/******************************  *      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 );   $max_num=max ( $value_y );           //最大值   $min_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 ( $pic,1,100*$i+$empty_size_x-5,$high+4,$allnum/$y_line_width*$i,$color_2 );  //数轴标记   }   $x_line_width=floor ( $high/30 );     //横网格线数目   $x_line_density=$x_line_width==0 ? 0 :floor ( $high/$y_line_width );  //横网格线密度   if ( $zero_y > $high )           //绘制横网格线   {    imagestring ( $pic,1,0,$high-3,round ( $min_num_add,$fix ),$color_2 ); //零点数轴标记    for ( $i=1; $i <= $x_line_width; $i++ )    {     imagesetthickness ( $pic,1 );     //网格线宽     imageline ( $pic,0+$empty_size_x,$high-$x_line_density*$i,$width+$empty_size_x,$high-$x_line_density*$i,$color_3 );     imagesetthickness ( $pic,2 );     //轴点线宽     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 );  //数轴标记    }   }   else   {    imagestring ( $pic,1,$empty_size_x-8,$zero_y,"0",$color_2 ); //零点数轴标记    for ( $i=1; $i <= ceil ( $x_line_width/2 ); $i++ )    {     imagesetthickness ( $pic,1 );     //网格线宽     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 );     }     imagesetthickness ( $pic,2 );     //轴点线宽     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 );   //数轴标记     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 );  //数轴标记     }    }   }  //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 );  }    /*  函数描述及例子  参数说明：  $value_y -------- 包含你想生成折线图的数组，要求键值从0开始递增。  $width--------生成的折线图的网格宽度（不算白边）  $high--------高度  $strong-------线条粗细（默认为1）  $fix-------数据保留的位数（默认为取整）  */    for ( $i=0; $i<100; $i++ )  {   $value = rand ( 1,200 );   $value_y[]=$value;  }  line_stats_pic ( $value_y,500,100,1,1 );  ?>