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<?php |
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/* |
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csscolor.php |
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Copyright 2004 Patrick Fitzgerald |
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http://www.barelyfitz.com/projects/csscolor/ |
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This program is free software; you can redistribute it and/or modify |
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it under the terms of the GNU General Public License as published by |
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the Free Software Foundation; either version 2 of the License, or |
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(at your option) any later version. |
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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*/ |
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define('CSS_COLOR_ERROR', 100); |
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class CSS_Color |
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{ |
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//================================================== |
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//==PARAMETERS====================================== |
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//================================================== |
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// $this->bg = array of CSS color values |
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// $this->bg[0] is the bg color |
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// $this->bg['+1'..'+5'] are lighter colors |
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// $this->bg['-1'..'-5'] are darker colors |
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var $bg = array(); |
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// $this->fg = array of foreground colors. |
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// Each color corresponds to a background color. |
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var $fg = array(); |
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// brightDiff is the minimum brightness difference |
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// between the background and the foreground. |
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// Note: you should not change this directly, |
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// instead use setBrightDiff() and getBrightDiff() |
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var $minBrightDiff = 126; |
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// colorDiff is the minimum color difference |
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// between the background and the foreground. |
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// Note: you should not change this directly, |
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// instead use setColorDiff() and getColorDiff() |
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var $minColorDiff = 500; |
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//================================================== |
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//==CONSTRUCTOR===================================== |
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//================================================== |
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function CSS_Color($bgHex, $fgHex='') |
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{ |
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// This is the constructor method for the class, |
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// which is called when a new object is created. |
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// Initialize the palette |
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$this->setPalette($bgHex, $fgHex); |
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} |
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//================================================== |
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//==METHODS========================================= |
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//================================================== |
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//-------------------------------------------------- |
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function setPalette($bgHex, $fgHex = '') |
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{ |
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// Initialize the color palettes |
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// If a foreground color was not specified, |
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// just use the background color. |
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if (!$fgHex) { |
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$fgHex = $bgHex; |
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} |
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// Clear the existing palette |
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$this->bg = array(); |
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$this->fg = array(); |
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// Make sure we got a valid hex value |
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if (!$this->isHex($bgHex)) { |
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$this->raiseError("background color '$bgHex' is not a hex color value", |
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__FUNCTION__, __LINE__); |
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return false; |
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} |
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// Set the bg color |
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$this->bg[0] = $bgHex; |
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$this->bg['+1'] = $this->lighten($bgHex, .85); |
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$this->bg['+2'] = $this->lighten($bgHex, .75); |
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$this->bg['+3'] = $this->lighten($bgHex, .5); |
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$this->bg['+4'] = $this->lighten($bgHex, .25); |
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$this->bg['+5'] = $this->lighten($bgHex, .1); |
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$this->bg['-1'] = $this->darken($bgHex, .85); |
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$this->bg['-2'] = $this->darken($bgHex, .75); |
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$this->bg['-3'] = $this->darken($bgHex, .5); |
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$this->bg['-4'] = $this->darken($bgHex, .25); |
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$this->bg['-5'] = $this->darken($bgHex, .1); |
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// Make sure we got a valid hex value |
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if (!$this->isHex($fgHex)) { |
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$this->raiseError("background color '$bgHex' is not a hex color value", |
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__FUNCTION__, __LINE__); |
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return false; |
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} |
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// Set up the foreground colors |
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$this->fg[0] = $this->calcFG( $this->bg[0], $fgHex); |
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$this->fg['+1'] = $this->calcFG( $this->bg['+1'], $fgHex); |
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$this->fg['+2'] = $this->calcFG( $this->bg['+2'], $fgHex); |
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$this->fg['+3'] = $this->calcFG( $this->bg['+3'], $fgHex); |
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$this->fg['+4'] = $this->calcFG( $this->bg['+4'], $fgHex); |
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$this->fg['+5'] = $this->calcFG( $this->bg['+5'], $fgHex); |
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$this->fg['-1'] = $this->calcFG( $this->bg['-1'], $fgHex); |
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$this->fg['-2'] = $this->calcFG( $this->bg['-2'], $fgHex); |
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$this->fg['-3'] = $this->calcFG( $this->bg['-3'], $fgHex); |
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$this->fg['-4'] = $this->calcFG( $this->bg['-4'], $fgHex); |
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$this->fg['-5'] = $this->calcFG( $this->bg['-5'], $fgHex); |
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} |
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//-------------------------------------------------- |
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function lighten($hex, $percent) |
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{ |
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return $this->mix($hex, $percent, 255); |
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} |
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//-------------------------------------------------- |
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function darken($hex, $percent) |
