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<?php |
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namespace luya\lazyload; |
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use luya\base\Widget; |
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use yii\base\InvalidConfigException; |
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use yii\helpers\Html; |
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use luya\web\View; |
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/** |
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* Image Lazy Loader. |
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* |
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* ```php |
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* <?= LazyLoad::widget(['src' => 'http://www.zephir.ch/img/zephir-logo.png']); ?> |
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* ``` |
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* |
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* In order to read more visit the [[concept-lazyload.md]] guide section. |
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* |
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* @author Basil Suter <[email protected]> |
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* @author Marc Stampfli <[email protected]> |
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* @author Alex Schmid <[email protected]> |
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* @since 1.0.0 |
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*/ |
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class LazyLoad extends Widget |
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{ |
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const JS_ASSET_KEY = 'lazyload.js.register'; |
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const CSS_ASSET_KEY = 'lazyload.css.register'; |
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const CSS_ASSET_KEY_PLACEHOLDER = 'lazyload.placeholder.css.register'; |
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/** |
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* @var string The path to the image you want to lazy load. |
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*/ |
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public $src; |
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/** |
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* @var string Path for the placeholder image that will be base64 encoded. |
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* @since 1.0.14 |
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*/ |
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public $placeholderSrc; |
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/** |
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* @var boolean Inline the placeholder source as base64 encoded string |
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* @since 1.0.14 |
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*/ |
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public $placeholderAsBase64 = false; |
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/** |
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* @var integer The width of the image, this information should be provided in order to display a placeholder. |
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*/ |
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public $width; |
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/** |
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* @var integer The height of the image, this information should be provided in order to display a placeholder. |
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*/ |
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public $height; |
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/** |
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* @var boolean Define whether a full image tag should be return or only the attributes. This can be applied when using the lazy loader in background images. |
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*/ |
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public $attributesOnly = false; |
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/** |
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* @var string Additional classes for the lazy load image. |
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*/ |
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public $extraClass; |
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/** |
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* @var array Options array for the html tag. This array can be used to pass e.g. a `title` or `alt` tag. |
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* @since 1.6.0 |
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*/ |
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public $options = []; |
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/** |
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* @var array Legacy support for older Browsers (Adds the IntersectionOberserver Polyfill, default: true) |
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* @since 1.6.0 |
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*/ |
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public $legacySupport = true; |
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/** |
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* @var array Optionally disable the automatic init of the lazyload function so you can override the JS options |
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* @since 1.6.0 |
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*/ |
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public $initJs = true; |
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/** |
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* @var string The default classes which will be registered. |
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* @since 1.6.1 |
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*/ |
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public $defaultCss = '.lazyimage-wrapper { |
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display: block; |
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width: 100%; |
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position: relative; |
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overflow: hidden; |
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} |
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.lazyimage { |
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position: absolute; |
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top: 50%; |
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left: 50%; |
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bottom: 0; |
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right: 0; |
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opacity: 0; |
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height: 100%; |
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width: 100%; |
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-webkit-transition: .5s ease-in-out opacity; |
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transition: .5s ease-in-out opacity; |
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-webkit-transform: translate(-50%,-50%); |
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transform: translate(-50%,-50%); |
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-o-object-fit: cover; |
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object-fit: cover; |
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-o-object-position: center center; |
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object-position: center center; |
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z-index: 20; |
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} |
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.lazyimage.loaded { |
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opacity: 1; |
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} |
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.lazyimage-placeholder { |
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display: block; |
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width: 100%; |
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height: auto; |
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background-color: #f0f0f0; |
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} |
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.nojs .lazyimage, |
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.nojs .lazyimage-placeholder, |
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.no-js .lazyimage, |
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.no-js .lazyimage-placeholder { |
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display: none; |
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}'; |
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/** |
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* @inheritdoc |
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*/ |
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public function init() |
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{ |
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parent::init(); |
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if ($this->src === null) { |
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throw new InvalidConfigException("The parameter src is required by the lazyload widget."); |
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} |
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// register the asset file |
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if ($this->legacySupport) { |
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IntersectionObserverPolyfillAsset::register($this->view); |
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} |
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LazyLoadAsset::register($this->view); |
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if ($this->initJs) { |
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// register js and css code with keys in order to ensure the registration is done only once |
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$this->view->registerJs("$.lazyLoad();", View::POS_READY, self::JS_ASSET_KEY); |
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} |
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$this->view->registerCss($this->defaultCss, [], self::CSS_ASSET_KEY); |
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} |
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/** |
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* Returns the aspect ration based on height or width. |
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* |
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* If no width or height is provided, the default value 56.25 will be returned. |
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* |
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* @return float A dot seperated ratio value |
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* @since 1.6.1 |
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*/ |
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protected function generateAspectRation() |
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{ |
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return ($this->height && $this->width) ? str_replace(',', '.', ($this->height / $this->width) * 100) : 56.25; |
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} |
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/** |
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* @inheritdoc |
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*/ |
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public function run() |
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{ |
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if ($this->placeholderSrc && $this->placeholderAsBase64) { |
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$this->placeholderSrc = 'data:image/jpg;base64,' . base64_encode(file_get_contents($this->placeholderSrc)); |
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} |
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if ($this->attributesOnly && !$this->placeholderSrc) { |
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return "class=\"js-lazyimage {$this->extraClass}\" data-src=\"$this->src\" data-width=\"$this->width\" data-height=\"$this->height\" data-as-background=\"1\""; |
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} |
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$tag = '<div class="lazyimage-wrapper ' . $this->extraClass . '">'; |
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$tag .= Html::tag('img', '', array_merge($this->options, ['class' => 'js-lazyimage lazyimage', 'data-src' => $this->src, 'data-width' => $this->width, 'data-height' => $this->height])); |
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if ($this->placeholderSrc) { |
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$tag .= Html::tag('img', '', ['class' => 'lazyimage-placeholder', 'src' => $this->placeholderSrc]); |
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} else { |
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$tag .= '<div class="lazyimage-placeholder"><div style="display: block; height: 0px; padding-bottom: ' . $this->generateAspectRation() . '%;"></div><div class="loader"></div></div>'; |
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} |
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$tag .= '<noscript><img class="lazyimage loaded ' . $this->extraClass . '" src="'.$this->src.'" /></noscript>'; |
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$tag .= '</div>'; |
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return $tag; |
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} |
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} |
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luyadev /
luya
Loading history...
This check marks implicit conversions of arrays to boolean values in a comparison. While in PHP an empty array is considered to be equal (but not identical) to false, this is not always apparent.
Consider making the comparison explicit by using
empty(..)or! empty(...)instead.