Basic principles of interaction with the user's computer with visual impairment
This material is an overview of the main assistive technologies that provide access to computer equipment to users with various visual impairments. Here, the main concepts of the implementation of alternative screen information will be considered to ensure its availability for people with missing or impaired vision.
Mainly, the article is aimed at ordinary users and aims to convey to the general mass of people information that a blind or visually impaired person can work with computer equipment, as well as highlight the general principles of this process. In addition, the material may be useful for those who have problems of this kind, as it can help them reduce the load on the visual system or, with further unfavorable development of the situation, facilitate the rehabilitation process, but the author hopes that the latter will be as small as possible.
The topic of the implementation of the availability of computer technology for users with visual limitations has recently become increasingly relevant. This is due to an increase in the load on the visual apparatus in the modern world and, as a result, an increase in the number of people with these health problems.
Various assistive technologies for blind and visually impaired, providing access to computer technology, have existed for more than a decade. However, not just many people have even a simple idea of ​​their existence, well, only target consumers directly possess detailed knowledge of the question (and not all of them), as well as a small number of people who either participate in the development or implementation of these technologies, or simply are super curious .
')
First you need to decide on a number of common key terms and concepts.
I. “Assistive technology” means any software, hardware or hardware / software solution designed to enhance, maintain or optimize the functional abilities of people with disabilities. Moreover, such a solution may be a built-in function of the product, its third-party extension, or even a separate product.
Ii. The target consumer of assistive technology is a person with disabilities. The invalid, in this case, is only a special case. This difference should be clearly understood. A disabled person is a legal characteristic, and a disabled person is physiological and more general. For example, a visually impaired user has limited physical ability regarding visual perception, but does not necessarily have a legally defined disability. In particular, according to some estimates, there are about 600,000 visually impaired people in the Russian Federation, and about 10 million people with certain visual impairments.
Iii. If we talk about assistive technologies only in relation to vision, then there is a separate term - “typhlotechnology” (typhlo from the Greek. Τυφλός - blind). In the future, we can use it. However, we note that it is more characteristic of the post-Soviet countries, and in English it is common to use the general term “assistive technology” and, if necessary, simply to clarify it “assistive technology for blind and visually impaired”.
Iv. When it comes to providing access to something for a user with disabilities, we touch upon the subject property as “accessibility”. In Russian, unfortunately, an absolutely exact equivalent of this word has not yet appeared, but nevertheless “accessibility” is the closest and most widely used, but very often even in Russian texts preference is given to the use of the English-language variant. It is also important to understand that the terms “accessibility” and “usability” are far from being synonymous. In general, the detailed disclosure of the topic of accessibility deserves separate consideration, so here this fact should be taken simply as a given.
V. It should be clearly understood that the restriction of opportunities can be not only physical, but also hardware, for example, a blind person and a sighted person using Apple’s “bare” technologies are in the same conditions regarding the ability to view flash animations, as it is for they are equally unavailable. That is, the target audience accessibility is actually much wider than just a collection of people with some physical disabilities. Such people are only a kind of litmus test of accessibility, as they have fewer technical alternatives. Therefore, the phrase "limited opportunities" and limited physical abilities "are far from identical and correlate as common and particular.
The rest of the terms and concepts we will introduce in the course of the presentation.
In general, there are three main concepts of alternative access to on-screen information:
The question of the use of a technology is solved depending on the type of visual impairment, and, unfortunately, often also on the financial capabilities of the user.
If a person has a residual vision, sufficient for direct perception of graphic information, then the first concept is basic for him. Also to its target users are people with color vision disorders, that is, color blind.
With little or no visual balance, the second and third concepts are basic, with the priority being given, as a rule, to the second. This is due to a number of technical and economic nuances. The priority of the third concept may be a consequence of either a specific type of user activity, or the presence of additional physical limitations, for example, simultaneous vision and hearing problems, which makes the use of voice access impossible.
Of course, a sighted or visually impaired person can also use voice or tactile accesses (although for the second he will need additional knowledge of tactile alphabets), but now the totally blind can no longer use the on-screen zoom. Nevertheless, few people, having the ability to work visually, refuse to do so, therefore, this situation is largely speculative.
Within the framework of this concept, the user works with on-screen information directly, only by transforming it by increasing or changing color parameters.
