Example code for drawing 24-hour histogram using php GD library

/*
24-hour bar chart
Author: taokey
QQ:29611705
* Editor: bbs.it-home.org
*/
 function h24($str){
 $hour = explode(",",$str);
 $hmax = max($hour);
 $ppix = 150/$hmax;
  //Calculate the height of the histogram
 $h0 = 190-$hour[0]*$ppix;
 $h1 = 190-$hour[1]*$ppix;
 $h2 = 190-$hour[2 ]*$ppix;
 $h3 = 190-$hour[3]*$ppix;
 $h4 = 190-$hour[4]*$ppix;
 $h5 = 190-$hour[5]*$ppix;
 $h6 = 190-$hour[6]*$ppix;
 $h7 = 190-$hour[7]*$ppix;
 $h8 = 190-$hour[8]*$ppix;
 $h9 = 190 -$hour[9]*$ppix;
 $h10 = 190-$hour[10]*$ppix;
 $h11 = 190-$hour[11]*$ppix;
 $h12 = 190-$hour[12 ]*$ppix;
 $h13 = 190-$hour[13]*$ppix;
 $h14 = 190-$hour[14]*$ppix;
 $h15 = 190-$hour[15]*$ppix;
 $h16 = 190-$hour[16]*$ppix;
 $h17 = 190-$hour[17]*$ppix;
 $h18 = 190-$hour[18]*$ppix;
 $h19 = 190 -$hour[19]*$ppix;
 $h20 = 190-$hour[20]*$ppix;
 $h21 = 190-$hour[21]*$ppix;
 $h22 = 190-$hour[22 ]*$ppix;
 $h23 = 190-$hour[23]*$ppix;
 //Create an img
 $img = imagecreate(755,210);
 //Background
 $ bgc = imagecolorallocate ($img, 245, 250, 254);
 //Black
 $bc = imagecolorallocate($img,0,0,0);
 //Draw the vertical axis
 imageline($img,15,30, 15,189, $bc);
 //Draw the horizontal axis
 imageline($img,15,190,750,190, $bc);
 //Draw the vertical axis points
 for($i=39,$j =10;$i<189;$i=$i+15,$j--){
 imageline($img,13,$i,15,$i, $bc);
 imagestring($img,1, 1,$i-4,$j."x", $bc);
 }
 //Draw horizontal axis points
 $t = true;
 for($i=31, $j=29;$i<750;$i=$j+1,$j=$j+15){
 if($t){
 $x=$i;
 $t=false;
 }else {
 $x=$i+1;
 $t=true;
 }
 imageline($img,$x,190,$x,192, $bc);
 }
   //竖轴标记
   $x = ceil($hmax/10);
   imagestring($img,2,10,15,"X=".$x,$bc);
   //竖轴标记
   //0点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,31,$h0,45,189,$color);
   imagestring($img,1,31,$h0-10,$hour[0],$color);
   imagechar($img,1,36,195,0,$bc);
   //1点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,61,$h1,75,189,$color);
   imagestring($img,1,61,$h1-10,$hour[1],$color);
   imagechar($img,1,66,195,1,$bc);
   //2点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,91,$h2,105,189,$color);
   imagestring($img,1,91,$h2-10,$hour[2],$color);
   imagechar($img,1,96,195,2,$bc);
   //3点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,121,$h3,135,189,$color);
   imagestring($img,1,121,$h3-10,$hour[3],$color);
   imagechar($img,1,126,195,3,$bc);
   //4点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,151,$h4,165,189,$color);
   imagestring($img,1,151,$h4-10,$hour[4],$color);
   imagechar($img,1,156,195,4,$bc);
   //5点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,181,$h5,195,189,$color);
   imagestring($img,1,181,$h5-10,$hour[5],$color);
   imagechar($img,1,186,195,5,$bc);
   //6点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,211,$h6,225,189,$color);
   imagestring($img,1,211,$h6-10,$hour[6],$color);
   imagechar($img,1,216,195,6,$bc);
   //7点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,241,$h7,255,189,$color);
   imagestring($img,1,241,$h7-10,$hour[7],$color);
   imagechar($img,1,246,195,7,$bc);
   //8点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,271,$h8,285,189,$color);
   imagestring($img,1,271,$h8-10,$hour[8],$color);
   imagechar($img,1,276,195,8,$bc);
   //9点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,301,$h9,315,189,$color);
   imagestring($img,1,301,$h9-10,$hour[9],$color);
   imagechar($img,1,306,195,9,$bc);
   //10点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,331,$h10,345,189,$color);
   imagestring($img,1,331,$h10-10,$hour[10],$color);
   imagestring($img,1,334,195,10,$bc);
   //11点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,361,$h11,375,189,$color);
   imagestring($img,1,361,$h11-10,$hour[11],$color);
   imagestring($img,1,364,195,11,$bc);
   //12点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,391,$h12,405,189,$color);
   imagestring($img,1,391,$h12-10,$hour[12],$color);
   imagestring($img,1,394,195,12,$bc);
   //13点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,421,$h13,435,189,$color);
   imagestring($img,1,421,$h13-10,$hour[13],$color);
   imagestring($img,1,424,195,13,$bc);
   //14点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,451,$h14,465,189,$color);
   imagestring($img,1,451,$h14-10,$hour[14],$color);
   imagestring($img,1,454,195,14,$bc);
   //15点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,481,$h15,495,189,$color);
   imagestring($img,1,481,$h15-10,$hour[15],$color);
   imagestring($img,1,481,195,15,$bc);
   //16点
$color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,511,$h16,525,189,$color);
   imagestring($img,1,511,$h16-10,$hour[16],$color);
   imagestring($img,1,511,195,16,$bc);
   //17点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,541,$h17,555,189,$color);
   imagestring($img,1,541,$h17-10,$hour[17],$color);
   imagestring($img,1,544,195,17,$bc);
   //18点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,571,$h18,585,189,$color);
   imagestring($img,1,571,$h18-10,$hour[18],$color);
   imagestring($img,1,571,195,18,$bc);
   //19点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,601,$h19,615,189,$color);
   imagestring($img,1,601,$h19-10,$hour[19],$color);
   imagestring($img,1,604,195,19,$bc);
   //20点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,631,$h20,645,189,$color);
   imagestring($img,1,631,$h20-10,$hour[20],$color);
   imagestring($img,1,634,195,20,$bc);
   //21点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,661,$h21,675,189,$color);
   imagestring($img,1,661,$h21-10,$hour[21],$color);
   imagestring($img,1,664,195,21,$bc);
   //22点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,691,$h22,705,189,$color);
   imagestring($img,1,691,$h22-10,$hour[22],$color);
   imagestring($img,1,694,195,22,$bc);
   //23点
   $color = imagecolorallocate($img, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
   imagefilledrectangle($img,721,$h23,735,189,$color);
   imagestring($img,1,721,$h23-10,$hour[23],$color);
   imagestring($img,1,724,195,23,$bc);
   //加个边框 加了之后不好看
   //imagerectangle($img, 0, 0, 754, 209, $bc);
   imagepng($img);
   imagedestroy($img);
}
$str = isset($_GET['str'])?$_GET['str']:"";
if($str){
   h24($str);
}
?>