Re: scrolling jerky

On 27 Apr 2012, Chris Young wrote:
> On Fri, 27 Apr 2012 08:23:18 +0100, Roger Darlington wrote:

>> On 25 Apr 2012, Michael Drake wrote:
>>> In article <be1b188652.rogerarm@rogerarm.freeuk.com>,
>>> Roger Darlington <rogerarm@freeuk.com> wrote:
>>
>>>> Scrolling very jerky on the vertical slider
>>
>>> Please see my response to your previous scrolling thread:
>>
>>> http://www.mail-archive.com/netsurf-users@netsurf-browser.org/msg03976.html
>>
>>> Your google URL is the scrolling frames issue.
>>
>> Thanks for that Michael. I have increased the Cache from 20MB to 90MB,
>> but there is still a very noticeable difference between scrolling the
>> two versions of the very same page (neither of which get anywhere near
>> 90MB it must be said...)

> Cache won't help, the issue is that "core" scrolls aren't optimised,
> so if you scroll a frame the entire contents of that frame will be
> redrawn - even if it is only scrolled a pixel. Conversely, if you
> scroll using the window scrollbar, the platform code handles the
> scroll. Usually the platform code is optimised, and will "shift" the
> area and just redraw the newly-exposed bit.

> Clearly NetSurf would benefit from some scrolling optimisation in the
> core, but I'm not sure if it is as easy as telling the frontend code
> to move a particular area and then redraw the newly exposed area.
> (not least because frontends don't currently have any concept of "move
> a particular area")

> Regards
> Chris



--

Cheers
Roger
"I suspect everyone, and yet, I suspect no-one" Inspector Cleuseau