PHP将文件转换为JPG

Question

目前，我了解文件到图像加密

首先，我上传一个文件，例如testing.txt文件，然后从该文件中获取字节数组。 然后，从该字节数组中，我要制作一个jpg文件。

如何从文件中获取字节数组？ 然后从字节数组制作一个jpg？

这是我的代码：

//file to by array
$filename = "testing.txt"; 
$handle = fopen($filename, "rb"); 
$fsize = filesize($filename); 
$contents = fread($handle, $fsize); 
$byteArray = unpack("N*",$contents);

echo "<pre>";
print_r($byteArray); 
echo "</pre>";


// from byte array to jpg
$fp = fopen("result.jpg", "wb");
$len = count($byteArray);
for ($i = 1; $i <= $len; $i++)
{
    $data = pack("C*",$byteArray[$i]);
    fwrite($fp, $data);
}
fclose($fp);

谢谢

Answer 1

这是一个代码示例，如何将文本数据转换为二进制数据，然后将其传递给图像。 如上面的评论所述，png是执行此操作的更好选择。

<?php
const CHARS = [
    'A', 'B', 'C', 'D', 'E',
    'F', 'G', 'H', 'I', 'J',
    'K', 'L', 'M', 'N', 'O',
    'P', 'Q', 'R', 'S', 'T',
    'U', 'V', 'W', 'X', 'Y',
    'Z', 'a', 'b', 'c', 'd',
    'e', 'f', 'g', 'h', 'i',
    'j', 'k', 'l', 'm', 'n',
    'o', 'p', 'q', 'r', 's',
    't', 'u', 'v', 'w', 'x',
    'y', 'z', '0', '1', '2',
    '3', '4', '5', '6', '7',
    '8', '9', '+', '/'
];

function charToInt($char) {
    return array_search($char, CHARS);
}

function textToBin($content) {
    $content_len = strlen($content);
    $bin = '';

    // Convert content into binary
    for ($a = 0; $a < $content_len; $a++) {
        $bin .= sprintf("%06d", decbin(charToInt($content[$a])));
    }

    // Fill rest of last chunk with zeros as padding and calculate offset
    $offset = 8 - (strlen($bin) % 8);
    $bin .= str_repeat("0", $offset);

    // Return binary string
    return $bin;
}

function makeImage($textFilePath) {
    //get text data and encode it to binary
    $data = base64_encode(file_get_contents($textFilePath));
    $binaryData = textToBin($data);

    //split binary data into 8 bit chunks
    $chunks = explode(" ", trim(chunk_split($binaryData, 8, " ")));

    // Add extra chunks to make total chuncks divisible by 3 for complete RGB pixels
    while (count($chunks) % 3 != 0) {
        $chunks[] = 0xFF;
    }
    // Calculate dimensions of image
    $dim = ceil(sqrt(count($chunks) / 3));
    $img = imagecreatetruecolor($dim, ceil(count($chunks) / $dim / 3));
    $colors = array();

    // Convert groups of 3 chunks into pixels
    for ($a = 0; $a < count($chunks); $a += 3) {
        array_push($colors, imagecolorallocate($img, bindec($chunks[$a]), bindec($chunks[$a+1]), bindec($chunks[$a+2])));
    }

    // Set color for each pixel
    for ($j = 0; $j < $dim; $j++) {
        for ($i = 0; $i < $dim; $i++) {
            @imagesetpixel($img, $i, $j, $colors[($j*$dim)+$i]);
        }
    }

    // Output image
    imagepng($img, 'output.png');
    imagedestroy($img);

}

makeImage($argv[1]);

运行php test.php <path to text file>转换文件并将其保存到output.png

Answer 2

如果要隐藏图像中的文本，请设置以下两个文件：

img.txt

Lorem ipsum dolor sit amet, cu vis assum mazim audiam, no everti recusabo mel. Facer hendrerit disputationi ei nam, ex nec vidit nonumes liberavisse. Oporteat qualisque eum id, vis semper vivendum vulputate at. Meis theophrastus vix in.

