gecko-dev/layout/svg/nsSVGSwitchFrame.cpp

/* -*- 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/. */

// Keep in (case-insensitive) order:
#include "gfxRect.h"
#include "SVGObserverUtils.h"
#include "nsSVGGFrame.h"
#include "mozilla/dom/SVGSwitchElement.h"
#include "nsSVGUtils.h"

using namespace mozilla;
using namespace mozilla::gfx;
using namespace mozilla::image;

class nsSVGSwitchFrame final : public nsSVGGFrame
{
  friend nsIFrame*
  NS_NewSVGSwitchFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
protected:
  explicit nsSVGSwitchFrame(ComputedStyle* aStyle)
    : nsSVGGFrame(aStyle, kClassID)
  {}

public:
  NS_DECL_FRAMEARENA_HELPERS(nsSVGSwitchFrame)

#ifdef DEBUG
  virtual void Init(nsIContent*       aContent,
                    nsContainerFrame* aParent,
                    nsIFrame*         aPrevInFlow) override;
#endif

#ifdef DEBUG_FRAME_DUMP
  virtual nsresult GetFrameName(nsAString& aResult) const override
  {
    return MakeFrameName(NS_LITERAL_STRING("SVGSwitch"), aResult);
  }
#endif

  virtual void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                                const nsDisplayListSet& aLists) override;

  // nsSVGDisplayableFrame interface:
  virtual void PaintSVG(gfxContext& aContext,
                        const gfxMatrix& aTransform,
                        imgDrawingParams& aPackage,
                        const nsIntRect* aDirtyRect = nullptr) override;
  nsIFrame* GetFrameForPoint(const gfxPoint& aPoint) override;
  virtual void ReflowSVG() override;
  virtual SVGBBox GetBBoxContribution(const Matrix &aToBBoxUserspace,
                                      uint32_t aFlags) override;

private:
  nsIFrame *GetActiveChildFrame();
};

//----------------------------------------------------------------------
// Implementation

nsIFrame*
NS_NewSVGSwitchFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle)
{
  return new (aPresShell) nsSVGSwitchFrame(aStyle);
}

NS_IMPL_FRAMEARENA_HELPERS(nsSVGSwitchFrame)

#ifdef DEBUG
void
nsSVGSwitchFrame::Init(nsIContent*       aContent,
                       nsContainerFrame* aParent,
                       nsIFrame*         aPrevInFlow)
{
  NS_ASSERTION(aContent->IsSVGElement(nsGkAtoms::svgSwitch),
               "Content is not an SVG switch");

  nsSVGGFrame::Init(aContent, aParent, aPrevInFlow);
}
#endif /* DEBUG */

void
nsSVGSwitchFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                                   const nsDisplayListSet& aLists)
{
  nsIFrame* kid = GetActiveChildFrame();
  if (kid) {
    BuildDisplayListForChild(aBuilder, kid, aLists);
  }
}

void
nsSVGSwitchFrame::PaintSVG(gfxContext& aContext,
                           const gfxMatrix& aTransform,
                           imgDrawingParams& aImgParams,
                           const nsIntRect* aDirtyRect)
{
  NS_ASSERTION(!NS_SVGDisplayListPaintingEnabled() ||
               (mState & NS_FRAME_IS_NONDISPLAY),
               "If display lists are enabled, only painting of non-display "
               "SVG should take this code path");

  if (StyleEffects()->mOpacity == 0.0){
    return;
  }

  nsIFrame *kid = GetActiveChildFrame();
  if (kid) {
    gfxMatrix tm = aTransform;
    if (kid->GetContent()->IsSVGElement()) {
      tm = static_cast<nsSVGElement*>(kid->GetContent())->
             PrependLocalTransformsTo(tm, eUserSpaceToParent);
    }
    nsSVGUtils::PaintFrameWithEffects(kid, aContext, tm, aImgParams, aDirtyRect);
  }
}


nsIFrame*
nsSVGSwitchFrame::GetFrameForPoint(const gfxPoint& aPoint)
{
  NS_ASSERTION(!NS_SVGDisplayListHitTestingEnabled() ||
               (mState & NS_FRAME_IS_NONDISPLAY),
               "If display lists are enabled, only hit-testing of non-display "
               "SVG should take this code path");

