+: opaque? ( color -- ? ) alpha>> 1 number= ;
+
+CONSTANT: transparent T{ rgba f 0.0 0.0 0.0 0.0 }
 CONSTANT: black T{ rgba f 0.0 0.0 0.0 1.0 }
 CONSTANT: blue T{ rgba f 0.0 0.0 1.0 1.0 }
 CONSTANT: cyan T{ rgba f 0 0.941 0.941 1 }
diff --git a/basis/colors/hsv/hsv-tests.factor b/basis/colors/hsv/hsv-tests.factor
index 8a736553bb..a825cacda8 100644
--- a/basis/colors/hsv/hsv-tests.factor
+++ b/basis/colors/hsv/hsv-tests.factor
@@ -24,3 +24,5 @@ USING: accessors kernel colors colors.hsv tools.test math ;
 
 [ 5/6 5/36 5/6 ] [ 5/6 5/6 5/6 hsv>rgb ] unit-test
 [ 1/6 0 1/6 ] [ 5/6 1 1/6 hsv>rgb ] unit-test
+
+[ 0.5 ] [ 180 0.1 0.2 0.5 <hsva> alpha>> ] unit-test
\ No newline at end of file