Bug 135670

Summary: Consolidate logic for calculating scrollbar page step size
Product: WebKit Reporter: Brent Fulgham <bfulgham>
Component: Layout and RenderingAssignee: Brent Fulgham <bfulgham>
Status: RESOLVED FIXED    
Severity: Normal CC: bfulgham, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: 528+ (Nightly build)   
Hardware: All   
OS: All   
Attachments:
Description Flags
Patch simon.fraser: review+

Brent Fulgham
Reported 2014-08-06 14:04:50 PDT
There are a number of places in WebCore where the same complicated declaration is used: int pageStep = std::max(std::max<int>(clientWidth * Scrollbar::minFractionToStepWhenPaging(), clientWidth - Scrollbar::maxOverlapBetweenPages()), 1); To ensure that the correct rounding/truncating and clamping are used in all of these places, we should create a method that does this job for us: int pageStep = Scrollbar::pageStep(clientWidth);
Attachments
Patch (8.03 KB, patch)
2014-08-06 14:12 PDT, Brent Fulgham 		simon.fraser: review+
DetailsFormatted DiffDiff
View All Add attachment proposed patch, testcase, etc.
Brent Fulgham
Comment 1 2014-08-06 14:11:03 PDT
Furthermore, attempt to reduce small scroll calculation errors by properly rounding fractional step amounts by using lroundf during the calculation of the step size.
Brent Fulgham
Comment 2 2014-08-06 14:12:45 PDT
Created attachment 236134 [details] Patch
Radar WebKit Bug Importer
Comment 3 2014-08-06 16:00:44 PDT
<rdar://problem/17938368>
Brent Fulgham
Comment 4 2014-08-06 16:04:24 PDT
Committed r172182: <http://trac.webkit.org/changeset/172182>
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