Craft\ImagerService::transformImage PHP Method

    public function transformImage($image, $transform, $transformDefaults, $configOverrides)
    {
        if (!$image) {
            return null;
            // there's nothing to see here, move along.
        }
        $this->configModel = new Imager_ConfigModel($configOverrides);
        $pathsModel = new Imager_ImagePathsModel($image);
        $this->imagineInstance = $this->_createImagineInstance();
        /**
         * Check all the things that could go wrong(tm)
         */
        if (!IOHelper::getRealPath($pathsModel->sourcePath)) {
            throw new Exception(Craft::t('Source folder “{sourcePath}” does not exist', array('sourcePath' => $pathsModel->sourcePath)));
        }
        if (!IOHelper::getRealPath($pathsModel->targetPath)) {
            IOHelper::createFolder($pathsModel->targetPath, craft()->config->get('defaultFolderPermissions'), true);
            if (!IOHelper::getRealPath($pathsModel->targetPath)) {
                throw new Exception(Craft::t('Target folder “{targetPath}” does not exist and could not be created', array('targetPath' => $pathsModel->targetPath)));
            }
            $pathsModel->targetPath = IOHelper::getRealPath($pathsModel->targetPath);
        }
        if ($pathsModel->targetPath && !IOHelper::isWritable($pathsModel->targetPath)) {
            throw new Exception(Craft::t('Target folder “{targetPath}” is not writeable', array('targetPath' => $pathsModel->targetPath)));
        }
        if (!IOHelper::fileExists($pathsModel->sourcePath . $pathsModel->sourceFilename)) {
            throw new Exception(Craft::t('Requested image “{fileName}” does not exist in path “{sourcePath}”', array('fileName' => $pathsModel->sourceFilename, 'sourcePath' => $pathsModel->sourcePath)));
        }
        if (!craft()->images->checkMemoryForImage($pathsModel->sourcePath . $pathsModel->sourceFilename)) {
            throw new Exception(Craft::t("Not enough memory available to perform this image operation."));
        }
        /**
         * Transform can be either an array or just an object.
         * Act accordingly and return the results the same way to the template.
         */
        $r = null;
        if (isset($transform[0])) {
            $transformedImages = array();
            foreach ($transform as $t) {
                $transformedImage = $this->_getTransformedImage($pathsModel, $transformDefaults != null ? array_merge($transformDefaults, $t) : $t);
                $transformedImages[] = $transformedImage;
            }
            $r = $transformedImages;
        } else {
            $transformedImage = $this->_getTransformedImage($pathsModel, $transformDefaults != null ? array_merge($transformDefaults, (array) $transform) : $transform);
            $r = $transformedImage;
        }
        $this->imageInstance = null;
        /**
         * If this was an ajax request, and optimization tasks were created, trigger them now.
         */
        if (craft()->request->isAjaxRequest() && $this->taskCreated && $this->getSetting('runTasksImmediatelyOnAjaxRequests')) {
            $this->_triggerTasksNow();
        }
        if (count($this->invalidatePaths) > 0) {
            craft()->imager_aws->invalidateCloudfrontPaths($this->invalidatePaths);
            $this->invalidatePaths = array();
        }
        return $r;
    }