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cc / input / snap_selection_strategy.cc [blame]
// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "cc/input/snap_selection_strategy.h"
#include <cmath>
namespace cc {
std::unique_ptr<SnapSelectionStrategy>
SnapSelectionStrategy::CreateForEndPosition(const gfx::PointF& current_position,
bool scrolled_x,
bool scrolled_y) {
return std::make_unique<EndPositionStrategy>(current_position, scrolled_x,
scrolled_y);
}
std::unique_ptr<SnapSelectionStrategy>
SnapSelectionStrategy::CreateForDirection(gfx::PointF current_position,
gfx::Vector2dF step,
bool use_fractional_offsets,
SnapStopAlwaysFilter filter) {
return std::make_unique<DirectionStrategy>(current_position, step, filter,
use_fractional_offsets);
}
std::unique_ptr<SnapSelectionStrategy>
SnapSelectionStrategy::CreateForEndAndDirection(gfx::PointF current_position,
gfx::Vector2dF displacement,
bool use_fractional_offsets) {
return std::make_unique<EndAndDirectionStrategy>(
current_position, displacement, use_fractional_offsets);
}
std::unique_ptr<SnapSelectionStrategy>
SnapSelectionStrategy::CreateForTargetElement(gfx::PointF current_position) {
return std::make_unique<EndPositionStrategy>(
current_position, true /* scrolled_x */, true /* scrolled_y */,
SnapTargetsPrioritization::kRequire);
}
bool SnapSelectionStrategy::HasIntendedDirection() const {
return true;
}
bool SnapSelectionStrategy::ShouldRespectSnapStop() const {
return false;
}
bool SnapSelectionStrategy::IsValidSnapArea(SearchAxis axis,
const SnapAreaData& area) const {
return axis == SearchAxis::kX
? area.scroll_snap_align.alignment_inline != SnapAlignment::kNone
: area.scroll_snap_align.alignment_block != SnapAlignment::kNone;
}
bool SnapSelectionStrategy::ShouldPrioritizeSnapTargets() const {
return false;
}
bool SnapSelectionStrategy::UsingFractionalOffsets() const {
return false;
}
bool EndPositionStrategy::ShouldSnapOnX() const {
return scrolled_x_;
}
bool EndPositionStrategy::ShouldSnapOnY() const {
return scrolled_y_;
}
gfx::PointF EndPositionStrategy::intended_position() const {
return current_position_;
}
gfx::PointF EndPositionStrategy::base_position() const {
return current_position_;
}
// |position| is unused in this method.
bool EndPositionStrategy::IsValidSnapPosition(SearchAxis axis,
float position) const {
return (scrolled_x_ && axis == SearchAxis::kX) ||
(scrolled_y_ && axis == SearchAxis::kY);
}
bool EndPositionStrategy::HasIntendedDirection() const {
return false;
}
bool EndPositionStrategy::ShouldPrioritizeSnapTargets() const {
return snap_targets_prioritization_ == SnapTargetsPrioritization::kRequire;
}
const std::optional<SnapSearchResult>& EndPositionStrategy::PickBestResult(
const std::optional<SnapSearchResult>& closest,
const std::optional<SnapSearchResult>& covering) const {
return covering.has_value() ? covering : closest;
}
std::unique_ptr<SnapSelectionStrategy> EndPositionStrategy::Clone() const {
return std::make_unique<EndPositionStrategy>(*this);
}
bool DirectionStrategy::ShouldSnapOnX() const {
return step_.x() != 0;
}
bool DirectionStrategy::ShouldSnapOnY() const {
return step_.y() != 0;
}
gfx::PointF DirectionStrategy::intended_position() const {
return current_position_ + step_;
}
gfx::PointF DirectionStrategy::base_position() const {
return current_position_;
}
bool DirectionStrategy::IsValidSnapPosition(SearchAxis axis,
float position) const {
// If not using fractional offsets then it is possible for the currently
// snapped area's offset, which is fractional, to not be equal to the current
// scroll offset, which is not fractional. Therefore we truncate the offsets
// so that any position within 1 of the current position is ignored.
