Accessibility/TextAttributes

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Attribute list

Gecko specific

Attribute name	Attribute description	Text attribute	Default text attribute
direction	rtl or ltr for bidi text	Yes	Yes
border	not sure how best to expose these properties, or whether to (same with outline CSS property)	Yes
language	What language is this text in, e.g. en-US	Yes	Yes
misspelled	"true" if it is marked by the inline spell checker for being incorrectly spelled (Note: in most cases a special underlining style will accompany this mark, and the underlining+style should also be exposed as a decoration attribute)	Yes
static	"true" for list bullet/numbering text or layout-inserted text (such as via CSS pseudo styles :before or :after)	Yes
z-index	a number which indicates how low/high an element is	Yes

IA2 proposed

Attribute name	Attribute description	Text attribute	Default text attribute
background-color	Background color as u, u, u	Yes	Yes
color	Foreground color as u, u, u	Yes	Yes
font-family	The computed font name	Yes	Yes
font-size	Font size in pixels	Yes	Yes
font-style	normal/italic/oblique	Yes	Yes
font-weight	The computed font weight, as a number	Yes	Yes
text-line-through-mode	continuous	Yes	Yes (empty implies none)
text-line-through-style	none/solid	Yes	Yes (empty implies none)
text-line-through-type	none/single	Yes	Yes (empty implies none)
text-underline-mode	none/continuous	Yes	Yes (empty implies none)
text-underline-style	none/solid	Yes	Yes (empty implies none)
text-underline-type	none/single	Yes	Yes (empty implies none)
text-underline-width	none/normal	Yes	Yes (empty implies none)
line-height	CSS2	Yes	Yes (empty implies none)
margin-bottom	CSS2	Yes	Yes (empty implies none)
margin-left	CSS2	Yes	Yes (empty implies none)
margin-right	CSS2	Yes	Yes (empty implies none)
text-align	left/center/right/justify	Yes	Yes
text-indent	CSS2	Yes	Yes (empty implies none)

Proposed API

Summary

Returns a collection of text attributes at the given offset. Calculates the range where returned attributes are stretched.

 nsIPersistentProperties getTextAttributes(in long offset,
                                           out long rangeStartOffset,
                                           out long rangeEndOffset);

Parameters

offset

[in] the given offset

rangeStartOffset

[out] the start offset of the result range

rangeEndOffset

[out] the end offset of the result range

Return Value

A collection of text attributes (the list of pairs consisted from name and value).

Questions

• What is the range hierarchy: are range nested or consecutive? Let we have a text 'abcdefghi'. If ranges are nested then we have two ranges: (0,9) and (3,6). If ranges are consecutive then we have three ranges (0, 3), (3, 6) and (6, 9).
• Should text attributes in a range be either relative to a parent (in the case of nested ranges) or previous (in the case of consecutive ranges) range or cumulative?

Events

Summary

When a certain text attribute is changed then 'EVENT_TEXT_ATTRIBUTE_CHANGED' event should be fired.

Questions

• How will AT know what attribute has been changed? Should the getTextAttributes() method return only last changed attribute?
• It's not clear how to track CSS style changes mapped to text attributes. Possibly some of those changes will lead accessible is recreated.

References

• IA2 Text Attributes - IAccessible2 Text Attributes Documentation