gecko-dev/gfx/layers/FrameMetrics.cpp

108 строки
3.8 KiB
C++

/* -*- 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/. */
#include "FrameMetrics.h"
#include "gfxPrefs.h"
#include "nsStyleConsts.h"
namespace mozilla {
namespace layers {
const FrameMetrics::ViewID FrameMetrics::NULL_SCROLL_ID = 0;
void
FrameMetrics::RecalculateViewportOffset()
{
if (!mIsRootContent) {
return;
}
CSSRect visualViewport = GetVisualViewport();
// If the visual viewport is contained within the layout viewport, we don't
// need to make any adjustments, so we can exit early.
//
// Additionally, if the composition bounds changes (due to an orientation
// change, window resize, etc.), it may take a few frames for mViewport to
// update and during that time, the visual viewport may be larger than the
// layout viewport. In such situations, we take an early exit if the visual
// viewport contains the layout viewport.
if (mViewport.Contains(visualViewport) || visualViewport.Contains(mViewport)) {
return;
}
// If visual viewport size is greater than the layout viewport, move the layout
// viewport such that it remains inside the visual viewport. Otherwise,
// move the layout viewport such that the visual viewport is contained
// inside the layout viewport.
if ((mViewport.Width() < visualViewport.Width() &&
!FuzzyEqualsMultiplicative(mViewport.Width(), visualViewport.Width())) ||
(mViewport.Height() < visualViewport.Height() &&
!FuzzyEqualsMultiplicative(mViewport.Height(), visualViewport.Height()))) {
if (mViewport.X() < visualViewport.X()) {
// layout viewport moves right
mViewport.MoveToX(visualViewport.X());
} else if (visualViewport.XMost() < mViewport.XMost()) {
// layout viewport moves left
mViewport.MoveByX(visualViewport.XMost() - mViewport.XMost());
}
if (mViewport.Y() < visualViewport.Y()) {
// layout viewport moves down
mViewport.MoveToY(visualViewport.Y());
} else if (visualViewport.YMost() < mViewport.YMost()) {
// layout viewport moves up
mViewport.MoveByY(visualViewport.YMost() - mViewport.YMost());
}
} else {
if (visualViewport.X() < mViewport.X()) {
mViewport.MoveToX(visualViewport.X());
} else if (mViewport.XMost() < visualViewport.XMost()) {
mViewport.MoveByX(visualViewport.XMost() - mViewport.XMost());
}
if (visualViewport.Y() < mViewport.Y()) {
mViewport.MoveToY(visualViewport.Y());
} else if (mViewport.YMost() < visualViewport.YMost()) {
mViewport.MoveByY(visualViewport.YMost() - mViewport.YMost());
}
}
}
void
ScrollMetadata::SetUsesContainerScrolling(bool aValue) {
MOZ_ASSERT_IF(aValue, gfxPrefs::LayoutUseContainersForRootFrames());
mUsesContainerScrolling = aValue;
}
static OverscrollBehavior
ToOverscrollBehavior(StyleOverscrollBehavior aBehavior)
{
switch (aBehavior) {
case StyleOverscrollBehavior::Auto:
return OverscrollBehavior::Auto;
case StyleOverscrollBehavior::Contain:
return OverscrollBehavior::Contain;
case StyleOverscrollBehavior::None:
return OverscrollBehavior::None;
}
MOZ_ASSERT_UNREACHABLE("Invalid overscroll behavior");
return OverscrollBehavior::Auto;
}
OverscrollBehaviorInfo
OverscrollBehaviorInfo::FromStyleConstants(StyleOverscrollBehavior aBehaviorX,
StyleOverscrollBehavior aBehaviorY)
{
OverscrollBehaviorInfo result;
result.mBehaviorX = ToOverscrollBehavior(aBehaviorX);
result.mBehaviorY = ToOverscrollBehavior(aBehaviorY);
return result;
}
StaticAutoPtr<const ScrollMetadata> ScrollMetadata::sNullMetadata;
}
}