MV Graphing Library

MV_graph.php

<?php

//This is a simple library to create bar and line graphs from data array.  
//Usage:
//$graph_instance = new GRAPH_CREATE()
//$graph_instance _> gather_data(<'bar_graph' or 'line_graph'>, <height in pixels>, <width in pixels>, <data array (requres
//a sub array with 'label' key and data points to be in sub array with 'value' key)>, <min data point>, 
//<max data point>,<text file name to save data in>, <array with RGB color values for graph>,<1 for automatically scaling graph
//to data>, <percentage from min/max value to space graph from top/bottom edge>);

//working example here http://michvaldes001.ddns.net/index.php?section_id=Apps&app_loaded=yes&app_id=weather_station&graph_type=line_graph
//and here http://michvaldes001.ddns.net/index.php?section_id=Apps&app_loaded=yes&app_id=weather_station&graph_type=bar_graph

class GRAPH_CREATE
	{
	//Gather data via function.
	public function gather_data($graph_type, $height, $width, $data_array, $min_data_point, $max_data_point, $image_name, $chart_color_array, $to_scale, $scale_percentage_offset)
		{
		$graph_line_amount = 20;
		$graph_canvas = imagecreatetruecolor($width, $height);
		$chart_color = imagecolorallocate($graph_canvas, $chart_color_array[0],$chart_color_array[1], $chart_color_array[2]);
		$blue = imagecolorallocate($graph_canvas, 10, 10, 150);
		$yellow = imagecolorallocate($graph_canvas, 255, 255, 0);
		
		if ($to_scale == 1)
			{
			$min_max_points = $this -> scale_graphs($data_array, $scale_percentage_offset);
			$min_data_point = $min_max_points[0];
			$max_data_point = $min_max_points[1];
			}		
		
		switch ($graph_type)
			{
			case 'bar_graph':
			$this -> draw_grid_lines($graph_canvas, $data_array, $blue, $width, $height, $graph_line_amount);
			$graph_canvas = $this -> bar_graph($height, $width, $data_array, $graph_canvas, $chart_color, $min_data_point, $max_data_point);
			$this -> chart_labels_draw($graph_canvas, $data_array, $yellow, $width, $height, $graph_line_amount, $min_data_point, $max_data_point);
			break;

			case 'line_graph':
			$this -> draw_grid_lines($graph_canvas, $data_array, $blue, $width, $height, $graph_line_amount);
			$graph_canvas = $this -> line_graph($height, $width, $data_array, $graph_canvas, $chart_color, $min_data_point, $max_data_point);
			$this -> chart_labels_draw($graph_canvas, $data_array, $yellow, $width, $height, $graph_line_amount,$min_data_point, $max_data_point);
			break;
			}
		$this -> draw_graph($graph_canvas, $image_name);


		}


	//Bar graph function.
	private function bar_graph($height, $width, $data_array, $graph_canvas, $chart_color, $min_data_point, $max_data_point)
		{
		$data_array = $data_array['value'];		
		$data_points_amount = sizeof($data_array);
		$bar_width = $width * (2/3);
		$x_coordinate = 0; 

		foreach ($data_array as $data_point)
				{
				$data_point = $height * (1 - (($data_point - $min_data_point) / ($max_data_point - $min_data_point)));		
				$x_coordinate = $x_coordinate + (($bar_width/ $data_points_amount) / 4);	
				imageline($graph_canvas, $x_coordinate, $data_point ,$x_coordinate + ($bar_width / $data_points_amount),$data_point, $chart_color);
				imageline($graph_canvas, $x_coordinate,$data_point , $x_coordinate, $height , $chart_color);
				$x_coordinate = $x_coordinate + ($bar_width / $data_points_amount);
				imageline($graph_canvas, $x_coordinate, $data_point , $x_coordinate, $height , $chart_color);
				$x_coordinate = $x_coordinate + (($bar_width / $data_points_amount) / 4);
				}
		return $graph_canvas;
		
		}

	//Line graph function.
	private function line_graph($height, $width, $data_array, $graph_canvas, $chart_color, $min_data_point, $max_data_point)
		{
		$data_array = $data_array['value'];		
		$data_points_amount = sizeof($data_array);
		$x_coordinate = ($width / $data_points_amount)/4; 
		$draw_point_count = 0;
		foreach ($data_array as $data_point)
				{
				$data_point = $height  * (1 - (($data_point - $min_data_point) / ($max_data_point - $min_data_point)));
				$data_point_next = $height  * (1 - ((next($data_array) - $min_data_point) / ($max_data_point - $min_data_point)));
				if ($draw_point_count < ($data_points_amount - 1))
					{
					imageline($graph_canvas, $x_coordinate, $data_point ,$x_coordinate + ($width / $data_points_amount),$data_point_next, $chart_color);
					}
				$x_coordinate = $x_coordinate + ($width / $data_points_amount);
				$draw_point_count++;
				}
		return $graph_canvas;
		
		}

	//Create grid lines.
	private function draw_grid_lines($graph_canvas, $data_array, $blue, $width, $height, $graph_line_amount)
		{


		for ($i = 1; $i <= $graph_line_amount; $i++)
			{
			imageline($graph_canvas, 0, ($height / $graph_line_amount) * $i , $width,($height / $graph_line_amount) * $i, $blue);
			}

		return $graph_canvas;	
		}

	//Create labels.
	private function chart_labels_draw($graph_canvas, $data_array, $yellow, $width, $height, $graph_line_amount,$min_data_point, $max_data_point)
		{
		$max_data_point = $max_data_point - $min_data_point;
		$data_array_values = $data_array['value'];
		$data_array_labels = $data_array['label'];
		$label_points_amount = sizeof($data_array_labels);

		for ($i = 0; $i <= $graph_line_amount; $i++)
			{
			imagestring($graph_canvas, 3, 3, ($height / $graph_line_amount) * $i, ($max_data_point - (($max_data_point / $graph_line_amount) * $i)) + $min_data_point, $yellow);
			}

		for ($i = 0; $i < $label_points_amount; $i++)
			{
			imagestring($graph_canvas, 3, (($width / $label_points_amount) * $i) + (($width / $label_points_amount)/4), $height - 15,  $data_array_labels[$i] , $yellow);
			}

		return $graph_canvas;
		}

	
	//Scale graphs to min/max values.
	private function scale_graphs($data_array, $scale_percentage_offset)
		{
		$scale_percentage_offset = $scale_percentage_offset * 0.01;
		$array_max = max($data_array['value']);
		$array_min = min($data_array['value']);		
		$array_median = (abs($array_max - $array_min)) * $scale_percentage_offset; 
		$min_data_point = $array_min - $array_median;
		$max_data_point = $array_max + $array_median;
		$min_max_array = array($min_data_point, $max_data_point);
		return $min_max_array;
		}


	//Render graph.
	private function draw_graph($graph_canvas, $image_name)
		{
		imagepng($graph_canvas, '<GRAPH DIRECTORY>' . $image_name . '.png');
		echo '<img src = "<GRAPH DIRECTORY>' . $image_name . '.png">';
		imagedestroy($graph_canvas);
		}	

	}

?>