add php color library csscolor.php
add php color library csscolor.php

file:b/lib/csscolor.php (new)
--- /dev/null
+++ b/lib/csscolor.php
@@ -1,1 +1,423 @@
-
+<?php
+/*
+ csscolor.php
+ Copyright 2004 Patrick Fitzgerald
+ http://www.barelyfitz.com/projects/csscolor/
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+
+define('CSS_COLOR_ERROR', 100);
+
+class CSS_Color 
+{
+  //==================================================
+  //==PARAMETERS======================================
+  //==================================================
+
+  // $this->bg = array of CSS color values
+  // $this->bg[0] is the bg color
+  // $this->bg['+1'..'+5'] are lighter colors
+  // $this->bg['-1'..'-5'] are darker colors
+  var $bg = array();
+
+  // $this->fg = array of foreground colors.
+  // Each color corresponds to a background color.
+  var $fg = array();
+
+  // brightDiff is the minimum brightness difference
+  // between the background and the foreground.
+  // Note: you should not change this directly,
+  // instead use setBrightDiff() and getBrightDiff()
+  var $minBrightDiff = 126;
+  
+  // colorDiff is the minimum color difference
+  // between the background and the foreground.
+  // Note: you should not change this directly,
+  // instead use setColorDiff() and getColorDiff()
+  var $minColorDiff = 500;
+
+  //==================================================
+  //==CONSTRUCTOR=====================================
+  //==================================================
+
+  function CSS_Color($bgHex, $fgHex='')
+  {
+    // This is the constructor method for the class,
+    // which is called when a new object is created.
+
+
+    // Initialize the palette
+    $this->setPalette($bgHex, $fgHex);
+  }
+
+  //==================================================
+  //==METHODS=========================================
+  //==================================================
+
+  //--------------------------------------------------
+  function setPalette($bgHex, $fgHex = '')
+  {
+    // Initialize the color palettes
+
+    // If a foreground color was not specified,
+    // just use the background color.
+    if (!$fgHex) {
+      $fgHex = $bgHex;
+    }
+
+    // Clear the existing palette
+    $this->bg = array();
+    $this->fg = array();
+
+    // Make sure we got a valid hex value
+    if (!$this->isHex($bgHex)) {
+      $this->raiseError("background color '$bgHex' is not a hex color value",
+			__FUNCTION__, __LINE__);
+      return false;
+    }
+
+    // Set the bg color
+    $this->bg[0] = $bgHex;
+
+    $this->bg['+1'] = $this->lighten($bgHex, .85);
+    $this->bg['+2'] = $this->lighten($bgHex, .75);
+    $this->bg['+3'] = $this->lighten($bgHex, .5);
+    $this->bg['+4'] = $this->lighten($bgHex, .25);
+    $this->bg['+5'] = $this->lighten($bgHex, .1);
+
+    $this->bg['-1'] = $this->darken($bgHex, .85);
+    $this->bg['-2'] = $this->darken($bgHex, .75);
+    $this->bg['-3'] = $this->darken($bgHex, .5);
+    $this->bg['-4'] = $this->darken($bgHex, .25);
+    $this->bg['-5'] = $this->darken($bgHex, .1);
+
+    // Make sure we got a valid hex value
+    if (!$this->isHex($fgHex)) {
+      $this->raiseError("background color '$bgHex' is not a hex color value",
+			__FUNCTION__, __LINE__);
+      return false;
+    }
+
+    // Set up the foreground colors
+    $this->fg[0]    = $this->calcFG( $this->bg[0], $fgHex);
+    $this->fg['+1'] = $this->calcFG( $this->bg['+1'], $fgHex);
+    $this->fg['+2'] = $this->calcFG( $this->bg['+2'], $fgHex);
+    $this->fg['+3'] = $this->calcFG( $this->bg['+3'], $fgHex);
+    $this->fg['+4'] = $this->calcFG( $this->bg['+4'], $fgHex);
+    $this->fg['+5'] = $this->calcFG( $this->bg['+5'], $fgHex);
+    $this->fg['-1'] = $this->calcFG( $this->bg['-1'], $fgHex);
+    $this->fg['-2'] = $this->calcFG( $this->bg['-2'], $fgHex);
+    $this->fg['-3'] = $this->calcFG( $this->bg['-3'], $fgHex);
+    $this->fg['-4'] = $this->calcFG( $this->bg['-4'], $fgHex);
+    $this->fg['-5'] = $this->calcFG( $this->bg['-5'], $fgHex);
+  }
+
+  //--------------------------------------------------
+  function lighten($hex, $percent)
+  {
+    return $this->mix($hex, $percent, 255);
+  }
+
+  //--------------------------------------------------
+  function darken($hex, $percent)
+  {
+    return $this->mix($hex, $percent, 0);
+  }
+
+  //--------------------------------------------------
+  function mix($hex, $percent, $mask)
+  {
+
+    // Make sure inputs are valid
+    if (!is_numeric($percent) || $percent < 0 || $percent > 1) {
+      $this->raiseError("percent=$percent is not valid",
+			__FUNCTION__, __LINE__);
+      return false;
+    }
+
+    if (!is_int($mask) || $mask < 0 || $mask > 255) {
+      $this->raiseError("mask=$mask is not valid",
+			__FUNCTION__, __LINE__);
+      return false;
+    }
+
+    $rgb = $this->hex2RGB($hex);
+    if (!is_array($rgb)) {
+      // hex2RGB will raise an error
+      return false;
+    }
+
+    for ($i=0; $i<3; $i++) {
+      $rgb[$i] = round($rgb[$i] * $percent) + round($mask * (1-$percent));
+
+      // In case rounding up causes us to go to 256
+      if ($rgb[$i] > 255) {
+	$rgb[$i] = 255;
+      }
+
+    }
+    return $this->RGB2Hex($rgb);
+  }
+
+  //--------------------------------------------------
+  function hex2RGB($hex)
+  {
+    //
+    // Given a hex color (rrggbb or rgb),
+    // returns an array (r, g, b) with decimal values
+    // If $hex is not the correct format,
+    // returns false.
