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PhabricatorImageTransformer.php
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Wed, Nov 20, 14:34

PhabricatorImageTransformer.php
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<?php
/**
* @task enormous Detecting Enormous Images
* @task save Saving Image Data
*/
final class PhabricatorImageTransformer {
public function executeMemeTransform(
PhabricatorFile $file,
$upper_text,
$lower_text) {
$image = $this->applyMemeToFile($file, $upper_text, $lower_text);
return PhabricatorFile::newFromFileData(
$image,
array(
'name' => 'meme-'.$file->getName(),
'ttl' => time() + 60 * 60 * 24,
));
}
public function executeThumbTransform(
PhabricatorFile $file,
$x,
$y) {
$image = $this->crudelyScaleTo($file, $x, $y);
return PhabricatorFile::newFromFileData(
$image,
array(
'name' => 'thumb-'.$file->getName(),
));
}
public function executeProfileTransform(
PhabricatorFile $file,
$x,
$min_y,
$max_y) {
$image = $this->crudelyCropTo($file, $x, $min_y, $max_y);
return PhabricatorFile::newFromFileData(
$image,
array(
'name' => 'profile-'.$file->getName(),
));
}
public function executePreviewTransform(
PhabricatorFile $file,
$size) {
$image = $this->generatePreview($file, $size);
return PhabricatorFile::newFromFileData(
$image,
array(
'name' => 'preview-'.$file->getName(),
));
}
public function executeConpherenceTransform(
PhabricatorFile $file,
$top,
$left,
$width,
$height) {
$image = $this->crasslyCropTo(
$file,
$top,
$left,
$width,
$height);
return PhabricatorFile::newFromFileData(
$image,
array(
'name' => 'conpherence-'.$file->getName(),
));
}
private function crudelyCropTo(PhabricatorFile $file, $x, $min_y, $max_y) {
$data = $file->loadFileData();
$img = imagecreatefromstring($data);
$sx = imagesx($img);
$sy = imagesy($img);
$scaled_y = ($x / $sx) * $sy;
if ($scaled_y > $max_y) {
// This image is very tall and thin.
$scaled_y = $max_y;
} else if ($scaled_y < $min_y) {
// This image is very short and wide.
$scaled_y = $min_y;
}
$cropped = $this->applyScaleWithImagemagick($file, $x, $scaled_y);
if ($cropped != null) {
return $cropped;
}
$img = $this->applyScaleTo(
$file,
$x,
$scaled_y);
return self::saveImageDataInAnyFormat($img, $file->getMimeType());
}
private function crasslyCropTo(PhabricatorFile $file, $top, $left, $w, $h) {
$data = $file->loadFileData();
$src = imagecreatefromstring($data);
$dst = $this->getBlankDestinationFile($w, $h);
$scale = self::getScaleForCrop($file, $w, $h);
$orig_x = $left / $scale;
$orig_y = $top / $scale;
$orig_w = $w / $scale;
$orig_h = $h / $scale;
imagecopyresampled(
$dst,
$src,
0, 0,
$orig_x, $orig_y,
$w, $h,
$orig_w, $orig_h);
return self::saveImageDataInAnyFormat($dst, $file->getMimeType());
}
/**
* Very crudely scale an image up or down to an exact size.
