<?php
include('class.jpeg_decoder.php');
$inputFile = "./input.jpg"; // Replace with your input file path
$jpeg_decoder_output_png = './output.png';
echo "<html><head><title>PHP JPEG Decoder Test</title></head><body>";
echo "<p>This is an experimental JPEG encoder and decoder ported to PHP from the JavaScript JPEG codec.</p>
<h1>Decoding: " . htmlspecialchars($inputFile) . "</h1>";
echo "<hr>";
echo "<h2>Decoder Output:</h2>";
echo "<pre style='background-color:#f0f0f0; border:1px solid #ccc; padding: 10px; max-height: 300px; overflow-y: scroll;'>";
try {
// --- Run the Decoder ---
list($frame, $jfif, $adobe, $components, $comments) = read_image_file($inputFile);
echo "</pre>"; // End decoder output pre block
echo "<hr>";
echo "<h2>Image Details:</h2>";
echo "<ul>";
echo "<li>Dimensions: {$frame['samplesPerLine']} x {$frame['scanLines']}</li>";
echo "<li>Precision: {$frame['precision']} bits</li>";
echo "<li>Mode: " . ($frame['baseline'] ? 'Baseline' : ($frame['progressive'] ? 'Progressive' : ($frame['extended'] ? 'Extended Sequential' : 'Unknown'))) . " (SOF Marker: 0x" . dechex($frame['type']) . ")</li>";
echo "<li>Components: " . count($frame['components']) . "</li>";
if ($jfif) echo "<li>JFIF Version: {$jfif['version']['major']}.{$jfif['version']['minor']}</li>";
if ($adobe) echo "<li>Adobe Marker Found: Yes (Transform: {$adobe['transformCode']})</li>";
if ($comments) echo "<li>Comments: " . count($comments) . "</li>";
echo "</ul>";
// --- Prepare for Image Output ---
$width = $frame['samplesPerLine'];
$height = $frame['scanLines'];
echo "<hr><h2>Processing Component Data for Output:</h2><pre>";
// Combine components into RGBA pixel data using getData
$pixelDataRGBA = getData($components, $width, $height, $adobe);
echo "</pre>";
// Prepare imageData structure (though copyToImageData doesn't strictly need it now)
$imageData = [
'width' => $width,
'height' => $height,
'data' => [] // Will be filled by copyToImageData (or directly assign $pixelDataRGBA)
];
// Copy (or just assign) the RGBA data
$imageData['data'] = $pixelDataRGBA;
// --- Create image with GD library ---
echo "<hr><h2>Creating PNG with GD:</h2>";
$image = imagecreatetruecolor($width, $height);
if (!$image) {
throw new Exception("GD: imagecreatetruecolor failed.");
}
// Enable alpha blending for transparency handling if needed (usually not for JPEG)
imagealphablending($image, true); // Blend alpha channel
imagesavealpha($image, true); // Save full alpha channel
$pixelIndex = 0;
for ($y = 0; $y < $height; $y++) {
for ($x = 0; $x < $width; $x++) {
if (!isset($imageData['data'][$pixelIndex+3])) {
// Data array might be shorter than expected if getData had issues
echo "<p>Warning: Ran out of pixel data at ($x, $y)</p>";
// Set pixel to black or break? Let's set to magenta for visibility
$color = imagecolorallocatealpha($image, 255, 0, 255, 0); // Opaque magenta
imagesetpixel($image, $x, $y, $color);
// Ensure pixelIndex advances correctly even on error if we continue
$pixelIndex += 4; // Move past the expected RGBA group
continue; // Skip to next pixel
}
$r = $imageData['data'][$pixelIndex++];
$g = $imageData['data'][$pixelIndex++];
$b = $imageData['data'][$pixelIndex++];
$a_byte = $imageData['data'][$pixelIndex++]; // Alpha 0-255
// GD alpha is 0 (opaque) to 127 (transparent)
$a_gd = floor((127 * (255 - $a_byte)) / 255); // Convert 0-255 alpha to 0-127 GD alpha
$a_gd = max(0, min(127, $a_gd)); // Clamp just in case
$color = imagecolorallocatealpha($image, $r, $g, $b, $a_gd);
if ($color === false) {
echo "<p>Warning: GD: imagecolorallocatealpha failed for pixel ($x, $y) with RGBA($r, $g, $b, $a_byte). Setting black.</p>";
$color = imagecolorallocatealpha($image, 0, 0, 0, 0); // Fallback: opaque black
}
imagesetpixel($image, $x, $y, $color);
}
}
echo "<p>GD Image object created.</p>";
// --- Save and Display ---
echo "<p>Saving PNG to: $jpeg_decoder_output_png</p>";
$saveResult = imagepng($image, $jpeg_decoder_output_png);
if (!$saveResult) {
echo "<p><b>Error: Failed to save PNG image! Check permissions and GD installation.</b></p>";
} else {
echo "<p>PNG saved successfully.</p>";
}
imagedestroy($image);
echo "<hr><h2>Comparison:</h2>";
echo "<h3>Original Input Image:</h3>";
echo "<img src='" . htmlspecialchars($inputFile) . "' alt='Original JPEG' title='Original JPEG' style='max-width: 400px; border: 1px solid blue;'>";
echo "<h3>Decoded Output Image (PNG):</h3>";
if ($saveResult) {
echo "<img src='" . htmlspecialchars($jpeg_decoder_output_png) . "?t=" . time() . "' alt='Decoded PNG' title='Decoded PNG' style='max-width: 400px; border: 1px solid green;'>"; // Add timestamp to avoid caching
} else {
echo "<p>(Failed to save decoded image)</p>";
}
} catch (Exception $e) {
echo '</pre><hr><h2 style="color: red;">Caught exception:</h2><pre>';
echo 'Message: ', htmlspecialchars($e->getMessage()), "\n";
echo 'File: ', $e->getFile(), "\n";
echo 'Line: ', $e->getLine(), "\n";
echo "\nStack trace:\n", htmlspecialchars($e->getTraceAsString());
echo "</pre>";
}
echo "</body></html>";
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input.png
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