gecko-dev/layout/svg/base/src/nsSVGGradientFrame.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
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 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Mozilla SVG project.
 *
 * The Initial Developer of the Original Code is
 * Scooter Morris.
 * Portions created by the Initial Developer are Copyright (C) 2004
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Scooter Morris <scootermorris@comcast.net>
 *
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 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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#ifndef __NS_SVGGRADIENTFRAME_H__
#define __NS_SVGGRADIENTFRAME_H__

#include "nsSVGDefsFrame.h"
#include "nsSVGValue.h"
#include "nsISVGValueObserver.h"
#include "nsWeakReference.h"
#include "nsIDOMSVGAnimatedString.h"
#include "nsSVGElement.h"

class nsIDOMSVGStopElement;

typedef nsSVGDefsFrame  nsSVGGradientFrameBase;

class nsSVGGradientFrame : public nsSVGGradientFrameBase,
                           public nsSVGValue,
                           public nsISVGValueObserver,
                           public nsSupportsWeakReference
{
public:
  friend nsIFrame* NS_NewSVGLinearGradientFrame(nsIPresShell* aPresShell, 
                                                nsIContent*   aContent,
                                                nsStyleContext* aContext);

  friend nsIFrame* NS_NewSVGRadialGradientFrame(nsIPresShell* aPresShell, 
                                                nsIContent*   aContent,
                                                nsStyleContext* aContext);

  friend nsIFrame* NS_NewSVGStopFrame(nsIPresShell* aPresShell, 
                                      nsIContent*   aContent, 
                                      nsIFrame*     aParentFrame,
                                      nsStyleContext* aContext);

  friend nsresult NS_GetSVGGradientFrame(nsIFrame**      result, 
                                         nsIURI*         aURI, 
                                         nsIContent*     aContent,
                                         nsIPresShell*   aPresShell);

  nsSVGGradientFrame(nsStyleContext* aContext) :
    nsSVGGradientFrameBase(aContext) {}

  enum {
    SVG_LINEAR_GRADIENT = 0,
    SVG_RADIAL_GRADIENT = 1
  };

  virtual PRUint16 GetGradientType() = 0;
  PRUint16 GetSpreadMethod();
  PRUint32 GetStopCount();

  void GetStopInformation(PRInt32 aIndex,
                          float *aOffset, nscolor *aColor, float *aOpacity);

  nsresult GetGradientTransform(nsIDOMSVGMatrix **retval,
                                nsSVGGeometryFrame *aSource);

  // nsISupports interface:
  NS_IMETHOD QueryInterface(const nsIID& aIID, void** aInstancePtr);
  NS_IMETHOD_(nsrefcnt) AddRef() { return NS_OK; }
  NS_IMETHOD_(nsrefcnt) Release() { return NS_OK; }

  // nsISVGValue interface:
  NS_IMETHOD SetValueString(const nsAString &aValue) { return NS_OK; }
  NS_IMETHOD GetValueString(nsAString& aValue) { return NS_ERROR_NOT_IMPLEMENTED; }

  // nsISVGValueObserver interface:
  NS_IMETHOD WillModifySVGObservable(nsISVGValue* observable, 
                                     nsISVGValue::modificationType aModType);
  NS_IMETHOD DidModifySVGObservable(nsISVGValue* observable, 
                                    nsISVGValue::modificationType aModType);

  // nsIFrame interface:
  NS_IMETHOD DidSetStyleContext();
  NS_IMETHOD RemoveFrame(nsIAtom*        aListName,
                         nsIFrame*       aOldFrame);

  virtual nsIAtom* GetType() const;  // frame type: nsGkAtoms::svgGradientFrame

  NS_IMETHOD AttributeChanged(PRInt32         aNameSpaceID,
                              nsIAtom*        aAttribute,
                              PRInt32         aModType);

#ifdef DEBUG
  // nsIFrameDebug interface:
  NS_IMETHOD GetFrameName(nsAString& aResult) const
  {
    return MakeFrameName(NS_LITERAL_STRING("SVGGradient"), aResult);
  }
#endif // DEBUG

  // nsISVGChildFrame interface:
  NS_IMETHOD PaintSVG(nsISVGRendererCanvas* canvas)
  {
    return NS_OK;  // override - our frames don't directly render
  }
  
private:

  // Helper methods to aid gradient implementation
  // ---------------------------------------------
  // The SVG specification allows gradient elements to reference another
  // gradient element to "inherit" its attributes or gradient stops. Reference
  // chains of arbitrary length are allowed, and loop checking is essential!
  // Use the following helpers to safely get attributes and stops.

