/data/wpcom-themes/monotone/csscolor.php
PHP | 423 lines | 219 code | 74 blank | 130 comment | 36 complexity | 79206e908e4c9de04f62528afb3ff8c7 MD5 | raw file
- <?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 = 128;
-
- // 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 $minColorDiff = 100;
- //==================================================
- //==CONSTRUCTOR=====================================
- //==================================================
- function CSS_Color($bgHex, $fgHex='')
- {
- // This is the constructor method for the class,
- // which is called when a new object is created.
- // Initialize this PEAR object so I can
- // use the PEAR error return mechanism
- // 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($bgHex)) {
- error_log("background color '$bgHex' is not a hex color value");
- 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));
- }
- }
- ?>