gecko/layout/svg/base/src/nsSVGClipPathFrame.cpp

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#include "nsIDOMDocument.h"
#include "nsIDocument.h"
#include "nsIDOMSVGClipPathElement.h"
#include "nsSVGClipPathFrame.h"
#include "nsGkAtoms.h"
#include "nsSVGUtils.h"
#include "nsSVGClipPathElement.h"
#include "gfxContext.h"
#include "nsIDOMSVGRect.h"

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

nsIFrame*
NS_NewSVGClipPathFrame(nsIPresShell* aPresShell, nsIContent* aContent, nsStyleContext* aContext)
{
  nsCOMPtr<nsIDOMSVGTransformable> transformable = do_QueryInterface(aContent);
  if (!transformable) {
#ifdef DEBUG
    printf("warning: trying to construct an SVGClipPathFrame for a content element that doesn't support the right interfaces\n");
#endif
    return nsnull;
  }

  return new (aPresShell) nsSVGClipPathFrame(aContext);
}

nsIContent *
NS_GetSVGClipPathElement(nsIURI *aURI, nsIContent *aContent)
{
  nsIContent* content = nsContentUtils::GetReferencedElement(aURI, aContent);

  nsCOMPtr<nsIDOMSVGClipPathElement> clipPath = do_QueryInterface(content);

  if (clipPath)
    return content;

  return nsnull;
}

nsresult
nsSVGClipPathFrame::ClipPaint(nsSVGRenderState* aContext,
                              nsISVGChildFrame* aParent,
                              nsIDOMSVGMatrix *aMatrix)
{
  // If the flag is set when we get here, it means this clipPath frame
  // has already been used painting the current clip, and the document
  // has a clip reference loop.
  if (mInUse) {
    NS_WARNING("Clip loop detected!");
    return NS_OK;
  }
  AutoClipPathReferencer clipRef(this);

  mClipParent = aParent,
  mClipParentMatrix = aMatrix;

  PRBool isTrivial = IsTrivial();

  nsAutoSVGRenderMode mode(aContext,
                           isTrivial ? nsSVGRenderState::CLIP
                                     : nsSVGRenderState::CLIP_MASK);

  for (nsIFrame* kid = mFrames.FirstChild(); kid;
       kid = kid->GetNextSibling()) {
    nsISVGChildFrame* SVGFrame = nsnull;
    CallQueryInterface(kid, &SVGFrame);
    if (SVGFrame) {
      SVGFrame->NotifyCanvasTMChanged(PR_TRUE);
      SVGFrame->PaintSVG(aContext, nsnull);
    }
  }

  if (isTrivial) {
    aContext->GetGfxContext()->Clip();
    aContext->GetGfxContext()->NewPath();
  }

  return NS_OK;
}

PRBool
nsSVGClipPathFrame::ClipHitTest(nsISVGChildFrame* aParent,
                                nsIDOMSVGMatrix *aMatrix,
                                float aX, float aY)
{
  // If the flag is set when we get here, it means this clipPath frame
  // has already been used in hit testing against the current clip,
  // and the document has a clip reference loop.
  if (mInUse) {
    NS_WARNING("Clip loop detected!");
    return PR_FALSE;
  }
  AutoClipPathReferencer clipRef(this);

  nsRect dirty;
  mClipParent = aParent,
  mClipParentMatrix = aMatrix;

  for (nsIFrame* kid = mFrames.FirstChild(); kid;
       kid = kid->GetNextSibling()) {
    nsISVGChildFrame* SVGFrame = nsnull;
    CallQueryInterface(kid, &SVGFrame);
    if (SVGFrame) {
      // Notify the child frame that we may be working with a
      // different transform, so it can update its covered region
      // (used to shortcut hit testing).
      SVGFrame->NotifyCanvasTMChanged(PR_FALSE);

      nsIFrame *temp = nsnull;
      nsresult rv = SVGFrame->GetFrameForPointSVG(aX, aY, &temp);
      if (NS_SUCCEEDED(rv) && temp)
        return PR_TRUE;
    }
  }
  return PR_FALSE;
}

PRBool
nsSVGClipPathFrame::IsTrivial()
{
  PRBool foundChild = PR_FALSE;

  for (nsIFrame* kid = mFrames.FirstChild(); kid;
       kid = kid->GetNextSibling()) {
    nsISVGChildFrame *svgChild = nsnull;
    CallQueryInterface(kid, &svgChild);

    if (svgChild) {
      // We consider a non-trivial clipPath to be one containing
      // either more than one svg child and/or a svg container
      if (foundChild || svgChild->IsDisplayContainer())
        return PR_FALSE;
      foundChild = PR_TRUE;
    }
  }
  return PR_TRUE;
}

nsIAtom *
nsSVGClipPathFrame::GetType() const
{
  return nsGkAtoms::svgClipPathFrame;
}

already_AddRefed<nsIDOMSVGMatrix>
nsSVGClipPathFrame::GetCanvasTM()
{
  NS_ASSERTION(mClipParentMatrix, "null parent matrix");

  nsSVGClipPathElement *clipPath = static_cast<nsSVGClipPathElement*>
                                              (mContent);

  nsCOMPtr<nsIDOMSVGMatrix> localTM = clipPath->GetLocalTransformMatrix();

  nsCOMPtr<nsIDOMSVGMatrix> canvasTM;

  if (localTM)
    mClipParentMatrix->Multiply(localTM, getter_AddRefs(canvasTM));
  else
    canvasTM = mClipParentMatrix;

  /* object bounding box? */
  PRUint16 units =
    clipPath->mEnumAttributes[nsSVGClipPathElement::CLIPPATHUNITS].GetAnimValue();

  if (mClipParent &&
      units == nsIDOMSVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
    nsCOMPtr<nsIDOMSVGRect> rect;
    nsresult rv = mClipParent->GetBBox(getter_AddRefs(rect));

    if (NS_SUCCEEDED(rv)) {
      float minx, miny, width, height;
      rect->GetX(&minx);
      rect->GetY(&miny);
      rect->GetWidth(&width);
      rect->GetHeight(&height);

      nsCOMPtr<nsIDOMSVGMatrix> tmp, fini;
      canvasTM->Translate(minx, miny, getter_AddRefs(tmp));
      tmp->ScaleNonUniform(width, height, getter_AddRefs(fini));
      canvasTM = fini;
    }
  }

  nsIDOMSVGMatrix* retval = canvasTM.get();
  NS_IF_ADDREF(retval);
  return retval;
}