C++ FrameMetrics类代码示例

bool
WheelScrollAnimation::DoSample(FrameMetrics& aFrameMetrics, const TimeDuration& aDelta)
{
  TimeStamp now = AsyncPanZoomController::GetFrameTime();
  CSSToParentLayerScale2D zoom = aFrameMetrics.GetZoom();

  // If the animation is finished, make sure the final position is correct by
  // using one last displacement. Otherwise, compute the delta via the timing
  // function as normal.
  bool finished = IsFinished(now);
  nsPoint sampledDest = finished
                        ? mDestination
                        : PositionAt(now);
  ParentLayerPoint displacement =
    (CSSPoint::FromAppUnits(sampledDest) - aFrameMetrics.GetScrollOffset()) * zoom;

  // Note: we ignore overscroll for wheel animations.
  ParentLayerPoint adjustedOffset, overscroll;
  mApzc.mX.AdjustDisplacement(displacement.x, adjustedOffset.x, overscroll.x);
  mApzc.mY.AdjustDisplacement(displacement.y, adjustedOffset.y, overscroll.y,
                              !aFrameMetrics.AllowVerticalScrollWithWheel());

  // If we expected to scroll, but there's no more scroll range on either axis,
  // then end the animation early. Note that the initial displacement could be 0
  // if the compositor ran very quickly (<1ms) after the animation was created.
  // When that happens we want to make sure the animation continues.
  if (!IsZero(displacement) && IsZero(adjustedOffset)) {
    // Nothing more to do - end the animation.
    return false;
  }

  aFrameMetrics.ScrollBy(adjustedOffset / zoom);
  return !finished;
}

bool
WheelScrollAnimation::DoSample(FrameMetrics& aFrameMetrics, const TimeDuration& aDelta)
{
  TimeStamp now = AsyncPanZoomController::GetFrameTime();
  CSSToParentLayerScale2D zoom = aFrameMetrics.GetZoom();

  // If the animation is finished, make sure the final position is correct by
  // using one last displacement. Otherwise, compute the delta via the timing
  // function as normal.
  bool finished = IsFinished(now);
  nsPoint sampledDest = finished
                        ? mDestination
                        : PositionAt(now);
  ParentLayerPoint displacement =
    (CSSPoint::FromAppUnits(sampledDest) - aFrameMetrics.GetScrollOffset()) * zoom;

  // Note: we ignore overscroll for wheel animations.
  ParentLayerPoint adjustedOffset, overscroll;
  mApzc.mX.AdjustDisplacement(displacement.x, adjustedOffset.x, overscroll.x);
  mApzc.mY.AdjustDisplacement(displacement.y, adjustedOffset.y, overscroll.y,
                              !aFrameMetrics.AllowVerticalScrollWithWheel());
  if (IsZero(adjustedOffset)) {
    // Nothing more to do - end the animation.
    return false;
  }

  aFrameMetrics.ScrollBy(adjustedOffset / zoom);
  return !finished;
}

static void
SetDisplayPortMargins(nsIDOMWindowUtils* aUtils,
                      nsIContent* aContent,
                      FrameMetrics& aMetrics)
{
  if (!aContent) {
    return;
  }
  nsCOMPtr<nsIDOMElement> element = do_QueryInterface(aContent);
  if (!element) {
    return;
  }

  ScreenMargin margins = aMetrics.GetDisplayPortMargins();
  aUtils->SetDisplayPortMarginsForElement(margins.left,
                                          margins.top,
                                          margins.right,
                                          margins.bottom,
                                          element, 0);
  CSSRect baseCSS = aMetrics.CalculateCompositedRectInCssPixels();
  nsRect base(0, 0,
              baseCSS.width * nsPresContext::AppUnitsPerCSSPixel(),
              baseCSS.height * nsPresContext::AppUnitsPerCSSPixel());
  nsLayoutUtils::SetDisplayPortBaseIfNotSet(aContent, base);
}