Of all the technologies, this is the most widely used, as among users of computer equipment with limited vision, an absolute majority of people with minor disabilities.
Perhaps, the function of the screen magnifier is familiar to almost everyone in one way or another, so it makes no sense to consider the implementation of this technology in detail. Its essence is reduced to the fact that programmatic methods are used to increase screen information. In this case, it may look different: an enlarged section of the screen, stretched across the entire display with smooth scrolling to show all the original content, an increase in the small portion of the screen in a single area, which you can direct like a normal magnifying glass and so on.
The transformation of graphic information is a more rare case, since the need for it is not so common. The need for these technologies are predominantly colorblind. For example, if there are problems with distinguishing between red and green colors, a person can use a program that displays a picture that changes the green color to blue, which eliminates the inconvenience of the problematic color pair. It is also just for visually impaired people that it may be useful to increase the contrast of the image or, on the contrary, make it more faded. For this reason, many software tools of this kind combine the functionality of screen zooming and graphics conversion, as well as some have the beginnings of voice access, if, for example, a person could not read any text, he can read it aloud with the program.
Of the most famous products of this kind, you can mention Windows Magnifier, ZoomText, MAGic and others.
Within this concept, a person no longer works with on-screen information directly. Before it is provided to the user, it is converted from text (less often graphics) to speech, that is, a full-fledged speech synthesizer is required to implement this technology.
Programs that provide voice access to screen information are called the generic term “screenreader”. In Russian-language terminology, they may appear under different names, but the most common is the “screen access program”. In particular, this term is enshrined at the legal level and appears in various legal documents, for example, for the Russian Federation it is GOST R 52873-2007 or R 52872-2007.
Here it is worth clarifying right away that the screenreader is not the same as the recently popular text-reading programs with synthesized voices, for example, Balabolka or MP3book2005. The screen access program is a much more complex and functional product. The usual TTS reader simply provides a shell for converting specific text to speech, while the screenreader allows you to fully work on a computer without visual control, including not only reading text from a file, but also browsing the Internet, tabular processors, sound editors, and so on. In particular, the first of the mentioned GOSTs provides the following formal definition: “screen access program: a software tool for reading textual information and voicing user actions using speech synthesizers and / or displaying the same through Braille displays”.
First you need to learn a few things.
First, the content of the display is not just a flat area with drawn pictures and written text, it is a collection of individual elements with a certain hierarchy. Of course, for people familiar with the principles of building a GUI, this is obvious, but for others, this information can become and, as a rule, becomes a revelation.
Secondly, the mouse is not the only tool for interacting with window controls and its contents, although many people often forget about this, including software developers. When working from the keyboard, there is such a thing as “system focus”. This is the area in which this or that screen object is currently located, with which the interaction will be carried out when pressing the control keys. For example, in a text editor window, the mouse cursor may be on the “Print” button, and the caret in the input field. The system focus will be located exactly at the place of the carriage, since it is with this object (editing field) that we will interact by pressing keys. Moving the system focus is also done using the keyboard.
Thirdly, modern technologies practically do not know how to transmit graphics through sound.
Now let's see how the user of the screen access program works by the example of Microsoft WordPad. In parallel with the reading it will be useful to also run this program and try to repeat all the actions. This will give an understanding of the fundamental differences in the ways of perceiving information. For simplicity, we will consider the old Wordpad from Windows XP with a classic menu.
We start Wordpad and a certain generalized program of screen access.
(Hereinafter, in block quotes is what the screen access program says. It should be understood that the user no longer receives absolutely any information.)
Screenreader read the window title (wordpad document) and named the object that contains the system focus (editor), that is, this edit field.
It should be noted that the window title looks like “Document - WordPad”, however neither the case of characters nor the hyphen of the screenreader is voiced. In the functional programs of screen access, special settings are responsible for this, but in the most common form, this will be the case.
Now enter the text "Hello world!".
(Hereinafter, phrases related to different keystrokes are separated by vertical lines).
The screenreader pronounces each printable character (here already with case information).
Now select the typed text. Since the work with the mouse for users of screen access programs is almost not available, you should use the hot keys - CTRL + A.
Screenreader pronounces the change that occurred on the screen, that is, selection (highlighted), and also voiced the object that was selected, that is, the text (hello world).
