[whatwg] Offscreen canvas (or canvas for web workers).

[Maciej Stachowiak]

On Mar 12, 2010, at 2:35 PM, Jonas Sicking wrote:

> On Fri, Mar 12, 2010 at 12:46 PM, Oliver Hunt <oliver at apple.com>  
> wrote:
>>
>> On Mar 12, 2010, at 12:16 PM, Jonas Sicking wrote:
>>> I'm not saying that the proposed API is bad. It just doesn't seem to
>>> solve the (seemingly most commonly requested) use case of
>>> rotating/scaling images. So if we want to solve those use cases we
>>> need to either come up with a separate API for that, or extend this
>>> proposal to solve that use case somehow.
>>
>> Just for reference I think one thing that people are forgetting  
>> that there is a difference between
>> being computationally faster, and being more responsive.
>
> As I mentioned in my email, if you look at the steps listed, enough of
> them happen *on the main thread* that you're spending far more of the
> main threads CPU cycles than you'd like. Possibly even more than doing
> all the resizing on the main thread.
>
> With the other improvements suggested by David things do definitely
> look different, but those are not in a proposal yet.

In general a copy is a fair bit faster than an image rotate or resize,  
though I don't know if it is faster enough for reasonable image sizes  
to matter.

Regards,
Maciej