public function contrast($color, $dark = null, $light = null, $threshold = null)
{
// filter: contrast(3.2);
// should be kept as is, so check for color
if (!$color instanceof Less_Tree_Color) {
return null;
}
if (!$light) {
$light = $this->rgba(255, 255, 255, 1.0);
}
if (!$dark) {
$dark = $this->rgba(0, 0, 0, 1.0);
}
if (!$dark instanceof Less_Tree_Color) {
$dark = new Less_Tree_Color(array(1, 1, 1));
//throw new Less_Exception_Compiler('The second argument to contrast must be a color' . ($dark instanceof Less_Tree_Expression ? ' (did you forgot commas?)' : '') );
}
if (!$light instanceof Less_Tree_Color) {
$light = new Less_Tree_Color(array(1, 1, 1));
//throw new Less_Exception_Compiler('The third argument to contrast must be a color' . ($light instanceof Less_Tree_Expression ? ' (did you forgot commas?)' : '') );
}
//Figure out which is actually light and dark!
if ($dark->luma() > $light->luma()) {
$t = $light;
$light = $dark;
$dark = $t;
}
if (!$threshold) {
$threshold = 0.43;
} else {
$threshold = Less_Functions::number($threshold);
}
if ($color->luma() < $threshold) {
return $light;
} else {
return $dark;
}
}