Suppose we selected the text in order to make it bold. As already noted, the option with the mouse is unacceptable, so the operation should be done through the menu. Thus, press Alt to open it.
Screenreader says the name of the area in which the system cursor (menu bar) has moved, then the first tab, which has got the focus (file), and its accelerator key (f).
We need the "Format" tab, so go to it by pressing the cursor arrow to the right four times.
Screenreader voices the name of each menu tab, which moves the system focus when you press the right arrow, as well as its accelerator. By the way, the menu could immediately click "M" and go to the "Format" tab, if the user knew in advance the accelerator.
Use the down arrow to open the tab, get to the desired item “Font ...” and activate it by pressing Enter.
Screenreader voices the zone where the system cursor (menu) falls, the item in focus and its accelerator (font sh), then reports the exit from the area (exit from the menu), voices the name of the new object in focus (font) and its type (combined editor ), as well as the first item of this list, which also gets into focus (arial) and its position in the list (26 of 231).
To go to the settings of the typeface, press Tab, where the double-down arrow moves to the “Bold” item and press Enter to apply.
The screenreader reads the name of the new object (typeface), its type (combined editor), the first item in focus (normal), its sequence number (1 of 4), then reads the next two points that we go through (italics and bold), and after applying and closing the menu, voices the transition of the system focus back to the edit field (editor).
It should be noted here that the task of establishing the bold pattern could be solved by means of the hot key CTRL + B in the selected text. Often, experienced users of screen access programs do not use menu items, but work through a large number of hot keys. This is also one of the characteristic features, since these people can remember many times more hotkeys than ordinary users, since they do not have at their disposal alternatives in the form of a mouse.
Until now, the screenreader only voiced the events occurring on the screen. Theoretically, all this could be done absolutely blindly. However, screen programs usually have their own commands that call specialized functions.
For example, the user wants to know what the formatting of text is on the screen. To do this, set the system cursor to the place of interest in the text and press a special global keyboard shortcut related to the screen access program.
Screenreader voices text formatting options under the cursor: typeface, font, size, alignment.
Separate screen access programs may provide an opportunity to get information about color parameters.
Screenreader reports that under the cursor is black text on a white background.
Now close WordPad by pressing Alt + F4, in the save dialog, pressing Tab will move to the refusal to save the document and confirm this choice by pressing Enter.
(Here the question mark means that the phrase can be read with interrogative intonation, if the speech synthesizer used supports this).
Screenreader reports the type of pop-up window (wordpad dialogue), reads the dialogue text (save changes to the document file?), Pronounces the object that the system focus falls on (yes button), after pressing Tab, pronounces the new object in focus (no button), after With the Enter key, the dialog closes and reads the title of the new window in focus (desktop), the object type (folder), since the desktop is just a folder, a message about the active window area (list view) and a shortcut under the system cursor (my documents) with its serial number (1 of 10).
It should be noted that the label was voiced by its text label, since speech cannot convey its graphic appearance.
When using different screen-access programs, the content of phrases may differ, for example, the edit fields may be called “editor”, “text” or “edit”, the order of reading the data in the system focus may be different, for example, “yes button” or “button yes " And so on. However, the principle itself will remain exactly as shown above.
It is important to understand the following:
The above features entail the following problems:
Among the most well-known screen access programs are JAWS for Windows, Window-Eyes, VoiceOver, and others.
Within the framework of this concept, the user also deals with on-screen information, which is previously converted into a convex relief perceived tactilely.
Additional software and hardware is required to provide tactile access.
In the role of the first are all the same screen-access programs, which, in this case, the text is sent not to the speech synthesizer, but to a special device - the “Braille display”. There are braille displays that do not support interaction with common screen access programs, but these are single exceptions. In general, to provide tactile access, the same screenreaders are used as for voice.
Braille is a special relief-dot font created especially for the blind by Frenchman Louis Braille in the 19th century. You can read more about braille in Wikipedia.
With a similar letter, text characters are made up of a combination of convex dots, originally grouped in six (Braille six-legged) —a rectangle of three in height and two in width. Due to the small variation of one six-point (2 ^ 6 = 64 variants of the location of points), many symbols occupy several cells. For example, the numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0 repeat the spelling of the first ten Latin letters A, B, C, D, E, F, G, H, I, and J. To To distinguish numbers from letters in writing there is a special “digital sign” from which to write any number. To designate, for example, that the text is written in italics, at its beginning and end it is necessary to set the corresponding sign. In its idea, this is similar to HTML tags (<i> italic text </ i>), only Braille appeared much earlier than the Internet.
