<?php 
session_start();
$_SESSION['code']= 0;
header("Content-type: image/png"); 
$im = @imagecreatetruecolor(70, 27) or die("建立影象失敗"); //建立圖片
$background_color = imagecolorallocate($im, 250, 250, 250); //圖片新增背景
imagefill($im,0,0,$background_color);
$border_color = imagecolorallocate($im,0,0,0); //邊框色
imagerectangle($im,0,0,69,26,$border_color);

//噪音線
for($i = 0;$i < 7;$i++){
    $x1 = rand(3,25);
    $y1 = rand(2,25);//開始位置
    
    $x2 = rand(45,68);//結束位置
    $y2 = rand(2,25);
    $line_color = imagecolorallocate($im,rand(190,255),rand(190,255),rand(190,255)); //噪音線顏色
    imageline($im,$x1,$y1,$x2,$y2,$line_color); 
}
//顯示的文字
$font_size = 18;
$first_num = 0;//圖片中顯示的數字，包含中文
$second_num = 0;

$first_value = 0;//後臺預算的數字
$second_value = 0;
$hanzi_num = array("一","二","三","四","五","六","七","八","九","十");

//$str_HanZiOrNot = rand(0,1);//是否是漢字的判斷
$result = 0;
$arrCapcher = array("+","-");
$capter = $arrCapcher[rand(0,1)];
switch ($capter){
    case "+":
        //產生第一個數字
        if(rand(0,1) == 0){// ==0表示純數字
            $first_num = rand(2,10);
            $first_value = $first_num;
        }
        else{       //漢字
            $index_ = rand(0,9);
            $first_num = $hanzi_num[$index_];
            $first_value = $index_ + 1;
        }
        //產生第二個數字
        if(rand(0,1) == 0){//      ==0純數字
            $second_num = rand(0,10);
            $second_value = $second_value;
        }
        else{
            $index_ = rand(0,9);
            $second_num = $hanzi_num[$index_];
            $second_value = $index_ + 1;
        }
        
        $result = $first_value + $second_value;
        break;
    case "-":
        //產生第一個數字
        if(rand(0,1) == 0){// ==0表示純數字
            $first_num = rand(3,10);
            $first_value = $first_num;
        }
        else{       //漢字
            $index_ = rand(0,9);
            $first_num = $hanzi_num[$index_];
            $first_value = $index_ + 1;
        }
        //產生第二個數字
        if(rand(0,1) == 0){//      ==0純數字
            $second_num = rand(0,$first_value-1);
            $second_value = $second_value;
        }
        else{
            $index_ = rand(0,$first_value-1);
            $second_num = $hanzi_num[$index_];
            $second_value = $index_ + 1;
        }
        
        $result = $first_value - $second_value;
        break;
}

$x = rand(2,5);
$arr_X_Y = array(array($x,rand(1,3)),array($x+$font_size,rand(1,4)),array($x+2*$font_size,rand(1,3)),array($x+3*$font_size,rand(1,4)));
$str_char = array($first_num,$capter,$second_num,"=","?");
$strs = "";//文字字串
foreach ($str_char as $value){
    $strs .= $value;
}
    $text_color = imagecolorallocate($im,rand(50,120),rand(50,120),rand(50,120)); 
    imagettftext($im,15,0,1,20,$text_color,"font/a.ttf",$strs); //輸入漢字時必須使用漢字的字型font
$_SESSION['code'] = $result;
imagepng($im); 
imagedestroy($im);
?>