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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/. */
#ifndef mozilla_layout_ScrollSnapInfo_h_
#define mozilla_layout_ScrollSnapInfo_h_
#include "mozilla/Maybe.h"
#include "mozilla/ScrollSnapTargetId.h"
#include "mozilla/ScrollTypes.h"
#include "mozilla/ServoStyleConsts.h"
#include "mozilla/layers/LayersTypes.h"
#include "nsPoint.h"
class nsIContent;
class nsIFrame;
struct nsRect;
struct nsSize;
struct nsStyleDisplay;
namespace mozilla {
enum class StyleScrollSnapStrictness : uint8_t;
class WritingMode;
struct SnapPoint {
SnapPoint() = default;
explicit SnapPoint(const nsPoint& aPoint)
: mX(Some(aPoint.x)), mY(Some(aPoint.y)) {}
SnapPoint(Maybe<nscoord>&& aX, Maybe<nscoord>&& aY)
: mX(std::move(aX)), mY(std::move(aY)) {}
bool operator==(const SnapPoint&) const = default;
Maybe<nscoord> mX;
Maybe<nscoord> mY;
};
struct ScrollSnapInfo {
using ScrollDirection = layers::ScrollDirection;
ScrollSnapInfo();
bool operator==(const ScrollSnapInfo&) const = default;
bool HasScrollSnapping() const;
bool HasSnapPositions() const;
void InitializeScrollSnapStrictness(WritingMode aWritingMode,
const nsStyleDisplay* aDisplay);
// The scroll frame's scroll-snap-type.
StyleScrollSnapStrictness mScrollSnapStrictnessX;
StyleScrollSnapStrictness mScrollSnapStrictnessY;
struct SnapTarget {
// The scroll positions corresponding to scroll-snap-align values.
SnapPoint mSnapPoint;
// https://drafts.csswg.org/css-scroll-snap/#scroll-snap-area
nsRect mSnapArea;
// https://drafts.csswg.org/css-scroll-snap/#propdef-scroll-snap-stop
StyleScrollSnapStop mScrollSnapStop = StyleScrollSnapStop::Normal;
// Use for tracking the last snapped target.
ScrollSnapTargetId mTargetId = ScrollSnapTargetId::None;
SnapTarget() = default;
SnapTarget(Maybe<nscoord>&& aSnapPositionX, Maybe<nscoord>&& aSnapPositionY,
const nsRect& aSnapArea, StyleScrollSnapStop aScrollSnapStop,
ScrollSnapTargetId aTargetId)
: mSnapPoint(std::move(aSnapPositionX), std::move(aSnapPositionY)),
mSnapArea(aSnapArea),
mScrollSnapStop(aScrollSnapStop),
mTargetId(aTargetId) {}
bool operator==(const SnapTarget& aOther) const = default;
};
CopyableTArray<SnapTarget> mSnapTargets;
// A utility function to iterate over the valid snap targets for the given
// |aDestination| until |aFunc| returns false.
void ForEachValidTargetFor(
const nsPoint& aDestination,
const std::function<bool(const SnapTarget&)>& aFunc) const;
struct ScrollSnapRange {
ScrollSnapRange() = default;
ScrollSnapRange(const nsRect& aSnapArea, ScrollDirection aDirection,
ScrollSnapTargetId aTargetId)
: mSnapArea(aSnapArea), mDirection(aDirection), mTargetId(aTargetId) {}
nsRect mSnapArea;
ScrollDirection mDirection;
ScrollSnapTargetId mTargetId;
bool operator==(const ScrollSnapRange& aOther) const = default;
nscoord Start() const {
return mDirection == ScrollDirection::eHorizontal ? mSnapArea.X()
: mSnapArea.Y();
}
nscoord End() const {
return mDirection == ScrollDirection::eHorizontal ? mSnapArea.XMost()
: mSnapArea.YMost();
}
// Returns true if |aPoint| is a valid snap position in this range.
bool IsValid(nscoord aPoint, nscoord aSnapportSize) const {
MOZ_ASSERT(End() - Start() > aSnapportSize);
return Start() <= aPoint && aPoint <= End() - aSnapportSize;
}
};
// An array of the range that the target element is larger than the snapport
// on the axis.
// Snap positions in this range will be valid snap positions in the case where
// the distance between the closest snap position and the second closest snap
// position is still larger than the snapport size.
// See https://drafts.csswg.org/css-scroll-snap-1/#snap-overflow
//
// Note: This range contains scroll-margin values.
CopyableTArray<ScrollSnapRange> mXRangeWiderThanSnapport;
CopyableTArray<ScrollSnapRange> mYRangeWiderThanSnapport;
// Note: This snapport size has been already deflated by scroll-padding.
nsSize mSnapportSize;
};
} // namespace mozilla
#endif // mozilla_layout_ScrollSnapInfo_h_
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