RE: hit regions

Also, using pixel-based hit regions can be problematic when anti-aliasing and transparency are considered...


-----Original Message-----
From: Rik Cabanier [] 
Sent: Sunday, August 19, 2012 6:18 PM
To: 'Chaals McCathieNevile';
Subject: RE: hit regions

It seems that hit regions can contain more accessibility information than image maps. Since people are building complex programs with Canvas, it probably needs more metadata.
I will read up more on issue 105 on the mailing list archive.

Studying the spec some more, I realize now that hit regions are allowed to overlap, but the second one always knocks out the first one.
This seems expensive since you will have to either store bunch of bitmaps, or do a bunch of planar mapping code to figure out the paths.
I think a parent region will also not be notified if the child is clicked.

> -----Original Message-----
> From: Chaals McCathieNevile []
> Sent: Sunday, August 19, 2012 4:00 AM
> To:; Rik Cabanier
> Subject: Re: hit regions
> On Sun, 19 Aug 2012 06:21:35 +0200, Rik Cabanier <>
> wrote:
> > I've been looking at the hit regions API and have some questions.
> [...]
> > 3.       There is nothing specific to canvas about hit regions. Would it
> > make sense to extend them later to other content such as images?
> Images have had image maps for a decade and a half already. ISSUE-105 
> asked if it made sense to go the other way around, and extend that to 
> canvas, but it seems that wheel wasn't the right colour.
> cheers
> Chaals
> --
> Chaals - standards declaimer

Received on Sunday, 19 August 2012 22:58:06 UTC