Making a Pie Chart Questionnaire with PHP_PHP Tutorial

In the survey program, we need to generate various charts based on statistical data to vividly represent the percentage of the survey. PHP also lives up to expectations in this regard. It can be implemented by loading the GD library from the beginning. Pie charts are a great way to see one value as a percentage of a total value. Now we will use PHP to implement a pie chart and tell you about the application of PHP in this area. Its design idea is: first use imagecreate() to generate a blank graphic, and then use the imageare() arc function to first draw an arc in the blank graphic, and then draw two lines to connect the center of the circle and the arc endpoints (PHP image function You cannot draw a fan shape), and then use the imagefilltoborder function to fill the fan shape. The program is implemented as follows:
$#@60;?php

/*
Convert angles to radians
*/
function radians ($degrees)
{
return($degrees * (pi()/180.0));
}
/*
** Get the value of x, y point on the circle with center (0, 0)
*/
function circle_point($degrees, $diameter)
{
$x = cos(radians($degrees)) * ($diameter/2);
$y = sin(radians($degrees)) * ($diameter/2);

return (array($x, $y));
}
//Parameters for filling the chart
$ChartDiameter = 200; //Chart diameter
$ChartFont = 2; // Chart font
$ChartFontHeight = imagefontheight($ChartFont);//Chart font size
$ChartData = array("75","45");//The data used to generate the chart can be obtained from the database Obtain to confirm
//$ChartLabel = array("yes", "no"); //The name corresponding to the data

//Determine the size of the graphic
$ChartWidth = $ChartDiameter + 20;
$ChartHeight = $ChartDiameter + 20 +
(($ChartFontHeight + 2) * count($ChartData));

//Determine the total number of statistics
for($index = 0; $index $#@60; count($ChartData); $index++)
{
$ChartTotal += $ChartData[$ index];
}

$ChartCenterX = $ChartDiameter/2 + 10;
$ChartCenterY = $ChartDiameter/2 + 10;

//Generate blank graphics
$image = imagecreate($ChartWidth, $ChartHeight);

//Assign color
$colorBody = imagecolorallocate($image, 0xFF, 0xFF, 0xFF);
$colorBorder = imagecolorallocate($image, 0x00, 0x00, 0x00);
$colorText = imagecolorallocate ($image, 0x00, 0x00, 0x00);

$colorSlice = imagecolorallocate($image, 0xFF, 0x00, 0x00);
$colorSlice[] = imagecolorallocate($image, 0x00, 0xFF, 0x00);

//Fill the background
imagefill($image, 0, 0, $colorBody);

/*
** Draw each sector
*/
$Degrees = 0;
for($index = 0; $index $#@60; count($ ChartData); $index++)
{
$StartDegrees = round($Degrees);
$Degrees += (($ChartData[$index]/$ChartTotal)*360);
$EndDegrees = round($Degrees);

$CurrentColor = $colorSlice[$index%(count($colorSlice))];

//Draw F
imagearc($image,$ChartCenterX,$ChartCenterY,$ChartDiameter,
$ChartDiameter,$StartDegrees,$EndDegrees, $CurrentColor);

//Draw a straight line
list($ArcX, $ArcY) = circle_point($StartDegrees, $ChartDiameter);
imageline($image,$ChartCenterX,$ChartCenterY,floor($ChartCenterX + $ArcX) ,
floor($ChartCenterY + $ArcY),$CurrentColor);
//Draw a straight line
list($ArcX, $ArcY) = circle_point($EndDegrees, $ChartDiameter);
imageline( $image,$ChartCenterX,$ChartCenterY,ceil($ChartCenterX + $ArcX),
ceil($ChartCenterY + $ArcY),$CurrentColor);

//Fill the sector
$MidPoint = round((($EndDegrees - $StartDegrees)/2) + $StartDegrees);
list($ArcX, $ArcY) = circle_point($MidPoint, $ChartDiameter /2);
imagefilltoborder($image,floor($ChartCenterX + $ArcX),floor($ChartCenterY + $ArcY),
$CurrentColor,$CurrentColor);
}

//画边框
imagearc($image,
$ChartCenterX,
$ChartCenterY,
$ChartDiameter,
$ChartDiameter,
0,
180,
$colorBorder);

imagearc($image,
$ChartCenterX,
$ChartCenterY,
$ChartDiameter,
$ChartDiameter,
180,
360,
$colorBorder);

imagearc($image,
$ChartCenterX,
$ChartCenterY,
$ChartDiameter+7,
$ChartDiameter+7,
0,
180,
$colorBorder);

imagearc($image,
$ChartCenterX,
$ChartCenterY,
$ChartDiameter+7,
$ChartDiameter+7,
180,
360,
$colorBorder);

imagefilltoborder($image,
floor($ChartCenterX + ($ChartDiameter/2) + 2),
$ChartCenterY,
$colorBorder,
$colorBorder);

//画图例
for($index = 0; $index $#@60; count($ChartData); $index++)
{
$CurrentColor = $colorSlice[$index%(count($colorSlice))];
$LineY = $ChartDiameter + 20 + ($index*($ChartFontHeight+2));

//draw color box
imagerectangle($image,
10,
$LineY,
10 + $ChartFontHeight,
$LineY+$ChartFontHeight,
$colorBorder);

imagefilltoborder($image,
12,
$LineY + 2,
$colorBorder,
$CurrentColor);

//画标签
imagestring($image,
$ChartFont,
20 + $ChartFontHeight,
$LineY,
"$ChartLabel[$index]: $ChartData[$index]",
$colorText);
}

//到此脚本 已经生了一幅图像的，现在需要的是把它发到浏览器上，重要的一点是要将标头发给浏览器，让它知道是一个GIF文件。不然的话你只能看到一堆奇怪的乱码

header("Content-type: image/gif");
//输出生成的图片
imagegif($image);
?$#@62;
保存为chart.php,运行程序其结果如图1.
但这是在服务器端生在GIF图片，我们要在HTML文件中应用就需要如下格式来调用它：
$#@60;?php
echo "$#@60;img src=chart.php $#@62; "
?$#@62;

　　注：运行环境为apache_1_3_12+php-4.0RC1+win98,windows平台下. 在PHP中图像函数都是在GD库中完成，GD库实际是处理GIF格式的免费软件。要加载GD扩展才能使用php4的GD库可以到www.phpuser.com下载。解压COPY php_gd.dll文件到PHP的执行目录，然后编辑php.ini配置文件，找到配置文件中;extension=php_gd.dll"这行 去掉"；"号，如果没有发现则在配置文件的Dynamic Extensions 后增加一行extension=php_gd.dl。最后运行phpinfo()函数，你就可以看到支持信息。