3.10.1 through 3.10.5 Intent and Techniques (from f2f)

Guideline 3.10 Help user to use and orient within viewports.

3.10.1 Highlight Viewport: The viewport with the current focus is
highlighted (including any frame that takes current focus) using a
highlight mechanism that does not rely on rendered text foreground and
background colors alone (e.g., a thick outline). (Level A)

Intent of Success Criterion 3.10.1

When a user agent presents content using multiple viewports, users
benefit from a clear indication of which viewport has focus. Simply
relying upon text foreground and background colors to indicate focus
may not provide sufficient, visually perceivable indication for users
with low vision. Highlighting of viewport frames using both color,
with sufficient contrast, and increase in viewport border thickness
can provide multiple visual cues that indicate focus.

Examples of Success Criterion 3.10.1

A music Web site allows the user to select which of the top 10 songs
are available for listening. Each song is presented in a graphical
viewport providing a music player. Using a keyboard based screen
magnification tool, a low vision user tabs between songs, with the
currently selected player viewport highlighted with a thick, yellow
border against a dark grey background.


3.10.2 Move Viewport to Selection: When a viewport's selection
changes, the viewport moves as necessary to ensure that the new
selection is at least partially in the viewport. (Level A)

Intent of Success Criterion 3.10.2

When content is presented within a viewport and the content extends
horizontally or vertically beyond the visible bounds of the viewport,
the user must be able to move to a selectable element or elements
which may be out of view, and to have the selected content
automatically move into view. For keyboard based users and users of
screen magnification tools, this allows users an efficient means to
view selected content without having to utilize scrolling controls to
locate and view the selection.

Examples of Success Criterion 3.10.2

A screen magnification user is performing a spell check of a blog
posting that is contained within a scrollable viewport. The text of
the blog posting exceeds the vertical size of the viewport. The
blogging software provides a key to move to the first, and then any
subsequent, unrecognized words. With two unrecognized words in the
posting, the user ignores the first selected word, and presses the
keystroke to move to the next which is currently out of view in the
last sentence of the posting. As the key is pressed, the viewport
scrolls to show the selected word.


3.10.3 Move Viewport to Focus: When a viewport's content focus
changes, the viewport moves as necessary to ensure that the new
content focus is at least partially in the viewport. (Level A)

Intent of Success Criterion 3.10.3

When content is presented within a viewport and the content extends
horizontally or vertically beyond the visible bounds of the viewport,
the user must be able to move to any focusable elements which may be
out of view, and to have the element receiving focus automatically
move into view. For keyboard based users and users of screen
magnification tools, this allows users an efficient means to view a
focused element without having to utilize scrolling controls to locate
and view the element with focus.

Examples of Success Criterion 3.10.3

A user of a screen reader is showing a sighted colleague how to
complete a registration form contained within a viewport. The form
exceeds the veritical bounds of the viewport, requiring vertical
scrolling to view the complete form content. As the screen reader
completes each form entry and presses the tab key, the next form
control in the tab order scrolls into view if it is not already
visible in the viewport.


3.10.4 Resizable: The user has the option to make graphical viewports
resizable, within the limits of the display, overriding any values
specified by the author. (Level A)

Intent of Success Criterion 3.10.4

If a graphical viewport contains content that exceeds the dimensions
of the viewport, users should have the option to increase the size of
the viewport to allow the full image to be displayed without
scrolling, within the limits of the physical display screen. This
benefits keyboard users who may find it difficult to scroll content
and users with cognitive or learning disabilities whose understanding
of the content is aided by being able to view the complete image.

Examples of Success Criterion 3.10.4

A viewport is used to display an image depicting an organization
chart. A user with a learning disability has difficulty maintaining a
mental representation of the organizational linkages for items out of
view. In order to facilitate their understanding of the organization,
the user drags the sizing icon on the corners of the viewport to allow
the entire chart to be displayed.

3.10.5 Scrollbars: Graphical viewports include scrollbars if the
rendered content (including after user preferences have been applied)
extends beyond the viewport dimensions, overriding any values
specified by the author. (Level A)

Intent of Success Criterion 3.10.5

When rendered content exceeds the horizontal and/or vertical bounds of
a graphical viewport, scrollbars provide a visible indication that not
all of the rendered content is currently visible within the viewport.
The scrollbars provide indication to users who may not be able to
otherwise recognize that the rendered content is not fully visible.

Examples of Success Criterion 3.10.5

A Web site presents a recipe within a viewport, and the length of the
recipe exceeds the vertical and horizontal dimension of the viewport,
though the step by step graphical depiction of the recipe does not
make this obvious. A user following the recipe, uses the scroll bar to
recognize that additional steps may be present, and scrolls them into
view.

Received on Friday, 26 February 2010 17:36:15 UTC