gecko-dev/layout/svg/nsSVGStopFrame.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "nsContainerFrame.h"
#include "nsFrame.h"
#include "nsGkAtoms.h"
#include "nsStyleContext.h"
#include "nsSVGEffects.h"

// This is a very simple frame whose only purpose is to capture style change
// events and propagate them to the parent.  Most of the heavy lifting is done
// within the nsSVGGradientFrame, which is the parent for this frame

class nsSVGStopFrame : public nsFrame
{
  friend nsIFrame*
  NS_NewSVGStopFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
protected:
  explicit nsSVGStopFrame(nsStyleContext* aContext)
    : nsFrame(aContext)
  {
    AddStateBits(NS_FRAME_IS_NONDISPLAY);
  }

public:
  NS_DECL_FRAMEARENA_HELPERS

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

  void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                        const nsRect&           aDirtyRect,
                        const nsDisplayListSet& aLists) override {}

  virtual nsresult AttributeChanged(int32_t         aNameSpaceID,
                                    nsIAtom*        aAttribute,
                                    int32_t         aModType) override;

  /**
   * Get the "type" of the frame
   *
   * @see nsGkAtoms::svgStopFrame
   */
  virtual nsIAtom* GetType() const override;

  virtual bool IsFrameOfType(uint32_t aFlags) const override
  {
    return nsFrame::IsFrameOfType(aFlags & ~(nsIFrame::eSVG));
  }

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

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

NS_IMPL_FRAMEARENA_HELPERS(nsSVGStopFrame)

//----------------------------------------------------------------------
// nsIFrame methods:

#ifdef DEBUG
void
nsSVGStopFrame::Init(nsIContent*       aContent,
                     nsContainerFrame* aParent,
                     nsIFrame*         aPrevInFlow)
{
  NS_ASSERTION(aContent->IsSVGElement(nsGkAtoms::stop), "Content is not a stop element");

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

nsIAtom *
nsSVGStopFrame::GetType() const
{
  return nsGkAtoms::svgStopFrame;
}

nsresult
nsSVGStopFrame::AttributeChanged(int32_t         aNameSpaceID,
                                 nsIAtom*        aAttribute,
                                 int32_t         aModType)
{
  if (aNameSpaceID == kNameSpaceID_None &&
      aAttribute == nsGkAtoms::offset) {
    MOZ_ASSERT(GetParent()->GetType() == nsGkAtoms::svgLinearGradientFrame ||
               GetParent()->GetType() == nsGkAtoms::svgRadialGradientFrame,
               "Observers observe the gradient, so that's what we must invalidate");
    nsSVGEffects::InvalidateDirectRenderingObservers(GetParent());
  }

  return nsFrame::AttributeChanged(aNameSpaceID, aAttribute, aModType);
}

// -------------------------------------------------------------------------
// Public functions
// -------------------------------------------------------------------------

nsIFrame* NS_NewSVGStopFrame(nsIPresShell*   aPresShell,
                             nsStyleContext* aContext)
{
  return new (aPresShell) nsSVGStopFrame(aContext);
}