bool
ClientLayerManager::ProgressiveUpdateCallback(bool aHasPendingNewThebesContent,
                                              FrameMetrics& aMetrics,
                                              bool aDrawingCritical)
{
#ifdef MOZ_WIDGET_ANDROID
  MOZ_ASSERT(aMetrics.IsScrollable());
  // This is derived from the code in
  // gfx/layers/ipc/CompositorParent.cpp::TransformShadowTree.
  CSSToLayerScale paintScale = aMetrics.LayersPixelsPerCSSPixel();
  const CSSRect& metricsDisplayPort =
    (aDrawingCritical && !aMetrics.mCriticalDisplayPort.IsEmpty()) ?
      aMetrics.mCriticalDisplayPort : aMetrics.mDisplayPort;
  LayerRect displayPort = (metricsDisplayPort + aMetrics.GetScrollOffset()) * paintScale;

  ScreenPoint scrollOffset;
  CSSToScreenScale zoom;
  bool ret = AndroidBridge::Bridge()->ProgressiveUpdateCallback(
    aHasPendingNewThebesContent, displayPort, paintScale.scale, aDrawingCritical,
    scrollOffset, zoom);
  aMetrics.SetScrollOffset(scrollOffset / zoom);
  aMetrics.SetZoom(zoom);
  return ret;
#else
  return false;
#endif
}

FrameMetrics::ViewID
CompositorChild::SharedFrameMetricsData::GetViewID()
{
  FrameMetrics* frame = static_cast<FrameMetrics*>(mBuffer->memory());
  MOZ_ASSERT(frame);
  // Not locking to read of mScrollId since it should not change after being
  // initially set.
  return frame->GetScrollId();
}

void
APZCCallbackHelper::UpdateCallbackTransform(const FrameMetrics& aApzcMetrics, const FrameMetrics& aActualMetrics)
{
    nsCOMPtr<nsIContent> content = nsLayoutUtils::FindContentFor(aApzcMetrics.GetScrollId());
    if (!content) {
        return;
    }
    CSSPoint scrollDelta = aApzcMetrics.GetScrollOffset() - aActualMetrics.GetScrollOffset();
    content->SetProperty(nsGkAtoms::apzCallbackTransform, new CSSPoint(scrollDelta),
                         nsINode::DeleteProperty<CSSPoint>);
}

void
ChromeProcessController::RequestContentRepaint(const FrameMetrics& aFrameMetrics)
{
  MOZ_ASSERT(IsRepaintThread());

  FrameMetrics metrics = aFrameMetrics;
  if (metrics.IsRootContent()) {
    APZCCallbackHelper::UpdateRootFrame(metrics);
  } else {
    APZCCallbackHelper::UpdateSubFrame(metrics);
  }
}

// Recursively create a new array of scrollables, preserving any scrollables
// that are still in the layer tree.
//
// aXScale and aYScale are used to calculate any values that need to be in
// chrome-document CSS pixels and aren't part of the rendering loop, such as
// the initial scroll offset for a new view.
static void
BuildViewMap(ViewMap& oldContentViews, ViewMap& newContentViews,
             nsFrameLoader* aFrameLoader, Layer* aLayer,
             float aXScale = 1, float aYScale = 1)
{
  ContainerLayer* container = aLayer->AsContainerLayer();
  if (!container)
    return;
  const FrameMetrics metrics = container->GetFrameMetrics();
  const ViewID scrollId = metrics.mScrollId;
  const gfx3DMatrix transform = aLayer->GetTransform();
  aXScale *= GetXScale(transform);
  aYScale *= GetYScale(transform);

