Draw a line

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- PHP Manual
- GD and Image Functions
- Draw a line

# imageline

(PHP 4, PHP 5, PHP 7, PHP 8)

imageline — Draw a line

### Description

imageline(
GdImage `$image`,
int `$x1`,
int `$y1`,
int `$x2`,
int `$y2`,
int `$color`
): bool

Draws a line between the two given points.

### Parameters

`image`

  A GdImage object, returned by one of the image creation functions, such as imagecreatetruecolor().

`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. A color identifier created with imagecolorallocate().

### Return Values

Returns `true` on success or `false` on failure.

### Changelog

Version | Description
--- | ---
8.0.0 | `image` expects a GdImage instance now; previously, a valid `gd` resource was expected.

### Examples

Example #1 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);
    }

    ?>

### See Also

- imagecreatetruecolor() - Create a new true color image
- imagecolorallocate() - Allocate a color for an image