  // Parse our xlink:href and set mNextGrad if we reference another gradient.
  void GetRefedGradientFromHref();

  // Helpers to look at our gradient and then along its reference chain (if any)
  // to find the first gradient with the specified attribute.
  nsIContent* GetGradientWithAttr(nsIAtom *aAttrName);

  // Some attributes are only valid on one type of gradient, and we *must* get
  // the right type or we won't have the data structures we require.
  nsIContent* GetGradientWithAttr(nsIAtom *aAttrName, nsIAtom *aGradType);

  // Get a stop element and (optionally) its frame (returns stop index/count)
  PRInt32 GetStopElement(PRInt32 aIndex, 
                         nsIDOMSVGStopElement * *aStopElement,
                         nsIFrame * *aStopFrame);

protected:

  // Use these inline methods instead of GetGradientWithAttr(..., aGradType)
  nsIContent* GetLinearGradientWithAttr(nsIAtom *aAttrName)
  {
    return GetGradientWithAttr(aAttrName, nsGkAtoms::svgLinearGradientFrame);
  }
  nsIContent* GetRadialGradientWithAttr(nsIAtom *aAttrName)
  {
    return GetGradientWithAttr(aAttrName, nsGkAtoms::svgRadialGradientFrame);
  }

  // We must loop check notifications too: see bug 330387 comment 18 + testcase
  // and comment 19. The mLoopFlag check is in Will/DidModifySVGObservable.
  void WillModify(modificationType aModType = mod_other)
  {
    mLoopFlag = PR_TRUE;
    nsSVGValue::WillModify(aModType);
    mLoopFlag = PR_FALSE;
  }
  void DidModify(modificationType aModType = mod_other)
  {
    mLoopFlag = PR_TRUE;
    nsSVGValue::DidModify(aModType);
    mLoopFlag = PR_FALSE;
  }

  // Get the value of our gradientUnits attribute
  PRUint16 GetGradientUnits();

  virtual ~nsSVGGradientFrame();

  // The graphic element our gradient is (currently) being applied to
  nsRefPtr<nsSVGElement>                 mSourceContent;

private:

  // href of the other gradient we reference (if any)
  nsCOMPtr<nsIDOMSVGAnimatedString>      mHref;

  // Frame of the gradient we reference (if any). Do NOT use this directly.
  // Use Get[Xxx]GradientWithAttr instead to ensure proper loop checking.
  nsSVGGradientFrame                    *mNextGrad;

  // Flag to mark this frame as "in use" during recursive calls along our
  // gradient's reference chain so we can detect reference loops. See:
  // http://www.w3.org/TR/SVG11/pservers.html#LinearGradientElementHrefAttribute
  PRPackedBool                           mLoopFlag;

  // Ideally we'd set mNextGrad by implementing Init(), but the frame of the
  // gradient we reference isn't available at that stage. Our only option is to
  // set mNextGrad lazily in GetGradientWithAttr, and to make that efficient
  // we need this flag. Our class size is the same since it just fills padding.
  PRPackedBool                           mInitialized;
};


// -------------------------------------------------------------------------
// Linear Gradients
// -------------------------------------------------------------------------

typedef nsSVGGradientFrame nsSVGLinearGradientFrameBase;

class nsSVGLinearGradientFrame : public nsSVGLinearGradientFrameBase
{
public:
  nsSVGLinearGradientFrame(nsStyleContext* aContext) :
    nsSVGLinearGradientFrameBase(aContext) {}

  void GetParameters(float *aX1, float *aY1, float *aX2, float *aY2);

  virtual PRUint16 GetGradientType() { return SVG_LINEAR_GRADIENT; }

  // nsIFrame interface:
  virtual nsIAtom* GetType() const;  // frame type: nsGkAtoms::svgLinearGradientFrame

  NS_IMETHOD AttributeChanged(PRInt32         aNameSpaceID,
                              nsIAtom*        aAttribute,
                              PRInt32         aModType);

#ifdef DEBUG
  // nsIFrameDebug interface:
  NS_IMETHOD GetFrameName(nsAString& aResult) const
  {
    return MakeFrameName(NS_LITERAL_STRING("SVGLinearGradient"), aResult);
  }
#endif // DEBUG

protected:
  float GradientLookupAttribute(nsIAtom *aAtomName, PRUint16 aEnumName);
};

// -------------------------------------------------------------------------
// Radial Gradients
// -------------------------------------------------------------------------

typedef nsSVGGradientFrame nsSVGRadialGradientFrameBase;

class nsSVGRadialGradientFrame : public nsSVGRadialGradientFrameBase
{
public:
  nsSVGRadialGradientFrame(nsStyleContext* aContext) :
    nsSVGRadialGradientFrameBase(aContext) {}

  void GetParameters(float *aCx, float *aCy, float *aR,
                     float *aFx, float *aFy);

  virtual PRUint16 GetGradientType() { return SVG_RADIAL_GRADIENT; }

  // nsIFrame interface:
  virtual nsIAtom* GetType() const;  // frame type: nsGkAtoms::svgRadialGradientFrame

  NS_IMETHOD AttributeChanged(PRInt32         aNameSpaceID,
                              nsIAtom*        aAttribute,
                              PRInt32         aModType);

#ifdef DEBUG
  // nsIFrameDebug interface:
  NS_IMETHOD GetFrameName(nsAString& aResult) const
  {
    return MakeFrameName(NS_LITERAL_STRING("SVGRadialGradient"), aResult);
  }
#endif // DEBUG

protected:
  float GradientLookupAttribute(nsIAtom *aAtomName, PRUint16 aEnumName,
                                nsIContent *aElement = nsnull);
};


nsIFrame* NS_NewSVGLinearGradientFrame(nsIPresShell*   aPresShell,
                                       nsIContent*     aContent,
                                       nsStyleContext* aContext);

nsIFrame* NS_NewSVGRadialGradientFrame(nsIPresShell*   aPresShell,
                                       nsIContent*     aContent,
                                       nsStyleContext* aContext);
#endif // __NS_SVGGRADIENTFRAME_H__