forked from mirrors/gecko-dev
a468f78119
When the layout viewport is smaller than the visual viewport and the user scrolls a web page, the layout viewport remains fixed to its position before the scroll event took place. However, the visual viewport moves according to the new scroll position. This patch addresses this issue by moving the layout viewport along with the visual viewport. MozReview-Commit-ID: 3Mk1o6AF2wr --HG-- extra : rebase_source : 8c6068059593038dc443cb9c96242483de97e9d9
107 lines
3.8 KiB
C++
107 lines
3.8 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 "FrameMetrics.h"
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#include "gfxPrefs.h"
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#include "nsStyleConsts.h"
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namespace mozilla {
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namespace layers {
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const FrameMetrics::ViewID FrameMetrics::NULL_SCROLL_ID = 0;
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void
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FrameMetrics::RecalculateViewportOffset()
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{
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if (!mIsRootContent) {
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return;
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}
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CSSRect visualViewport = GetVisualViewport();
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// If the visual viewport is contained within the layout viewport, we don't
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// need to make any adjustments, so we can exit early.
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//
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// Additionally, if the composition bounds changes (due to an orientation
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// change, window resize, etc.), it may take a few frames for mViewport to
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// update and during that time, the visual viewport may be larger than the
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// layout viewport. In such situations, we take an early exit if the visual
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// viewport contains the layout viewport.
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if (mViewport.Contains(visualViewport) || visualViewport.Contains(mViewport)) {
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return;
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}
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// If visual viewport size is greater than the layout viewport, move the layout
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// viewport such that it remains inside the visual viewport. Otherwise,
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// move the layout viewport such that the visual viewport is contained
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// inside the layout viewport.
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if ((mViewport.Width() < visualViewport.Width() &&
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!FuzzyEqualsMultiplicative(mViewport.Width(), visualViewport.Width())) ||
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(mViewport.Height() < visualViewport.Height() &&
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!FuzzyEqualsMultiplicative(mViewport.Height(), visualViewport.Height()))) {
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if (mViewport.X() < visualViewport.X()) {
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// layout viewport moves right
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mViewport.MoveToX(visualViewport.X());
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} else if (visualViewport.XMost() < mViewport.XMost()) {
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// layout viewport moves left
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mViewport.MoveByX(visualViewport.XMost() - mViewport.XMost());
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}
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if (mViewport.Y() < visualViewport.Y()) {
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// layout viewport moves down
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mViewport.MoveToY(visualViewport.Y());
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} else if (visualViewport.YMost() < mViewport.YMost()) {
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// layout viewport moves up
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mViewport.MoveByY(visualViewport.YMost() - mViewport.YMost());
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}
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} else {
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if (visualViewport.X() < mViewport.X()) {
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mViewport.MoveToX(visualViewport.X());
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} else if (mViewport.XMost() < visualViewport.XMost()) {
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mViewport.MoveByX(visualViewport.XMost() - mViewport.XMost());
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}
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if (visualViewport.Y() < mViewport.Y()) {
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mViewport.MoveToY(visualViewport.Y());
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} else if (mViewport.YMost() < visualViewport.YMost()) {
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mViewport.MoveByY(visualViewport.YMost() - mViewport.YMost());
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}
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}
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}
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void
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ScrollMetadata::SetUsesContainerScrolling(bool aValue) {
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MOZ_ASSERT_IF(aValue, gfxPrefs::LayoutUseContainersForRootFrames());
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mUsesContainerScrolling = aValue;
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}
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static OverscrollBehavior
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ToOverscrollBehavior(StyleOverscrollBehavior aBehavior)
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{
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switch (aBehavior) {
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case StyleOverscrollBehavior::Auto:
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return OverscrollBehavior::Auto;
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case StyleOverscrollBehavior::Contain:
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return OverscrollBehavior::Contain;
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case StyleOverscrollBehavior::None:
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return OverscrollBehavior::None;
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}
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MOZ_ASSERT_UNREACHABLE("Invalid overscroll behavior");
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return OverscrollBehavior::Auto;
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}
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OverscrollBehaviorInfo
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OverscrollBehaviorInfo::FromStyleConstants(StyleOverscrollBehavior aBehaviorX,
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StyleOverscrollBehavior aBehaviorY)
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{
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OverscrollBehaviorInfo result;
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result.mBehaviorX = ToOverscrollBehavior(aBehaviorX);
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result.mBehaviorY = ToOverscrollBehavior(aBehaviorY);
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return result;
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}
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StaticAutoPtr<const ScrollMetadata> ScrollMetadata::sNullMetadata;
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}
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}
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