Carousel Specification

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Stefan Ivanov edited this page Oct 8, 2019 · 21 revisions

Konstantin Dinev | Date:
Radoslav Mirchev | Date:
Simeon Simeonov | Date:

1. Revision History

Version	User	Date	Notes
0.1	Stanka Bozalieva	Oct 5, 2018	Initial draft
0.2	Stefan Ivanov	Oct 9, 2019	Update - in progress

A carousel component is used to browse a collection of slides like galleries of images, cards, on-boarding tutorials or page-based interfaces. It can be used as a separate full – screen element or inside another component

2. Objectives

igx-carousel can be used as standalone component in order to show a set of slides. It should be highly customizable, providing capabilities like slide transitions and animations, hide\show navigation buttons, dynamically load images, i18n and accessibility support.

## 3. User Stories

End user

As end user I would like to:

Be able to navigate through a set of slides.
Be able to navigate the slides via Next and Previous soft buttons.
Be able to navigate the slides via the keyboard arrows.
Be able to select and show a particular slide from the collection through pager/thumbs.
Be able to interact with the slide so that it would open other relevant content.
Have an indication about the current slide in the context of the collection.

Developer

As a developer I want to:

Be able to provide the slides to be displayed using ngFor directive.

<igx-carousel [interval]="interval" [pause]="pause" [loop]="loop">
     <igx-slide *ngFor="let slide of slides;" [active]="slide.active">
         <img [src]="slide.image">
     </igx-slide>
</igx-carousel>

Be able to provide the slides to be displayed through pure markup

<igx-carousel [interval]="interval" [pause]="pause" [loop]="loop">
    <igx-slide [active]="slide.active">
        <img [src]="...">
    </igx-slide>
    <igx-slide>
        <img [src]="...">
    </igx-slide>
</igx-carousel>

I expect to have buttons for moving to the Next/Previous slide.
I expect to have templatable indicators that support precise navigation, show the current status/active slide and progress. Such a template can be created for gots (Page indicators - iOS), a small thumb for every slide, or another custom layout.
I want to create slide templates that can trigger an action that would take the user to a news article for example
The indication area is to be replaced with informative text, e.g. “3 of 6”, when there would be more than 5 slides.
I want to utilize touch gestures on the carousel such as:
- Flick left or right to change the active slide
- Pan left/right to peek to the next/previous slide without changing the active slide unless panning beyond a certain threshold and lifting your finger
I want to show more than one slide at a time (similar to coverflow on MacOS)
I want to be disable navigation of the carousel which would hide dots/thumbnail indicators and navigation buttons
Height ( % ) vertical direction
Width ( % ) horizontal direction
I want to be able to make the carousel slides loop (false by default allowing the first slide can only go forward/ last slide can only go backwards)
I want to configure the carousel to auto-play on every 3 seconds or another arbitrary amount of time (auto-play is disabled by default)
- On touch devices auto-play pauses when a long press is performed on the current slide
- On desktop devices auto-play pauses on mouse enter on the carousel and un-pauses on mouse leave after a 2 second timeout or another arbitrary amount of time
I want to be able to set active slide shown by default when the page loads
I want to set the active slide programmatically
I expect to have default animations with slide transitions and be able to configure them

4. Acceptance criteria

Have carousel that shows image/set of images.
Have carousel that should navigation button and image indicators.
Have the ability to stop, pause or play the image transition.
Have the ability to change current active slide.

5. Functionality

End User Experience

igx-carousel should always display initial image and navigation buttons or image indicators.

Developer Experience

igx-carousel should provide properties, events and methods what will manage carousel configuration and behaviors.

User Interface

The end user interface consists of:

Navigation buttons
Slide indicators
Slides container

6. API

Options

loop - Should the carousel wrap back to the first slide after it reaches the last. Defaults to true.
pause - Should the carousel stop playing on user interaction. Defaults to true.
interval - The amount of time in milliseconds between slides transition.
navigation - Controls should the carousel render the left/right navigation buttons. Defaults to true.
total - The number of slides the carousel currently has.
current - The index of the slide currently showing.
isPlaying - Returns whether the carousel is paused/playing.
isDestroyed - If the carousel is destroyed (ngOnDestroy was called).

Events

onSlideChanged - Emitted on slide change.
onSlideAdded - Emitted when a slide is being added to the carousel.
onSlideRemoved - Emitted whe a slide is being removed from the carousel.
onCarouselPaused - Emitted when the carousel is pausing.
onCarouselPlaying - Emitted when the carousel starts/resumes playing.

Methods

play() - Emits onCarouselPlaying event and starts the transition between slides.
stop() - Emits onCarouselPaused event and stops the transition between slides.
prev() - Switches to the previous slide. Emits onSlideChanged event.
next() - Switches to the next slide. Emits onSlideChanged event.
add(slide: IgxSlide) - Adds a slide to the carousel. Emits onSlideAdded event.
remove(slide: IgxSlide) - Removes an existing slide from the carousel. Emits onSlideRemoved event.
get(index: Number) - Returns the slide with the given index or null.
select(slide: IgxSlide, direction: Direction) - Selects the slide and the direction to transition to. Emits onSlideChanged event.

7. Accessibility

7.1 ARIA support

Roles:
role="button" https://www.w3.org/TR/wai-aria/roles#button
role="list" https://www.w3.org/TR/wai-aria/roles#list
Attributes:
aria-label="carousel" https://www.w3.org/TR/wai-aria/states_and_properties#aria-label
aria-label="setAriaLabel(slide)" - slide based
aria-selected="slide.active" https://www.w3.org/TR/wai-aria/states_and_properties#aria-selected

7.2 Keyboard navigation

8. Internationalization

8.1 RTL support

8.2 Localizable strings

The informative text for the indication area that reads e.g. "3 of 6" should have a localizable string for the "of" text.