Part of Item:
Comment Type: TE
Comment (including rationale for proposed change):
If it is sufficient that the change in presentation of text can be
programmatically determined, then most changes in presentation (other,
perhaps, than in bitmapped images) will meet this criterion. The user agent,
after all, requires this information in order to render the change.
However, programmatic determination of the change in presentation is not
sufficient to meet the requirements of user agents and assistive technologies
providing presentations in other modalities (or in the same modality with
different stylistic requirements according to the needs of the user with a
disability). How is the user agent supposed to map the change in presentation
to a corresponding change, whether in text or in presentation, in its
generated rendering, if the purpose or meaning of the variation in
presentation cannot be programmatically determined? In the worst case, it
could simply \"announce\" the change, e.g., \"voice pitch flat\" or \"font size
14pt\" and leave the user to try to work out the significance, if any, of this;
but a better solution is to use the capabilities of the technology to convey
the meaning or significance of the change, while also allowing \"merely
decorative\" changes having no meaningful purpose to be ignored.
This shortcoming of the current criterion is addressed in the proposal below.
\"The meaning or purpose of the change in presentation of text can be
programmatically determined\". Alternatively, just \"purpose\" could be used in
place of \"meaning or purpose\" in the above. Alternatively, keep this criterion
as is and add a more stringent requirement at level 2 or level 3.
SC 1.3.1 and 1.3.4 have been combined to read "Information and relationships conveyed through presentation can be programmatically determined or are available in text, and notification of changes to these is available to user agents, including assistive technologies." This wording ensures that it is the meaning conveyed by the presentation that must be programmatically determined, and allows the author to indicate the meaning in text if it is not feasible to do so programmatically. The How to Meet document describes this in some detail.