From 6e69e10b2df3aa6b4721c5a41f217cfa5ae3ef9e Mon Sep 17 00:00:00 2001
From: Johnson <jwpage@gmail.com>
Date: Sun, 31 Aug 2014 09:43:17 +1000
Subject: [PATCH] Rewrite Gd\Color::alpha2gd for improved performance

---
 src/Intervention/Image/Gd/Color.php | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/src/Intervention/Image/Gd/Color.php b/src/Intervention/Image/Gd/Color.php
index 1d62cdd1..51ba1606 100644
--- a/src/Intervention/Image/Gd/Color.php
+++ b/src/Intervention/Image/Gd/Color.php
@@ -215,15 +215,12 @@ class Color extends AbstractColor
      */
     private function alpha2gd($input)
     {
-        $range_input = range(1, 0, 1/127);
-        $range_output = range(0, 127);
+        $oldMin = 0;
+        $oldMax = 1;
 
-        foreach ($range_input as $key => $value) {
-            if ($value <= $input) {
-                return $range_output[$key];
-            }
-        }
+        $newMin = 127;
+        $newMax = 0;
 
-        return 127;
+        return ceil(((($input- $oldMin) * ($newMax - $newMin)) / ($oldMax - $oldMin)) + $newMin);
     }
 }