/**
* Standard modular run function for snippet hooks. Generates XHTML to insert into a page using AJAX.
*
* @return tempcode The snippet
*/
function run()
{
$theme = get_param('theme');
$equation = get_param('css_equation');
require_code('themewizard');
$css_path = get_custom_file_base() . '/themes/' . $theme . '/css_custom/global.css';
if (!file_exists($css_path)) {
$css_path = get_file_base() . '/themes/default/css/global.css';
}
$css_file_contents = file_get_contents($css_path, FILE_TEXT);
$seed = find_theme_seed($theme);
$dark = strpos($css_file_contents, '#000000; /* {$,wizard, 100% W/B} */') !== false;
$colours = calculate_theme($seed, $theme, 'equations', 'colours', $dark);
$parsed_equation = parse_css_colour_expression($equation);
if (is_null($parsed_equation)) {
return make_string_tempcode('');
}
$answer = execute_css_colour_expression($parsed_equation, $colours[0]);
if (is_null($answer)) {
return make_string_tempcode('');
}
return make_string_tempcode('#' . $answer);
}
/**
* Execute CSS colour expression.
*
* @param mixed Expression tree (array) OR leaf (string).
* @param array Known colours at this point.
* @return ?string RRGGBB colour or possibly just a number (NULL: answer cannot be computed).
*/
function execute_css_colour_expression($expression, $colours)
{
if (!is_array($expression)) {
if (preg_match('#^[0-9A-Fa-f]{6}$#', $expression) != 0) {
return $expression;
}
if (preg_match('#^\\#[0-9A-Fa-f]{6}$#', $expression) != 0) {
return substr($expression, 1);
}
if (preg_match('#^\\d+$#', $expression) != 0) {
return $expression;
}
foreach ($colours as $colour => $actual_colour) {
if ($colour == $expression) {
return $actual_colour;
}
}
return NULL;
// Couldn't find it - we'll have to instruct it to come back to it
}
$operation = $expression[0];
$operand_a = execute_css_colour_expression($expression[1], $colours);
if (is_null($operand_a)) {
return NULL;
}
/*if (($operation=='+') && ($expression[2][0]=='*') && (!is_array($expression[2][1])) && ((($expression[2][2]=='!W/B') && ($colours['L/D']=='light')) || (($expression[2][2]=='W/B') && ($colours['L/D']=='dark'))))
{
$operation='-';
$expression[2][2]='FFFFFF';
} else
{
// if (($operation=='-') && ($expression[2][0]=='*') && (!is_array($expression[2][1])) && ((($expression[2][2]=='W/B') && ($colours['L/D']=='light')) || (($expression[2][2]=='!W/B') && ($colours['L/D']=='dark'))))
// $operation='+';
}*/
$operand_b = execute_css_colour_expression($expression[2], $colours);
if (is_null($operand_b)) {
return NULL;
}
if ($operation[0] == '&') {
$operand_c = str_replace('%', '', substr($operation, 1));
$operation = '&';
}
switch ($operation) {
/* These are percentage modifiers */
case 'sat_to':
list($h, $s, $v) = rgb_to_hsv($operand_a);
$result = $s == 0 ? hsv_to_rgb(floatval($h), floatval($s), floatval(fix_colour(255 * intval($operand_b) / 100.0))) : hsv_to_rgb(floatval($h), floatval(fix_colour(255 * intval($operand_b) / 100.0)), floatval($v));
break;
case 'sat_add':
list($h, $s, $v) = rgb_to_hsv($operand_a);
$result = hsv_to_rgb(floatval($h), floatval(fix_colour($s + intval($operand_b))), floatval($v));
break;
case 'sat':
list($h, $s, $v) = rgb_to_hsv($operand_a);
$result = hsv_to_rgb(floatval($h), floatval(fix_colour($s * intval($operand_b) / 100.0)), floatval($v));
break;
case 'val_to':
list($h, $s, $v) = rgb_to_hsv($operand_a);
$result = hsv_to_rgb(floatval($h), floatval($s), floatval(fix_colour(255 * intval($operand_b) / 100.0)));
