113 lines
3.2 KiB
PHP
113 lines
3.2 KiB
PHP
<?php
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/**
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* @author Joas Schilling <nickvergessen@owncloud.com>
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* @author Morris Jobke <hey@morrisjobke.de>
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* @author Olivier Paroz <github@oparoz.com>
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*
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* @copyright Copyright (c) 2015, ownCloud, Inc.
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* @license AGPL-3.0
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*
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* This code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, version 3,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License, version 3,
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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*
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*/
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namespace OC\Preview;
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use Imagick;
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/**
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* Creates a PNG preview using ImageMagick via the PECL extension
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*
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* @package OC\Preview
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*/
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abstract class Bitmap extends Provider {
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/**
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* {@inheritDoc}
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*/
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public function getThumbnail($path, $maxX, $maxY, $scalingup, $fileview) {
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$tmpPath = $fileview->toTmpFile($path);
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if (!$tmpPath) {
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return false;
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}
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// Creates \Imagick object from bitmap or vector file
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try {
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$bp = $this->getResizedPreview($tmpPath, $maxX, $maxY);
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} catch (\Exception $e) {
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\OCP\Util::writeLog('core', 'ImageMagick says: ' . $e->getmessage(), \OCP\Util::ERROR);
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return false;
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}
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unlink($tmpPath);
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//new bitmap image object
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$image = new \OC_Image();
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$image->loadFromData($bp);
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//check if image object is valid
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return $image->valid() ? $image : false;
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}
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/**
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* Returns a preview of maxX times maxY dimensions in PNG format
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*
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* * The default resolution is already 72dpi, no need to change it for a bitmap output
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* * It's possible to have proper colour conversion using profileimage().
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* ICC profiles are here: http://www.color.org/srgbprofiles.xalter
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* * It's possible to Gamma-correct an image via gammaImage()
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*
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* @param string $tmpPath the location of the file to convert
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* @param int $maxX
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* @param int $maxY
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*
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* @return \Imagick
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*/
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private function getResizedPreview($tmpPath, $maxX, $maxY) {
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$bp = new Imagick();
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// Layer 0 contains either the bitmap or a flat representation of all vector layers
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$bp->readImage($tmpPath . '[0]');
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$bp = $this->resize($bp, $maxX, $maxY);
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$bp->setImageFormat('png');
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return $bp;
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}
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/**
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* Returns a resized \Imagick object
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*
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* If you want to know more on the various methods available to resize an
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* image, check out this link : @link https://stackoverflow.com/questions/8517304/what-the-difference-of-sample-resample-scale-resize-adaptive-resize-thumbnail-im
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*
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* @param \Imagick $bp
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* @param int $maxX
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* @param int $maxY
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*
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* @return \Imagick
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*/
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private function resize($bp, $maxX, $maxY) {
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list($previewWidth, $previewHeight) = array_values($bp->getImageGeometry());
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// We only need to resize a preview which doesn't fit in the maximum dimensions
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if ($previewWidth > $maxX || $previewHeight > $maxY) {
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// TODO: LANCZOS is the default filter, CATROM could bring similar results faster
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$bp->resizeImage($maxX, $maxY, imagick::FILTER_LANCZOS, 1, true);
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}
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return $bp;
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}
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}
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