  if (metrics.IsScrollable()) {
    nscoord auPerDevPixel = aFrameLoader->GetPrimaryFrameOfOwningContent()
                                        ->PresContext()->AppUnitsPerDevPixel();
    nsContentView* view = FindViewForId(oldContentViews, scrollId);
    if (view) {
      // View already exists. Be sure to propagate scales for any values
      // that need to be calculated something in chrome-doc CSS pixels.
      ViewConfig config = view->GetViewConfig();
      aXScale *= config.mXScale;
      aYScale *= config.mYScale;
      view->mFrameLoader = aFrameLoader;
    } else {
      // View doesn't exist, so generate one. We start the view scroll offset at
      // the same position as the framemetric's scroll offset from the layer.
      // The default scale is 1, so no need to propagate scale down.
      ViewConfig config;
      config.mScrollOffset = nsPoint(
        NSIntPixelsToAppUnits(metrics.mViewportScrollOffset.x, auPerDevPixel) * aXScale,
        NSIntPixelsToAppUnits(metrics.mViewportScrollOffset.y, auPerDevPixel) * aYScale);
      view = new nsContentView(aFrameLoader, scrollId, config);
    }

    view->mViewportSize = nsSize(
      NSIntPixelsToAppUnits(metrics.mViewport.width, auPerDevPixel) * aXScale,
      NSIntPixelsToAppUnits(metrics.mViewport.height, auPerDevPixel) * aYScale);
    view->mContentSize = nsSize(
      NSIntPixelsToAppUnits(metrics.mContentSize.width, auPerDevPixel) * aXScale,
      NSIntPixelsToAppUnits(metrics.mContentSize.height, auPerDevPixel) * aYScale);

    newContentViews[scrollId] = view;
  }

  for (Layer* child = aLayer->GetFirstChild();
       child; child = child->GetNextSibling()) {
    BuildViewMap(oldContentViews, newContentViews, aFrameLoader, child,
                 aXScale, aYScale);
  }
}

/**
 * Scroll the scroll frame associated with |aContent| to the scroll position
 * requested in |aMetrics|.
 * The scroll offset in |aMetrics| is updated to reflect the actual scroll
 * position.
 * The displayport stored in |aMetrics| and the callback-transform stored on
 * the content are updated to reflect any difference between the requested
 * and actual scroll positions.
 */
static void
ScrollFrame(nsIContent* aContent,
            FrameMetrics& aMetrics)
{
  // Scroll the window to the desired spot
  nsIScrollableFrame* sf = nsLayoutUtils::FindScrollableFrameFor(aMetrics.GetScrollId());
  if (sf) {
    sf->SetScrollableByAPZ(!aMetrics.IsScrollInfoLayer());
  }

  bool scrollUpdated = false;
  CSSPoint apzScrollOffset = aMetrics.GetScrollOffset();
  CSSPoint actualScrollOffset = ScrollFrameTo(sf, apzScrollOffset, scrollUpdated);

  if (scrollUpdated) {
    if (aMetrics.IsScrollInfoLayer()) {
      // In cases where the APZ scroll offset is different from the content scroll
      // offset, we want to interpret the margins as relative to the APZ scroll
      // offset except when the frame is not scrollable by APZ. Therefore, if the
      // layer is a scroll info layer, we leave the margins as-is and they will
      // be interpreted as relative to the content scroll offset.
      if (nsIFrame* frame = aContent->GetPrimaryFrame()) {
        frame->SchedulePaint();
      }
    } else {
      // Correct the display port due to the difference between mScrollOffset and the
      // actual scroll offset.
      APZCCallbackHelper::AdjustDisplayPortForScrollDelta(aMetrics, actualScrollOffset);
    }
  } else {
    // For whatever reason we couldn't update the scroll offset on the scroll frame,
    // which means the data APZ used for its displayport calculation is stale. Fall
    // back to a sane default behaviour. Note that we don't tile-align the recentered
    // displayport because tile-alignment depends on the scroll position, and the
    // scroll position here is out of our control. See bug 966507 comment 21 for a
    // more detailed explanation.
    RecenterDisplayPort(aMetrics);
  }

  aMetrics.SetScrollOffset(actualScrollOffset);

