PHP绘制心电形状曲线统计图表[源码]

　　 先看下最终效果:

下面为PHP代码:

/******************************  
*            折线图生成函数  
******************************/  
function line_stats_pic($value_y,$width,$high,$strong=1,$fix=0){  
//y值处理函数  
function line_point_y($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;  
}  
 
//参数处理  
$allnum=sizeof($value_y);  
$maxmax_num=max($value_y);                            //最大值  
$minmin_num=min($value_y);                            //最小值  
$limit_m=$max_num-$min_num;                        //极差  
$max_num_add=$max_num+$limit_m*0.1;                //轴最大值  
$min_num_add=$min_num-$limit_m*0.1;                //轴最小值  
$limit=$max_num_add-$min_num_add;                 //极差-坐标轴y  
$y_pxdensity=($max_num_add-$min_num_add)/$high;    //y轴密度  
$x_pxdensity=floor($width/$allnum);                //x轴密度  
reset($value_y);                                 //将数组指针归零  
$i=0;  
foreach($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);    //零点的y值  
$empty_size_x=(strlen($max_num) > strlen($min_num) ? strlen($max_num) : strlen($min_num))*5+3;                    //左边空白  
 
//图片流开始  
header("Content-type:image/png");  
$pic=imagecreate($width+$empty_size_x+10,$high+13);  
imagecolorallocate($pic,255,255,255);         //背景色  
$color_1=imagecolorallocate($pic,30,144,255); //线条色  
$color_2=imagecolorallocate($pic,0,0,0);     //黑色  
$color_3=imagecolorallocate($pic,194,194,194);//灰色  
//绘制网格  
imagesetthickness($pic,1);                    //网格线宽  
$y_line_width=floor($width/100);             //纵网格线数目  
$y_line_density=$y_line_width==0 ? 0 :floor($width/$y_line_width); //纵网格线密度  
$point_zero_y=$zero_y > $high ? $high : $zero_y;  
imagestring($pic,1,$empty_size_x-1,$high+4,"0",$color_2); //零点数轴标记  
for($i=1;$i = $y_line_width;$i++){            //绘制纵网格线  
    imagesetthickness($pic,1);                 //网格线宽  
    imageline($pic,$y_line_density*$i+$empty_size_x,0,$y_line_density*$i+$empty_size_x,$high,$color_3);  
    imagesetthickness($pic,2);                 //轴点线宽  
    imageline($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,1,10