imageline

画一条线段 (PHP 3, PHP 4, PHP 5)
bool imageline ( resource image, int x1, int y1, int x2, int y2, int color )

说明

imageline()color 颜色在图像 image 中从坐标 x1y1x2y2(图像左上角为 0, 0)画一条线段。

例 843. 画一条粗线

<?php

function imagelinethick($image, $x1, $y1, $x2, $y2, $color, $thick = 1)
{
   
/* &#19979;&#38754;&#20004;&#34892;&#21482;&#22312;&#32447;&#27573;&#30452;&#35282;&#30456;&#20132;&#26102;&#22909;&#20351;
   imagesetthickness($image, $thick);
   return imageline($image, $x1, $y1, $x2, $y2, $color);
   */
   
if ($thick == 1) {
       return
imageline($image, $x1, $y1, $x2, $y2, $color);
   }
   
$t = $thick / 2 - 0.5;
   if (
$x1 == $x2 || $y1 == $y2) {
       return
imagefilledrectangle($image, round(min($x1, $x2) - $t), round(min($y1, $y2) - $t), round(max($x1, $x2) + $t), round(max($y1, $y2) + $t), $color);
   }
   
$k = ($y2 - $y1) / ($x2 - $x1); //y = kx + q
   
$a = $t / sqrt(1 + pow($k, 2));
   
$points = array(
       
round($x1 - (1+$k)*$a), round($y1 + (1-$k)*$a),
       
round($x1 - (1-$k)*$a), round($y1 - (1+$k)*$a),
       
round($x2 + (1+$k)*$a), round($y2 - (1-$k)*$a),
       
round($x2 + (1-$k)*$a), round($y2 + (1+$k)*$a),
   );
   
imagefilledpolygon($image, $points, 4, $color);
   return
imagepolygon($image, $points, 4, $color);
}

?>

参见 imagecreatetruecolor()imagecolorallocate()