PHP 实现的将图片转换为TXT

PHP实例
<?php
/*
2015年10月19日10:24:59
*/
// 关上一幅图像
$file_name='d:ascii_dora.png';
$chars = "$@B%8&WM#*oahkbdpqwmZO0QLCJUYXzcvunxrjft/|()1{}[]?-_+~<>i!lI;:,"^`'. ";
function getimgchars($color_tran,$chars){
  $length = strlen($chars);
  $alpha=$color_tran['alpha'];
  $r=$color_tran['red'];
  $g=$color_tran['green'];
  $b=$color_tran['blue'];
  $gray = intval(0.2126 * $r + 0.7152 * $g + 0.0722 * $b);
  if($gray==0){
    return '.';
  }
  if($gray<196){
     $unit = (256.0 + 1)/$length;
    return $chars[intval($gray/$unit)];
  }
  return " ";
}
function color_img($color_tran,$chars){
  $length = strlen($chars);
  $alpha=$color_tran['alpha'];
  $r=$color_tran['red'];
  $g=$color_tran['green'];
  $b=$color_tran['blue'];
  $gray = intval(0.2126 * $r + 0.7152 * $g + 0.0722 * $b);
  $rand=rand (0,$length-1);
  $color="rgb(".$r.",".$g.",".$b.")";
  $char=$chars[$rand];
  return '<span style="color:'.$color.'" >'.$char."</span>";;
  
}
function resize_img($file_name,$chars,$flage=true){
  //header('Content-Type: image/jpeg');
  list($width,$height,$type) = getimagesize($file_name);
  $fun='imagecreatefrom' . image_type_to_extension($type,false);
  if($type==3){
    $flage=false;
  }
  $fun($file_name);
  $new_height =100;
  $percent=$height/$new_height;
  $new_width=$width/$percent;
  $image_p = imagecreatetruecolor($new_width,$new_height);
  $image = $fun($file_name);
  imagecopyresampled($image_p,$image,$new_width,$new_height,$width,$height);
  if($flage){
    return $image_p;
  }else{
    return $image;
  }
}
$im=resize_img($file_name,$chars);
$width=imagesx($im);
$height=imagesy($im);
$back_text="";
for($i=1;$i<=$height;$i++){
  for($j=1;$j<=$width;$j++){
    $color_index = imagecolorat($im,$j-1,$i-1);
    $color_tran = imagecolorsforindex($im,$color_index);
    $back_text.=color_img($color_tran,false);
  }
  $back_text.="<br/>";
}
 
echo "<pre>";
echo $back_text;
echo "</pre>";
//file_put_contents('1.txt',$back_text);