GeezerVison

The World Wide Web, restored to 800 pixels of glory.

GeezerVison is showing next.angular.dev — NgOptimizedImage • Angular

API

    
      class NgOptimizedImage implements OnInit ,OnChanges {}

Name of the source image. Image name will be processed by the image loader and the final URL will be applied as the src property of the image.

A comma separated list of width or density descriptors. The image name will be taken from ngSrc and combined with the list of width or density descriptors to generate the final srcset property of the image.

Example:

<img ngSrc="hello.jpg" ngSrcset="100w, 200w" />  =>
<img src="path/hello.jpg" srcset="path/hello.jpg?w=100 100w, path/hello.jpg?w=200 200w" />

The base sizes attribute passed through to the <img> element. Providing sizes causes the image to create an automatic responsive srcset.

For responsive images: the intrinsic width of the image in pixels. For fixed size images: the desired rendered width of the image in pixels.

For responsive images: the intrinsic height of the image in pixels. For fixed size images: the desired rendered height of the image in pixels.

The desired decoding behavior for the image. Defaults to auto if not explicitly set, matching native browser behavior.

Use async to decode the image off the main thread (non-blocking), sync for immediate decoding (blocking), or auto to let the browser decide the optimal strategy.

Spec

The desired loading behavior (lazy, eager, or auto). Defaults to lazy, which is recommended for most images.

Warning: Setting images as loading="eager" or loading="auto" marks them as non-priority images and can hurt loading performance. For images which may be the LCP element, use the priority attribute instead of loading.

Indicates whether this image should have a high priority.

Data to pass through to custom loaders.

Disables automatic srcset generation for this image.

Sets the image to "fill mode", which eliminates the height/width requirement and adds styles such that the image fills its containing element.

A URL or data URL for an image to be used as a placeholder while this image loads.

Configuration object for placeholder settings. Options:

blur: Setting this to false disables the automatic CSS blur.

Returns an image url formatted for use with the CSS background-image property. Expects one of:

A base64 encoded image, which is wrapped and passed through.
A boolean. If true, calls the image loader to generate a small placeholder url.

@paramplaceholderInputstring | boolean

@returnsstring | boolean | null

Determines if blur should be applied, based on an optional boolean property blur within the optional configuration object placeholderConfig.

@paramplaceholderConfigImagePlaceholderConfig | undefined

@returnsboolean

Description

Directive that improves image loading performance by enforcing best practices.

NgOptimizedImage ensures that the loading of the Largest Contentful Paint (LCP) image is prioritized by:

Automatically setting the fetchpriority attribute on the <img> tag
Lazy loading non-priority images by default
Automatically generating a preconnect link tag in the document head

In addition, the directive:

Generates appropriate asset URLs if a corresponding ImageLoader function is provided
Automatically generates a srcset
Requires that width and height are set
Warns if width or height have been set incorrectly
Warns if the image will be visually distorted when rendered

Usage Notes

Follow the steps below to enable and use the directive:

Import it into a Component.
Optionally provide an ImageLoader if you use an image hosting service.
Update the necessary <img> tags in templates and replace src attributes with ngSrc. Using a ngSrc allows the directive to control when the src gets set, which triggers an image download.

Step 1: import the NgOptimizedImage directive.

@Component({
  imports: [NgOptimizedImage],
})
class MyPage {}

Step 2: configure a loader.

To use the default loader: no additional code changes are necessary. The URL returned by the generic loader will always match the value of "src". In other words, this loader applies no transformations to the resource URL and the value of the ngSrc attribute will be used as is.

To use an existing loader for a third-party image service: add the provider factory for your chosen service to the providers array. In the example below, the Imgix loader is used:

import {provideImgixLoader} from '@angular/common';

// Call the function and add the result to the `providers` array:
providers: [
  provideImgixLoader("https://my.base.url/"),
],

The NgOptimizedImage directive provides the following functions:

If you use a different image provider, you can create a custom loader function as described below.

To use a custom loader: provide your loader function as a value for the IMAGE_LOADER DI token.

import {IMAGE_LOADER, ImageLoaderConfig} from '@angular/common';

// Configure the loader using the `IMAGE_LOADER` token.
providers: [
  {
     provide: IMAGE_LOADER,
     useValue: (config: ImageLoaderConfig) => {
       return `https://example.com/${config.src}-${config.width}.jpg`;
     }
  },
],

Step 3: update <img> tags in templates to use ngSrc instead of src.

<img ngSrc="logo.png" width="200" height="100">

You are visitor 01402520 — GeezerVison does not store the pages you look up.
Best viewed with Netscape Navigator 4.7 or Internet Explorer 6 at 800×600. No cookies required.