Fennec/Features/readability

Feature	Status	ETA	Owner
Text Readability	Concept	2011-07-01	Thomas Arend

Summary

Optimize zoom, reflow, and font sizes for best text readability.

Next Steps

• UX direction on high-level approach (see below).
• Need an owner, implementation plan, and estimates for chosen approach.

Open Issues

We need to choose a high-level approach.

Whichever approach we choose will probably require iteration and tuning, so we should plan to enable it on mozilla-central at the start of a development cycle. (This means that if we start development work during the Firefox 6 cycle, we should probably plan on landing or enabling it no sooner than the start of the Firefox 7 cycle.)

Approach	Pros	Cons
Fennec 4.0 style - On double tap, change minimum font size based on width of tapped element (bug 611555).	Was possible to implement mostly in the front-end, late in the 4.0 cycle Does not affect layout of pages until they are zoomed.	Does not work well with pinch zoom. Mangles layout of some pages. Does not work well with elements like input fields. Requires re-layout after zoom (can be slow).
Android style - On zoom, re-wrap text based on the zoom level (bug 578179).	Works well with pinch zoom - the user can zoom text to any size and it will still fit on screen. Android users expect it and like it. Does not affect layout of pages until they are zoomed. Does not mangle layout on most pages. Works well with elements like input fields.	Requires re-layout after zoom (can be slow). Will still mangle layout on a few pages.
iPhone style - Set a minimum font size per element based on its text width (bug 627842).	Does not require re-layout after zoom. With proper tuning, can avoid mangling most layouts. Can probably work well with elements like input fields.	Does not work well with pinch zoom. Will still mangle layout on a few pages. Alters layout on pages even before they are zoomed. For Safari, web developers often work around layout mangling by adding -webkit-text-size-adjust CSS styles. Will they bother doing similar work for Fennec? May not meet Android user expectations. Some implementation issues need to be worked out to avoid feedback loops in the layout engine.

Related Bugs & Dependencies

• bug 578179 - Option to wrap text to screen width rather than container width
• bug 611555 - should reflow on zoom [see dependencies for related bugs]
• bug 627842 - Allow minimum font size based on size of frame
• bug 598736 - Use higher-quality image scaling. (Affects readability of text in IMG elements.)

Legend (remove if you like)

	Healthy: feature is progressing as expected.
	Blocked: feature is currently blocked.
	At Risk: feature is at risk of missing its targeted release.
ETA	Estimated date for completion of the current feature task. Overall ETA for the feature is the product release date.