scroll_snap_data.h | Explore in Territory

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CC_INPUT_SCROLL_SNAP_DATA_H_
#define CC_INPUT_SCROLL_SNAP_DATA_H_

#include <optional>
#include <set>
#include <utility>
#include <vector>

#include "base/gtest_prod_util.h"
#include "cc/cc_export.h"
#include "cc/paint/element_id.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/geometry/vector2d_f.h"
#include "ui/gfx/range/range_f.h"

namespace cc {

class SnapSelectionStrategy;

// See https://www.w3.org/TR/css-scroll-snap-1/#snap-axis
enum class SnapAxis : unsigned { … };

// A helper enum to specify the the axis when doing calculations.
enum class SearchAxis : unsigned { … };

// See https://www.w3.org/TR/css-scroll-snap-1/#snap-strictness
enum class SnapStrictness : unsigned { … };

// See https://www.w3.org/TR/css-scroll-snap-1/#scroll-snap-align
enum class SnapAlignment : unsigned { … };

struct ScrollSnapType { … };

struct ScrollSnapAlign { … };

// This struct represents a snap area that is considered to be a viable
// alternative to the snap area that was selected for the associated
// SnapSearchResult.
// The snap area is a viable alternative because it:
// - is a snap target in both axes, and
// - is aligned with its associated SnapSearchResult's snap area in the
//     main axis of that SnapSearchResult.
// This alternative may be considered to be a better choice if it is also
// aligned with the SnapSearchResult of the cross axis.
struct SnapSearchResultAlternative { … };

// This class includes snap offset and visible range needed to perform a snap
// operation on one axis for a specific area. The data can be used to determine
// whether this snap area provides a valid snap position for the current scroll.
class SnapSearchResult { … };

// Snap area is a bounding box that could be snapped to when a scroll happens in
// its scroll container.
// This data structure describes the data needed for SnapCoordinator if we want
// to snap to this snap area.
struct SnapAreaData { … };

struct TargetSnapAreaElementIds { … };

SnapAreaList;

// Represents the result of a call to SnapContainerData::FindSnapPosition.
struct SnapPositionData { … };

// Snap container is a scroll container that at least one snap area assigned to
// it.  If the snap-type is not 'none', then it can be snapped to one of its
// snap areas when a scroll happens.
// This data structure describes the data needed for SnapCoordinator to perform
// snapping in the snap container.
//
// Note that the snap area data should only be used when snap-type is not 'none'
// There is not guarantee that this information is up-to-date otherwise. In
// fact, we skip updating these info as an optiomization.
class CC_EXPORT SnapContainerData { … };

CC_EXPORT std::ostream& operator<<(std::ostream&, const SnapAreaData&);
CC_EXPORT std::ostream& operator<<(std::ostream&, const SnapContainerData&);

}  // namespace cc

#endif  // CC_INPUT_SCROLL_SNAP_DATA_H_
chromium/cc/input/scroll_snap_data.h
