From a4ac1b85922c7c19a2ca19a1451188e426399108 Mon Sep 17 00:00:00 2001
From: Ilyas Salikhov <salikhoff@gmail.com>
Date: Thu, 31 Jul 2014 13:04:06 +0400
Subject: [PATCH] First version + composer.json + README

---
 ColorInterpolator/Color.php             | 133 ++++++++++++++++++++++++
 ColorInterpolator/ColorInterpolator.php |  43 ++++++++
 README.md                               |  19 +++-
 composer.json                           |  19 ++++
 4 files changed, 211 insertions(+), 3 deletions(-)
 create mode 100644 ColorInterpolator/Color.php
 create mode 100644 ColorInterpolator/ColorInterpolator.php
 create mode 100644 composer.json

diff --git a/ColorInterpolator/Color.php b/ColorInterpolator/Color.php
new file mode 100644
index 0000000..6e276e5
--- /dev/null
+++ b/ColorInterpolator/Color.php
@@ -0,0 +1,133 @@
+<?php
+
+namespace Intaro\ColorInterpolator;
+
+class Color
+{
+    protected $r;
+    protected $g;
+    protected $b;
+
+    protected $h;
+    protected $s;
+    protected $v;
+
+    public function __construct($rgb = null)
+    {
+        if ($rgb) {
+            $this->setRgb($rgb);
+        }
+    }
+
+    public function setRgb($rgb)
+    {
+        if (strlen($rgb) < 6) {
+            for ($i = 0; $i < 7 - strlen($rgb); $i++)
+                $rgb = "0" . $rgb;
+        }
+
+        if (strlen($rgb) > 6) {
+            $rgb = substr($rgb, strlen($rgb)-6, 6);
+        }
+
+        $this->r = hexdec(substr($rgb, 0, 2)) / 255;
+        $this->g = hexdec(substr($rgb, 2, 2)) / 255;
+        $this->b = hexdec(substr($rgb, 4, 2)) / 255;
+
+        $this->convertRgbToHsv();
+    }
+
+    public function getRgb()
+    {
+        return dechex($this->r*255) . dechex($this->g*255) . dechex($this->b*255);
+    }
+
+    public function setHsv(array $hsv)
+    {
+        $this->h = $hsv['h'];
+        $this->s = $hsv['s'];
+        $this->v = $hsv['v'];
+
+        $this->convertHsvToRgb();
+    }
+
+    public function getHsv()
+    {
+        return [
+            'h' => $this->h,
+            's' => $this->s,
+            'v' => $this->v,
+        ];
+    }
+
+    protected function convertHsvToRgb()
+    {
+        //1
+        $h = $this->h * 6;
+        //2
+        $i = floor($h);
+        $f = $h - $i;
+        //3
+        $m = $this->v * (1 - $this->s);
+        $n = $this->v * (1 - $this->s * $f);
+        $k = $this->v * (1 - $this->s * (1 - $f));
+        //4
+        switch ($i) {
+            case 0:
+                list($this->r,$this->g,$this->b) = array($this->v,$k,$m);
+                break;
+            case 1:
+                list($this->r,$this->g,$this->b) = array($n,$this->v,$m);
+                break;
+            case 2:
+                list($this->r,$this->g,$this->b) = array($m,$this->v,$k);
+                break;
+            case 3:
+                list($this->r,$this->g,$this->b) = array($m,$n,$this->v);
+                break;
+            case 4:
+                list($this->r,$this->g,$this->b) = array($k,$m,$this->v);
+                break;
+            case 5:
+            case 6: //for when $H=1 is given
+                list($this->r,$this->g,$this->b) = array($this->v,$m,$n);
+                break;
+        }
+
+        return $this;
+    }
+
+    protected function convertRgbToHsv()
+    {
+
+       $min = min($this->r, $this->g, $this->b);
+       $max = max($this->r, $this->g, $this->b);
+       $del = $max - $min;
+
+       $v = $max;
