Category: Source

<?php

/**
 * draw_triangle
 *
 * Draw a filled triangle.
 *
 * @version 0.4
 * @author Contributors at eXorithm
 * @link /algorithm/view/draw_triangle Listing at eXorithm
 * @link /algorithm/history/draw_triangle History at eXorithm
 * @license /home/show/license
 *
 * @param array $points This should be a list of six numbers that define the points of the triange (x1, y1, x2, y2, x3, y3)
 * @param string $color (hex color code) The color of the triangle
 * @return resource GD image
 */
function draw_triangle($points=array(0=>'0',1=>'0',2=>'0',3=>'8',4=>'8',5=>'4'),$color='000000')
{
	if (count($points)!=6) {
		throw new Exception('The points must be an array of 6 integers.');
	}
	
	$image = image_create_alpha(max($points[0], $points[2], $points[4])+1, max($points[1], $points[3], $points[5])+1);
	
	$red = hexdec(substr($color, 0, 2));
	$green  = hexdec(substr($color, 2, 2));
	$blue  = hexdec(substr($color, 4, 2));
		
	$color = imagecolorallocatealpha($image, $red, $green, $blue, 0);
	
	imagefilledpolygon($image, $points, 3, $color);
	
	return $image;
}

/**
 * image_create_alpha
 *
 * Helper function to create a new blank image with transparency.
 *
 * @version 0.1
 * @author Contributors at eXorithm
 * @link /algorithm/view/image_create_alpha Listing at eXorithm
 * @link /algorithm/history/image_create_alpha History at eXorithm
 * @license /home/show/license
 *
 * @param mixed $width 
 * @param mixed $height 
 * @return resource GD image
 */
function image_create_alpha($width='',$height='')
{
	// Create a normal image and apply required settings
	$img = imagecreatetruecolor($width, $height);
	imagealphablending($img, false);
	imagesavealpha($img, true);
	
	// Apply the transparent background
	$trans = imagecolorallocatealpha($img, 0, 0, 0, 127);
	for ($x = 0; $x < $width; $x++)
	{
		for ($y = 0; $y < $height; $y++)
		{
			imagesetpixel($img, $x, $y, $trans);
		}
	}
	
	return $img;
}

?>

<?php

/**
 * weather_forecast
 *
 * Display the weather for a location. Look up using the Google weather API.
 *
 * @version 1.4
 * @author Contributors at eXorithm
 * @link /algorithm/view/weather_forecast Listing at eXorithm
 * @link /algorithm/history/weather_forecast History at eXorithm
 * @license /home/show/license
 *
 * @param mixed $location The location to get the weather for. Can be a city, zip code, or postal code.
 * @param mixed $units The units to get the temperature in.
 * @param string $header_color (hex color code) Color of the header
 * @param string $day_header_color (hex color code) Color of the header for each of the days
 * @param string $day_color (hex color code) Color of the cells containing the forecasts
 * @return string HTML
 */
function weather_forecast($location='Sydney, Australia',$units='c',$header_color='f0f0f0',$day_header_color='d0ffd0',$day_color='f0f0f0')
{
	$weather = file_get_contents('http://www.google.com/ig/api?weather='.urlencode($location));
	
	$xml = simplexml_load_string($weather);
	
	if (!isset($xml->weather->forecast_conditions)) {
		throw new Exception('Data could not be retreived for location '.$location);
	}
	
	$location = $xml->weather->forecast_information->city['data'];
						                                          
	// four day outlook
	for ($i = 0; $i < 4; $i++){
		if ($xml->weather->forecast_conditions->$i) {
			$forecast_day[] = $xml->weather->forecast_conditions->$i->day_of_week['data'];
			$forecast_condition[] = $xml->weather->forecast_conditions->$i->condition['data'];
			$low = $xml->weather->forecast_conditions->$i->low['data'];
			if ($units=='k')
				$low = round((($low - 32)*5/9) + 273, 1);
			else if ($units=='c')
				$low = round(($low - 32)*5/9, 1);
			$forecast_low[] = $low;
			$high = $xml->weather->forecast_conditions->$i->high['data'];
			if ($units=='k')
				$high = round((($high - 32)*5/9) + 273, 1);
			else if ($units=='c')
				$high = round(($high - 32)*5/9, 1);
			$forecast_high[] = $high;
			$forecast_icon[] = $xml->weather->forecast_conditions->$i->icon['data'];
		}
	}
	
	// current
	$condition = $xml->weather->current_conditions->condition['data'];
	$temp = $xml->weather->current_conditions->temp_f['data'];
	if ($units=='k')
		$temp = round((($temp - 32)*5/9) + 273, 1);
	else if ($units=='c')
		$temp = round(($temp - 32)*5/9, 1);
	$icon = $xml->weather->current_conditions->icon['data'];
	
