纯PHP生成的一个树叶图片画图例子

效果：

提示：保存到PHP文件然后在浏览器中打后即可看到和效果图一样的一张图片。
代码如下:
<?php

$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);

?>