imageline

Draw a line

&reftitle.description; `bool` `imageline` `GdImage` `image` `int` `x1` `int` `y1` `int` `x2` `int` `y2` `int` `color`

Draws a line between the two given points.

&reftitle.parameters;

&gd.image.description;

`x1`

- x-coordinate for first point.

`y1`

- y-coordinate for first point.

`x2`

- x-coordinate for second point.

`y2`

- y-coordinate for second point.

`color`

- The line color. &gd.identifier.color;

&reftitle.returnvalues;

&return.success;

&reftitle.changelog;

&Version; | &Description;
&gd.changelog.image-param;

&reftitle.examples;

### Drawing a thick line

    <?php

    function imagelinethick($image, $x1, $y1, $x2, $y2, $color, $thick = 1)
    {
        /* this way it works well only for orthogonal lines
        imagesetthickness($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);
    }

    ?>

&reftitle.seealso;

- `imagecreatetruecolor`
- `imagecolorallocate`