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{ |
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return $this->mix($hex, $percent, 0); |
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} |
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//-------------------------------------------------- |
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function mix($hex, $percent, $mask) |
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{ |
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// Make sure inputs are valid |
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if (!is_numeric($percent) || $percent < 0 || $percent > 1) { |
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$this->raiseError("percent=$percent is not valid", |
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__FUNCTION__, __LINE__); |
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return false; |
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} |
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if (!is_int($mask) || $mask < 0 || $mask > 255) { |
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$this->raiseError("mask=$mask is not valid", |
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__FUNCTION__, __LINE__); |
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return false; |
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} |
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$rgb = $this->hex2RGB($hex); |
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if (!is_array($rgb)) { |
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// hex2RGB will raise an error |
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return false; |
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} |
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for ($i=0; $i<3; $i++) { |
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$rgb[$i] = round($rgb[$i] * $percent) + round($mask * (1-$percent)); |
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// In case rounding up causes us to go to 256 |
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if ($rgb[$i] > 255) { |
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$rgb[$i] = 255; |
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} |
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} |
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return $this->RGB2Hex($rgb); |
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} |
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//-------------------------------------------------- |
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function hex2RGB($hex) |
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{ |
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// |
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// Given a hex color (rrggbb or rgb), |
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// returns an array (r, g, b) with decimal values |
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// If $hex is not the correct format, |
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// returns false. |
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// |
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// example: |
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// $d = hex2RGB('#abc'); |
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// if (!$d) { error } |
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// Regexp for a valid hex digit |
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$d = '[a-fA-F0-9]'; |
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// Make sure $hex is valid |
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if (preg_match("/^($d$d)($d$d)($d$d)\$/", $hex, $rgb)) { |
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return array( |
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hexdec($rgb[1]), |
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hexdec($rgb[2]), |
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hexdec($rgb[3]) |
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); |
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} |
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if (preg_match("/^($d)($d)($d)$/", $hex, $rgb)) { |
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return array( |
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hexdec($rgb[1] . $rgb[1]), |
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hexdec($rgb[2] . $rgb[2]), |
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hexdec($rgb[3] . $rgb[3]) |
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); |
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} |
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$this->raiseError("cannot convert hex '$hex' to RGB", __FUNCTION__, __LINE__); |
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return false; |
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} |
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//-------------------------------------------------- |
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function RGB2Hex($rgb) |
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{ |
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// Given an array(rval,gval,bval) consisting of |
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// decimal color values (0-255), returns a hex string |
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// suitable for use with CSS. |
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// Returns false if the input is not in the correct format. |
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// Example: |
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// $h = RGB2Hex(array(255,0,255)); |
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// if (!$h) { error }; |
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// Make sure the input is valid |
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if(!$this->isRGB($rgb)) { |
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$this->raiseError("RGB value is not valid", __FUNCTION__, __LINE__); |
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return false; |
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} |
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$hex = ""; |
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for($i=0; $i < 3; $i++) { |
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// Convert the decimal digit to hex |
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$hexDigit = dechex($rgb[$i]); |
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// Add a leading zero if necessary |
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if(strlen($hexDigit) == 1) { |
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$hexDigit = "0" . $hexDigit; |
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} |
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// Append to the hex string |
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$hex .= $hexDigit; |
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} |
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// Return the complete hex string |
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return $hex; |
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} |
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//-------------------------------------------------- |
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function isHex($hex) |
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{ |
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// Returns true if $hex is a valid CSS hex color. |
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// The "#" character at the start is optional. |
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// Regexp for a valid hex digit |
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$d = '[a-fA-F0-9]'; |
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// Make sure $hex is valid |
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if (preg_match("/^#?$d$d$d$d$d$d\$/", $hex) || |
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preg_match("/^#?$d$d$d\$/", $hex)) { |
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return true; |
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} |
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return false; |
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} |
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//-------------------------------------------------- |
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function isRGB($rgb) |
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{ |
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// Returns true if $rgb is an array with three valid |
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// decimal color digits. |
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if (!is_array($rgb) || count($rgb) != 3) { |
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return false; |
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} |
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for($i=0; $i < 3; $i++) { |
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// Get the decimal digit |
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$dec = intval($rgb[$i]); |
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// Make sure the decimal digit is between 0 and 255 |
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if (!is_int($dec) || $dec < 0 || $dec > 255) { |
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return false; |
