As mentioned before, mobile devices and mobile platforms support many accessibility features. Still, with those features, it is unclear what to do and how to implement accessibility features to cover different cases when using mobile applications.
To define and make clearer accessibility scenarios, W3C created a standard called Web Content Accessibility Guidelines or shorter WCAG.
As the name says, this standard was created for the web (initially developed in the 90s and ‘00s). At that time, mobile devices were not primarily used as they are today. Because of that, WCAG had some updates and changes over the years, but the most important thing this standard has defined are principles for covering cases for application accessibility.
There are four main principles:
- Perceivable
- Operable
- Understandable
- Robust
When talking about the perceivable principle, this is how it is defined:
Information and user interface components must be presentable to users in ways they can perceive.
By definition, this principle covers the application content and how users can access every part of the application.
The operable principle is defined as:
User interface components and navigation must be operable.
This principle covers and defines guidelines about how the application works - e.g., input mechanisms, assistive technologies, etc.
Another fundamental principle is understandable:
Information and the operation of the user interface must be understandable.
This principle covers the aspect of distinctiveness, readability, and ease of use.
The last principle is robust, which is defined as:
Content must be robust enough that it can be interpreted by a wide variety of user agents, including assistive technologies.
The main idea of this principle is to make your application compatible with assistive technologies.
Beyond just defining principles, WCAG defines guidelines, success criteria, and techniques on how to satisfy or implement guidelines for every principle.
Another important thing about WCAG is the definition of levels – A, AA, and AAA. The most basic one is A, while the AAA defines that all guidelines should be implemented.
In the following chapters, every principle with its guidelines will be described in more detail.
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