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

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    // the time this repaint request was fired, consider this request out of date
    // and drop it; setting a zoom based on the out-of-date resolution can have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);
}

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;
}

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 = shell->GetResolution();

    // 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;
    }

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

  MOZ_ASSERT(nsLayoutUtils::HasDisplayPort(content));
  SetDisplayPortMargins(shell, content, aMetrics);
  SetPaintRequestTime(content, aMetrics.GetPaintRequestTime());
}

void
AppendToString(std::stringstream& aStream, const FrameMetrics& m,
               const char* pfx, const char* sfx, bool detailed)
{
  aStream << pfx;
  AppendToString(aStream, m.GetCompositionBounds(), "{ [cb=");
  AppendToString(aStream, m.GetScrollableRect(), "] [sr=");
  AppendToString(aStream, m.GetScrollOffset(), "] [s=");
  if (m.GetDoSmoothScroll()) {
    AppendToString(aStream, m.GetSmoothScrollOffset(), "] [ss=");
  }
  AppendToString(aStream, m.GetDisplayPort(), "] [dp=");
  AppendToString(aStream, m.GetCriticalDisplayPort(), "] [cdp=");
  AppendToString(aStream, m.GetBackgroundColor(), "] [color=");
  if (!detailed) {
    AppendToString(aStream, m.GetScrollId(), "] [scrollId=");
    if (m.GetScrollParentId() != FrameMetrics::NULL_SCROLL_ID) {
      AppendToString(aStream, m.GetScrollParentId(), "] [scrollParent=");
    }
    if (m.IsRootContent()) {
      aStream << "] [rcd";
    }
    if (m.HasClipRect()) {
      AppendToString(aStream, m.ClipRect(), "] [clip=");
    }
    AppendToString(aStream, m.GetZoom(), "] [z=", "] }");
  } else {
    AppendToString(aStream, m.GetDisplayPortMargins(), " [dpm=");
    aStream << nsPrintfCString("] um=%d", m.GetUseDisplayPortMargins()).get();
    AppendToString(aStream, m.GetRootCompositionSize(), "] [rcs=");
    AppendToString(aStream, m.GetViewport(), "] [v=");
    aStream << nsPrintfCString("] [z=(ld=%.3f r=%.3f",
            m.GetDevPixelsPerCSSPixel().scale,
            m.GetPresShellResolution()).get();
    AppendToString(aStream, m.GetCumulativeResolution(), " cr=");
    AppendToString(aStream, m.GetZoom(), " z=");
    AppendToString(aStream, m.GetExtraResolution(), " er=");
    aStream << nsPrintfCString(")] [u=(%d %d %lu)",
            m.GetScrollOffsetUpdated(), m.GetDoSmoothScroll(),
            m.GetScrollGeneration()).get();
    AppendToString(aStream, m.GetScrollParentId(), "] [p=");
    aStream << nsPrintfCString("] [i=(%ld %lld %d)] }",
            m.GetPresShellId(), m.GetScrollId(), m.IsRootContent()).get();
  }
  aStream << sfx;
}

void
AppendToString(std::stringstream& aStream, const FrameMetrics& m,
               const char* pfx, const char* sfx, bool detailed)
{
  aStream << pfx;
  AppendToString(aStream, m.mCompositionBounds, "{ cb=");
  AppendToString(aStream, m.mScrollableRect, " sr=");
  AppendToString(aStream, m.GetScrollOffset(), " s=");
  if (m.GetDoSmoothScroll()) {
    AppendToString(aStream, m.GetSmoothScrollOffset(), " ss=");
  }
  AppendToString(aStream, m.mDisplayPort, " dp=");
  AppendToString(aStream, m.mCriticalDisplayPort, " cdp=");
  AppendToString(aStream, m.GetBackgroundColor(), " color=");
  if (!detailed) {
    AppendToString(aStream, m.GetScrollId(), " scrollId=");
    if (m.GetScrollParentId() != FrameMetrics::NULL_SCROLL_ID) {
      AppendToString(aStream, m.GetScrollParentId(), " scrollParent=");
    }
    aStream << nsPrintfCString(" z=%.3f }", m.GetZoom().scale).get();
  } else {
    AppendToString(aStream, m.GetDisplayPortMargins(), " dpm=");
    aStream << nsPrintfCString(" um=%d", m.GetUseDisplayPortMargins()).get();
    AppendToString(aStream, m.GetRootCompositionSize(), " rcs=");
    AppendToString(aStream, m.GetViewport(), " v=");
    aStream << nsPrintfCString(" z=(ld=%.3f r=%.3f cr=%.3f z=%.3f er=%.3f)",
            m.mDevPixelsPerCSSPixel.scale, m.mPresShellResolution,
            m.mCumulativeResolution.scale, m.GetZoom().scale,
            m.GetExtraResolution().scale).get();
    aStream << nsPrintfCString(" u=(%d %d %lu)",
            m.GetScrollOffsetUpdated(), m.GetDoSmoothScroll(),
            m.GetScrollGeneration()).get();
    AppendToString(aStream, m.GetScrollParentId(), " p=");
    aStream << nsPrintfCString(" i=(%ld %lld) }",
            m.GetPresShellId(), m.GetScrollId()).get();
  }
  aStream << sfx;
}