	// build the HTML
	$header = "<tr><td colspan=\"".count($forecast_day)."\" bgcolor=\"#$header_color\">";
	if ($icon!='')
		$header .= "<img align=\"left\" src=\"http://www.google.com$icon\">";
	$header .= "<b>$location</b><br>Currently <i>$condition</i> <b>$temp$units</b>";
	$header .= "</td></tr>\n<tr>";
	$data = "<tr>\n";
	
	for ($i = 0; $i < count($forecast_day); $i++){
		$header .= "<td width=\"130\" bgcolor=\"#$day_header_color\"><b>$forecast_day[$i]</b></td>";
		$data .= "<td bgcolor=\"#$day_color\">";
		$data .= "<img src=\"http://www.google.com$forecast_icon[$i]\">";
		$data .= "<br><i>$forecast_condition[$i]</i>";
		$data .= "<br>high <b>$forecast_high[$i]$units</b>";
		$data .= "<br>low <b>$forecast_low[$i]$units</b>";
		$data .= "</td>\n";
	}
	
	$header .= "</tr>";
	$data .= "</tr>";
	
	return "<table cellpadding=\"5\" cellspacing=\"3\">\n$header\n$data\n</table>";
}

?>

<?php

/**
 * address_elevation
 *
 * Returns the elevation (in meters) above sea level for an address.
 *
 * @version 0.2
 * @author Contributors at eXorithm
 * @link /algorithm/view/address_elevation Listing at eXorithm
 * @link /algorithm/history/address_elevation History at eXorithm
 * @license /home/show/license
 *
 * @param mixed $address The address to get the elevation for.
 * @return mixed
 */
function address_elevation($address='Denver, Colorado')
{
	// get the lat/long for this address
	$data = file_get_contents("http://maps.google.com/maps/geo?output=csv&q=".urlencode($address));
	$arr = explode(",", $data);
	if (count($arr)>=4) {
		if ($arr[0]==200) {
			// get the elevation for this lat/long
			$data = file_get_contents("http://maps.googleapis.com/maps/api/elevation/xml?sensor=false&locations=".$arr[2].','.$arr[3]);
			$obj = simplexml_load_string($data);
			if ($obj instanceof SimpleXMLElement) {
				$obj = (array) $obj;
				$obj = $obj['result'];
				if ($obj instanceof SimpleXMLElement) {
					$obj = (array) $obj;
					return $obj['elevation'];
				} else {
					throw new Exception('Elevation lookup failed');
				}
			} else {
				throw new Exception('Elevation lookup failed');
			}
		} else {
			throw new Exception('Address lookup failed');
		}
	} else {
		throw new Exception('Address lookup failed');
	}
}

?>

<?php

/**
 * create_gradient
 *
 * Create an image that is a color gradient.
 *
 * @version 0.1
 * @author Contributors at eXorithm
 * @link /algorithm/view/create_gradient Listing at eXorithm
 * @link /algorithm/history/create_gradient History at eXorithm
 * @license /home/show/license
 *
 * @param string $start_color (hex color code) The start color of the gradient.
 * @param string $end_color (hex color code) The end color of the gradient.
 * @param number $size The length of the resulting image.
 * @param number $thickness The thickness of the resulting image.
 * @param mixed $orientation The orientation of the gradient.
 * @return resource GD image
 */
function create_gradient($start_color='ffffff',$end_color='000000',$size=100,$thickness=5,$orientation='')
{
	if ($orientation=="vertical") {
		$img=imagecreatetruecolor($thickness,$size);
	} else {
		$img=imagecreatetruecolor($size,$thickness);
	}
	
	$start_r  = hexdec(substr($start_color, 0, 2));
	$start_g  = hexdec(substr($start_color, 2, 2));
	$start_b  = hexdec(substr($start_color, 4, 2));
	
	$end_r  = hexdec(substr($end_color, 0, 2));
	$end_g = hexdec(substr($end_color, 2, 2));
	$end_b = hexdec(substr($end_color, 4, 2));
	
	for ($i=0;$i<$size;$i++) {
		$red = round($start_r - ($start_r-$end_r) * ($i / ($size-1)));
		$green = round($start_g - ($start_g-$end_g) * ($i / ($size-1)));
		$blue = round($start_b - ($start_b-$end_b) * ($i / ($size-1)));
		$color = imagecolorallocate($img, $red, $green, $blue);
		if ($orientation=="vertical") {
			for ($k=0;$k<$thickness;$k++)
				imagesetpixel($img, $k, $i, $color);
		} else {
			for ($k=0;$k<$thickness;$k++)
				imagesetpixel($img, $i, $k, $color);
		}
	}
	
	return  $img;
}

?>

<?php

/**
 * duotone_image
 *
 * Change an image into a tinted grayscale.
 *
 * @version 0.5
 * @author Contributors at eXorithm
 * @link /algorithm/view/duotone_image Listing at eXorithm
 * @link /algorithm/history/duotone_image History at eXorithm
 * @license /home/show/license
 *
 * @param resource $image (GD image) The image to duotone.
 * @param number $rplus Red value to increase or decrease.
 * @param number $gplus Green value to increase or decrease.
 * @param number $bplus Blue value to increase or decrease.
 * @param bool $pcnt If checked, the values for rplus, gplus and bplus will be treated as percentages.
 * @return resource GD image
 */
function duotone_image($image=null,$rplus=0,$gplus=0,$bplus=60,$pcnt=false)
{
	// Adapted from http://www.tuxradar.com/practicalphp/11/2/21
	
