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Linearization Issue #58 #114
There is a long discussion about this on my previous Pull request between Ian Pouncy, Patrick, and Alastair. See the discussion at issue #89
SC Short title
Linearisation: A mechanism is available to view content as a single column, except for parts of the content where the spatial layout is essential to the function and understanding of the content.
Content can be viewed in a single column. All text is presented in single column format and the Line Length SC ensures that all lines of text word wrap to fit the available space. Data tables will have a standard tabular display, a two-dimensional matrix. Some user agents do not support active data such as form controls in reflow. In these cases the content author is not responsible for creating content that reflows.
good PDF reflow
Properly reflowed PDF text.
bad PDF relow
Improper characters used by the author for spaces. This causes words to jam together with reflow. This authoring problem occurs frequently with PDF.
One important need of most people with low vision is to reconfigure a presentation from a normal two-dimensional page to a one-dimensional organization of data. This is not always the case, but it is a frequent need. For quick scanning the original structure may be useful to scan for recognizable items. This is usually done when the user knows a page and is looking for just one thing. In cases where careful examination of the page is necessary one column presentation is needed. The reasons are given below.
Continuous Reading: Many people, with and without disabilities, find it more difficult to read when they must scroll from the bottom of a column of text to the top of another column. With low vision the need is greater. To go from one column to next frequently requires paging up several screens to get from the bottom of one column to the top of the next. Additionally, using a small scrollbar and cursor is difficult with limited sight. This makes getting from the bottom of a column and finding the top of the next column more difficult. Reading flow degrades and comprehension suffers.
Existing Relevant Techniques
G57: Ordering the content in a meaningful sequence (Note: Correct Reading Sequence and meaningful sequence are the same in this context.)
HTML: Write content so that the source order of perceivable elements defines a correct reading sequence. It is perfectly appropriate to include items that are not displayed to users in any convenient order. Such elements do not disrupt the correct reading sequence of the entire page. Make sure that elements that are not to be perceived are marked in a standard way like "display: none" or "visibility: hidden" so they can be ignored by a reformatting program. Test your document with no style in your user agent(s). See that it makes sense as a page and is fully operable. After this content is arranged and tested, positioning and other block formatting of the page. Use style sheets for positioning so that it can be removed and the resulting view is readable and operable.
HTML Source Order vs CSS Display Order - Adrian Roselli
Reflow is ready, and so is Line length - Wayne Dick, 15 November 2016
Reflow to Single Column - WCAG 1.4.8 item 5 or New item LVTF GitHub SC Issue #7