Simple PHP Bar Graph using GD library

เราสามารถสร้าง bar graph แบบง่ายๆ ด้วย GD Library (PHP) ได้
<html>

<head>

<title>Simple Bar Graph</title>

</head>

<body>

<?php

//ข้อมูล

$data = array('100', '200', '300', '400', '500', '350', '270');

$cols = array('Sun', 'Mon', 'Tue', 'Wen', 'Thu', 'Fir', 'Sat');

// find the largest data

$max = 0;

for ($i = 0; $i < 7; $i++) {

    if ($data[$i] > $max) {

        $max = $data[$i];

    }

}

// image width , height px

$im = imagecreate(320, 255);



// ค่าสีต่างๆ

$white = imagecolorallocate($im, 255, 255, 255);

$black = imagecolorallocate($im, 0, 0, 0);

$red = imagecolorallocate($im, 255, 0, 0);

$green = imagecolorallocate($im, 0, 255, 0);

$blue = imagecolorallocate($im, 0, 0, 255);



// bar x1 position

$x = 15;

// bar $y1 position

$y = 230;

// width of bars

$x_width = 20;

// height of bars, will be calculated later

$y_ht = 0;

// get into some meat now, cheese for vegetarians;

for ($i = 0; $i < 7; $i++) {

    // no validation so check if $max = 0 later;

    $y_ht = ($data[$i] / $max) * 100;

    imagerectangle($im, $x, $y, $x + $x_width, ($y - $y_ht), $red);

    imagestring($im, 2, $x - 1, $y + 1, $cols[$i], $black);

    imagestring($im, 2, $x, $y - $y_ht - 15, $data[$i], $black);

    // 20 is diff between two bars;

    $x += ($x_width + 20);

}



// draw X, Y Co-Ordinate

imageline($im, 10, 5, 10, 230, $blue);

imageline($im, 10, 230, 300, 230, $blue);



//เขียนข้อความ

imagestring($im, 3, 15, 5, "Students", $black);

imagestring($im, 5, 100, 50, "Simple Graph", $red);

imagestring($im, 5, 90, 75, "by Goragod.com", $green);



// สร้างรูปภาพ

imagejpeg($im, "graph.jpeg", 90);

imagedestroy($im);

echo "<img src='graph.jpeg'><p></p>";

?>

</body>

</html>
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