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imagepolygon

Name

imagepolygon — Draws an unfilled polygon.

Synopsis

string imagepolygon(image, points, vertices, color);
int image: Image identifier
array points: Array of points
int vertices: Number of vertices
int color: Specified color

Returns

TRUE on success; FALSE on error

Description

This can be a difficult function to understand and use. The array specifying the drawing coordinates must contain both the x and y coordinates of each point in the polygon. For example, array(100,100,125,125,150,150,200,200,100,100) indicates that the first point is at (100,100), the second at (125,125), and so on. The polygon must have at least three vertices for the function to work; a good way to determine the number of vertices is to count the array using count() and divide by two. A point is made up of two values. If you used user input to assign the polygon points, you can use the modulus operator (%) to determine whether an even number of values were given.

Example

Example 431. Create an unfilled red polygon

header("Content-type: image/png");
$im = imagecreate(200, 200);
$green = imagecolorallocate($im, 0, 255, 0);
$red = imagecolorallocate($im, 255, 0, 0);
$points = array(100, 10, 150, 50, 160, 80, 10, 150, 100, 10);
$vertices = count($points) / 2;
imagepolygon($im, $points, $vertices, $red);
imagepng($im);
imagedestroy($im);



PHP Functions Essential Reference. Copyright © 2002 by New Riders Publishing (Authors: Zak Greant, Graeme Merrall, Torben Wilson, Brett Michlitsch). This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/). The authors of this book have elected not to choose any options under the OPL. This online book was obtained from http://www.fooassociates.com/phpfer/ and is designed to provide information about the PHP programming language, focusing on PHP version 4.0.4 for the most part. The information is provided on an as-is basis, and no warranty or fitness is implied. All persons and entities shall have neither liability nor responsibility to any person or entity with respect to any loss or damage arising from the information contained in this book.

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