class.ilPreviewRenderer.php

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<?php
/* Copyright (c) 1998-2012 ILIAS open source, Extended GPL, see docs/LICENSE */

require_once("./Services/Preview/classes/class.ilPreviewSettings.php");

abstract class ilPreviewRenderer
{
        public function getName()
        {
                $name = get_class($this);
                
                if (strpos($name, "il") === 0)
                        $name = substr($name, 2);
                
                if (strpos($name, "Renderer") === (strlen($name) - 8))
                        $name = substr($name, 0, strlen($name) - 8) . " Renderer";
                
                return $name;
        }
        
        public final function isPlugin()
        {
                $filepath = "./Services/Preview/classes/class." . get_class($this) . ".php";
                return !is_file($filepath);
        }
        
        public abstract function getSupportedRepositoryTypes();
        
        public function supports($preview)
        {
                // contains type?
                return in_array($preview->getObjType(), $this->getSupportedRepositoryTypes());
        }
        
        public final function render($preview, $obj, $async)
        {
                $preview->setRenderDate(ilUtil::now());
                $preview->setRenderStatus(ilPreview::RENDER_STATUS_PENDING);
                $preview->save();
                
                // TODO: this should be done in background if $async is true
                
                // the deriving renderer should deliver images
                require_once("./Services/Preview/classes/class.ilRenderedImage.php");
                $images = $this->renderImages($obj);
                
                // process each image
                if (is_array($images) && count($images) > 0)
                {
                        $success = false;
                        foreach ($images as $idx => $image)     
                        {
                                // create the ending preview image
                                $success |= $this->createPreviewImage(
                                        $image->getImagePath(), 
                                        sprintf($preview->getFilePathFormat(), $idx + 1));

                                // if the image is temporary we can delete it
                                if($image->isTemporary())
                                        $image->delete();                                       
                        }

                        $preview->setRenderDate(ilUtil::now());
                        $preview->setRenderStatus($success ? ilPreview::RENDER_STATUS_CREATED : ilPreview::RENDER_STATUS_FAILED);
                        return $success;
                }
                else
                {
                        $preview->setRenderDate(ilUtil::now());
                        $preview->setRenderStatus(ilPreview::RENDER_STATUS_FAILED);
                        return false;
                }
        }
        
        private function createPreviewImage($src_img_path, $dest_img_path)
        {
                // create resize argument
                $imgSize = $this->getImageSize();
                $resizeArg = $imgSize . "x" . $imgSize . (ilUtil::isWindows() ? "^" : "\\") . ">";
                
                // cmd: convert $src_img_path -background white -flatten -resize 280x280 -quality 85 -sharpen 0x0.5 $dest_img_path
                $args = sprintf(
                        "%s -background white -flatten -resize %s -quality %d -sharpen 0x0.5 %s",
                        ilUtil::escapeShellArg($src_img_path),
                        $resizeArg,
                        $this->getImageQuality(),
                        ilUtil::escapeShellArg($dest_img_path));
                
                ilUtil::execConvert($args);
                
                return is_file($dest_img_path);
        }
        
        protected abstract function renderImages($obj);
        
        protected final function getImageSize()
        {
                return ilPreviewSettings::getImageSize();
        }
        
        protected final function getImageQuality()
        {
                return ilPreviewSettings::getImageQuality();
        }
        
        protected final function getMaximumNumberOfPreviews()
        {
                return ilPreviewSettings::getMaximumPreviews();
        }
}
?>