C++ FrameMetrics::SetScrollOffset方法代码示例

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().ToScaleFactor();
  const CSSRect& metricsDisplayPort =
    (aDrawingCritical && !aMetrics.GetCriticalDisplayPort().IsEmpty()) ?
      aMetrics.GetCriticalDisplayPort() : aMetrics.GetDisplayPort();
  LayerRect displayPort = (metricsDisplayPort + aMetrics.GetScrollOffset()) * paintScale;

  ParentLayerPoint scrollOffset;
  CSSToParentLayerScale zoom;
  bool ret = AndroidBridge::Bridge()->ProgressiveUpdateCallback(
    aHasPendingNewThebesContent, displayPort, paintScale.scale, aDrawingCritical,
    scrollOffset, zoom);
  aMetrics.SetScrollOffset(scrollOffset / zoom);
  aMetrics.SetZoom(CSSToParentLayerScale2D(zoom));
  return ret;
#else
  return false;
#endif
}

 FrameMetrics GetPinchableFrameMetrics()
 {
   FrameMetrics fm;
   fm.SetCompositionBounds(ParentLayerRect(200, 200, 100, 200));
   fm.SetScrollableRect(CSSRect(0, 0, 980, 1000));
   fm.SetScrollOffset(CSSPoint(300, 300));
   fm.SetZoom(CSSToParentLayerScale2D(2.0, 2.0));
   // APZC only allows zooming on the root scrollable frame.
   fm.SetIsRootContent(true);
   // the visible area of the document in CSS pixels is x=300 y=300 w=50 h=100
   return fm;
 }

void
APZCCallbackHelper::UpdateSubFrame(nsIContent* aContent,
                                   FrameMetrics& aMetrics)
{
    // Precondition checks
    MOZ_ASSERT(aContent);
    MOZ_ASSERT(aMetrics.GetUseDisplayPortMargins());
    if (aMetrics.GetScrollId() == FrameMetrics::NULL_SCROLL_ID) {
        return;
    }

    nsCOMPtr<nsIDOMWindowUtils> utils = GetDOMWindowUtils(aContent);
    if (!utils) {
        return;
    }

    // We currently do not support zooming arbitrary subframes. They can only
    // be scrolled, so here we only have to set the scroll position and displayport.

    nsIScrollableFrame* sf = nsLayoutUtils::FindScrollableFrameFor(aMetrics.GetScrollId());
    bool scrollUpdated = false;
    CSSPoint actualScrollOffset = ScrollFrameTo(sf, aMetrics.GetScrollOffset(), scrollUpdated);

    nsCOMPtr<nsIDOMElement> element = do_QueryInterface(aContent);
    if (element) {
        if (scrollUpdated) {
            AdjustDisplayPortForScrollDelta(aMetrics, actualScrollOffset);
        } else {
            RecenterDisplayPort(aMetrics);
        }
        gfx::IntSize alignment = gfxPrefs::LayersTilesEnabled()
            ? gfx::IntSize(gfxPrefs::LayersTileWidth(), gfxPrefs::LayersTileHeight()) :
              gfx::IntSize(0, 0);
        LayerMargin margins = aMetrics.GetDisplayPortMargins();
        utils->SetDisplayPortMarginsForElement(margins.left,
                                               margins.top,
                                               margins.right,
                                               margins.bottom,
                                               alignment.width,
                                               alignment.height,
                                               element, 0);
        CSSRect baseCSS = aMetrics.CalculateCompositedRectInCssPixels();
        nsRect base(baseCSS.x * nsPresContext::AppUnitsPerCSSPixel(),
                    baseCSS.y * nsPresContext::AppUnitsPerCSSPixel(),
                    baseCSS.width * nsPresContext::AppUnitsPerCSSPixel(),
                    baseCSS.height * nsPresContext::AppUnitsPerCSSPixel());
        nsLayoutUtils::SetDisplayPortBaseIfNotSet(aContent, base);
    }

    aMetrics.SetScrollOffset(actualScrollOffset);
}

/**
 * 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>);
  }
}

TEST_F(APZCBasicTester, Overzoom) {
  // the visible area of the document in CSS pixels is x=10 y=0 w=100 h=100
  FrameMetrics fm;
  fm.SetCompositionBounds(ParentLayerRect(0, 0, 100, 100));
  fm.SetScrollableRect(CSSRect(0, 0, 125, 150));
  fm.SetScrollOffset(CSSPoint(10, 0));
  fm.SetZoom(CSSToParentLayerScale2D(1.0, 1.0));
  fm.SetIsRootContent(true);
  apzc->SetFrameMetrics(fm);

  MakeApzcZoomable();

  EXPECT_CALL(*mcc, RequestContentRepaint(_)).Times(1);