	$imagex = imagesx($image);
	$imagey = imagesy($image);
	
	$image2 = imagecreatetruecolor($imagex, $imagey);
	imagesavealpha($image2, true);
	imagealphablending($image2, false);
	
	for ($x = 0; $x <$imagex; ++$x) {
		for ($y = 0; $y <$imagey; ++$y) {
			$rgb = imagecolorat($image, $x, $y);
			$color = imagecolorsforindex($image, $rgb);
			$grey = floor(($color['red']+$color['green']+$color['blue'])/3);
			if ($pcnt) {
				$red = $grey + $grey*($rplus/150);
				$green = $grey + $grey*($gplus/150);
				$blue = $grey + $grey*($bplus/150);
			} else {
				$red = $grey + $rplus;
				$green = $grey + $gplus;
				$blue = $grey + $bplus;
			}
			
			if ($red > 255) $red = 255;
			if ($green > 255) $green = 255;
			if ($blue > 255) $blue = 255;
			if ($red < 0) $red = 0;
			if ($green < 0) $green = 0;
			if ($blue < 0) $blue = 0;
			
			$newcol = imagecolorallocatealpha($image2, $red,$green,$blue,$color['alpha']);
			imagesetpixel ($image2, $x, $y, $newcol);
		}
	}
	
	return $image2;
}

?>

<?php

/**
 * make_change
 *
 * Calculate the number of different ways there are to make change for a given amount.
 *
 * @version 0.1
 * @author Contributors at eXorithm
 * @link /algorithm/view/make_change Listing at eXorithm
 * @link /algorithm/history/make_change History at eXorithm
 * @license /home/show/license
 *
 * @param number $amount How many cents you want to make change for.
 * @param array $coins The coin denominations you have.
 * @return mixed
 */
function make_change($amount=100,$coins=array(0=>'1',1=>'5',2=>'10',3=>'25'))
{
	$coin_count = count($coins);
	
	$table = array();
	
	for ($i = -1; $i <= $amount; $i++) {
		for($j = -1; $j <= $coin_count; $j++) {
			// Rules
			// 1: table[0,0] or table[0,x] = 1
			// 2: talbe[i <= -1, x] = 0
			// 3: table[x, j <= -1] = 0
			
			$total = 0;
				 
			// first sub-problem
			// count(n, m-1)
			$n = $i;
			$m = $j-1;
			if ($n == 0) // rule 1
				$total += 1;
			else if ($n <= -1) // rule 2
				$total += 0;
			else if (($m <= 0) && ($n >= 1))
				$total += 0;
			else
				$total += $table[$n][$m];
			
			// second sub-problem
			// count(n-S[m], m)
			if (($j-1) <= -1)
				$total += 0;
			else {
				$n = $i - $coins[$j - 1];
				$m = $j;
				if ($n == 0) // rule 1
					$total += 1;
				else if ($n <= -1) // rule 2
					$total += 0;
				else if (($m <= 0) && ($n >= 1)) // rule 3
					$total += 0;
				else
					$total += $table[$n][$m];
			}
			
			$table[$i][$j] = $total;
		}
	}
	return $table[$i-1][$j-1];
}

?>

<?php

/**
 * show_address
 *
 * Given an address, show the location on a map.
 *
 * @version 0.6
 * @author Contributors at eXorithm
 * @link /algorithm/view/show_address Listing at eXorithm
 * @link /algorithm/history/show_address History at eXorithm
 * @license /home/show/license
 *
 * @param mixed $address The address to find.
 * @return array latitude/longitude
 */
function show_address($address='The White House
1600 Pennsylvania Ave NW
Washington, DC
20500')
{
	$data = file_get_contents("http://maps.googleapis.com/maps/api/geocode/json?address=".urlencode($address)."&sensor=false");
	$obj = json_decode($data);
	if ($obj) {
		if (isset($obj->results[0]->geometry->location)) {
			$loc = $obj->results[0]->geometry->location;
			return array('latitude'=>$loc->lat, 'longitude'=>$loc->lng);
		} else {
			throw new Exception('Lookup failed and/or address does not exist!');
		}
	} else {
		throw new Exception('Lookup failed and/or address does not exist!');
	}
}

?>