Dynamic bar chart in using PHP

This class creates a PNG image bar graph for inclusion in HTML pages. The graph can display one or more data sets in user defined colors.

The font size, font color background color, spacing between sets of bars, labels, and tick marks are all set by the user. You can also design this bar chart by adding some css styles as per your website colour combinations.

Dynamic bar chart

SimpleBar.class.php Class file

Below is the PHP class to generate bar chart using php and mysql. Create a simpleBar.class.php page and add below code.

<?php

// SimpleBar Class

// Use Under GNU License Agreement

class SimpleBar {

private $xgutter = 20; // left/right margin

private $ygutter = 20; // top/bottom margin

private $bottomspace = 30; // gap at the bottom

private $internalgap = 20; // space between bars

private $cells = array(); // labels/amounts for bar chart

private $totalwidth; // width of the image

private $totalheight; // height of the image

private $font; // the font to use

function __construct( $width, $height, $font ) {

$this->totalwidth = $width;

$this->totalheight = $height;

$this->font = $font;

}

function addBar( $label, $amount ) {

$this->cells[ $label ] = $amount;

}

private function _getTextSize( $cellwidth ) {

$textsize = (int)($this->bottomspace);

if ( $cellwidth < 10 ) {

$cellwidth = 10;

}

foreach ( $this->cells as $key=>$val ) {

while ( true ) {

$box = ImageTTFbBox( $textsize, 0, $this->font, $key );

$textwidth = abs( $box[2] );

if ( $textwidth < $cellwidth ) {

break;

}

$textsize--;

}

return $textsize;

}

function draw() {

$image = imagecreate( $this->totalwidth, $this->totalheight );

$red = ImageColorAllocate($image, 230, 230, 230);

$blue = ImageColorAllocate($image, 200, 100, 100 );

$black = ImageColorAllocate($image, 0, 100, 255 );

$max = max( $this->cells );

$total = count( $this->cells );

$graphCanX = ( $this->totalwidth - $this->xgutter*2 );

$graphCanY = ( $this->totalheight - $this->ygutter*2

- $this->bottomspace );

$posX = $this->xgutter;

$posY = $this->totalheight - $this->ygutter - $this->bottomspace;

$cellwidth = (int)(( $graphCanX -

( $this->internalgap * ( $total-1 ) )) / $total) ;

$textsize = $this->_getTextSize( $cellwidth );

foreach ( $this->cells as $key=>$val ) {

$cellheight = (int)(($val/$max) * $graphCanY);

$center = (int)($posX+($cellwidth/2));

imagefilledrectangle( $image, $posX, ($posY-$cellheight),

($posX+$cellwidth), $posY, $blue );

$box = imageTTFbBox( $textsize, 0, $this->font, $key );

$tw = $box[2];

ImageTTFText( $image, $textsize, 0, ($center-($tw/2)),

($this->totalheight-$this->ygutter), $black,

$this->font, $key );

$posX += ( $cellwidth + $this->internalgap);

}

imagepng( $image );

}

simple-bar-chart.php file

Create simple-bar-chart.php page and copy paste below code to generate bar chart from mysql data. It will add your mysql database table’s data and generate bar chart.

<?php

header("Content-type: image/png");

include("SimpleBar.class.php");

$graph = new SimpleBar( 500, 300, "verdana.ttf" );

$graph->addBar( "USA", 200 );

$graph->addBar( "India", 400 );

$graph->addBar( "UK", 240 );

$graph->addBar( "Australia", 170 );

$graph->addBar( "UAE", 270 );

$graph->draw();

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Dynamic bar chart in using PHP

SimpleBar.class.php Class file

simple-bar-chart.php file

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