ion-img

shadow

Contents

• Usage
• Properties
• Events
• CSS Shadow Parts

Img is a tag that will lazily load an image when ever the tag is in the viewport. This is extremely useful when generating a large list as images are only loaded when they're visible. The component uses Intersection Observer internally, which is supported in most modern browser, but falls back to a setTimeout when it is not supported.

Usage

Angular

<ion-list>
  <ion-item *ngFor="let item of items">
    <ion-thumbnail slot="start">
      <ion-img [src]="item.src"></ion-img>
    </ion-thumbnail>
    <ion-label>{{item.text}}</ion-label>
  </ion-item>
</ion-list>

React

import React from 'react';
import { IonList, IonItem, IonThumbnail, IonImg, IonLabel, IonContent } from '@ionic/react';

type Item = {
  src: string;
  text: string;
};
const items: Item[] = [{ src: 'http://placekitten.com/g/200/300', text: 'a picture of a cat' }];

export const ImgExample: React.FC = () => (
  <IonContent>
    <IonList>
      {items.map((image, i) => (
        <IonItem key={i}>
          <IonThumbnail slot="start">
            <IonImg src={image.src} />
          </IonThumbnail>
          <IonLabel>{image.text}</IonLabel>
        </IonItem>
      ))}
    </IonList>
  </IonContent>
);

Stencil

import { Component, h } from '@stencil/core';

@Component({
  tag: 'img-example',
  styleUrl: 'img-example.css'
})
export class ImgExample {
  private items = [{
    'text': 'Item 1',
    'src': '/path/to/external/file.png'
  }, {
    'text': 'Item 2',
    'src': '/path/to/external/file.png'
  }, {
    'text': 'Item 3',
    'src': '/path/to/external/file.png'
  }];

  render() {
    return [
      <ion-list>
        {this.items.map(item =>
          <ion-item>
            <ion-thumbnail slot="start">
              <ion-img src={item.src}></ion-img>
            </ion-thumbnail>
            <ion-label>{item.text}</ion-label>
          </ion-item>
        )}
      </ion-list>
    ];
  }
}

Vue

<template>
  <ion-list>
    <ion-item v-for="item in items" :key="item.src">
      <ion-thumbnail slot="start">
        <ion-img :src="item.src"></ion-img>
      </ion-thumbnail>
      <ion-label>{{item.text}}</ion-label>
    </ion-item>
  </ion-list>
</template>

<script>
import { IonImg, IonItem, IonLabel, IonList, IonThumbnail } from '@ionic/vue';
import { defineComponent } from 'vue';

export default defineComponent({
  components: { IonImg, IonItem, IonLabel, IonList, IonThumbnail },
  setup() {
    const items = [{
      'text': 'Item 1',
      'src': '/path/to/external/file.png'
    }, {
      'text': 'Item 2',
      'src': '/path/to/external/file.png'
    }, {
      'text': 'Item 3',
      'src': '/path/to/external/file.png'
    }];
    return { items }
  }
});
</script>

Properties

alt

Description	This attribute defines the alternative text describing the image. Users will see this text displayed if the image URL is wrong, the image is not in one of the supported formats, or if the image is not yet downloaded.
Attribute	alt
Type	string ｜ undefined
Default	undefined

src

Description	The image URL. This attribute is mandatory for the <img> element.
Attribute	src
Type	string ｜ undefined
Default	undefined

Events

Name	Description
ionError	Emitted when the img fails to load
ionImgDidLoad	Emitted when the image has finished loading
ionImgWillLoad	Emitted when the img src has been set

CSS Shadow Parts

Name	Description
image	The inner img element.