Ngx Picture

What is this?

Since in almost every project I am working on, there are the same requirements/wishes for showing Images, I decided to develop exactly that and pack as a angular-component.

These requirements are:

Lazyloading

Load the images only if they are needed. In fact nothing new here, but almost any solution I came across is using one IntersectionObserver per Image. I want to use One IntersectionObserver for ALL Images

Preloading

The Images should be preloaded before injecting them into the DOM.

Decoding

In Browsers that support new Image().decode() it should be used, as this is massively reducing the load on the main-thread.

Src-Sets

I want to be able to switch Images depending on the current screensize. Of coursethe first thought is to use the shiny <picture> element, but because its not possible to get notified about changes of currentSrc BEFORE the image is injected into the DOM (and therefore it's not possible to preload or decode) this dies not meet the requirements. Because my layouts are responsive anyways, and in every project I make use of FlexLayoutModule, the points to switch Images should match the breakpoints in FlexLayoutMoule.

ChangeDetectionStrategy

For performance reasons I want to use ChangeDetectionStrategy.OnPush

How to install?

You can install with yarn, npm or ng

yarn add @mralexandernickel/ngx-picture

npm install @mralexandernickel/ngx-picture

ng add @mralexandernickel/ngx-picture

How to use?

<lib-ngx-picture
  [images]="item"
  [fallbackImage]="fallbackImage"
></lib-ngx-picture>

The Images property/input has to be of type INgxPictureSet | string.

(..to be continued...)

Demo

Here you can find a simple Demo Application

Development server

Run ng serve for a dev server. Navigate to http://localhost:4200/. The app will automatically reload if you change any of the source files.

Code scaffolding

Run ng generate component component-name to generate a new component. You can also use ng generate directive|pipe|service|class|guard|interface|enum|module.

Build

Run ng build to build the project. The build artifacts will be stored in the dist/ directory. Use the --prod flag for a production build.

Running unit tests

Run ng test to execute the unit tests via Karma.

Running end-to-end tests

Run ng e2e to execute the end-to-end tests via Protractor.

Further help

To get more help on the Angular CLI use ng help or go check out the Angular CLI README.