+    //
+    // example:
+    // $d = hex2RGB('#abc');
+    // if (!$d) { error }
+
+    // Regexp for a valid hex digit
+    $d = '[a-fA-F0-9]';
+    
+    // Make sure $hex is valid
+    if (preg_match("/^($d$d)($d$d)($d$d)\$/", $hex, $rgb)) {
+      
+      return array(
+		   hexdec($rgb[1]),
+		   hexdec($rgb[2]),
+		   hexdec($rgb[3])
+		   );
+    }
+    if (preg_match("/^($d)($d)($d)$/", $hex, $rgb)) {
+      
+      return array(
+		   hexdec($rgb[1] . $rgb[1]),
+		   hexdec($rgb[2] . $rgb[2]),
+		   hexdec($rgb[3] . $rgb[3])
+		   );
+    }
+
+    $this->raiseError("cannot convert hex '$hex' to RGB", __FUNCTION__, __LINE__);
+    return false;
+  }
+
+  //--------------------------------------------------
+  function RGB2Hex($rgb)
+  {
+    // Given an array(rval,gval,bval) consisting of
+    // decimal color values (0-255), returns a hex string
+    // suitable for use with CSS.
+    // Returns false if the input is not in the correct format.
+    // Example:
+    // $h = RGB2Hex(array(255,0,255));
+    // if (!$h) { error };
+
+    // Make sure the input is valid
+    if(!$this->isRGB($rgb)) {
+      $this->raiseError("RGB value is not valid", __FUNCTION__, __LINE__);
+      return false;
+    }
+
+    $hex = "";
+    for($i=0; $i < 3; $i++) {
+
+      // Convert the decimal digit to hex
+      $hexDigit = dechex($rgb[$i]);
+
+      // Add a leading zero if necessary
+      if(strlen($hexDigit) == 1) {
+	$hexDigit = "0" . $hexDigit;
+      }
+
+      // Append to the hex string
+      $hex .= $hexDigit;
+    }
+
+    // Return the complete hex string
+    return $hex;
+  }
+
+  //--------------------------------------------------
+  function isHex($hex)
+  {
+    // Returns true if $hex is a valid CSS hex color.
+    // The "#" character at the start is optional.
+
+    // Regexp for a valid hex digit
+    $d = '[a-fA-F0-9]';
+    
+    // Make sure $hex is valid
+    if (preg_match("/^#?$d$d$d$d$d$d\$/", $hex) ||
+	preg_match("/^#?$d$d$d\$/", $hex)) {
+      return true;
+    }
+    return false;
+  }
+
+  //--------------------------------------------------
+  function isRGB($rgb)
+  {
+    // Returns true if $rgb is an array with three valid
+    // decimal color digits.
+
+    if (!is_array($rgb) || count($rgb) != 3) {
+      return false;
+    }
+
+    for($i=0; $i < 3; $i++) {
+
+      // Get the decimal digit
+      $dec = intval($rgb[$i]);
+
+      // Make sure the decimal digit is between 0 and 255
+      if (!is_int($dec) || $dec < 0 || $dec > 255) {
+	return false;
+      }
+    }
+
+    return true;
+  }
+
+  //--------------------------------------------------
+  function calcFG($bgHex, $fgHex)
+  {
+    // Given a background color $bgHex and a foreground color $fgHex,
+    // modifies the foreground color so it will have enough contrast
+    // to be seen against the background color.
+    //
+    // The following parameters are used:
+    // $this->minBrightDiff
+    // $this->minColorDiff
+
+    // Loop through brighter and darker versions
+    // of the foreground color.
