/**
* Color blending
*
* @param callable $mode
* @param Color $color1
* @param Color $color2
* @return ColorNode
*/
protected function colorBlend(callable $mode, Color $color1, Color $color2)
{
$ab = $color1->getAlpha();
// backdrop
$as = $color2->getAlpha();
// source
$r = [];
// result
$ar = $as + $ab * (1 - $as);
$rgb1 = $color1->rgb;
$rgb2 = $color2->rgb;
for ($i = 0; $i < 3; $i++) {
$cb = $rgb1[$i] / 255;
$cs = $rgb2[$i] / 255;
$cr = call_user_func($mode, $cb, $cs);
if ($ar) {
$cr = ($as * $cs + $ab * ($cb - $as * ($cb + $cs - $cr))) / $ar;
}
$r[$i] = $cr * 255;
}
return new ColorNode($r, $ar);
}
/**
* @covers getAlpha
*/
public function testAlpha()
{
$color = new Color();
$this->assertEquals(1, $color->getAlpha());
}
