NEW247857
Get rid of subtract-one-whole-pixel hack in Multi-column 
https://bugs.webkit.org/show_bug.cgi?id=247857
Summary Get rid of subtract-one-whole-pixel hack in Multi-column
Ahmad Saleem
Reported 2022-11-13 04:02:05 PST
Hi Team, Just going through Blink Commits, I noticed another commit, where we have still one pixel hack present in our code. Webkit GitHub - https://github.com/WebKit/WebKit/blob/5a9504aef82d929917a680a05a3fc17f7f6b4dde/Source/WebCore/rendering/RenderMultiColumnSet.cpp#LL816 & https://github.com/WebKit/WebKit/blob/5a9504aef82d929917a680a05a3fc17f7f6b4dde/Source/WebCore/rendering/RenderMultiColumnSet.cpp#L821 & Blink Commit - https://chromium.googlesource.com/chromium/blink/+/b0bf11d2c22b4b0a6775322b9dd955cdfe9f8c19 JSFiddle Failing - https://jsfiddle.net/1o9fy8gx/show (Firefox Nightly 108 shows line below & Chrome Canary 110 was broken and was not rendering this for some time) Just wanted to raise this bug so we can get rid of it as well. Thanks!
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Radar WebKit Bug Importer
Comment 1 2022-11-20 04:03:15 PST
<rdar://problem/102559272>
Ahmad Saleem
Comment 2 2023-11-03 03:08:51 PDT
LayoutUnit repaintLogicalBottom = (isHorizontalWritingMode() ? fragmentedFlowRepaintRect.maxY() : fragmentedFlowRepaintRect.maxX()); // Figure out the start and end columns for the layer and only check within that range so that // we don't walk the entire column row. unsigned startColumn; unsigned endColumn; columnIntervalForBlockRangeInFragmentedFlow(repaintLogicalTop, repaintLogicalBottom, startColumn, endColumn); and void RenderMultiColumnSet::columnIntervalForBlockRangeInFragmentedFlow(LayoutUnit logicalTopInFragmentedFlow, LayoutUnit logicalBottomInFragmentedFlow, unsigned& firstColumn, unsigned& lastColumn) const { ASSERT(logicalTopInFragmentedFlow <= logicalBottomInFragmentedFlow); firstColumn = columnIndexAtOffset(logicalTopInFragmentedFlow); lastColumn = columnIndexAtOffset(logicalBottomInFragmentedFlow); // logicalBottomInFragmentedFlow is an exclusive endpoint, so some additional adjustments may be necessary. if (lastColumn > firstColumn && LayoutUnit(logicalTopInFragmentedFlow(lastColumn)) == LayoutUnit(logicalBottomInFragmentedFlow)) --lastColumn; } __ ^ this might work. Didn't tried. __ I attached unprefixed test case in URL field.
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