Software Screen Off

A screen reader is a software application that attempts to identify and interpret what is being displayed on the screen. This is then presented to a blind user as speech (by text-to-speech) or by driving a braille display. Screen readers are used by people with little or no functional vision: people with some vision often use screen magnifiers.

Types of screen reader

CLI (text) screen readers

In early operating systems such as MS-DOS which employed a Command Line Interface (CLI), the screen display consisted of characters mapping directly to a screen buffer in memory and a cursor position. Input was by keyboard. fotografia copyright. All this information could therefore all be obtained from the system by hooking the flow of information around the system and reading the screen buffer and communicating the results to the user. This was relatively easy to engineer. Screen readers were developed for early personal computers such as the BBC Micro [1].

GUI screen readers

Off-screen models

With the arrival of graphical user interfaces (GUIs), the situation became more complicated. A GUI has characters and graphics drawn on the screen at particular positions, and as such there is no textual representation of the graphical contents of the display. di David S.