/kalium/inc/lib/colors.inc.php

<?php

/**

 * This class can be used to get the most common colors in an image.

 * It needs one parameter:

 * 	$image - the filename of the image you want to process.

 * Optional parameters:

 *

 *	$count - how many colors should be returned. 0 mmeans all. default=20

 *	$reduce_brightness - reduce (not eliminate) brightness variants? default=true

 *	$reduce_gradients - reduce (not eliminate) gradient variants? default=true

 *	$delta - the amount of gap when quantizing color values.

 *		Lower values mean more accurate colors. default=16

 *

 * Author: 	Csongor Zalatnai

 *

 * Modified By: Kepler Gelotte - Added the gradient and brightness variation

 * 	reduction routines. Kudos to Csongor for an excellent class. The original

 * 	version can be found at:

 *

 *	http://www.phpclasses.org/browse/package/3370.html

 *

 */

if ( ! defined( 'ABSPATH' ) ) {

	exit; // Direct access not allowed.

}



class GetMostCommonColors

{

	var $PREVIEW_WIDTH    = 150;

	var $PREVIEW_HEIGHT   = 150;



	var $error;



	/**

	 * Returns the colors of the image in an array, ordered in descending order, where the keys are the colors, and the values are the count of the color.

	 *

	 * @return array

	 */

	function Get_Color( $img, $count=20, $reduce_brightness=true, $reduce_gradients=true, $delta=16 )

	{

		if (is_readable( $img ))

		{

			if ( $delta > 2 )

			{

				$half_delta = $delta / 2 - 1;

			}

			else

			{

				$half_delta = 0;

			}

			// WE HAVE TO RESIZE THE IMAGE, BECAUSE WE ONLY NEED THE MOST SIGNIFICANT COLORS.

			$size = GetImageSize($img);

			$scale = 1;

			if ($size[0]>0)

			$scale = min($this->PREVIEW_WIDTH/$size[0], $this->PREVIEW_HEIGHT/$size[1]);

			if ($scale < 1)

			{

				$width = floor($scale*$size[0]);

				$height = floor($scale*$size[1]);

			}

			else

			{

				$width = $size[0];

				$height = $size[1];

			}

			$image_resized = imagecreatetruecolor($width, $height);

			if ($size[2] == 1)

			$image_orig = imagecreatefromgif($img);

			if ($size[2] == 2)

			$image_orig = imagecreatefromjpeg($img);

			if ($size[2] == 3)

			$image_orig = imagecreatefrompng($img);

			// WE NEED NEAREST NEIGHBOR RESIZING, BECAUSE IT DOESN'T ALTER THE COLORS

			imagecopyresampled($image_resized, $image_orig, 0, 0, 0, 0, $width, $height, $size[0], $size[1]);

			$im = $image_resized;

			$imgWidth = imagesx($im);

			$imgHeight = imagesy($im);

			$total_pixel_count = 0;

			for ($y=0; $y < $imgHeight; $y++)

			{

				for ($x=0; $x < $imgWidth; $x++)

				{

					$total_pixel_count++;

					$index = imagecolorat($im,$x,$y);

					$colors = imagecolorsforindex($im,$index);

					// ROUND THE COLORS, TO REDUCE THE NUMBER OF DUPLICATE COLORS

					if ( $delta > 1 )

					{

						$colors['red'] = intval((($colors['red'])+$half_delta)/$delta)*$delta;

						$colors['green'] = intval((($colors['green'])+$half_delta)/$delta)*$delta;

						$colors['blue'] = intval((($colors['blue'])+$half_delta)/$delta)*$delta;

						if ($colors['red'] >= 256)

						{

							$colors['red'] = 255;

						}

						if ($colors['green'] >= 256)

						{

							$colors['green'] = 255;

						}

						if ($colors['blue'] >= 256)

						{

							$colors['blue'] = 255;

						}



					}



					$hex = substr("0".dechex($colors['red']),-2).substr("0".dechex($colors['green']),-2).substr("0".dechex($colors['blue']),-2);



					if ( ! isset( $hexarray[$hex] ) )

					{

						$hexarray[$hex] = 1;

					}

					else

					{

						$hexarray[$hex]++;

					}

				}

			}



			// Reduce gradient colors

			if ( $reduce_gradients )

			{

				// if you want to *eliminate* gradient variations use:

				// ksort( $hexarray );

				arsort( $hexarray, SORT_NUMERIC );



				$gradients = array();

				foreach ($hexarray as $hex => $num)

				{

					if ( ! isset($gradients[$hex]) )

					{

						$new_hex = $this->_find_adjacent( $hex, $gradients, $delta );

						$gradients[$hex] = $new_hex;

					}

					else

					{

						$new_hex = $gradients[$hex];

					}



					if ($hex != $new_hex)

					{

						$hexarray[$hex] = 0;

						$hexarray[$new_hex] += $num;

					}

				}

			}



			// Reduce brightness variations

			if ( $reduce_brightness )