  // APZ transforms inputs assuming we applied the exact scroll offset it
  // requested (|apzScrollOffset|). Since we may not have, record the difference
  // between what APZ asked for and what we actually applied, and apply it to
  // input events to compensate.
  if (aContent) {
    CSSPoint scrollDelta = apzScrollOffset - actualScrollOffset;
    aContent->SetProperty(nsGkAtoms::apzCallbackTransform, new CSSPoint(scrollDelta),
                          nsINode::DeleteProperty<CSSPoint>);
  }
}

void
APZCCallbackHelper::UpdateRootFrame(FrameMetrics& aMetrics)
{
  if (aMetrics.GetScrollId() == FrameMetrics::NULL_SCROLL_ID) {
    return;
  }
  nsIContent* content = nsLayoutUtils::FindContentFor(aMetrics.GetScrollId());
  if (!content) {
    return;
  }

  nsCOMPtr<nsIPresShell> shell = GetPresShell(content);
  if (!shell || aMetrics.GetPresShellId() != shell->GetPresShellId()) {
    return;
  }

  MOZ_ASSERT(aMetrics.GetUseDisplayPortMargins());

  if (gfxPrefs::APZAllowZooming()) {
    // If zooming is disabled then we don't really want to let APZ fiddle
    // with these things. In theory setting the resolution here should be a
    // no-op, but setting the SPCSPS is bad because it can cause a stale value
    // to be returned by window.innerWidth/innerHeight (see bug 1187792).

    float presShellResolution = nsLayoutUtils::GetResolution(shell);

    // If the pres shell resolution has changed on the content side side
    // the time this repaint request was fired, consider this request out of date
    // and drop it; setting a zoom based on the out-of-date resolution can have
    // the effect of getting us stuck with the stale resolution.
    if (presShellResolution != aMetrics.GetPresShellResolution()) {
      return;
    }

    // Set the scroll port size, which determines the scroll range. For example if
    // a 500-pixel document is shown in a 100-pixel frame, the scroll port length would
    // be 100, and gecko would limit the maximum scroll offset to 400 (so as to prevent
    // overscroll). Note that if the content here was zoomed to 2x, the document would
    // be 1000 pixels long but the frame would still be 100 pixels, and so the maximum
    // scroll range would be 900. Therefore this calculation depends on the zoom applied
    // to the content relative to the container.
    // Note that this needs to happen before scrolling the frame (in UpdateFrameCommon),
    // otherwise the scroll position may get clamped incorrectly.
    CSSSize scrollPort = aMetrics.CalculateCompositedSizeInCssPixels();
    nsLayoutUtils::SetScrollPositionClampingScrollPortSize(shell, scrollPort);

    // The pres shell resolution is updated by the the async zoom since the
    // last paint.
    presShellResolution = aMetrics.GetPresShellResolution()
                        * aMetrics.GetAsyncZoom().scale;
    nsLayoutUtils::SetResolutionAndScaleTo(shell, presShellResolution);
  }

  // Do this as late as possible since scrolling can flush layout. It also
  // adjusts the display port margins, so do it before we set those.
  ScrollFrame(content, aMetrics);

  SetDisplayPortMargins(shell, content, aMetrics);
}

void
ChromeProcessController::RequestContentRepaint(const FrameMetrics& aFrameMetrics)
{
  MOZ_ASSERT(NS_IsMainThread());

  if (aFrameMetrics.GetScrollId() == FrameMetrics::NULL_SCROLL_ID) {
    return;
  }

  nsCOMPtr<nsIContent> targetContent = nsLayoutUtils::FindContentFor(aFrameMetrics.GetScrollId());
  if (targetContent) {
    FrameMetrics metrics = aFrameMetrics;
    APZCCallbackHelper::UpdateSubFrame(targetContent, metrics);
  }
}

TEST_F(APZCPinchTester, Panning_TwoFinger_ZoomDisabled) {
  // set up APZ
  apzc->SetFrameMetrics(GetPinchableFrameMetrics());
  MakeApzcUnzoomable();

  nsEventStatus statuses[3];  // scalebegin, scale, scaleend
  PinchWithPinchInput(apzc, 250, 350, 200, 300, 10, &statuses);