*/
private function crudelyScaleTo(PhabricatorFile $file, $dx, $dy) {
$scaled = $this->applyScaleWithImagemagick($file, $dx, $dy);
if ($scaled != null) {
return $scaled;
}
$dst = $this->applyScaleTo($file, $dx, $dy);
return self::saveImageDataInAnyFormat($dst, $file->getMimeType());
}
private function getBlankDestinationFile($dx, $dy) {
$dst = imagecreatetruecolor($dx, $dy);
imagesavealpha($dst, true);
imagefill($dst, 0, 0, imagecolorallocatealpha($dst, 255, 255, 255, 127));
return $dst;
}
private function applyScaleTo(PhabricatorFile $file, $dx, $dy) {
$data = $file->loadFileData();
$src = imagecreatefromstring($data);
$x = imagesx($src);
$y = imagesy($src);
$scale = min(($dx / $x), ($dy / $y), 1);
$sdx = $scale * $x;
$sdy = $scale * $y;
$dst = $this->getBlankDestinationFile($dx, $dy);
imagesavealpha($dst, true);
imagefill($dst, 0, 0, imagecolorallocatealpha($dst, 255, 255, 255, 127));
imagecopyresampled(
$dst,
$src,
($dx - $sdx) / 2, ($dy - $sdy) / 2,
0, 0,
$sdx, $sdy,
$x, $y);
return $dst;
}
public static function getPreviewDimensions(PhabricatorFile $file, $size) {
$metadata = $file->getMetadata();
$x = idx($metadata, PhabricatorFile::METADATA_IMAGE_WIDTH);
$y = idx($metadata, PhabricatorFile::METADATA_IMAGE_HEIGHT);
if (!$x || !$y) {
$data = $file->loadFileData();
$src = imagecreatefromstring($data);
$x = imagesx($src);
$y = imagesy($src);
}
$scale = min($size / $x, $size / $y, 1);
$dx = max($size / 4, $scale * $x);
$dy = max($size / 4, $scale * $y);
$sdx = $scale * $x;
$sdy = $scale * $y;
return array(
'x' => $x,
'y' => $y,
'dx' => $dx,
'dy' => $dy,
'sdx' => $sdx,
'sdy' => $sdy
);
}
public static function getScaleForCrop(
PhabricatorFile $file,
$des_width,
$des_height) {
$metadata = $file->getMetadata();
$width = $metadata[PhabricatorFile::METADATA_IMAGE_WIDTH];
$height = $metadata[PhabricatorFile::METADATA_IMAGE_HEIGHT];
if ($height < $des_height) {
$scale = $height / $des_height;
} else if ($width < $des_width) {
$scale = $width / $des_width;
} else {
$scale_x = $des_width / $width;
$scale_y = $des_height / $height;
$scale = max($scale_x, $scale_y);
}
return $scale;
}
private function generatePreview(PhabricatorFile $file, $size) {
$data = $file->loadFileData();
$src = imagecreatefromstring($data);
$dimensions = self::getPreviewDimensions($file, $size);
$x = $dimensions['x'];
$y = $dimensions['y'];
$dx = $dimensions['dx'];
$dy = $dimensions['dy'];
$sdx = $dimensions['sdx'];
$sdy = $dimensions['sdy'];
$dst = $this->getBlankDestinationFile($dx, $dy);
imagecopyresampled(
$dst,
$src,
($dx - $sdx) / 2, ($dy - $sdy) / 2,
0, 0,
$sdx, $sdy,
$x, $y);
return self::saveImageDataInAnyFormat($dst, $file->getMimeType());
}
private function applyMemeToFile(
PhabricatorFile $file,
$upper_text,
$lower_text) {
$data = $file->loadFileData();
$img_type = $file->getMimeType();
$imagemagick = PhabricatorEnv::getEnvConfig('files.enable-imagemagick');
if ($img_type != 'image/gif' || $imagemagick == false) {
return $this->applyMemeTo(
$data, $upper_text, $lower_text, $img_type);
}
$data = $file->loadFileData();
$input = new TempFile();
Filesystem::writeFile($input, $data);
list($out) = execx('convert %s info:', $input);
$split = phutil_split_lines($out);
if (count($split) > 1) {
return $this->applyMemeWithImagemagick(
$input,
$upper_text,
$lower_text,
count($split),
$img_type);
} else {
return $this->applyMemeTo($data, $upper_text, $lower_text, $img_type);
}
}
private function applyMemeTo(
$data,
$upper_text,
$lower_text,
$mime_type) {
$img = imagecreatefromstring($data);
// Some PNGs have color palettes, and allocating the dark border color
// fails and gives us whatever's first in the color table. Copy the image
// to a fresh truecolor canvas before working with it.