break;
case 'val_add':
list($h, $s, $v) = rgb_to_hsv($operand_a);
$result = hsv_to_rgb(floatval($h), floatval($s), floatval(fix_colour($v + intval($operand_b))));
break;
case 'val':
list($h, $s, $v) = rgb_to_hsv($operand_a);
$result = hsv_to_rgb(floatval($h), floatval($s), floatval(fix_colour($v * intval($operand_b) / 100.0)));
break;
case 'hue_to':
list($h, $s, $v) = rgb_to_hsv($operand_a);
$result = hsv_to_rgb(floatval(fix_colour(255 * intval($operand_b) / 100.0, true)), floatval($s), floatval($v));
break;
case 'hue_add':
list($h, $s, $v) = rgb_to_hsv($operand_a);
$result = hsv_to_rgb(floatval(fix_colour($h + intval($operand_b), true)), floatval($s), floatval($v));
break;
case 'hue':
list($h, $s, $v) = rgb_to_hsv($operand_a);
$result = hsv_to_rgb(floatval(fix_colour($h * intval($operand_b) / 100.0, true) % 255), floatval($s), floatval($v));
break;
case '&':
$red = hexdec(substr($operand_a, 0, 2));
$green = hexdec(substr($operand_a, 2, 2));
$blue = hexdec(substr($operand_a, 4, 2));
$fraction = 1.0 - $operand_c / 100.0;
$red_b = hexdec(substr($operand_b, 0, 2));
$green_b = hexdec(substr($operand_b, 2, 2));
$blue_b = hexdec(substr($operand_b, 4, 2));
$red = intval($fraction * $red + (1 - $fraction) * $red_b);
$green = intval($fraction * $green + (1 - $fraction) * $green_b);
$blue = intval($fraction * $blue + (1 - $fraction) * $blue_b);
$result = str_pad(dechex(fix_colour($red)), 2, '0', STR_PAD_LEFT) . str_pad(dechex(fix_colour($green)), 2, '0', STR_PAD_LEFT) . str_pad(dechex(fix_colour($blue)), 2, '0', STR_PAD_LEFT);
break;
case '*':
$red = intval(round(floatval(hexdec(substr($operand_b, 0, 2)) * intval($operand_a)) / 100.0));
$green = intval(round(floatval(hexdec(substr($operand_b, 2, 2)) * intval($operand_a)) / 100.0));
$blue = intval(round(floatval(hexdec(substr($operand_b, 4, 2)) * intval($operand_a)) / 100.0));
/*if ((($expression[2]==='W/B') && ($colours['L/D']=='dark')) || (($expression[2]==='!W/B') && ($colours['L/D']=='light')))
{
$red=255-$red;
$green=255-$green;
$blue=255-$blue;
}*/
$result = str_pad(dechex($red), 2, '0', STR_PAD_LEFT) . str_pad(dechex($green), 2, '0', STR_PAD_LEFT) . str_pad(dechex($blue), 2, '0', STR_PAD_LEFT);
break;
/* These are communicative combinators */
/* These are communicative combinators */
case '+':
$red = fix_colour(hexdec(substr($operand_a, 0, 2)) + hexdec(substr($operand_b, 0, 2)));
$green = fix_colour(hexdec(substr($operand_a, 2, 2)) + hexdec(substr($operand_b, 2, 2)));
$blue = fix_colour(hexdec(substr($operand_a, 4, 2)) + hexdec(substr($operand_b, 4, 2)));
$result = str_pad(dechex($red), 2, '0', STR_PAD_LEFT) . str_pad(dechex($green), 2, '0', STR_PAD_LEFT) . str_pad(dechex($blue), 2, '0', STR_PAD_LEFT);
break;
case '-':
$red = fix_colour(hexdec(substr($operand_a, 0, 2)) - hexdec(substr($operand_b, 0, 2)));
$green = fix_colour(hexdec(substr($operand_a, 2, 2)) - hexdec(substr($operand_b, 2, 2)));
$blue = fix_colour(hexdec(substr($operand_a, 4, 2)) - hexdec(substr($operand_b, 4, 2)));
$result = str_pad(dechex($red), 2, '0', STR_PAD_LEFT) . str_pad(dechex($green), 2, '0', STR_PAD_LEFT) . str_pad(dechex($blue), 2, '0', STR_PAD_LEFT);
break;
/* These are miscellaneous */
/* These are miscellaneous */
case 'shift':
if (intval($operand_b) == 1) {
$result = substr($operand_a, 4) . substr($operand_a, 0, 4);
} else {
$result = substr($operand_a, 2) . substr($operand_a, 0, 2);
}
break;
}
return $result;
}