  PinchWithPinchInputAndCheckStatus(apzc, ScreenIntPoint(50, 50), 0.5, true);

  fm = apzc->GetFrameMetrics();
  EXPECT_EQ(0.8f, fm.GetZoom().ToScaleFactor().scale);
  // bug 936721 - PGO builds introduce rounding error so
  // use a fuzzy match instead
  EXPECT_LT(std::abs(fm.GetScrollOffset().x), 1e-5);
  EXPECT_LT(std::abs(fm.GetScrollOffset().y), 1e-5);
}

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

  if (scrollUpdated) {
    // Correct the display port due to the difference between mScrollOffset and the
    // actual scroll offset.
    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 DoPinchTest(bool aShouldTriggerPinch,
                   nsTArray<uint32_t> *aAllowedTouchBehaviors = nullptr)
  {
    apzc->SetFrameMetrics(GetPinchableFrameMetrics());
    MakeApzcZoomable();

    if (aShouldTriggerPinch) {
      // One repaint request for each gesture.
      EXPECT_CALL(*mcc, RequestContentRepaint(_)).Times(2);
    } else {
      EXPECT_CALL(*mcc, RequestContentRepaint(_)).Times(0);
    }

    int touchInputId = 0;
    if (mGestureBehavior == AsyncPanZoomController::USE_GESTURE_DETECTOR) {
      PinchWithTouchInputAndCheckStatus(apzc, 250, 300, 1.25, touchInputId, aShouldTriggerPinch, aAllowedTouchBehaviors);
    } else {
      PinchWithPinchInputAndCheckStatus(apzc, 250, 300, 1.25, aShouldTriggerPinch);
    }

    FrameMetrics fm = apzc->GetFrameMetrics();

    if (aShouldTriggerPinch) {
      // the visible area of the document in CSS pixels is now x=305 y=310 w=40 h=80
      EXPECT_EQ(2.5f, fm.GetZoom().ToScaleFactor().scale);
      EXPECT_EQ(305, fm.GetScrollOffset().x);
      EXPECT_EQ(310, fm.GetScrollOffset().y);
    } else {
      // The frame metrics should stay the same since touch-action:none makes
      // apzc ignore pinch gestures.
      EXPECT_EQ(2.0f, fm.GetZoom().ToScaleFactor().scale);
      EXPECT_EQ(300, fm.GetScrollOffset().x);
      EXPECT_EQ(300, fm.GetScrollOffset().y);
    }

    // part 2 of the test, move to the top-right corner of the page and pinch and
    // make sure we stay in the correct spot
    fm.SetZoom(CSSToParentLayerScale2D(2.0, 2.0));
    fm.SetScrollOffset(CSSPoint(930, 5));
    apzc->SetFrameMetrics(fm);
    // the visible area of the document in CSS pixels is x=930 y=5 w=50 h=100

    if (mGestureBehavior == AsyncPanZoomController::USE_GESTURE_DETECTOR) {
      PinchWithTouchInputAndCheckStatus(apzc, 250, 300, 0.5, touchInputId, aShouldTriggerPinch, aAllowedTouchBehaviors);
    } else {
      PinchWithPinchInputAndCheckStatus(apzc, 250, 300, 0.5, aShouldTriggerPinch);
    }

    fm = apzc->GetFrameMetrics();

    if (aShouldTriggerPinch) {
      // the visible area of the document in CSS pixels is now x=880 y=0 w=100 h=200
      EXPECT_EQ(1.0f, fm.GetZoom().ToScaleFactor().scale);
      EXPECT_EQ(880, fm.GetScrollOffset().x);
      EXPECT_EQ(0, fm.GetScrollOffset().y);
    } else {
      EXPECT_EQ(2.0f, fm.GetZoom().ToScaleFactor().scale);
      EXPECT_EQ(930, fm.GetScrollOffset().x);
      EXPECT_EQ(5, fm.GetScrollOffset().y);
    }
  }

/**
 * Advances a fling by an interpolated amount based on the Android OverScroller.
 * This should be called whenever sampling the content transform for this
 * frame. Returns true if the fling animation should be advanced by one frame,
 * or false if there is no fling or the fling has ended.
 */
bool
AndroidFlingAnimation::DoSample(FrameMetrics& aFrameMetrics,
                                const TimeDuration& aDelta)
{
  bool shouldContinueFling = true;

  mFlingDuration += aDelta.ToMilliseconds();
  mOverScroller->ComputeScrollOffset(mFlingDuration, &shouldContinueFling);

  int32_t currentX = 0;
  int32_t currentY = 0;
  mOverScroller->GetCurrX(&currentX);
  mOverScroller->GetCurrY(&currentY);
  ParentLayerPoint offset((float)currentX, (float)currentY);
  ParentLayerPoint preCheckedOffset(offset);

  bool hitBoundX = CheckBounds(mApzc.mX, offset.x, mFlingDirection.x, &(offset.x));
  bool hitBoundY = CheckBounds(mApzc.mY, offset.y, mFlingDirection.y, &(offset.y));

