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PhabricatorFileImageTransform.php
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Sat, Jan 25, 08:08

PhabricatorFileImageTransform.php
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<?php
abstract class PhabricatorFileImageTransform extends PhabricatorFileTransform {
private $file;
private $data;
private $image;
private $imageX;
private $imageY;
/**
* Get an estimate of the transformed dimensions of a file.
*
* @param PhabricatorFile File to transform.
* @return list<int, int>|null Width and height, if available.
*/
public function getTransformedDimensions(PhabricatorFile $file) {
return null;
}
public function canApplyTransform(PhabricatorFile $file) {
if (!$file->isViewableImage()) {
return false;
}
if (!$file->isTransformableImage()) {
return false;
}
return true;
}
protected function willTransformFile(PhabricatorFile $file) {
$this->file = $file;
$this->data = null;
$this->image = null;
$this->imageX = null;
$this->imageY = null;
}
protected function getFileProperties() {
return array();
}
protected function applyCropAndScale(
$dst_w, $dst_h,
$src_x, $src_y,
$src_w, $src_h,
$use_w, $use_h,
$scale_up) {
// Figure out the effective destination width, height, and offsets.
$cpy_w = min($dst_w, $use_w);
$cpy_h = min($dst_h, $use_h);
// If we aren't scaling up, and are copying a very small source image,
// we're just going to center it in the destination image.
if (!$scale_up) {
$cpy_w = min($cpy_w, $src_w);
$cpy_h = min($cpy_h, $src_h);
}
$off_x = ($dst_w - $cpy_w) / 2;
$off_y = ($dst_h - $cpy_h) / 2;
if ($this->shouldUseImagemagick()) {
$argv = array();
$argv[] = '-coalesce';
$argv[] = '-shave';
$argv[] = $src_x.'x'.$src_y;
$argv[] = '-resize';
if ($scale_up) {
$argv[] = $dst_w.'x'.$dst_h;
} else {
$argv[] = $dst_w.'x'.$dst_h.'>';
}
$argv[] = '-bordercolor';
$argv[] = 'rgba(255, 255, 255, 0)';
$argv[] = '-border';
$argv[] = $off_x.'x'.$off_y;
return $this->applyImagemagick($argv);
}
$src = $this->getImage();
$dst = $this->newEmptyImage($dst_w, $dst_h);
$trap = new PhutilErrorTrap();
$ok = @imagecopyresampled(
$dst,
$src,
$off_x, $off_y,
$src_x, $src_y,
$cpy_w, $cpy_h,
$src_w, $src_h);
$errors = $trap->getErrorsAsString();
$trap->destroy();
if ($ok === false) {
throw new Exception(
pht(
'Failed to imagecopyresampled() image: %s',
$errors));
}
$data = PhabricatorImageTransformer::saveImageDataInAnyFormat(
$dst,
$this->file->getMimeType());
return $this->newFileFromData($data);
}
protected function applyImagemagick(array $argv) {
$tmp = new TempFile();
Filesystem::writeFile($tmp, $this->getData());
$out = new TempFile();
$future = new ExecFuture('convert %s %Ls %s', $tmp, $argv, $out);
// Don't spend more than 10 seconds resizing; just fail if it takes longer
// than that.
$future->setTimeout(10)->resolvex();
$data = Filesystem::readFile($out);
return $this->newFileFromData($data);
}
/**
* Create a new @{class:PhabricatorFile} from raw data.
*
* @param string Raw file data.
*/
protected function newFileFromData($data) {
if ($this->file) {
$name = $this->file->getName();
} else {
$name = 'default.png';
}
$defaults = array(
'canCDN' => true,
'name' => $this->getTransformKey().'-'.$name,
);
$properties = $this->getFileProperties() + $defaults;
return PhabricatorFile::newFromFileData($data, $properties);
}
/**
* Create a new image filled with transparent pixels.
*
* @param int Desired image width.
* @param int Desired image height.
* @return resource New image resource.
