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b9b9e38dd9
This avoids arbitrary precision loss when computing REM units and so on, which is particularly important if we ever change the base of our app units (but useful regardless). Differential Revision: https://phabricator.services.mozilla.com/D79928
48 lines
1.6 KiB
C++
48 lines
1.6 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* A namespace class for static muti-column utilities. */
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#include "mozilla/ColumnUtils.h"
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#include <algorithm>
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#include "nsContainerFrame.h"
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#include "nsLayoutUtils.h"
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namespace mozilla {
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/* static */
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nscoord ColumnUtils::GetColumnGap(const nsContainerFrame* aFrame,
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nscoord aPercentageBasis) {
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const auto& columnGap = aFrame->StylePosition()->mColumnGap;
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if (columnGap.IsNormal()) {
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return aFrame->StyleFont()->mFont.size.ToAppUnits();
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}
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return nsLayoutUtils::ResolveGapToLength(columnGap, aPercentageBasis);
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}
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/* static */
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nscoord ColumnUtils::ClampUsedColumnWidth(const Length& aColumnWidth) {
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// Per spec, used values will be clamped to a minimum of 1px.
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return std::max(CSSPixel::ToAppUnits(1), aColumnWidth.ToAppUnits());
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}
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/* static */
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nscoord ColumnUtils::IntrinsicISize(uint32_t aColCount, nscoord aColGap,
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nscoord aColISize) {
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MOZ_ASSERT(aColCount > 0, "Cannot compute with zero columns!");
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// Column box's inline-size times number of columns (n), plus n-1 column gaps.
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nscoord iSize = aColISize * aColCount + aColGap * (aColCount - 1);
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// The multiplication above can make 'iSize' negative (integer overflow),
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// so use std::max to protect against that.
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return std::max(iSize, aColISize);
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}
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} // namespace mozilla
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