  nsIFrame *kid = GetActiveChildFrame();
  nsSVGDisplayableFrame* svgFrame = do_QueryFrame(kid);
  if (svgFrame) {
    // Transform the point from our SVG user space to our child's.
    gfxPoint point = aPoint;
    gfxMatrix m =
      static_cast<const nsSVGElement*>(GetContent())->
        PrependLocalTransformsTo(gfxMatrix(), eChildToUserSpace);
    m = static_cast<const nsSVGElement*>(kid->GetContent())->
          PrependLocalTransformsTo(m, eUserSpaceToParent);
    if (!m.IsIdentity()) {
      if (!m.Invert()) {
        return nullptr;
      }
      point = m.TransformPoint(point);
    }
    return svgFrame->GetFrameForPoint(point);
  }

  return nullptr;
}

void
nsSVGSwitchFrame::ReflowSVG()
{
  NS_ASSERTION(nsSVGUtils::OuterSVGIsCallingReflowSVG(this),
               "This call is probably a wasteful mistake");

  MOZ_ASSERT(!(GetStateBits() & NS_FRAME_IS_NONDISPLAY),
             "ReflowSVG mechanism not designed for this");

  if (!nsSVGUtils::NeedsReflowSVG(this)) {
    return;
  }

  // If the NS_FRAME_FIRST_REFLOW bit has been removed from our parent frame,
  // then our outer-<svg> has previously had its initial reflow. In that case
  // we need to make sure that that bit has been removed from ourself _before_
  // recursing over our children to ensure that they know too. Otherwise, we
  // need to remove it _after_ recursing over our children so that they know
  // the initial reflow is currently underway.

  bool isFirstReflow = (mState & NS_FRAME_FIRST_REFLOW);

  bool outerSVGHasHadFirstReflow =
    (GetParent()->GetStateBits() & NS_FRAME_FIRST_REFLOW) == 0;

  if (outerSVGHasHadFirstReflow) {
    RemoveStateBits(NS_FRAME_FIRST_REFLOW); // tell our children
  }

  nsOverflowAreas overflowRects;

  nsIFrame *child = GetActiveChildFrame();
  nsSVGDisplayableFrame* svgChild = do_QueryFrame(child);
  if (svgChild) {
    MOZ_ASSERT(!(child->GetStateBits() & NS_FRAME_IS_NONDISPLAY),
               "Check for this explicitly in the |if|, then");
    svgChild->ReflowSVG();

    // We build up our child frame overflows here instead of using
    // nsLayoutUtils::UnionChildOverflow since SVG frame's all use the same
    // frame list, and we're iterating over that list now anyway.
    ConsiderChildOverflow(overflowRects, child);
  }

  if (isFirstReflow) {
    // Make sure we have our filter property (if any) before calling
    // FinishAndStoreOverflow (subsequent filter changes are handled off
    // nsChangeHint_UpdateEffects):
    SVGObserverUtils::UpdateEffects(this);
  }

  FinishAndStoreOverflow(overflowRects, mRect.Size());

  // Remove state bits after FinishAndStoreOverflow so that it doesn't
  // invalidate on first reflow:
  RemoveStateBits(NS_FRAME_FIRST_REFLOW | NS_FRAME_IS_DIRTY |
                  NS_FRAME_HAS_DIRTY_CHILDREN);
}

SVGBBox
nsSVGSwitchFrame::GetBBoxContribution(const Matrix &aToBBoxUserspace,
                                      uint32_t aFlags)
{
  nsIFrame* kid = GetActiveChildFrame();
  nsSVGDisplayableFrame* svgKid = do_QueryFrame(kid);
  if (svgKid) {
    nsIContent *content = kid->GetContent();
    gfxMatrix transform = ThebesMatrix(aToBBoxUserspace);
    if (content->IsSVGElement()) {
      transform = static_cast<nsSVGElement*>(content)->
                    PrependLocalTransformsTo(transform);
    }
    return svgKid->GetBBoxContribution(ToMatrix(transform), aFlags);
  }
  return SVGBBox();
}

nsIFrame *
nsSVGSwitchFrame::GetActiveChildFrame()
{
  nsIContent *activeChild =
    static_cast<mozilla::dom::SVGSwitchElement*>(GetContent())->GetActiveChild();

  if (activeChild) {
    for (nsIFrame* kid = mFrames.FirstChild(); kid;
         kid = kid->GetNextSibling()) {

      if (activeChild == kid->GetContent()) {
        return kid;
      }
    }
  }
  return nullptr;
}