  FrameMetrics fm = apzc->GetFrameMetrics();

  // It starts from (300, 300), then moves the focus point from (250, 350) to
  // (200, 300) pans by (50, 50) screen pixels, but there is a 2x zoom, which
  // causes the scroll offset to change by half of that (25, 25) pixels.
  EXPECT_EQ(325, fm.GetScrollOffset().x);
  EXPECT_EQ(325, fm.GetScrollOffset().y);
  EXPECT_EQ(2.0, fm.GetZoom().ToScaleFactor().scale);
}

static void
SetDisplayPortMargins(nsIPresShell* aPresShell,
                      nsIContent* aContent,
                      const FrameMetrics& aMetrics)
{
  if (!aContent) {
    return;
  }

  ScreenMargin margins = aMetrics.GetDisplayPortMargins();
  nsLayoutUtils::SetDisplayPortMargins(aContent, aPresShell, margins, 0);
  CSSRect baseCSS = aMetrics.CalculateCompositedRectInCssPixels();
  nsRect base(0, 0,
              baseCSS.width * nsPresContext::AppUnitsPerCSSPixel(),
              baseCSS.height * nsPresContext::AppUnitsPerCSSPixel());
  nsLayoutUtils::SetDisplayPortBaseIfNotSet(aContent, base);
}

bool
GenericScrollAnimation::DoSample(FrameMetrics& aFrameMetrics, const TimeDuration& aDelta)
{
  TimeStamp now = mApzc.GetFrameTime();
  CSSToParentLayerScale2D zoom = aFrameMetrics.GetZoom();

  // If the animation is finished, make sure the final position is correct by
  // using one last displacement. Otherwise, compute the delta via the timing
  // function as normal.
  bool finished = IsFinished(now);
  nsPoint sampledDest = finished
                        ? mDestination
                        : PositionAt(now);
  ParentLayerPoint displacement =
    (CSSPoint::FromAppUnits(sampledDest) - aFrameMetrics.GetScrollOffset()) * zoom;

  if (finished) {
    mApzc.mX.SetVelocity(0);
    mApzc.mY.SetVelocity(0);
  } else if (!IsZero(displacement)) {
    // Velocity is measured in ParentLayerCoords / Milliseconds
    float xVelocity = displacement.x / aDelta.ToMilliseconds();
    float yVelocity = displacement.y / aDelta.ToMilliseconds();
    mApzc.mX.SetVelocity(xVelocity);
    mApzc.mY.SetVelocity(yVelocity);
  }

  // Note: we ignore overscroll for generic animations.
  ParentLayerPoint adjustedOffset, overscroll;
  mApzc.mX.AdjustDisplacement(displacement.x, adjustedOffset.x, overscroll.x);
  mApzc.mY.AdjustDisplacement(displacement.y, adjustedOffset.y, overscroll.y,
                              mForceVerticalOverscroll);

  // If we expected to scroll, but there's no more scroll range on either axis,
  // then end the animation early. Note that the initial displacement could be 0
  // if the compositor ran very quickly (<1ms) after the animation was created.
  // When that happens we want to make sure the animation continues.
  if (!IsZero(displacement) && IsZero(adjustedOffset)) {
    // Nothing more to do - end the animation.
    return false;
  }

  aFrameMetrics.ScrollBy(adjustedOffset / zoom);
  return !finished;
}

bool
APZCCallbackHelper::HasValidPresShellId(nsIDOMWindowUtils* aUtils,
                                        const FrameMetrics& aMetrics)
{
    MOZ_ASSERT(aUtils);

    uint32_t presShellId;
    nsresult rv = aUtils->GetPresShellId(&presShellId);
    MOZ_ASSERT(NS_SUCCEEDED(rv));
    return NS_SUCCEEDED(rv) && aMetrics.GetPresShellId() == presShellId;
}