+    // The numbers here represent the amount of
+    // foreground color to mix with black and white.
+    foreach (array(1, 0.75, 0.5, 0.25, 0) as $percent) {
+
+      $darker = $this->darken($fgHex, $percent);
+      $lighter = $this->lighten($fgHex, $percent);
+
+      $darkerBrightDiff  = $this->brightnessDiff($bgHex, $darker);
+      $lighterBrightDiff = $this->brightnessDiff($bgHex, $lighter);
+
+      if ($lighterBrightDiff > $darkerBrightDiff) {
+	$newFG = $lighter;
+	$newFGBrightDiff = $lighterBrightDiff;
+      } else {
+	$newFG = $darker;
+	$newFGBrightDiff = $darkerBrightDiff;
+      }
+      $newFGColorDiff = $this->colorDiff($bgHex, $newFG);
+
+      if ($newFGBrightDiff >= $this->minBrightDiff &&
+	  $newFGColorDiff >= $this->minColorDiff) {
+	break;
+      }
+    }
+
+    return $newFG;
+  }
+
+  //--------------------------------------------------
+  function getMinBrightDiff()
+  {
+    return $this->minBrightDiff;
+  }
+  function setMinBrightDiff($b, $resetPalette = true)
+  {
+    $this->minBrightDiff = $b;
+    if ($resetPalette) {
+      $this->setPalette($this->bg[0],$this->fg[0]);
+    }
+  }
+
+  //--------------------------------------------------
+  function getMinColorDiff()
+  {
+    return $this->minColorDiff;
+  }
+  function setMinColorDiff($d, $resetPalette = true)
+  {
+    $this->minColorDiff = $d;
+    if ($resetPalette) {
+      $this->setPalette($this->bg[0],$this->fg[0]);
+    }
+  }
+
+  //--------------------------------------------------
+  function brightness($hex)
+  {
+    // Returns the brightness value for a color,
+    // a number between zero and 178.
+    // To allow for maximum readability, the difference between
+    // the background brightness and the foreground brightness
+    // should be greater than 125.
+
+    $rgb = $this->hex2RGB($hex);
+    if (!is_array($rgb)) {
+      // hex2RGB will raise an error
+      return false;
+    }
+
+    return( (($rgb[0] * 299) + ($rgb[1] * 587) + ($rgb[2] * 114)) / 1000 );
+  }
+
+  //--------------------------------------------------
+  function brightnessDiff($hex1, $hex2)
+  {
+    // Returns the brightness value for a color,
+    // a number between zero and 178.
+    // To allow for maximum readability, the difference between
+    // the background brightness and the foreground brightness
+    // should be greater than 125.
+
+    $b1 = $this->brightness($hex1);
+    $b2 = $this->brightness($hex2);
+    if (is_bool($b1) || is_bool($b2)) {
+      return false;
+    }
+    return abs($b1 - $b2);
+  }
+
+  //--------------------------------------------------
+  function colorDiff($hex1, $hex2)
+  {
+    // Returns the contrast between two colors,
+    // an integer between 0 and 675.
+    // To allow for maximum readability, the difference between
+    // the background and the foreground color should be > 500.
+
+    $rgb1 = $this->hex2RGB($hex1);
+    $rgb2 = $this->hex2RGB($hex2);
+
+    if (!is_array($rgb1) || !is_array($rgb2)) {
+      // hex2RGB will raise an error
+      return -1;
+    }
+
+    $r1 = $rgb1[0];
+    $g1 = $rgb1[1];
+    $b1 = $rgb1[2];
+
+    $r2 = $rgb2[0];
+    $g2 = $rgb2[1];
+    $b2 = $rgb2[2];
+
+    return(abs($r1-$r2) + abs($g1-$g2) + abs($b1-$b2));
+  }
+
+}
+
+?>
+

--- /dev/null
+++ b/lib/csscolor.test.php
@@ -1,1 +1,37 @@
+<?php
 
+// Tell the browser that this is CSS instead of HTML
+header("Content-type: text/css");
+
+// Get the color generating code
+include_once("csscolor.php");
+
+// Set the error handing for csscolor.
+// If an error occurs, print the error
+// within a CSS comment so we can see
+// it in the CSS file.
+
+
+// Define a couple color palettes
+$base = new CSS_Color('C9E3A6');
+$highlight = new CSS_Color('746B8E');
+
+// Trigger an error just to see what happens
+// $trigger = new CSS_Color('');
+
+?>
+
+
+.box {
+
+  /* Use the base color, two shades darker */
+  background:#<?php echo $base->bg['-2'] ?>;
+
+  /* Use the corresponding foreground color */
+  color:#<?php echo $base->fg['-2'] ?>;
+
+  /* Use the highlight color as a border */
+  border:5px solid #<?php echo $highlight->bg['0'] ?>
+
+}
+