09c04-1.php

介绍PHP5的给类型函数应用

<?php
// Define the chart creation function.
// Have parameters for the data itself and a maximum height for the chart.
// You can also pass in 4 color parameters, for the border,
//   background, bars, and the grid - These are optional.
function create_chart($data, $height,
        $bars = 'red', $bg = 'white', $border = 'black', $grid = '#DDD') {
    // First of all let's ensure that every time we call this we
    // generate a new 'number' for this chart, it's needed to distinguish
    // if we have multiple charts on one page:
    static $idx = 0;
    $idx++;
    
    // Consider height to be 2 pixels less to take into account the borders:
    $height -= 2;
    
    // Now let's calculate our scale factor, add in a little because for
    // visual purposes we don't want it to ever hit the top.
    $scale = $height / (max($data) * 1.05);
    
    // Calculate our width:
    $width = count($data);
    
    // Now we can create some basic CSS that will be used by this:
    echo "
<style>
#chartout{$idx} {
    position: relative;
    height: ", $height + 2, "px;
    width: ", $width + 2, "px;
    background-color: {$border};
}
#chartin{$idx} {
    position: absolute;
    top: 1px;
    left: 1px;
    height: {$height}px;
    width: {$width}px;
    background-color: {$bg};
}
.bar{$idx} {
    position: absolute;
    bottom: 0px;
    background-color: {$bars};
    width: 1px;
    overflow: hidden;
}
.grid{$idx} {
    position: absolute;
    left: 0px;
    height: 1px;
    width: {$width}px;
    background-color: {$grid};
    padding: 0px;
    margin: 0px;
    overflow: hidden;
}
</style>
";

    // Now output the basic parts of the chart:
    echo "
<div id='chartout{$idx}'><div id='chartin{$idx}'>
";

    // Now create a grid pattern, divide the space into 5ths
    foreach(range(1,3) as $line) {
        $lh = round($line * ($height / 5));
        echo "<div class='grid{$idx}' style='top: {$lh}px'></div>\n";
    }
        
    // Now run through all elements of the array, making the actual bars
    foreach ($data as $pos => $val) {
        $barheight = round($val * $scale);
        echo "<div class='bar{$idx}' style='left:{$pos}px;
height:{$barheight}px'></div>\n";
    }
    
    // Finish off:
    echo "\n</div></div>\n";
}

// Let's generate 200 random points of data in two different arrays
$chartdata = array();
$chartdata2 = array();
for ($i = 0; $i < 200; $i++) {
    $chartdata[$i] = rand(1,1000);
    $chartdata2[$i] = rand(1,1000);
}

// Now generate a chart based upon this, 100 pixels tall:
create_chart($chartdata, 100);

// Generate another one that is only 50 pixels tall, with different colors
create_chart($chartdata2, 50, '#0C0', 'black', 'black', '#666');
?>