$truecolor = imagecreatetruecolor(imagesx($img), imagesy($img));
imagecopy($truecolor, $img, 0, 0, 0, 0, imagesx($img), imagesy($img));
$img = $truecolor;
$phabricator_root = dirname(phutil_get_library_root('phabricator'));
$font_root = $phabricator_root.'/resources/font/';
$font_path = $font_root.'tuffy.ttf';
if (Filesystem::pathExists($font_root.'impact.ttf')) {
$font_path = $font_root.'impact.ttf';
}
$text_color = imagecolorallocate($img, 255, 255, 255);
$border_color = imagecolorallocatealpha($img, 0, 0, 0, 110);
$border_width = 4;
$font_max = 200;
$font_min = 5;
for ($i = $font_max; $i > $font_min; $i--) {
$fit = $this->doesTextBoundingBoxFitInImage(
$img,
$upper_text,
$i,
$font_path);
if ($fit['doesfit']) {
$x = ($fit['imgwidth'] - $fit['txtwidth']) / 2;
$y = $fit['txtheight'] + 10;
$this->makeImageWithTextBorder($img,
$i,
$x,
$y,
$text_color,
$border_color,
$border_width,
$font_path,
$upper_text);
break;
}
}
for ($i = $font_max; $i > $font_min; $i--) {
$fit = $this->doesTextBoundingBoxFitInImage($img,
$lower_text, $i, $font_path);
if ($fit['doesfit']) {
$x = ($fit['imgwidth'] - $fit['txtwidth']) / 2;
$y = $fit['imgheight'] - 10;
$this->makeImageWithTextBorder(
$img,
$i,
$x,
$y,
$text_color,
$border_color,
$border_width,
$font_path,
$lower_text);
break;
}
}
return self::saveImageDataInAnyFormat($img, $mime_type);
}
private function makeImageWithTextBorder($img, $font_size, $x, $y,
$color, $stroke_color, $bw, $font, $text) {
$angle = 0;
$bw = abs($bw);
for ($c1 = $x - $bw; $c1 <= $x + $bw; $c1++) {
for ($c2 = $y - $bw; $c2 <= $y + $bw; $c2++) {
if (!(($c1 == $x - $bw || $x + $bw) &&
$c2 == $y - $bw || $c2 == $y + $bw)) {
$bg = imagettftext($img, $font_size,
$angle, $c1, $c2, $stroke_color, $font, $text);
}
}
}
imagettftext($img, $font_size, $angle,
$x , $y, $color , $font, $text);
}
private function doesTextBoundingBoxFitInImage($img,
$text, $font_size, $font_path) {
// Default Angle = 0
$angle = 0;
$bbox = imagettfbbox($font_size, $angle, $font_path, $text);
$text_height = abs($bbox[3] - $bbox[5]);
$text_width = abs($bbox[0] - $bbox[2]);
return array(
"doesfit" => ($text_height * 1.05 <= imagesy($img) / 2
&& $text_width * 1.05 <= imagesx($img)),
"txtwidth" => $text_width,
"txtheight" => $text_height,
"imgwidth" => imagesx($img),
"imgheight" => imagesy($img),
);
}
private function applyScaleWithImagemagick(PhabricatorFile $file, $dx, $dy) {
$img_type = $file->getMimeType();
$imagemagick = PhabricatorEnv::getEnvConfig('files.enable-imagemagick');
if ($img_type != 'image/gif' || $imagemagick == false) {
return null;
}
$data = $file->loadFileData();
$src = imagecreatefromstring($data);
$x = imagesx($src);
$y = imagesy($src);
if (self::isEnormousGIF($x, $y)) {
return null;
}
$scale = min(($dx / $x), ($dy / $y), 1);
$sdx = $scale * $x;
$sdy = $scale * $y;
$input = new TempFile();
Filesystem::writeFile($input, $data);
$resized = new TempFile();
$future = new ExecFuture(
'convert %s -coalesce -resize %sX%s%s %s',
$input,
$sdx,
$sdy,
'!',
$resized);
// Don't spend more than 10 seconds resizing; just fail if it takes longer
// than that.
$future->setTimeout(10)->resolvex();
return Filesystem::readFile($resized);
}
private function applyMemeWithImagemagick(
$input,
$above,
$below,
$count,
$img_type) {
$output = new TempFile();
$future = new ExecFuture(
'convert %s -coalesce +adjoin %s_%s',
$input,
$input,
'%09d');
$future->setTimeout(10)->resolvex();
$output_files = array();
for ($ii = 0; $ii < $count; $ii++) {
$frame_name = sprintf('%s_%09d', $input, $ii);
$output_name = sprintf('%s_%09d', $output, $ii);
$output_files[] = $output_name;
$frame_data = Filesystem::readFile($frame_name);
$memed_frame_data = $this->applyMemeTo(
$frame_data,
$above,
$below,
$img_type);
Filesystem::writeFile($output_name, $memed_frame_data);
}
$future = new ExecFuture('convert -loop 0 %Ls %s', $output_files, $output);
$future->setTimeout(10)->resolvex();
return Filesystem::readFile($output);
}
/* -( Detecting Enormous Files )------------------------------------------- */
/**
* Determine if an image is enormous (too large to transform).