和

img.php

<?php

/**
 *
 * PHP Convert a Text-File to a PNG (and reverse)
 *
 * https://stackoverflow.com/q/51416394/5201919
 *
 * powered by adilbo.com
 *
 */

// HEADLINE TO BROWSER
echo '<pre><h1>PHP Convert a Text-File to a PNG (and reverse)</h1>';

// DEBUG INFOS TO BROWSER
echo '<h2>INPUT (img.txt)</h2><b>TEXT</b><br>';

// MAIN FUNCTION CALL TO WRITE TEXT TO IMAGE
$textInput = text2image( 'img.txt', 'img.png' );

// DEBUG INFOS TO BROWSER
echo $textInput . '<br><b>BINARY</b><br>';
echo implode( ' ', str_split( ascii2hex($textInput), 2) );
echo '<h2>OUTPUT (img.png)</h2>';
echo '<b>IMAGE (1x1 Pixel)</b><br>';
echo '<img border="1" src="img.png">';

// MAIN FUNCTION CALL TO GET TEXT FROM IMAGE
$textOutput = image2text( 'img.png' );

// DEBUG INFOS TO BROWSER
echo '<br><br><b>TEXT</b><br>' . $textOutput;
echo '<br><b>BINARY</b><br>';
echo implode( ' ', str_split( ascii2hex($textOutput), 2) );
echo '<br><br><b>"L o r e m" - Controll Values</b><br>';
echo strtoupper( dechex( ord( 'L' ) ) ) . ' ';
echo strtoupper( dechex( ord( 'o' ) ) ) . ' ';
echo strtoupper( dechex( ord( 'r' ) ) ) . ' ';
echo strtoupper( dechex( ord( 'e' ) ) ) . ' ';
echo strtoupper( dechex( ord( 'm' ) ) );

// HELPER FUNCTIONS
function ascii2hex( $ascii ) {

  // ini var
  $string = '';

  // loop string each digit
  for ($i = 0 ; $i < strlen( $ascii ) ; $i ++ ) {

    // convert ascii value to hex
    $byte = strtoupper( dechex( ord( substr( $ascii, $i, 1 ) ) ) );

    // add hex value two-digits
    $string .= str_repeat( '0', 2 - strlen( $byte ) ) . $byte;

  // end loop
  }

  // give back
  return $string;
}

function hex2ascii( $hex ) {

  // ini var
  $string = '';

  // loop string each two digits
  for ($i = 0 ; $i < strlen( $hex ) ; $i += 2 ) {

    // add each two digits hex2dec and then to ascii
    $string .= chr( hexdec( substr( $hex, $i, 2 ) ) );

  // end loop
  }

  // give back
  return $string;
}

function text2image( $textFilename, $imageFilename ) {

  // READ TEXT FILE TO STRING
  $string = file_get_contents( $textFilename );

  // OPEN PNG-IMAGE FOR WRITING DATA
  $fileHandl = fopen( $imageFilename, 'wb' );

  // WRITE PNG-IMAGE-PART
  fwrite( $fileHandl, hex2bin( '89504e470d0a1a0a0000000d494844520000000100000001010300000025db56ca00000003504c5445000000a77a3dda0000000174524e530040e6d8660000000a4944415408d76360000000020001e221bc330000000049454e44ae426082' ) );

  // WRITE CONVERTET DATA TO IMAGE FILE
  fwrite( $fileHandl, ascii2hex($string) );

  // CLOSE IMAGE FILE AFTER WRITING
  fclose( $fileHandl );

  // give back clear ascii text from file
  return $string;

}

function image2text( $imageFilename ) {

  // get image data (with offset of 95 chars for the PNG-Image Part)
  $binaryData = file_get_contents( 'img.png', FALSE, NULL, 95 );

  // convert data from hex to ascii string
  $text = hex2ascii( $binaryData );

  // give back
  return $text;

}

它将生成一个名为img.png的透明1x1像素PNG图片， img.png包含您的文字，您还可以从图片中读取文字！

图像看起来不是那么好，就像@DmytroZasiadko的答案一样，但是带有“从图像中读取文本”功能；-)