+
+       if ($del == 0) {
+          $h = 0;
+          $s = 0;
+       } else {
+          $s = $del / $max;
+
+          $delR = ( ( ( $max - $this->r ) / 6 ) + ( $del / 2 ) ) / $del;
+          $delG = ( ( ( $max - $this->g ) / 6 ) + ( $del / 2 ) ) / $del;
+          $delB = ( ( ( $max - $this->b ) / 6 ) + ( $del / 2 ) ) / $del;
+
+          if      ($this->r == $max) $h = $delB - $delG;
+          else if ($this->g == $max) $h = ( 1 / 3 ) + $delR - $delB;
+          else if ($this->b == $max) $h = ( 2 / 3 ) + $delG - $delR;
+
+          if ($h < 0) $h++;
+          if ($h > 1) $h--;
+       }
+
+       $this->h = $h;
+       $this->s = $s;
+       $this->v = $v;
+
+       return $this;
+    }
+}
diff --git a/ColorInterpolator/ColorInterpolator.php b/ColorInterpolator/ColorInterpolator.php
new file mode 100644
index 0000000..1241e88
--- /dev/null
+++ b/ColorInterpolator/ColorInterpolator.php
@@ -0,0 +1,43 @@
+<?php
+
+namespace Intaro\ColorInterpolator;
+
+class ColorInterpolator
+{
+    public static function interpolate(Color $color1, Color $color2, $part = 0.5)
+    {
+        $color = new Color();
+        $hsv = [
+            'h' => null,
+            's' => null,
+            'v' => null,
+        ];
+        $color1Hsv = $color1->getHsv();
+        $color2Hsv = $color2->getHsv();
+
+        foreach ($hsv as $key => $value) {
+            if ($color1Hsv[$key] < $color2Hsv[$key]) {
+                $outLength = 1 - $color2Hsv[$key] + $color1Hsv[$key];
+                if ($key == 'h' && $outLength < 0.5) {
+                    $hsv[$key] = $color2Hsv[$key] + $outLength * $part;
+                    if ($hsv[$key] > 1)
+                        $hsv[$key]--;
+                } else {
+                    $hsv[$key] = ($color2Hsv[$key] - $color1Hsv[$key]) * $part + $color1Hsv[$key];
+                }
+            } else {
+                $outLength = 1 - $color1Hsv[$key] + $color2Hsv[$key];
+                if ($key == 'h' && $outLength < 0.5) {
+                    $hsv[$key] = $color1Hsv[$key] + $outLength * $part;
+                    if ($hsv[$key] > 1)
+                        $hsv[$key]--;
+                } else {
+                    $hsv[$key] = ($color1Hsv[$key] - $color2Hsv[$key]) * $part + $color2Hsv[$key];
+                }
+            }
+        }
+        $color->setHsv($hsv);
+
+        return $color;
+    }
+}
diff --git a/README.md b/README.md
index e9f4433..78e7ddb 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,17 @@
-color-interpolator
-==================
+# Color Interpolator
 
-Interpolate color in the spectral band
+Interpolate color in the spectral band.
+
+## Usage
+
+```php
+use Intaro\ColorInterpolator\Color;
+use Intaro\ColorInterpolator\ColorInterpolator;
+
+// start rgb color
+$startColor = new Color('5fb8df');
+// ending rgb color
+$endingColor = new Color('3b9bcf');
+
+$color = ColorInterpolator::interpolate($startColor, $endingColor);
+```
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..f24eb9f
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,19 @@
+{
+    "name": "intaro/color-interpolator",
+    "description": "Interpolate color in the spectral band",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Intaro Soft",
+            "email": "mail@intaro.ru"
+        }
+    ],
+    "require": {
+        "php": ">=5.4.4"
+    },
+    "autoload": {
+        "psr-0": {
+            "Intaro\\": ""
+        }
+    }
+}