PHP | imageopenpolygon() Function

The imageopenpolygon() function is an inbuilt function in PHP which is used to draws an open polygon.

Syntax:

bool imageopenpolygon( resource $image, array $points,
int $num_points, int $color )

Parameters: This function accepts four parameters as mentioned above and described below:

• $image: It specifies the image resource to work on.
• $points: It specifies the points of polygon.
• $num_points: It specifies the number of points.
• $color: It specifies the color of polygon.

Return Value: This function returns TRUE on success or FALSE on failure.

Below examples illustrate the imageopenpolygon() function in PHP:

Example 1: In this example, we will draw polygon on a blank drawing.

<?php

// Create a blank image
$image = imagecreatetruecolor(400, 300);

// Prepare the colors
$red = imagecolorallocate($image, 255, 0, 0);

// Points of array
$points =  array(
    80, 150,
    150, 250,
    300, 250,
    370, 150,
    230, 50,
    80, 150
);

// Create an polygon
imageopenpolygon($image, $points, 6, $red);

// Output to browser
header('Content-type: image/png');
imagepng($image);
imagedestroy($image);
?>

Output:

Example 2: In this example, drawing polygon on a image.

<?php

// Create an image instance
$image = imagecreatefrompng(
'https://media.geeksforgeeks.org/wp-content/uploads/geeksforgeeks-13.png');

// Prepare the colors
$red = imagecolorallocate($image, 255, 0, 0);

// Points of array
$points =  array(
    10, 10,
    660, 10,
    660, 100,
    10, 100,
    10, 10
);

// Create an polygon
imageopenpolygon($image, $points, 5, $red);

// Output to browser
header('Content-type: image/png');
imagepng($image);
imagedestroy($image);
?>

Output:

Reference: https://www.php.net/manual/en/function.imageopenpolygon.php