# imageline

## 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); } ?>```