In order to partially solve the problem of small variability of six points, in computer implementation of Braille, an extended cell of eight points is used more often - a rectangle of four in height and two in width. Here, the upper six points perform standard functions, and the lower two are used to display additional information about the character or cursor. Also for computer braille, rules other than typographical are often used, and, unfortunately, the spelling of universal characters, for example, punctuation, may also differ in different language versions. Even within the framework of a single Russian Braille, there are differences, if we compare, for example, modern books with those printed in the eighties. All this, plus a number of social and physiological features, makes mastering Braille literacy, especially in several languages, a rather non-trivial task. Therefore, many blind people do not know braille, especially those who have lost their sight as an adult. By some estimates, only 10% of blind people know and use Braille.
In general, a modern tactile display is an electromechanical device, consisting of a Braille line (several cells of six or eight points) and some controls (buttons and scrollers), combined in one case. Scroller' , .
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Mainly, the article is aimed at ordinary users and aims to convey to the general mass of people information that a blind or visually impaired person can work with computer equipment, as well as highlight the general principles of this process. In addition, the material may be useful for those who have problems of this kind, as it can help them reduce the load on the visual system or, with further unfavorable development of the situation, facilitate the rehabilitation process, but the author hopes that the latter will be as small as possible.
Introduction
The topic of the implementation of the availability of computer technology for users with visual limitations has recently become increasingly relevant. This is due to an increase in the load on the visual apparatus in the modern world and, as a result, an increase in the number of people with these health problems.
Various assistive technologies for blind and visually impaired, providing access to computer technology, have existed for more than a decade. However, not just many people have even a simple idea of ​​their existence, well, only target consumers directly possess detailed knowledge of the question (and not all of them), as well as a small number of people who either participate in the development or implementation of these technologies, or simply are super curious .
')
First you need to decide on a number of common key terms and concepts.
I. “Assistive technology” means any software, hardware or hardware / software solution designed to enhance, maintain or optimize the functional abilities of people with disabilities. Moreover, such a solution may be a built-in function of the product, its third-party extension, or even a separate product.
Ii. The target consumer of assistive technology is a person with disabilities. The invalid, in this case, is only a special case. This difference should be clearly understood. A disabled person is a legal characteristic, and a disabled person is physiological and more general. For example, a visually impaired user has limited physical ability regarding visual perception, but does not necessarily have a legally defined disability. In particular, according to some estimates, there are about 600,000 visually impaired people in the Russian Federation, and about 10 million people with certain visual impairments.
Iii. If we talk about assistive technologies only in relation to vision, then there is a separate term - “typhlotechnology” (typhlo from the Greek. Τυφλός - blind). In the future, we can use it. However, we note that it is more characteristic of the post-Soviet countries, and in English it is common to use the general term “assistive technology” and, if necessary, simply to clarify it “assistive technology for blind and visually impaired”.
Iv. When it comes to providing access to something for a user with disabilities, we touch upon the subject property as “accessibility”. In Russian, unfortunately, an absolutely exact equivalent of this word has not yet appeared, but nevertheless “accessibility” is the closest and most widely used, but very often even in Russian texts preference is given to the use of the English-language variant. It is also important to understand that the terms “accessibility” and “usability” are far from being synonymous. In general, the detailed disclosure of the topic of accessibility deserves separate consideration, so here this fact should be taken simply as a given.
V. It should be clearly understood that the restriction of opportunities can be not only physical, but also hardware, for example, a blind person and a sighted person using Apple’s “bare” technologies are in the same conditions regarding the ability to view flash animations, as it is for they are equally unavailable. That is, the target audience accessibility is actually much wider than just a collection of people with some physical disabilities. Such people are only a kind of litmus test of accessibility, as they have fewer technical alternatives. Therefore, the phrase "limited opportunities" and limited physical abilities "are far from identical and correlate as common and particular.
The rest of the terms and concepts we will introduce in the course of the presentation.
Basic concepts
In general, there are three main concepts of alternative access to on-screen information:
- Increase and transform graphics,
- Voice access,
- Tactile access.