*
* Attackers can perform a denial of service attack by uploading highly
* compressible images with enormous dimensions but a very small filesize.
* Transforming them (e.g., into thumbnails) may consume huge quantities of
* memory and CPU relative to the resources required to transmit the file.
*
* In general, we respond to these images by declining to transform them, and
* using a default thumbnail instead.
*
* @param int Width of the image, in pixels.
* @param int Height of the image, in pixels.
* @return bool True if this image is enormous (too large to transform).
* @task enormous
*/
public static function isEnormousImage($x, $y) {
// This is just a sanity check, but if we don't have valid dimensions we
// shouldn't be trying to transform the file.
if (($x <= 0) || ($y <= 0)) {
return true;
}
return ($x * $y) > (4096 * 4096);
}
/**
* Determine if a GIF is enormous (too large to transform).
*
* For discussion, see @{method:isEnormousImage}. We need to be more
* careful about GIFs, because they can also have a large number of frames
* despite having a very small filesize. We're more conservative about
* calling GIFs enormous than about calling images in general enormous.
*
* @param int Width of the GIF, in pixels.
* @param int Height of the GIF, in pixels.
* @return bool True if this image is enormous (too large to transform).
* @task enormous
*/
public static function isEnormousGIF($x, $y) {
if (self::isEnormousImage($x, $y)) {
return true;
}
return ($x * $y) > (800 * 800);
}
/* -( Saving Image Data )-------------------------------------------------- */
/**
* Save an image resource to a string representation suitable for storage or
* transmission as an image file.
*
* Optionally, you can specify a preferred MIME type like `"image/png"`.
* Generally, you should specify the MIME type of the original file if you're
* applying file transformations. The MIME type may not be honored if
* Phabricator can not encode images in the given format (based on available
* extensions), but can save images in another format.
*
* @param resource GD image resource.
* @param string? Optionally, preferred mime type.
* @return string Bytes of an image file.
* @task save
*/
public static function saveImageDataInAnyFormat($data, $preferred_mime = '') {
$preferred = null;
switch ($preferred_mime) {
case 'image/gif':
$preferred = self::saveImageDataAsGIF($data);
break;
case 'image/png':
$preferred = self::saveImageDataAsPNG($data);
break;
}
if ($preferred !== null) {
return $preferred;
}
$data = self::saveImageDataAsJPG($data);
if ($data !== null) {
return $data;
}
$data = self::saveImageDataAsPNG($data);
if ($data !== null) {
return $data;
}
$data = self::saveImageDataAsGIF($data);
if ($data !== null) {
return $data;
}
throw new Exception(pht('Failed to save image data into any format.'));
}
/**
* Save an image in PNG format, returning the file data as a string.
*
* @param resource GD image resource.
* @return string|null PNG file as a string, or null on failure.
* @task save
*/
private static function saveImageDataAsPNG($image) {
if (!function_exists('imagepng')) {
return null;
}
ob_start();
$result = imagepng($image, null, 9);
$output = ob_get_clean();
if (!$result) {
return null;
}
return $output;
}
/**
* Save an image in GIF format, returning the file data as a string.
*
* @param resource GD image resource.
* @return string|null GIF file as a string, or null on failure.
* @task save
*/
private static function saveImageDataAsGIF($image) {
if (!function_exists('imagegif')) {
return null;
}
ob_start();
$result = imagegif($image);
$output = ob_get_clean();
if (!$result) {
return null;
}
return $output;
}
/**
* Save an image in JPG format, returning the file data as a string.
*
* @param resource GD image resource.
* @return string|null JPG file as a string, or null on failure.
* @task save
*/
private static function saveImageDataAsJPG($image) {
if (!function_exists('imagejpeg')) {
return null;
}
ob_start();
$result = imagejpeg($image);
$output = ob_get_clean();
if (!$result) {
return null;
}
return $output;
}
}

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