PHP 实现的将图片转换为TXT

$file_name='d:asciidora.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[$rand];
return ''.$char."";;

}

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.="
";
}

echo "

";

echo $back_text;

echo "