The question of the use of a technology is solved depending on the type of visual impairment, and, unfortunately, often also on the financial capabilities of the user.
If a person has a residual vision, sufficient for direct perception of graphic information, then the first concept is basic for him. Also to its target users are people with color vision disorders, that is, color blind.
With little or no visual balance, the second and third concepts are basic, with the priority being given, as a rule, to the second. This is due to a number of technical and economic nuances. The priority of the third concept may be a consequence of either a specific type of user activity, or the presence of additional physical limitations, for example, simultaneous vision and hearing problems, which makes the use of voice access impossible.
Of course, a sighted or visually impaired person can also use voice or tactile accesses (although for the second he will need additional knowledge of tactile alphabets), but now the totally blind can no longer use the on-screen zoom. Nevertheless, few people, having the ability to work visually, refuse to do so, therefore, this situation is largely speculative.
Increase and convert graphics
Within the framework of this concept, the user works with on-screen information directly, only by transforming it by increasing or changing color parameters.
Of all the technologies, this is the most widely used, as among users of computer equipment with limited vision, an absolute majority of people with minor disabilities.
Perhaps, the function of the screen magnifier is familiar to almost everyone in one way or another, so it makes no sense to consider the implementation of this technology in detail. Its essence is reduced to the fact that programmatic methods are used to increase screen information. In this case, it may look different: an enlarged section of the screen, stretched across the entire display with smooth scrolling to show all the original content, an increase in the small portion of the screen in a single area, which you can direct like a normal magnifying glass and so on.
The transformation of graphic information is a more rare case, since the need for it is not so common. The need for these technologies are predominantly colorblind. For example, if there are problems with distinguishing between red and green colors, a person can use a program that displays a picture that changes the green color to blue, which eliminates the inconvenience of the problematic color pair. It is also just for visually impaired people that it may be useful to increase the contrast of the image or, on the contrary, make it more faded. For this reason, many software tools of this kind combine the functionality of screen zooming and graphics conversion, as well as some have the beginnings of voice access, if, for example, a person could not read any text, he can read it aloud with the program.
Of the most famous products of this kind, you can mention Windows Magnifier, ZoomText, MAGic and others.
Voice access
Within this concept, a person no longer works with on-screen information directly. Before it is provided to the user, it is converted from text (less often graphics) to speech, that is, a full-fledged speech synthesizer is required to implement this technology.
Programs that provide voice access to screen information are called the generic term “screenreader”. In Russian-language terminology, they may appear under different names, but the most common is the “screen access program”. In particular, this term is enshrined at the legal level and appears in various legal documents, for example, for the Russian Federation it is GOST R 52873-2007 or R 52872-2007.
Here it is worth clarifying right away that the screenreader is not the same as the recently popular text-reading programs with synthesized voices, for example, Balabolka or MP3book2005. The screen access program is a much more complex and functional product. The usual TTS reader simply provides a shell for converting specific text to speech, while the screenreader allows you to fully work on a computer without visual control, including not only reading text from a file, but also browsing the Internet, tabular processors, sound editors, and so on. In particular, the first of the mentioned GOSTs provides the following formal definition: “screen access program: a software tool for reading textual information and voicing user actions using speech synthesizers and / or displaying the same through Braille displays”.
How it works
First you need to learn a few things.
First, the content of the display is not just a flat area with drawn pictures and written text, it is a collection of individual elements with a certain hierarchy. Of course, for people familiar with the principles of building a GUI, this is obvious, but for others, this information can become and, as a rule, becomes a revelation.
Secondly, the mouse is not the only tool for interacting with window controls and its contents, although many people often forget about this, including software developers. When working from the keyboard, there is such a thing as “system focus”. This is the area in which this or that screen object is currently located, with which the interaction will be carried out when pressing the control keys. For example, in a text editor window, the mouse cursor may be on the “Print” button, and the caret in the input field. The system focus will be located exactly at the place of the carriage, since it is with this object (editing field) that we will interact by pressing keys. Moving the system focus is also done using the keyboard.
Thirdly, modern technologies practically do not know how to transmit graphics through sound.
Now let's see how the user of the screen access program works by the example of Microsoft WordPad. In parallel with the reading it will be useful to also run this program and try to repeat all the actions. This will give an understanding of the fundamental differences in the ways of perceiving information. For simplicity, we will consider the old Wordpad from Windows XP with a classic menu.
