gfx/layers/FrameMetrics.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "FrameMetrics.h"
   8
   9 #include "gfxUtils.h"
  10 #include "nsStyleConsts.h"
  11 #include "nsStyleStruct.h"
  12 #include "mozilla/WritingModes.h"
  13 #include "mozilla/gfx/Types.h"
  14
  15 namespace mozilla {
  16 namespace layers {
  17
  18 const ScrollableLayerGuid::ViewID ScrollableLayerGuid::NULL_SCROLL_ID = 0;
  19
  20 void FrameMetrics::RecalculateLayoutViewportOffset() {
  21   if (!mIsRootContent) {
  22     return;
  23   }
  24   KeepLayoutViewportEnclosingVisualViewport(GetVisualViewport(),
  25                                             mScrollableRect, mLayoutViewport);
  26 }
  27
  28 /* static */
  29 void FrameMetrics::KeepLayoutViewportEnclosingVisualViewport(
  30     const CSSRect& aVisualViewport, const CSSRect& aScrollableRect,
  31     CSSRect& aLayoutViewport) {
  32   // If the visual viewport is contained within the layout viewport, we don't
  33   // need to make any adjustments, so we can exit early.
  34   //
  35   // Additionally, if the composition bounds changes (due to an orientation
  36   // change, window resize, etc.), it may take a few frames for aLayoutViewport
  37   // to update and during that time, the visual viewport may be larger than the
  38   // layout viewport. In such situations, we take an early exit if the visual
  39   // viewport contains the layout viewport.
  40   if (aLayoutViewport.Contains(aVisualViewport) ||
  41       aVisualViewport.Contains(aLayoutViewport)) {
  42     return;
  43   }
  44
  45   // If visual viewport size is greater than the layout viewport, move the
  46   // layout viewport such that it remains inside the visual viewport. Otherwise,
  47   // move the layout viewport such that the visual viewport is contained
  48   // inside the layout viewport.
  49   if ((aLayoutViewport.Width() < aVisualViewport.Width() &&
  50        !FuzzyEqualsMultiplicative(aLayoutViewport.Width(),
  51                                   aVisualViewport.Width())) ||
  52       (aLayoutViewport.Height() < aVisualViewport.Height() &&
  53        !FuzzyEqualsMultiplicative(aLayoutViewport.Height(),
  54                                   aVisualViewport.Height()))) {
  55     if (aLayoutViewport.X() < aVisualViewport.X()) {
  56       // layout viewport moves right
  57       aLayoutViewport.MoveToX(aVisualViewport.X());
  58     } else if (aVisualViewport.XMost() < aLayoutViewport.XMost()) {
  59       // layout viewport moves left
  60       aLayoutViewport.MoveByX(aVisualViewport.XMost() -
  61                               aLayoutViewport.XMost());
  62     }
  63     if (aLayoutViewport.Y() < aVisualViewport.Y()) {
  64       // layout viewport moves down
  65       aLayoutViewport.MoveToY(aVisualViewport.Y());
  66     } else if (aVisualViewport.YMost() < aLayoutViewport.YMost()) {
  67       // layout viewport moves up
  68       aLayoutViewport.MoveByY(aVisualViewport.YMost() -
  69                               aLayoutViewport.YMost());
  70     }
  71   } else {
  72     if (aVisualViewport.X() < aLayoutViewport.X()) {
  73       aLayoutViewport.MoveToX(aVisualViewport.X());
  74     } else if (aLayoutViewport.XMost() < aVisualViewport.XMost()) {
  75       aLayoutViewport.MoveByX(aVisualViewport.XMost() -
  76                               aLayoutViewport.XMost());
  77     }
  78     if (aVisualViewport.Y() < aLayoutViewport.Y()) {
  79       aLayoutViewport.MoveToY(aVisualViewport.Y());
  80     } else if (aLayoutViewport.YMost() < aVisualViewport.YMost()) {
  81       aLayoutViewport.MoveByY(aVisualViewport.YMost() -
  82                               aLayoutViewport.YMost());
  83     }
  84   }
  85
  86   // Regardless of any adjustment above, the layout viewport is not allowed
  87   // to go outside the scrollable rect.
