Bitmap/Bézier curves/Cubic: Difference between revisions

=={{header|PHP}}==

[[Image:Cubic bezier curve PHP.png|right]]

{{works with|PHP| with GD library}}

Outputs image to the right directly to browser or stdout. Based on [[#Python|Python]] code below.

<lang php>

<?

$image = imagecreate(200, 200);

// The first allocated color will be the background color:

imagecolorallocate($image, 255, 255, 255);

$color = imagecolorallocate($image, 255, 0, 0);

cubicbezier($image, $color, 160, 10, 10, 40, 30, 160, 150, 110);

imagepng($image);

function cubicbezier($img, $col, $x0, $y0, $x1, $y1, $x2, $y2, $x3, $y3, $n = 20) {

$pts = array();

for($i = 0; $i <= $n; $i++) {

$t = $i / $n;

$t1 = 1 - $t;

$a = pow($t1, 3);

$b = 3 * $t * pow($t1, 2);

$c = 3 * pow($t, 2) * $t1;

$d = pow($t, 3);

$x = round($a * $x0 + $b * $x1 + $c * $x2 + $d * $x3);

$y = round($a * $y0 + $b * $y1 + $c * $y2 + $d * $y3);

$pts[$i] = array($x, $y);

}

for($i = 0; $i < $n; $i++) {

imageline($img, $pts[$i][0], $pts[$i][1], $pts[$i+1][0], $pts[$i+1][1], $col);

}

}

</lang>