We start Wordpad and a certain generalized program of screen access.
wordpad document editor
(Hereinafter, in block quotes is what the screen access program says. It should be understood that the user no longer receives absolutely any information.)
Screenreader read the window title (wordpad document) and named the object that contains the system focus (editor), that is, this edit field.
It should be noted that the window title looks like “Document - WordPad”, however neither the case of characters nor the hyphen of the screenreader is voiced. In the functional programs of screen access, special settings are responsible for this, but in the most common form, this will be the case.
Now enter the text "Hello world!".
n big | p | and | in | e | t | comma | space | m | and | p | exclamation mark
(Hereinafter, phrases related to different keystrokes are separated by vertical lines).
The screenreader pronounces each printable character (here already with case information).
Now select the typed text. Since the work with the mouse for users of screen access programs is almost not available, you should use the hot keys - CTRL + A.
hello world
Screenreader pronounces the change that occurred on the screen, that is, selection (highlighted), and also voiced the object that was selected, that is, the text (hello world).
Suppose we selected the text in order to make it bold. As already noted, the option with the mouse is unacceptable, so the operation should be done through the menu. Thus, press Alt to open it.
menu bar file f
Screenreader says the name of the area in which the system cursor (menu bar) has moved, then the first tab, which has got the focus (file), and its accelerator key (f).
We need the "Format" tab, so go to it by pressing the cursor arrow to the right four times.
edit n | view in | insert a | format m
Screenreader voices the name of each menu tab, which moves the system focus when you press the right arrow, as well as its accelerator. By the way, the menu could immediately click "M" and go to the "Format" tab, if the user knew in advance the accelerator.
Use the down arrow to open the tab, get to the desired item “Font ...” and activate it by pressing Enter.
menu font w | exit from the menu font combined editor arial 26 of 231
Screenreader voices the zone where the system cursor (menu) falls, the item in focus and its accelerator (font sh), then reports the exit from the area (exit from the menu), voices the name of the new object in focus (font) and its type (combined editor ), as well as the first item of this list, which also gets into focus (arial) and its position in the list (26 of 231).
To go to the settings of the typeface, press Tab, where the double-down arrow moves to the “Bold” item and press Enter to apply.
outline combined editor normal 1 of 4 | italics | fatty | editor
The screenreader reads the name of the new object (typeface), its type (combined editor), the first item in focus (normal), its sequence number (1 of 4), then reads the next two points that we go through (italics and bold), and after applying and closing the menu, voices the transition of the system focus back to the edit field (editor).
It should be noted here that the task of establishing the bold pattern could be solved by means of the hot key CTRL + B in the selected text. Often, experienced users of screen access programs do not use menu items, but work through a large number of hot keys. This is also one of the characteristic features, since these people can remember many times more hotkeys than ordinary users, since they do not have at their disposal alternatives in the form of a mouse.
Until now, the screenreader only voiced the events occurring on the screen. Theoretically, all this could be done absolutely blindly. However, screen programs usually have their own commands that call specialized functions.
For example, the user wants to know what the formatting of text is on the screen. To do this, set the system cursor to the place of interest in the text and press a special global keyboard shortcut related to the screen access program.
bold arial 10 points left justified
Screenreader voices text formatting options under the cursor: typeface, font, size, alignment.
Separate screen access programs may provide an opportunity to get information about color parameters.
black on white
Screenreader reports that under the cursor is black text on a white background.
Now close WordPad by pressing Alt + F4, in the save dialog, pressing Tab will move to the refusal to save the document and confirm this choice by pressing Enter.
wordpad dialog save changes to file document? yes button | no button | desktop folder view my documents list 1 of 10
(Here the question mark means that the phrase can be read with interrogative intonation, if the speech synthesizer used supports this).
Screenreader reports the type of pop-up window (wordpad dialogue), reads the dialogue text (save changes to the document file?), Pronounces the object that the system focus falls on (yes button), after pressing Tab, pronounces the new object in focus (no button), after With the Enter key, the dialog closes and reads the title of the new window in focus (desktop), the object type (folder), since the desktop is just a folder, a message about the active window area (list view) and a shortcut under the system cursor (my documents) with its serial number (1 of 10).
It should be noted that the label was voiced by its text label, since speech cannot convey its graphic appearance.
