PHP line chart generation functions and examples

/*
* php generates line chart
* by bbs.it-home.org
*/
function line_stats_pic($value_y,$width,$high,$strong=1,$ fix=0){
 //y value processing function
 function line_point_y($num,$width,$high,$max_num_add,$min_num_add,$y_pxdensity){
 $return=$high-floor(($num-$min_num_add+ $y_pxdensity)/(($max_num_add-$min_num_add)/$high));
 return $return;
}

 //Parameter processing
 $allnum=sizeof($value_y);
 $max_num=max($value_y) ; //Maximum value
 $min_num=min($value_y); //Minimum value
 $limit_m=$max_num-$min_num; //Extreme difference
 $max_num_add=$max_num+$limit_m*0.1; //Maximum value of axis
 $min_num_add=$min_num-$limit_m*0.1; //Axis minimum value
 $limit=$max_num_add-$min_num_add; //Range - coordinate axis y
 $y_pxdensity=($max_num_add-$min_num_add)/$high; / /y-axis density
 $x_pxdensity=floor($width/$allnum); //x-axis density
 reset($value_y); //Reset the array pointer to zero
 $i=0;
 foreach($value_y as $val ){
 $point_y[$i]=line_point_y($val,$width,$high,$max_num_add,$min_num_add,$y_pxdensity);
 $i++;
 }
 $zero_y=line_point_y(0,$width,$high ,$max_num_add,$min_num_add,$y_pxdensity); //Y value at zero point
 $empty_size_x=(strlen($max_num) > strlen($min_num) ? strlen($max_num) : strlen($min_num))*5+ 3; //The left blank

 //The image stream starts
 header("Content-type:image/png");
 $pic=imagecreate($width+$empty_size_x+10,$high+13);
 imagecolorallocate($ pic,255,255,255); //Background color
 $color_1=imagecolorallocate($pic,30,144,255); //Line color
 $color_2=imagecolorallocate($pic,0,0,0); //Black
 $color_3=imagecolorallocate( $pic,194,194,194); //Gray
 //Draw grid
 imagesethickness($pic,1); //Grid line width
 $y_line_width=floor($width/100); //Number of vertical grid lines
 $y_line_density=$y_line_width==0 ? 0 :floor($width/$y_line_width); //Vertical grid line density
 $point_zero_y=$zero_y > $high ? $high : $zero_y;
 imagestring($pic, 1,$empty_size_x-1,$high+4,"0",$color_2); //Zero point axis mark
 for($i=1;$i <= $y_line_width;$i++){ //Draw vertical network Grid line
 imagesethickness($pic,1); //Grid line width
 imageline($pic,$y_line_density*$i+$empty_size_x,0,$y_line_density*$i+$empty_size_x,$high,$color_3);
 imagesethickness ($pic,2); //Axis point line width
 imageline($pic,$y_line_density*$i+$empty_size_x,$point_zero_y-4,$y_line_density*$i+$empty_size_x,$point_zero_y,$color_2);
 imagestring( $pic,1,100*$i+$empty_size_x-5,$high+4,$allnum/$y_line_width*$i,$color_2); //Axis markers
 }
 $x_line_width=floor($high/30); // Number of horizontal grid lines
 $x_line_density=$x_line_width==0 ? 0 :floor($high/$y_line_width); //Density of horizontal grid lines
 if($zero_y > $high){ //Draw horizontal grid Line
 imagestring($pic,1,0,$high-3,round($min_num_add,$fix),$color_2); //Zero point axis mark
 for($i=1;$i <= $x_line_width; $i++){
 imagesethickness($pic,1); //Grid line width
 imageline($pic,0+$empty_size_x,$high-$x_line_density*$i,$width+$empty_size_x,$high-$x_line_density* $i,$color_3);
 imagesethickness($pic,2); //axis point line width
 imageline($pic,0+$empty_size_x,$high-$x_line_density*$i,3+$empty_size_x,$high- $x_line_density*$i,$color_2);
 imagestring($pic,1,0,$high-$x_line_density*$i-3,round($limit/$x_line_width*$i+$min_num_add,$fix),$color_2 ); //Number axis label
 }
 }else{
 imagestring($pic,1,$empty_size_x-8,$zero_y,"0",$color_2); //Zero point axis label
 for($i=1;$ i <= ceil($x_line_width/2);$i++){
 imagesethickness($pic,1); //Grid line width
 imageline($pic,0+$empty_size_x,$zero_y-$x_line_density*$i ,$width+$empty_size_x,$zero_y-$x_line_density*$i,$color_3);
 if($zero_y+$x_line_density*$i < $high){
 imageline($pic,0+$empty_size_x,$zero_y+$x_line_density *$i,$width+$empty_size_x,$zero_y+$x_line_density*$i,$color_3);
 }
 imagesethickness($pic,2); //axis point line width
 imageline($pic,0+$empty_size_x,$ zero_y-$x_line_density*$i,3+$empty_size_x,$zero_y-$x_line_density*$i,$color_2);
 if($zero_y+$x_line_density*$i < $high){
 imageline($pic,0+ $empty_size_x,$zero_y+$x_line_density*$i,3+$empty_size_x,$zero_y+$x_line_density*$i,$color_2);
 }
 imagestring($pic,1,0,$zero_y-$x_line_density*$i-3 ,round($limit/$x_line_width*$i,$fix),$color_2); //Number axis label
 if($zero_y+$x_line_density*$i < $high){
 imagestring($pic,1,0, $zero_y+$x_line_density*$i-3,round(-$limit/$x_line_width*$i,$fix),$color_2); //Axis markers
 }
 }
 }
  //绘制轴线
  imagesetthickness($pic,2);    //轴线宽
  imageline($pic,1+$empty_size_x,0,1+$empty_size_x,$high,$color_2);
  if($zero_y > $high){       //x轴位置
    imageline($pic,0+$empty_size_x,$high,$width+$empty_size_x,$high,$color_2);
  }else{
    imageline($pic,0+$empty_size_x,$zero_y,$width+$empty_size_x,$zero_y,$color_2);
  }
  //产生折线
  $point_x=0;
  $j=0;
  imagesetthickness($pic,$strong); //线条粗细
  while($j+1 < $allnum){
  imageline($pic,$point_x+2+$empty_size_x,$point_y[$j],$point_x+$x_pxdensity+2+$empty_size_x,$point_y[$j+1],$color_1);
  $point_x+=$x_pxdensity;
    $j++;
  }
  imagepng($pic);
  imagedestroy($pic);
  }

  for($i=0;$i<100;$i++){
      $value = rand(1,200);
      $value_y[]=$value;
  }
  line_stats_pic($value_y,500,100,1,1);
?>