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[PHPBB-17692] Fix EXIF orientation during client-side resize #7016

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[PHPBB-17692] Fix EXIF orientation during client-side resize #7016

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719fc9b
[ticket/17692] Fix EXIF orientation during client-side resize
gvp9000 Aug 24, 2026
d379a3c
[ticket/17692] Load EXIF compatibility layer for Plupload
gvp9000 Aug 24, 2026
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239 changes: 239 additions & 0 deletions phpBB/assets/javascript/plupload.exif-compat.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,239 @@
/**
* phpBB Plupload EXIF/JPEG compatibility layer.
*
* Purpose:
* - Keep phpBB 3.3.17's original assets/plupload/plupload.full.min.js untouched.
* - Fix modern-browser EXIF orientation handling without editing the bundled vendor file.
*
* Must be loaded AFTER plupload.full.min.js and BEFORE assets/javascript/plupload.js.
*/
(function (window) {
'use strict';

// Preserve the behaviour of the previous custom build: modern browsers are
// treated as already applying EXIF orientation while decoding JPEG images.
window.browserRotates = true;

function byteAt(binary, offset) {
return binary.charCodeAt(offset) & 255;
}

/**
* Reset EXIF Orientation (IFD0 tag 0x0112) to 1 in a JPEG binary string.
* Malformed/unsupported metadata is left untouched.
*/
function normalizeExifOrientation(binary) {
if (typeof binary !== 'string' || binary.length < 12 ||
byteAt(binary, 0) !== 0xFF || byteAt(binary, 1) !== 0xD8) {
return binary;
}

var position = 2;

while (position + 4 <= binary.length) {
if (byteAt(binary, position) !== 0xFF) {
position++;
continue;
}

var marker = byteAt(binary, position + 1);

// Start Of Scan / End Of Image: no more metadata headers follow.
if (marker === 0xDA || marker === 0xD9) {
break;
}

// Standalone markers have no length field.
if (marker === 0xD8 || marker === 0x01 ||
(marker >= 0xD0 && marker <= 0xD7)) {
position += 2;
continue;
}

var segmentLength = (byteAt(binary, position + 2) << 8) |
byteAt(binary, position + 3);

if (segmentLength < 2 || position + 2 + segmentLength > binary.length) {
break;
}

var payload = position + 4;

if (marker === 0xE1 &&
payload + 14 <= binary.length &&
binary.substr(payload, 6) === 'Exif\x00\x00') {

var tiff = payload + 6;
var littleEndian =
byteAt(binary, tiff) === 0x49 && byteAt(binary, tiff + 1) === 0x49;
var bigEndian =
byteAt(binary, tiff) === 0x4D && byteAt(binary, tiff + 1) === 0x4D;

if (!littleEndian && !bigEndian) {
return binary;
}

function read16(offset) {
return littleEndian
? byteAt(binary, offset) | (byteAt(binary, offset + 1) << 8)
: (byteAt(binary, offset) << 8) | byteAt(binary, offset + 1);
}

function read32(offset) {
if (littleEndian) {
return (
byteAt(binary, offset) |
(byteAt(binary, offset + 1) << 8) |
(byteAt(binary, offset + 2) << 16) |
(byteAt(binary, offset + 3) << 24)
) >>> 0;
}

return (
(byteAt(binary, offset) << 24) |
(byteAt(binary, offset + 1) << 16) |
(byteAt(binary, offset + 2) << 8) |
byteAt(binary, offset + 3)
) >>> 0;
}

if (tiff + 8 > binary.length || read16(tiff + 2) !== 42) {
return binary;
}

var ifd0Offset = read32(tiff + 4);
var ifd0 = tiff + ifd0Offset;

if (ifd0Offset > binary.length || ifd0 + 2 > binary.length) {
return binary;
}

var entries = read16(ifd0);

for (var index = 0; index < entries; index++) {
var entry = ifd0 + 2 + index * 12;

if (entry + 12 > binary.length) {
return binary;
}

if (read16(entry) === 0x0112 &&
read16(entry + 2) === 3 &&
read32(entry + 4) === 1) {

var valuePosition = entry + 8;
var replacement = littleEndian ? '\x01\x00' : '\x00\x01';

return binary.substring(0, valuePosition) +
replacement +
binary.substring(valuePosition + 2);
}
}

return binary;
}

position += 2 + segmentLength;
}

return binary;
}

// Keep the helper globally available, matching the previous template's API.
window.phpbbNormalizeExifOrientation = normalizeExifOrientation;

function patchHtml5Runtime() {
var moxie = window.moxie;

if (!moxie || !moxie.runtime || !moxie.runtime.Runtime) {
return;
}

var Runtime = moxie.runtime.Runtime;
var OriginalHtml5Runtime = Runtime.getConstructor('html5');

if (!OriginalHtml5Runtime || OriginalHtml5Runtime.__phpbbExifCompatWrapped) {
return;
}

function PhpbbHtml5Runtime() {
// Build the completely stock HTML5 runtime first.
OriginalHtml5Runtime.apply(this, arguments);

var shim = this.getShim && this.getShim();
var OriginalImage = shim && shim.Image;

if (!OriginalImage) {
return;
}

function PhpbbHtml5Image() {
// Build the completely stock HTML5 image extension first.
OriginalImage.apply(this, arguments);

var originalResize = this.resize;
var originalGetAsBinaryString = this.getAsBinaryString;
var didResize = false;
var preserveHeaders = true;

if (typeof originalResize === 'function') {
this.resize = function (rect, ratio, options) {
didResize = true;
preserveHeaders = !options || options.preserveHeaders !== false;

var tiff = this.meta && this.meta.tiff;

// Stock mOxie rotates again when preserveHeaders=false.
// The old custom build bypassed that transform because the
// browser had already oriented the decoded pixels. Feeding
// Orientation=1 only for the stock resize call gives the same
// result without editing the vendor library.
if (window.browserRotates === true && !preserveHeaders && tiff) {
var hadOrientation = Object.prototype.hasOwnProperty.call(tiff, 'Orientation');
var originalOrientation = tiff.Orientation;
tiff.Orientation = 1;

try {
return originalResize.apply(this, arguments);
} finally {
if (hadOrientation) {
tiff.Orientation = originalOrientation;
} else {
delete tiff.Orientation;
}
}
}

return originalResize.apply(this, arguments);
};
}

if (typeof originalGetAsBinaryString === 'function') {
this.getAsBinaryString = function (type, quality) {
var binary = originalGetAsBinaryString.apply(this, arguments);
var jpeg = (type || this.type) === 'image/jpeg';

if (!didResize || !jpeg || typeof binary !== 'string') {
return binary;
}

// With preserved headers, the old custom build made the
// re-encoded upright pixels explicitly Orientation=1.
if (window.browserRotates === true && preserveHeaders) {
binary = normalizeExifOrientation(binary);
}

return binary;
};
}
}

shim.Image = PhpbbHtml5Image;
}

PhpbbHtml5Runtime.__phpbbExifCompatWrapped = true;
Runtime.addConstructor('html5', PhpbbHtml5Runtime);
}

patchHtml5Runtime();
}(window));
1 change: 1 addition & 0 deletions phpBB/styles/prosilver/template/plupload.html
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Original file line number Diff line number Diff line change
Expand Up @@ -72,4 +72,5 @@
}
</script>
<!-- INCLUDEJS {T_ASSETS_PATH}/plupload/plupload.full.min.js -->
<!-- INCLUDEJS {T_ASSETS_PATH}/javascript/plupload.exif-compat.js -->
<!-- INCLUDEJS {T_ASSETS_PATH}/javascript/plupload.js -->
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