Generate random images in PHP

README.md

Generate random images in PHP

Why?

• Because you can
• Because you have time to spare
• Maybe you think they look cool or want to save them for wallpapers or something
• Maybe it reminds you of that one time... You know which time I'm talking about

Requirements

• PHP >= 7.0
• GD image processing library, which you probably already have
• Some time to waste

randomimagegenerator.php

<?php
/**
 * @author Chris Zuber
 * @license http://opensource.org/licenses/GPL-3.0 GNU General Public License, version 3 (GPL-3.0)
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
namespace RandomImageGenerator;
/**
 * Image width
 * @var integer
 */
const X = 1920;

/**
 * Image height
 * @var integer
 */
const Y = 1200;

/**
 * Number of shapes to draw
 * @var integer
 */
const SHAPES = 500;

/**
 * Various available styles for arcs
 * @var Arary
 */
const ARC_STYLES = [
	IMG_ARC_PIE,
	IMG_ARC_CHORD,
	IMG_ARC_EDGED,
	IMG_ARC_NOFILL
];

/**
 * Create a random polygon with number of points between 0 & $max_pts
 * @param  resource  $im      The image reource
 * @param  integer   $max_pts Max number of point to use
 * @return void
 */
function random_polygon($im, Int $max_pts = 20)
{
	$color = imagecolorallocatealpha($im, ...random_color_alpha());
	$pts = random_pts(random_int(3, $max_pts));
	$num = count($pts) / 2;
	imagefilledpolygon($im, $pts, $num, $color);
}

/**
 * Creates a random arc of a random color
 * @param  resource $im The image resource
 * @return void
 */
function random_arc($im)
{
	$cx = random_int(0, X);
	$cy = random_int(0, Y);
	$w = random_int(0, X);
	$h = random_int(0, Y);
	$s = random_int(0, 360);
	$e = random_int(0, 360);
	$col = imagecolorallocatealpha($im, ...random_color_alpha());
	$style = ARC_STYLES[random_int(0, 3)];
	imagefilledarc($im, $cx, $cy, $w, $h, $s, $e, $col, $style);
}

/**
 * Draws a randomly colored pixel at a random location
 * @param  resource $im The image resource
 * @return void
 */
function random_pixel($im)
{
	$color = imagecolorallocate($im, ...random_color_alpha());
	$x = random_int(0, X);
	$y = random_int(0, Y);
	imagesetpixel($im, $x, $y, $color);
}

/**
 * Generates an array of random alpha color values.
 * @return Array [r, g, b, a]
 */
function random_color_alpha(): Array
{
	return [
		random_int(0, 255),
		random_int(0, 255),
		random_int(0, 255),
		random_int(0, 127)
	];
}

/**
 * Generates an array of random color values
 * @return Array [r, g, b]
 */
function random_color(): Array
{
	return [random_int(0, 255), random_int(0, 255), random_int(0, 255)];
}

/**
 * Generates a set of random points for a polygon [x1,y1, x2,y2,...]
 * @param  integer $length Number of sets of points to generate
 * @return Array           The resulting array of points
 */
function random_pts($length): Array
{
	$pts = [];
	for($n = 0; $n < $length; $n++) {
		$pts[] = random_int(0, X);
		$pts[] = random_int(0, Y);
	}
	return $pts;
}

header('Content-type: image/png');
$im = imagecreatetruecolor(X, Y);
for ($i = 0; $i < SHAPES; $i++) {
	switch(random_int(1, 2)) {
		case 1:
			random_arc($im);
			break;
		case 2:
			random_polygon($im);
			break;
	}
}
imagepng($im);
imagedestroy($im);