纯PHP生成的一个树叶图片画图例子

$im=imagecreate(670,500);
$white = imagecolorallocate($im, 0xff, 0xff, 0xff);
$g = imagecolorallocate($im, 0x00, 0x00, 0x00);
define("pii",m_pi/180);
function drawleaf($g,$x,$y,$l,$a){

        global $im;
        $b = 50;
        $c =9;
        $s1 = 2;
        $s2 = 3 ;
        $s3 = 1.2;
        if($l > $s1)
        {
            $x2 = $x + $l * cos($a * pii);
            $y2 = $y + $l * sin($a * pii);
            $x2r = $x2 + $l / $s2 * cos(($a + $b) * pii);
            $y2r = $y2 + $l / $s2 * sin(($a + $b) * pii);
            $x2l = $x2 +$l / $s2 * cos(($a - $b) * pii);
            $y2l = $y2 + $l / $s2 * sin(($a - $b) * pii);

            $x1 = $x + $l / $s2 * cos($a * pii);
            $y1 = $y + $l / $s2 * sin($a * pii);
            $x1l = $x1 + $l / $s2 * cos(($a - $b) * pii);
            $y1l = $y1 + $l / $s2 * sin(($a - $b) * pii);
            $x1r = $x1 + $l / $s2 * cos(($a + $b) * pii);
            $y1r = $y1 + $l / $s2 * sin(($a + $b) * pii);

            imageline($im,(int)$x,  (int)$y,  (int)$x2,  (int)$y2,  $g);
            imageline($im,(int)$x2, (int)$y2, (int)$x2r, (int)$y2r, $g);
            imageline($im,(int)$x2, (int)$y2, (int)$x2l, (int)$y2l, $g);
            imageline($im,(int)$x1, (int)$y1, (int)$x1l, (int)$y1l, $g);
            imageline($im,(int)$x1, (int)$y1, (int)$x1r, (int)$y1r, $g);

            drawleaf($g, $x2,  $y2,  $l / $s3, $a + $c);
            drawleaf($g, $x2r, $y2r, $l / $s2, $a + $b);
            drawleaf($g, $x2l, $y2l, $l / $s2, $a - $b);
            drawleaf($g, $x1l, $y1l, $l / $s2, $a - $b);
            drawleaf($g, $x1r, $y1r, $l / $s2, $a + $b);
           }
}
drawleaf($g,300,500,100,270);
header("content-type: image/png");
imagepng($im);

?>