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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "ScrollSnapInfo.h"
#include "nsPoint.h"
#include "nsRect.h"
#include "nsStyleStruct.h"
#include "mozilla/WritingModes.h"
namespace mozilla {
ScrollSnapInfo::ScrollSnapInfo()
: mScrollSnapStrictnessX(StyleScrollSnapStrictness::None),
mScrollSnapStrictnessY(StyleScrollSnapStrictness::None) {}
bool ScrollSnapInfo::HasScrollSnapping() const {
return mScrollSnapStrictnessY != StyleScrollSnapStrictness::None ||
mScrollSnapStrictnessX != StyleScrollSnapStrictness::None;
}
bool ScrollSnapInfo::HasSnapPositions() const {
if (!HasScrollSnapping()) {
return false;
}
for (const auto& target : mSnapTargets) {
if ((target.mSnapPoint.mX &&
mScrollSnapStrictnessX != StyleScrollSnapStrictness::None) ||
(target.mSnapPoint.mY &&
mScrollSnapStrictnessY != StyleScrollSnapStrictness::None)) {
return true;
}
}
return false;
}
void ScrollSnapInfo::InitializeScrollSnapStrictness(
WritingMode aWritingMode, const nsStyleDisplay* aDisplay) {
if (aDisplay->mScrollSnapType.strictness == StyleScrollSnapStrictness::None) {
return;
}
mScrollSnapStrictnessX = StyleScrollSnapStrictness::None;
mScrollSnapStrictnessY = StyleScrollSnapStrictness::None;
switch (aDisplay->mScrollSnapType.axis) {
case StyleScrollSnapAxis::X:
mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
break;
case StyleScrollSnapAxis::Y:
mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
break;
case StyleScrollSnapAxis::Block:
if (aWritingMode.IsVertical()) {
mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
} else {
mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
}
break;
case StyleScrollSnapAxis::Inline:
if (aWritingMode.IsVertical()) {
mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
} else {
mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
}
break;
case StyleScrollSnapAxis::Both:
mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
break;
}
}
void ScrollSnapInfo::ForEachValidTargetFor(
const nsPoint& aDestination,
const std::function<bool(const SnapTarget&)>& aFunc) const {
for (const auto& target : mSnapTargets) {
nsPoint snapPoint(
mScrollSnapStrictnessX != StyleScrollSnapStrictness::None &&
target.mSnapPoint.mX
? *target.mSnapPoint.mX
: aDestination.x,
mScrollSnapStrictnessY != StyleScrollSnapStrictness::None &&
target.mSnapPoint.mY
? *target.mSnapPoint.mY
: aDestination.y);
nsRect snappedPort = nsRect(snapPoint, mSnapportSize);
// Ignore snap points if snapping to the point would leave the snap area
// outside of the snapport.
// https://drafts.csswg.org/css-scroll-snap-1/#snap-scope
//
// NOTE: We don't use BaseRect::Intersects() here since the function returns
// false in cases where the given rectangle is empty.
if (!snappedPort.EdgeInclusiveIntersection(target.mSnapArea)) {
continue;
}
if (!aFunc(target)) {
break;
}
}
}
} // namespace mozilla
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