			{

				// if you want to *eliminate* brightness variations use:

				// ksort( $hexarray );

				arsort( $hexarray, SORT_NUMERIC );



				$brightness = array();

				foreach ($hexarray as $hex => $num)

				{

					if ( ! isset($brightness[$hex]) )

					{

						$new_hex = $this->_normalize( $hex, $brightness, $delta );

						$brightness[$hex] = $new_hex;

					}

					else

					{

						$new_hex = $brightness[$hex];

					}



					if ($hex != $new_hex)

					{

						$hexarray[$hex] = 0;

						$hexarray[$new_hex] += $num;

					}

				}

			}



			arsort( $hexarray, SORT_NUMERIC );



			// convert counts to percentages

			foreach ($hexarray as $key => $value)

			{

				$hexarray[$key] = (float)$value / $total_pixel_count;

			}



			if ( $count > 0 )

			{

				// only works in PHP5

				// return array_slice( $hexarray, 0, $count, true );



				$arr = array();

				foreach ($hexarray as $key => $value)

				{

					if ($count == 0)

					{

						break;

					}

					$count--;

					$arr[$key] = $value;

				}

				return $arr;

			}

			else

			{

				return $hexarray;

			}



		}

		else

		{

			$this->error = "Image ".$img." does not exist or is unreadable";

			return false;

		}

	}



	function _normalize( $hex, $hexarray, $delta )

	{

		$lowest = 255;

		$highest = 0;

		$colors['red'] = hexdec( substr( $hex, 0, 2 ) );

		$colors['green']  = hexdec( substr( $hex, 2, 2 ) );

		$colors['blue'] = hexdec( substr( $hex, 4, 2 ) );



		if ($colors['red'] < $lowest)

		{

			$lowest = $colors['red'];

		}

		if ($colors['green'] < $lowest )

		{

			$lowest = $colors['green'];

		}

		if ($colors['blue'] < $lowest )

		{

			$lowest = $colors['blue'];

		}



		if ($colors['red'] > $highest)

		{

			$highest = $colors['red'];

		}

		if ($colors['green'] > $highest )

		{

			$highest = $colors['green'];

		}

		if ($colors['blue'] > $highest )

		{

			$highest = $colors['blue'];

		}



		// Do not normalize white, black, or shades of grey unless low delta

		if ( $lowest == $highest )

		{

			if ($delta <= 32)

			{

				if ( $lowest == 0 || $highest >= (255 - $delta) )

				{

					return $hex;

				}

			}

			else

			{

				return $hex;

			}

		}



		for (; $highest < 256; $lowest += $delta, $highest += $delta)

		{

			$new_hex = substr("0".dechex($colors['red'] - $lowest),-2).substr("0".dechex($colors['green'] - $lowest),-2).substr("0".dechex($colors['blue'] - $lowest),-2);



			if ( isset( $hexarray[$new_hex] ) )

			{

				// same color, different brightness - use it instead

				return $new_hex;

			}

		}



		return $hex;

	}



	function _find_adjacent( $hex, $gradients, $delta )

	{

		$red = hexdec( substr( $hex, 0, 2 ) );

		$green  = hexdec( substr( $hex, 2, 2 ) );

		$blue = hexdec( substr( $hex, 4, 2 ) );



		if ($red > $delta)

		{

			$new_hex = substr("0".dechex($red - $delta),-2).substr("0".dechex($green),-2).substr("0".dechex($blue),-2);

			if ( isset($gradients[$new_hex]) )

			{

				return $gradients[$new_hex];

			}

		}

		if ($green > $delta)

		{

			$new_hex = substr("0".dechex($red),-2).substr("0".dechex($green - $delta),-2).substr("0".dechex($blue),-2);

			if ( isset($gradients[$new_hex]) )

			{

				return $gradients[$new_hex];

			}

		}

		if ($blue > $delta)

		{

			$new_hex = substr("0".dechex($red),-2).substr("0".dechex($green),-2).substr("0".dechex($blue - $delta),-2);

			if ( isset($gradients[$new_hex]) )

			{

				return $gradients[$new_hex];

			}

		}



		if ($red < (255 - $delta))

		{

			$new_hex = substr("0".dechex($red + $delta),-2).substr("0".dechex($green),-2).substr("0".dechex($blue),-2);

			if ( isset($gradients[$new_hex]) )

			{

				return $gradients[$new_hex];

			}

		}

		if ($green < (255 - $delta))

		{

			$new_hex = substr("0".dechex($red),-2).substr("0".dechex($green + $delta),-2).substr("0".dechex($blue),-2);

			if ( isset($gradients[$new_hex]) )

			{

				return $gradients[$new_hex];

			}

		}

		if ($blue < (255 - $delta))

		{

			$new_hex = substr("0".dechex($red),-2).substr("0".dechex($green),-2).substr("0".dechex($blue + $delta),-2);

			if ( isset($gradients[$new_hex]) )

			{

				return $gradients[$new_hex];

			}

		}



		return $hex;

	}

}