Bug 133436

Summary:

Don't scroll to non-integral scroll offsets

Product:

WebKit

Reporter:

Simon Fraser (smfr) <simon.fraser>

Component:

New Bugs

Assignee:

Simon Fraser (smfr) <simon.fraser>

Status:

RESOLVED FIXED

Severity:

Normal

CC:

andersca, bdakin, cmarcelo, commit-queue, jamesr, luiz, simon.fraser, thorton, tonikitoo

Priority:

Keywords:

InRadar

Version:

528+ (Nightly build)

Hardware:

Unspecified

OS:

Unspecified

Attachments:

Description	Flags
Patch	none

Description Simon Fraser (smfr) 2014-06-01 12:43:34 PDT

Don't scroll to non-integral scroll offsets

Comment 1 Simon Fraser (smfr) 2014-06-01 12:45:53 PDT

Created attachment 232351 [details]
Patch

Comment 2 Simon Fraser (smfr) 2014-06-01 12:46:17 PDT

<rdar://problem/17088336>

Comment 3 zalan 2014-06-01 13:24:59 PDT

Comment on attachment 232351 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=232351&action=review

> Source/WebCore/page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.mm:324
> +    // FIXME: when we support half-pixel scroll positions on Retina displays, this will need to round to half pixels.

half-pixel -> device pixel

> Source/WebCore/page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.mm:325
> +    FloatPoint roundedPosition(roundf(scrollPosition.x()), roundf(scrollPosition.y()));

I am wondering whether the input devices that send integral values do integer truncation or rounding. (and whether we should mimic that behavior)

Comment 4 Darin Adler 2014-06-01 14:49:04 PDT

Comment on attachment 232351 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=232351&action=review

>> Source/WebCore/page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.mm:325
>> +    FloatPoint roundedPosition(roundf(scrollPosition.x()), roundf(scrollPosition.y()));
> 
> I am wondering whether the input devices that send integral values do integer truncation or rounding. (and whether we should mimic that behavior)

Is this the single correct bottleneck for the rounding? What about the setScrollPositionWithoutContentEdgeConstraints and setScrollLayerPosition functions?

Comment 5 Simon Fraser (smfr) 2014-06-01 15:34:47 PDT

(In reply to comment #4)
> (From update of attachment 232351 [details])
> View in context: https://bugs.webkit.org/attachment.cgi?id=232351&action=review
> 
> >> Source/WebCore/page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.mm:325
> >> +    FloatPoint roundedPosition(roundf(scrollPosition.x()), roundf(scrollPosition.y()));
> > 
> > I am wondering whether the input devices that send integral values do integer truncation or rounding. (and whether we should mimic that behavior)
> 
> Is this the single correct bottleneck for the rounding? What about the setScrollPositionWithoutContentEdgeConstraints and setScrollLayerPosition functions?

This is the bottleneck, yes.

Comment 6 WebKit Commit Bot 2014-06-01 16:07:51 PDT

Comment on attachment 232351 [details]
Patch

Clearing flags on attachment: 232351

Committed r169519: <http://trac.webkit.org/changeset/169519>

Comment 7 WebKit Commit Bot 2014-06-01 16:07:55 PDT

All reviewed patches have been landed.  Closing bug.