  ParentLayerPoint velocity = mPreviousVelocity;

  // Sometimes the OverScroller fails to update the offset for a frame.
  // If the frame can still scroll we just use the velocity from the previous
  // frame. However, if the frame can no longer scroll in the direction
  // of the fling, then end the animation.
  if (offset != mPreviousOffset) {
    if (aDelta.ToMilliseconds() > 0) {
      mOverScroller->GetCurrSpeedX(&velocity.x);
      mOverScroller->GetCurrSpeedY(&velocity.y);

      velocity.x /= 1000;
      velocity.y /= 1000;

      mPreviousVelocity = velocity;
    }
  } else if ((fabsf(offset.x - preCheckedOffset.x) > BOUNDS_EPSILON) || (fabsf(offset.y - preCheckedOffset.y) > BOUNDS_EPSILON)) {
    // The page is no longer scrolling but the fling animation is still animating beyond the page bounds. If it goes
    // beyond the BOUNDS_EPSILON then it has overflowed and will never stop. In that case, stop the fling animation.
    shouldContinueFling = false;
  } else if (hitBoundX && hitBoundY) {
    // We can't scroll any farther along either axis.
    shouldContinueFling = false;
  }

  float speed = velocity.Length();

  // gfxPrefs::APZFlingStoppedThreshold is only used in tests.
  if (!shouldContinueFling || (speed < gfxPrefs::APZFlingStoppedThreshold())) {
    if (shouldContinueFling) {
      // The OverScroller thinks it should continue but the speed is below
      // the stopping threshold so abort the animation.
      mOverScroller->AbortAnimation();
    }
    // This animation is going to end. If DeferHandleFlingOverscroll
    // has not been called and there is still some velocity left,
    // call it so that fling hand off may occur if applicable.
    if (!mSentBounceX && !mSentBounceY && (speed > 0.0f)) {
      DeferHandleFlingOverscroll(velocity);
    }
    return false;
  }

  mPreviousOffset = offset;

  mApzc.SetVelocityVector(velocity);
  aFrameMetrics.SetScrollOffset(offset / aFrameMetrics.GetZoom());

  // If we hit a bounds while flinging, send the velocity so that the bounce
  // animation can play.
  if (hitBoundX || hitBoundY) {
    ParentLayerPoint bounceVelocity = velocity;

    if (!mSentBounceX && hitBoundX && fabsf(offset.x - mStartOffset.x) > BOUNDS_EPSILON) {
      mSentBounceX = true;
    } else {
      bounceVelocity.x = 0.0f;
    }

    if (!mSentBounceY && hitBoundY && fabsf(offset.y - mStartOffset.y) > BOUNDS_EPSILON) {
      mSentBounceY = true;
    } else {
      bounceVelocity.y = 0.0f;
    }
    if (!IsZero(bounceVelocity)) {
      DeferHandleFlingOverscroll(bounceVelocity);
    }
  }

  return true;
}

void
APZCCallbackHelper::UpdateRootFrame(nsIDOMWindowUtils* aUtils,
                                    FrameMetrics& aMetrics)
{
    // Precondition checks
    MOZ_ASSERT(aUtils);
    MOZ_ASSERT(aMetrics.GetUseDisplayPortMargins());
    if (aMetrics.GetScrollId() == FrameMetrics::NULL_SCROLL_ID) {
        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.
    CSSSize scrollPort = aMetrics.CalculateCompositedSizeInCssPixels();
    aUtils->SetScrollPositionClampingScrollPortSize(scrollPort.width, scrollPort.height);

    // Scroll the window to the desired spot
    nsIScrollableFrame* sf = nsLayoutUtils::FindScrollableFrameFor(aMetrics.GetScrollId());
    bool scrollUpdated = false;
    CSSPoint actualScrollOffset = ScrollFrameTo(sf, aMetrics.GetScrollOffset(), scrollUpdated);

    if (scrollUpdated) {
        // Correct the display port due to the difference between mScrollOffset and the
        // actual scroll offset.
        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);

    // The pres shell resolution is updated by the the async zoom since the
    // last paint.
    float presShellResolution = aMetrics.GetPresShellResolution()
                              * aMetrics.GetAsyncZoom().scale;
    aUtils->SetResolutionAndScaleTo(presShellResolution, presShellResolution);

    // Finally, we set the displayport.
    nsCOMPtr<nsIContent> content = nsLayoutUtils::FindContentFor(aMetrics.GetScrollId());
    if (!content) {
        return;
    }
    nsCOMPtr<nsIDOMElement> element = do_QueryInterface(content);
    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(content, base);
}