forked from mirrors/gecko-dev
105 lines
3.4 KiB
C++
105 lines
3.4 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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#include "ScrollSnapInfo.h"
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#include "nsPoint.h"
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#include "nsRect.h"
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#include "nsStyleStruct.h"
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#include "mozilla/WritingModes.h"
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namespace mozilla {
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ScrollSnapInfo::ScrollSnapInfo()
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: mScrollSnapStrictnessX(StyleScrollSnapStrictness::None),
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mScrollSnapStrictnessY(StyleScrollSnapStrictness::None) {}
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bool ScrollSnapInfo::HasScrollSnapping() const {
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return mScrollSnapStrictnessY != StyleScrollSnapStrictness::None ||
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mScrollSnapStrictnessX != StyleScrollSnapStrictness::None;
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}
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bool ScrollSnapInfo::HasSnapPositions() const {
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if (!HasScrollSnapping()) {
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return false;
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}
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for (const auto& target : mSnapTargets) {
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if ((target.mSnapPoint.mX &&
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mScrollSnapStrictnessX != StyleScrollSnapStrictness::None) ||
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(target.mSnapPoint.mY &&
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mScrollSnapStrictnessY != StyleScrollSnapStrictness::None)) {
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return true;
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}
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}
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return false;
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}
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void ScrollSnapInfo::InitializeScrollSnapStrictness(
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WritingMode aWritingMode, const nsStyleDisplay* aDisplay) {
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if (aDisplay->mScrollSnapType.strictness == StyleScrollSnapStrictness::None) {
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return;
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}
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mScrollSnapStrictnessX = StyleScrollSnapStrictness::None;
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mScrollSnapStrictnessY = StyleScrollSnapStrictness::None;
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switch (aDisplay->mScrollSnapType.axis) {
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case StyleScrollSnapAxis::X:
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mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
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break;
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case StyleScrollSnapAxis::Y:
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mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
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break;
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case StyleScrollSnapAxis::Block:
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if (aWritingMode.IsVertical()) {
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mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
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} else {
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mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
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}
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break;
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case StyleScrollSnapAxis::Inline:
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if (aWritingMode.IsVertical()) {
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mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
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} else {
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mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
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}
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break;
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case StyleScrollSnapAxis::Both:
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mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
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mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
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break;
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}
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}
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void ScrollSnapInfo::ForEachValidTargetFor(
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const nsPoint& aDestination,
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const std::function<bool(const SnapTarget&)>& aFunc) const {
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for (const auto& target : mSnapTargets) {
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nsPoint snapPoint(
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mScrollSnapStrictnessX != StyleScrollSnapStrictness::None &&
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target.mSnapPoint.mX
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? *target.mSnapPoint.mX
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: aDestination.x,
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mScrollSnapStrictnessY != StyleScrollSnapStrictness::None &&
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target.mSnapPoint.mY
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? *target.mSnapPoint.mY
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: aDestination.y);
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nsRect snappedPort = nsRect(snapPoint, mSnapportSize);
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// Ignore snap points if snapping to the point would leave the snap area
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// outside of the snapport.
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// https://drafts.csswg.org/css-scroll-snap-1/#snap-scope
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if (!snappedPort.Intersects(target.mSnapArea)) {
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continue;
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}
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if (!aFunc(target)) {
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break;
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}
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}
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}
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} // namespace mozilla
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