if (axis == SearchAxis::kX) {
float delta = position - current_position_.x();
if (!use_fractional_offsets_)
delta = delta > 0 ? std::floor(delta) : std::ceil(delta);
return (step_.x() > 0 && delta > 0) || // "Right" arrow
(step_.x() < 0 && delta < 0); // "Left" arrow
} else {
float delta = position - current_position_.y();
if (!use_fractional_offsets_)
delta = delta > 0 ? std::floor(delta) : std::ceil(delta);
return (step_.y() > 0 && delta > 0) || // "Down" arrow
(step_.y() < 0 && delta < 0); // "Up" arrow
}
}
bool DirectionStrategy::IsValidSnapArea(SearchAxis axis,
const SnapAreaData& area) const {
return SnapSelectionStrategy::IsValidSnapArea(axis, area) &&
(snap_stop_always_filter_ == SnapStopAlwaysFilter::kIgnore ||
area.must_snap);
}
const std::optional<SnapSearchResult>& DirectionStrategy::PickBestResult(
const std::optional<SnapSearchResult>& closest,
const std::optional<SnapSearchResult>& covering) const {
// We choose the |closest| result only if the default landing position (using
// the default step) is not a valid snap position (not making a snap area
// covering the snapport), or the |closest| is closer than the default landing
// position.
if (!closest.has_value())
return covering;
if (!covering.has_value())
return closest;
// "Right" or "Down" arrow.
if ((step_.x() > 0 || step_.y() > 0) &&
closest.value().snap_offset() < covering.value().snap_offset()) {
return closest;
}
// "Left" or "Up" arrow.
if ((step_.x() < 0 || step_.y() < 0) &&
closest.value().snap_offset() > covering.value().snap_offset()) {
return closest;
}
return covering;
}
bool DirectionStrategy::UsingFractionalOffsets() const {
return use_fractional_offsets_;
}
std::unique_ptr<SnapSelectionStrategy> DirectionStrategy::Clone() const {
return std::make_unique<DirectionStrategy>(*this);
}
bool EndAndDirectionStrategy::ShouldSnapOnX() const {
return displacement_.x() != 0;
}
bool EndAndDirectionStrategy::ShouldSnapOnY() const {
return displacement_.y() != 0;
}
gfx::PointF EndAndDirectionStrategy::intended_position() const {
return current_position_ + displacement_;
}
gfx::PointF EndAndDirectionStrategy::base_position() const {
return current_position_ + displacement_;
}
bool EndAndDirectionStrategy::IsValidSnapPosition(SearchAxis axis,
float position) const {
// If not using fractional offsets then it is possible for the currently
// snapped area's offset, which is fractional, to not be equal to the current
// scroll offset, which is not fractional. Therefore we round the offsets so
// that any position within 0.5 of the current position is ignored.
if (axis == SearchAxis::kX) {
float delta = position - current_position_.x();
if (!use_fractional_offsets_)
delta = std::round(delta);
return (displacement_.x() > 0 && delta > 0) || // Right
(displacement_.x() < 0 && delta < 0); // Left
} else {
float delta = position - current_position_.y();
if (!use_fractional_offsets_)
delta = std::round(delta);
return (displacement_.y() > 0 && delta > 0) || // Down
(displacement_.y() < 0 && delta < 0); // Up
}
}
bool EndAndDirectionStrategy::ShouldRespectSnapStop() const {
return true;
}
const std::optional<SnapSearchResult>& EndAndDirectionStrategy::PickBestResult(
const std::optional<SnapSearchResult>& closest,
const std::optional<SnapSearchResult>& covering) const {
return covering.has_value() ? covering : closest;
}
bool EndAndDirectionStrategy::UsingFractionalOffsets() const {
return use_fractional_offsets_;
}
std::unique_ptr<SnapSelectionStrategy> EndAndDirectionStrategy::Clone() const {
return std::make_unique<EndAndDirectionStrategy>(*this);
}
} // namespace cc