Example code for dynamically generating line charts with PHP GD library

/**
* php GD library generates line charts, bar charts, and pie charts
* by bbs.it-home.org
*/
$img_gao=170;
$img_kuan=0;
$jiange=30;//The abscissa between points Interval, the width of the generated image will automatically change according to the amount of incoming data
$zuo=20;//Leave blank on the left side
$you=20;//Leave blank on the right side
$shang=20;//Leave it on the top Empty
$xia=20;//Leave blank
$zuidashujuzhi=1;
$p_x = array();//Point abscissa
$p_y = array();//Point ordinate
$y_name=split( ",",$_GET["x_name"]);
if ($_GET["a"]=="") die("error id:0");
$shuju=split(",",$_GET ["a"]);
//Get the maximum value on the vertical axis
for($i=0;$i　if(!is_numeric($shuju[$i])) die("error id:1");
　if($shuju[$i]>$zuidashujuzhi) $zuidashujuzhi=$shuju[$i];
}
//Get the image width
$img_kuan=$zuo+$you +count($shuju)*$jiange;
//Then create image resources
$image = imagecreate($img_kuan,$img_gao);
//Gray background
$white = imagecolorallocate($image, 0xEE, 0xEE, 0xEE) ;
//The coordinate axis is displayed in black
$zuobiao_yanse = imagecolorallocate($image, 0x00, 0x00, 0x00);
//The polyline is displayed in blue
$xian_yanse = imagecolorallocate($image, 0x00, 0x00, 0xFF);
 //Draw coordinates
//Horizontal axis
imageline ($image, $zuo, $img_gao-$xia, $img_kuan-$you/2, $img_gao-$xia, $zuobiao_yanse);
//Vertical axis
imageline ( $image, $zuo, $shang/2, $zuo, $img_gao-$xia, $zuobiao_yanse);
//Get the coordinates of each point
for($i=0;$i　array_push ($p_x, $zuo+$i*$jiange);
　array_push ($p_y, $shang+round(($img_gao-$shang-$xia)*(1-$shuju[$i] /$zuidashujuzhi)));
}
//Vertical axis scale
imageline ( $image, $zuo, $shang, $zuo+6, $shang, $zuobiao_yanse);
imagestring ( $image, 1, $zuo/ 4, $shang,$zuidashujuzhi, $zuobiao_yanse);
imageline ( $image, $zuo, $shang+($img_gao-$shang-$xia)*1/4, $zuo+6, $shang+($img_gao-$ shang-$xia)*1/4, $zuobiao_yanse);
imagestring ( $image, 1, $zuo/4, $shang+($img_gao-$shang-$xia)*1/4,$zuidashujuzhi*3/4 , $zuobiao_yanse);
imageline ( $image, $zuo, $shang+($img_gao-$shang-$xia)*2/4, $zuo+6, $shang+($img_gao-$shang-$xia)*2 /4, $zuobiao_yanse);
imagestring ($image, 1, $zuo/4, $shang+($img_gao-$shang-$xia)*2/4,$zuidashujuzhi*2/4, $zuobiao_yanse);
imageline ($image, $zuo, $shang+($img_gao-$shang-$xia)*3/4, $zuo+6, $shang+($img_gao-$shang-$xia)*3/4, $zuobiao_yanse);
imagestring ($image, 1, $zuo/4, $shang+($img_gao-$shang-$xia)*3/4,$zuidashujuzhi*1/4, $zuobiao_yanse);
//Horizontal axis scale
for( $i=0;$i　imageline ( $image, $zuo+$i*$jiange, $img_gao-$xia, $zuo+$i*$jiange, $img_gao-$ xia-6, $zuobiao_yanse);
　imagestring ( $image, 1, $zuo+$i*$jiange-$jiange/4, $shang+($img_gao-$shang-$xia)+2,$y_name[$i] , $zuobiao_yanse);
}
//Polyline
$shuju_yanse_int=0;
for($i=0;$i　if( $i+1<>count($shuju)){
　　imageline ( $image, $p_x[$i], $p_y[$i], $p_x[$i+1], $p_y[$i+1 ], $xian_yanse);
　　 imagefilledrectangle($image, $p_x[$i]-1, $p_y[$i]-1, $p_x[$i]+1, $p_y[$i]+1, $xian_yanse );
　}
}
//The last loop did not draw the last point effect, here we need to add
imagefilledrectangle($image, $p_x[count($shuju)-1]-1, $p_y[count($ shuju)-1]-1, $p_x[count($shuju)-1]+1, $p_y[count($shuju)-1]+1, $xian_yanse);
 //Mark data values
for($i=0;$i　imagestring ( $image, 3, $p_x[$i]+4, $p_y[$i]- 12,$shuju[$i], $zuobiao_yanse);
}
//Set the file header
header('Content-type: image/png');
//Output image
imagepng($image);
/ /Release resources
imagedestroy($image);
?>

Second, how to use Insert the following code where the image needs to be displayed:

Instructions: The value of a is calculated by yourself; The text format of a is a string of several data connected by ",", which is passed in through the get method. Since writing Chinese into graphics requires more PHP environment configuration, here is an HTML solution: You only need to dynamically generate a table to place the horizontal axis coordinate scale names based on the number of data.

Example:

for($ i=0;$i<12;$i++) {　echo "";}?>

".$i."月