When using different screen-access programs, the content of phrases may differ, for example, the edit fields may be called “editor”, “text” or “edit”, the order of reading the data in the system focus may be different, for example, “yes button” or “button yes " And so on. However, the principle itself will remain exactly as shown above.
What follows from this
It is important to understand the following:
- The user of the screen access program almost never has a spatial view of the screen contents. For example, to open the menu, he presses Alt, but he may not know exactly where this panel is on the screen (one of the clearest examples of exclusion from this rule is VoiceOver on iOS).
- Due to the fact that it is impossible to convey images with speech, such a user is not able to get an idea of ​​graphic information. For example, changing the picture of the worker has become invisible to him.
- Due to the fact that when working with the screen access program, as a rule, only the system focus object plus some common elements such as the window title are sounded, the user may not notice any elements of the screen contents. For example, by opening the program menu, he needs to manually go through the focus on all items in order to get a comprehensive view. As a rule, in programs of screen access there is a function of reading the entire screen, which speaks all the available elements. However, it is usually necessary to activate it specifically, because during normal work reading of all elements every time is not required.
- Since the mouse cursor is presented graphically and clearly not tied to specific objects, like the system focus, its movement on the screen cannot be informatively reflected in the speech form. This leads to the fact that the user of screen access programs is practically unable to use the mouse in their work. Different screenreaders offer these or other ways to implement mouse accessibility without the aid of sight, but a full-fledged alternative to visual work has not yet been created. All of them are still only auxiliary, to which users resort only when the keyboard control is completely impossible.
The above features entail the following problems:
- The inability to obtain most of the graphic information.
- Low or absent availability of a number of interfaces built exclusively on graphics or mouse control.
- Often lower performance due to the inability to quickly cover the entire contents of the screen.
- Dependence of work on additional software. For example, in the event of a crash or complete failure of the screen access program, further use of the computer may become impossible (therefore, experienced users usually have several installed screenreaders). However, the problem of voice access to the BIOS has not been resolved so far, since in this mode, downloading the speaking software is not possible.
Among the most well-known screen access programs are JAWS for Windows, Window-Eyes, VoiceOver, and others.
Tactile access
Within the framework of this concept, the user also deals with on-screen information, which is previously converted into a convex relief perceived tactilely.
Additional software and hardware is required to provide tactile access.
In the role of the first are all the same screen-access programs, which, in this case, the text is sent not to the speech synthesizer, but to a special device - the “Braille display”. There are braille displays that do not support interaction with common screen access programs, but these are single exceptions. In general, to provide tactile access, the same screenreaders are used as for voice.
Braille is a special relief-dot font created especially for the blind by Frenchman Louis Braille in the 19th century. You can read more about braille in Wikipedia.
With a similar letter, text characters are made up of a combination of convex dots, originally grouped in six (Braille six-legged) —a rectangle of three in height and two in width. Due to the small variation of one six-point (2 ^ 6 = 64 variants of the location of points), many symbols occupy several cells. For example, the numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0 repeat the spelling of the first ten Latin letters A, B, C, D, E, F, G, H, I, and J. To To distinguish numbers from letters in writing there is a special “digital sign” from which to write any number. To designate, for example, that the text is written in italics, at its beginning and end it is necessary to set the corresponding sign. In its idea, this is similar to HTML tags (<i> italic text </ i>), only Braille appeared much earlier than the Internet.
In order to partially solve the problem of small variability of six points, in computer implementation of Braille, an extended cell of eight points is used more often - a rectangle of four in height and two in width. Here, the upper six points perform standard functions, and the lower two are used to display additional information about the character or cursor. Also for computer braille, rules other than typographical are often used, and, unfortunately, the spelling of universal characters, for example, punctuation, may also differ in different language versions. Even within the framework of a single Russian Braille, there are differences, if we compare, for example, modern books with those printed in the eighties. All this, plus a number of social and physiological features, makes mastering Braille literacy, especially in several languages, a rather non-trivial task. Therefore, many blind people do not know braille, especially those who have lost their sight as an adult. By some estimates, only 10% of blind people know and use Braille.
In general, a modern tactile display is an electromechanical device, consisting of a Braille line (several cells of six or eight points) and some controls (buttons and scrollers), combined in one case. Scroller' , .
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Source: https://habr.com/ru/post/149815/
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