  88   aLayoutViewport = aLayoutViewport.MoveInsideAndClamp(aScrollableRect);
  89 }
  90
  91 ScrollSnapInfo::ScrollSnapInfo()
  92     : mScrollSnapStrictnessX(StyleScrollSnapStrictness::None),
  93       mScrollSnapStrictnessY(StyleScrollSnapStrictness::None) {}
  94
  95 bool ScrollSnapInfo::HasScrollSnapping() const {
  96   return mScrollSnapStrictnessY != StyleScrollSnapStrictness::None ||
  97          mScrollSnapStrictnessX != StyleScrollSnapStrictness::None;
  98 }
  99
 100 bool ScrollSnapInfo::HasSnapPositions() const {
 101   return (!mSnapPositionX.IsEmpty() &&
 102           mScrollSnapStrictnessX != StyleScrollSnapStrictness::None) ||
 103          (!mSnapPositionY.IsEmpty() &&
 104           mScrollSnapStrictnessY != StyleScrollSnapStrictness::None);
 105 }
 106
 107 void ScrollSnapInfo::InitializeScrollSnapStrictness(
 108     WritingMode aWritingMode, const nsStyleDisplay* aDisplay) {
 109   if (aDisplay->mScrollSnapType.strictness == StyleScrollSnapStrictness::None) {
 110     return;
 111   }
 112
 113   mScrollSnapStrictnessX = StyleScrollSnapStrictness::None;
 114   mScrollSnapStrictnessY = StyleScrollSnapStrictness::None;
 115
 116   switch (aDisplay->mScrollSnapType.axis) {
 117     case StyleScrollSnapAxis::X:
 118       mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
 119       break;
 120     case StyleScrollSnapAxis::Y:
 121       mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
 122       break;
 123     case StyleScrollSnapAxis::Block:
 124       if (aWritingMode.IsVertical()) {
 125         mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
 126       } else {
 127         mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
 128       }
 129       break;
 130     case StyleScrollSnapAxis::Inline:
 131       if (aWritingMode.IsVertical()) {
 132         mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
 133       } else {
 134         mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
 135       }
 136       break;
 137     case StyleScrollSnapAxis::Both:
 138       mScrollSnapStrictnessX = aDisplay->mScrollSnapType.strictness;
 139       mScrollSnapStrictnessY = aDisplay->mScrollSnapType.strictness;
 140       break;
 141   }
 142 }
 143
 144 static OverscrollBehavior ToOverscrollBehavior(
 145     StyleOverscrollBehavior aBehavior) {
 146   switch (aBehavior) {
 147     case StyleOverscrollBehavior::Auto:
 148       return OverscrollBehavior::Auto;
 149     case StyleOverscrollBehavior::Contain:
 150       return OverscrollBehavior::Contain;
 151     case StyleOverscrollBehavior::None:
 152       return OverscrollBehavior::None;
 153   }
 154   MOZ_ASSERT_UNREACHABLE("Invalid overscroll behavior");
 155   return OverscrollBehavior::Auto;
 156 }
 157
 158 OverscrollBehaviorInfo OverscrollBehaviorInfo::FromStyleConstants(
 159     StyleOverscrollBehavior aBehaviorX, StyleOverscrollBehavior aBehaviorY) {
 160   OverscrollBehaviorInfo result;
 161   result.mBehaviorX = ToOverscrollBehavior(aBehaviorX);
 162   result.mBehaviorY = ToOverscrollBehavior(aBehaviorY);
 163   return result;
 164 }
 165
 166 void ScrollMetadata::SetBackgroundColor(
 167     const gfx::sRGBColor& aBackgroundColor) {
 168   mBackgroundColor = gfx::ToDeviceColor(aBackgroundColor);
 169 }
 170
 171 StaticAutoPtr<const ScrollMetadata> ScrollMetadata::sNullMetadata;
 172
 173 }  // namespace layers
 174 }  // namespace mozilla