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} |
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} |
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return true; |
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} |
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//-------------------------------------------------- |
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function calcFG($bgHex, $fgHex) |
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{ |
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// Given a background color $bgHex and a foreground color $fgHex, |
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// modifies the foreground color so it will have enough contrast |
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// to be seen against the background color. |
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// |
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// The following parameters are used: |
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// $this->minBrightDiff |
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// $this->minColorDiff |
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// Loop through brighter and darker versions |
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// of the foreground color. |
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// The numbers here represent the amount of |
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// foreground color to mix with black and white. |
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foreach (array(1, 0.75, 0.5, 0.25, 0) as $percent) { |
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$darker = $this->darken($fgHex, $percent); |
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$lighter = $this->lighten($fgHex, $percent); |
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$darkerBrightDiff = $this->brightnessDiff($bgHex, $darker); |
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$lighterBrightDiff = $this->brightnessDiff($bgHex, $lighter); |
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if ($lighterBrightDiff > $darkerBrightDiff) { |
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$newFG = $lighter; |
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$newFGBrightDiff = $lighterBrightDiff; |
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} else { |
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$newFG = $darker; |
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$newFGBrightDiff = $darkerBrightDiff; |
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} |
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$newFGColorDiff = $this->colorDiff($bgHex, $newFG); |
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if ($newFGBrightDiff >= $this->minBrightDiff && |
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$newFGColorDiff >= $this->minColorDiff) { |
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break; |
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} |
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} |
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return $newFG; |
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} |
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//-------------------------------------------------- |
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function getMinBrightDiff() |
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{ |
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return $this->minBrightDiff; |
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} |
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function setMinBrightDiff($b, $resetPalette = true) |
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{ |
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$this->minBrightDiff = $b; |
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if ($resetPalette) { |
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$this->setPalette($this->bg[0],$this->fg[0]); |
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} |
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} |
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//-------------------------------------------------- |
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function getMinColorDiff() |
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{ |
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return $this->minColorDiff; |
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} |
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function setMinColorDiff($d, $resetPalette = true) |
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{ |
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$this->minColorDiff = $d; |
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if ($resetPalette) { |
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$this->setPalette($this->bg[0],$this->fg[0]); |
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} |
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} |
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//-------------------------------------------------- |
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function brightness($hex) |
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{ |
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// Returns the brightness value for a color, |
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// a number between zero and 178. |
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// To allow for maximum readability, the difference between |
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// the background brightness and the foreground brightness |
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// should be greater than 125. |
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$rgb = $this->hex2RGB($hex); |
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if (!is_array($rgb)) { |
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// hex2RGB will raise an error |
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return false; |
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} |
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return( (($rgb[0] * 299) + ($rgb[1] * 587) + ($rgb[2] * 114)) / 1000 ); |
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} |
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//-------------------------------------------------- |
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function brightnessDiff($hex1, $hex2) |
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{ |
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// Returns the brightness value for a color, |
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// a number between zero and 178. |
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// To allow for maximum readability, the difference between |
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// the background brightness and the foreground brightness |
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// should be greater than 125. |
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$b1 = $this->brightness($hex1); |
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$b2 = $this->brightness($hex2); |
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if (is_bool($b1) || is_bool($b2)) { |
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return false; |
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} |
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return abs($b1 - $b2); |
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} |
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//-------------------------------------------------- |
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function colorDiff($hex1, $hex2) |
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{ |
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// Returns the contrast between two colors, |
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// an integer between 0 and 675. |
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// To allow for maximum readability, the difference between |
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// the background and the foreground color should be > 500. |
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$rgb1 = $this->hex2RGB($hex1); |
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$rgb2 = $this->hex2RGB($hex2); |
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if (!is_array($rgb1) || !is_array($rgb2)) { |
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// hex2RGB will raise an error |
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return -1; |
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} |
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$r1 = $rgb1[0]; |
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$g1 = $rgb1[1]; |
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$b1 = $rgb1[2]; |
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$r2 = $rgb2[0]; |
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$g2 = $rgb2[1]; |
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$b2 = $rgb2[2]; |
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return(abs($r1-$r2) + abs($g1-$g2) + abs($b1-$b2)); |
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} |
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} |
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?> |
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