Hello,
I am using a tutorial script for generating a basic bar graph. I have attempted to convert this script into an object-oriented script. However, upon attempting to define the graph, it is not successfully generated. Here is my code:
<?
class Graph
{
var $values;
var $image;
var $image_width = 450;
var $image_height = 300;
var $margin = 20;
var $bar_size = 20;
var $horizontal_lines = 20;
var $bar_colour;
var $border_colour;
var $background_colour;
var $line_colour;
function CreateGraph()
{
$this->image = imagecreate($this->image_width, $this->image_height);
}
function SetSize($width, $height)
{
$this->image_width = $width;
$this->image_height = $height;
}
function SetMargin($size)
{
$this->margin = $size;
}
function SetBarSize($size)
{
$this->bar_size = $size;
}
function SetHorLines($size)
{
$this->horizontal_lines = $size;
}
function HexConvert($rgb)
{
return array(
base_convert(substr($rgb, 0, 2), 16, 10),
base_convert(substr($rgb, 2, 2), 16, 10),
base_convert(substr($rgb, 4, 2), 16, 10),
);
}
function SetColours($bars, $background, $border, $line)
{
// This is hex based, similar to CSS, it is converted by HexConvert
$bars = $this->HexConvert($bars);
$background= $this->HexConvert($background);
$border= $this->HexConvert($border);
$line = $this->HexConvert($line);
$this->bar_colour = imagecolorallocate($this->image, $bars[0], $bars[1], $bars[2]);
$this->background_colour = imagecolorallocate($this->image, $background[0], $background[1], $background[2]);
$this->border_colour = imagecolorallocate($this->image, $border[0], $border[1], $border[2]);
$this->line_colour =imagecolorallocate($this->image, $line [0], $line [1], $line [2]);
}
function DrawBorders()
{
imagefilledrectangle($this->image,1,1,$this->image_width-2,$this->image_height-2,$this->border_colour);
imagefilledrectangle($this->image,$this->margin,$this->margin,$this->image_width-1-$this->margin,$this->image_height-1-$this->margin,$this->background_colour);
}
function DrawHorLines($horizontal_gap, $ratio)
{
for($i=1;$i<=$this->horizontal_lines;$i++)
{
$y = $this->image_height - $this->margin - $horizontal_gap * $i ;
imageline($this->image, $this->margin, $y, $this->image_width - $this->margin, $y, $this->line_colour);
$v = intval($horizontal_gap * $i / $ratio);
imagestring($this->image, 0, 5, $y-5, $v, $this->bar_colour);
}
}
function DrawBars($graph_height, $gap, $ratio)
{
for($i=0;$i< $total_bars; $i++)
{
list($key,$value)=each($this->values);
$x1= $this->margin + $gap + $i * ($gap+$this->bar_size) ;
$x2= $x1 + $this->bar_size;
$y1 = $this->margin +$graph_height- intval($value * $ratio) ;
$y2 = $this->image_height-$this->margin;
imagestring($this->image,0,$x1+3,$y1-10,$value,$this->bar_colour);
imagestring($this->image,0,$x1+3,$this->image_height-15,$key,$this->bar_colour);
imagefilledrectangle($this->image,$x1,$y1,$x2,$y2,$this->bar_colour);
}
}
function DrawGraph()
{
$graph_width=$this->image_width - $this->margin * 2;
$graph_height=$this->image_height - $this->margin * 2;
$total_bars = count($values);
$gap = ($graph_width- $total_bars * $this->bar_width ) / ($total_bars +1);
$this->DrawBorders();
$max_value=max($values);
$ratio = $graph_height / $max_value;
$horizontal_gap = $graph_height / $horizontal_lines;
$this->DrawHorLines($horizontal_gap, $ratio);
$this->DrawBars($graph_height, $gap, $ratio);
}
function OutputGraph()
{
header("Content-type:image/png");
imagepng($this->image);
}
}
?>
I expect this to be my misunderstanding of how object orientated codes work. I'm also open to any suggestions for improvement.
Edit: Here is the script where I use the class.
<?
include "bargraph.class.php";
$graph = new Graph;
$graph->SetSize(450, 300);
$graph->CreateGraph();
$graph->SetMargin(20);
$graph->SetBarSize(20);
$graph->SetHorLines(20);
$graph->SetColours("FFFFFF", "C0C0C0", "000000", "000000");
$graph->DrawGraph();
$graph->OutputGraph();
?>