*/
protected function newEmptyImage($w, $h) {
$w = (int)$w;
$h = (int)$h;
if (($w <= 0) || ($h <= 0)) {
throw new Exception(
pht('Can not create an image with nonpositive dimensions.'));
}
$trap = new PhutilErrorTrap();
$img = @imagecreatetruecolor($w, $h);
$errors = $trap->getErrorsAsString();
$trap->destroy();
if ($img === false) {
throw new Exception(
pht(
'Unable to imagecreatetruecolor() a new empty image: %s',
$errors));
}
$trap = new PhutilErrorTrap();
$ok = @imagesavealpha($img, true);
$errors = $trap->getErrorsAsString();
$trap->destroy();
if ($ok === false) {
throw new Exception(
pht(
'Unable to imagesavealpha() a new empty image: %s',
$errors));
}
$trap = new PhutilErrorTrap();
$color = @imagecolorallocatealpha($img, 255, 255, 255, 127);
$errors = $trap->getErrorsAsString();
$trap->destroy();
if ($color === false) {
throw new Exception(
pht(
'Unable to imagecolorallocatealpha() a new empty image: %s',
$errors));
}
$trap = new PhutilErrorTrap();
$ok = @imagefill($img, 0, 0, $color);
$errors = $trap->getErrorsAsString();
$trap->destroy();
if ($ok === false) {
throw new Exception(
pht(
'Unable to imagefill() a new empty image: %s',
$errors));
}
return $img;
}
/**
* Get the pixel dimensions of the image being transformed.
*
* @return list<int, int> Width and height of the image.
*/
protected function getImageDimensions() {
if ($this->imageX === null) {
$image = $this->getImage();
$trap = new PhutilErrorTrap();
$x = @imagesx($image);
$y = @imagesy($image);
$errors = $trap->getErrorsAsString();
$trap->destroy();
if (($x === false) || ($y === false) || ($x <= 0) || ($y <= 0)) {
throw new Exception(
pht(
'Unable to determine image dimensions with '.
'imagesx()/imagesy(): %s',
$errors));
}
$this->imageX = $x;
$this->imageY = $y;
}
return array($this->imageX, $this->imageY);
}
/**
* Get the raw file data for the image being transformed.
*
* @return string Raw file data.
*/
protected function getData() {
if ($this->data !== null) {
return $this->data;
}
$file = $this->file;
$max_size = (1024 * 1024 * 4);
$img_size = $file->getByteSize();
if ($img_size > $max_size) {
throw new Exception(
pht(
'This image is too large to transform. The transform limit is %s '.
'bytes, but the image size is %s bytes.',
new PhutilNumber($max_size),
new PhutilNumber($img_size)));
}
$data = $file->loadFileData();
$this->data = $data;
return $this->data;
}
/**
* Get the GD image resource for the image being transformed.
*
* @return resource GD image resource.
*/
protected function getImage() {
if ($this->image !== null) {
return $this->image;
}
if (!function_exists('imagecreatefromstring')) {
throw new Exception(
pht(
'Unable to transform image: the imagecreatefromstring() function '.
'is not available. Install or enable the "gd" extension for PHP.'));
}
$data = $this->getData();
$data = (string)$data;
// First, we're going to write the file to disk and use getimagesize()
// to determine its dimensions without actually loading the pixel data
// into memory. For very large images, we'll bail out.
// In particular, this defuses a resource exhaustion attack where the
// attacker uploads a 40,000 x 40,000 pixel PNGs of solid white. These
// kinds of files compress extremely well, but require a huge amount
// of memory and CPU to process.
$tmp = new TempFile();
Filesystem::writeFile($tmp, $data);
$tmp_path = (string)$tmp;
$trap = new PhutilErrorTrap();
$info = @getimagesize($tmp_path);
$errors = $trap->getErrorsAsString();
$trap->destroy();
unset($tmp);
if ($info === false) {
throw new Exception(
pht(
'Unable to get image information with getimagesize(): %s',
$errors));
}
list($width, $height) = $info;
if (($width <= 0) || ($height <= 0)) {
throw new Exception(
pht(
'Unable to determine image width and height with getimagesize().'));
}
$max_pixels = (4096 * 4096);
$img_pixels = ($width * $height);
if ($img_pixels > $max_pixels) {
throw new Exception(
pht(
'This image (with dimensions %spx x %spx) is too large to '.
'transform. The image has %s pixels, but transforms are limited '.
'to images with %s or fewer pixels.',
new PhutilNumber($width),
new PhutilNumber($height),
new PhutilNumber($img_pixels),
new PhutilNumber($max_pixels)));
}
$trap = new PhutilErrorTrap();
$image = @imagecreatefromstring($data);
$errors = $trap->getErrorsAsString();
$trap->destroy();
if ($image === false) {
throw new Exception(
pht(
'Unable to load image data with imagecreatefromstring(): %s',
$errors));
}
$this->image = $image;
return $this->image;
}
private function shouldUseImagemagick() {
if (!PhabricatorEnv::getEnvConfig('files.enable-imagemagick')) {
return false;
}
if ($this->file->getMimeType() != 'image/gif') {
return false;
}
// Don't try to preserve the animation in huge GIFs.
list($x, $y) = $this->getImageDimensions();
if (($x * $y) > (512 * 512)) {
return false;
}
return true;
}
}

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