Files
Mozilla/mozilla/layout/mathml/base/src/nsMathMLContainerFrame.h
shaver%netscape.com 4ffbe71b5d initial and long-awaited import of MathML for Roger Sidje and his crew
git-svn-id: svn://10.0.0.236/trunk@48481 18797224-902f-48f8-a5cc-f745e15eee43
1999-09-21 02:12:01 +00:00

144 lines
5.7 KiB
C++

/*
* 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 http://www.mozilla.org/MPL/
*
* 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 Mozilla MathML Project.
*
* The Initial Developer of the Original Code is The University Of
* Queensland. Portions created by The University Of Queensland are
* Copyright (C) 1999 The University Of Queensland. All Rights Reserved.
*
* Contributor(s):
* Roger B. Sidje <rbs@maths.uq.edu.au>
* David J. Fiddes <D.J.Fiddes@hw.ac.uk>
*/
#ifndef nsMathMLContainerFrame_h___
#define nsMathMLContainerFrame_h___
#include "nsCOMPtr.h"
#include "nsIViewManager.h"
#include "nsHTMLContainerFrame.h"
#include "nsMathMLOperators.h"
#include "nsIMathMLFrame.h"
/*
* Base class for MathML container frames. It acts like an inferred
* mrow. By default, this frame uses its Reflow() method to lay its
* children horizontally and ensure that their baselines are aligned.
*
* This frame is a *math-aware frame* in the sense that given the
* markup <tag>base arguments</tag>, the method ReResolveStyleContext()
* can be used to render the 'base' in normal-font, and the 'arguments'
* in small-font. This is a common functionality to tags like msub, msup,
* msubsup, mover, munder, munderover, mmultiscripts. All are derived
* from this base class. They use SetInitialChildList() to trigger
* ReResolveStyleContext() for the very first time as soon as all their
* children are known. However, each of these tags has its own Reflow()
* method to lay its children as appropriate, thus overriding the default
* Reflow() method in this base class.
*
* Other tags like mi that do not have 'arguments' can be derived from
* this base class as well. The class caters for empty arguments.
* Notice that mi implements its own ReResolveStyleContext() method
* to switch to a normal-font (rather than italics) if its text content
* is not a single character (as per the MathML REC).
*
* In general therefore, to derive other tags from this base class,
* ReResolveStyleContext() must be coded to produce the desired stylistic
* effects. For example, mfrac has its own ReResolveStyleContext() method
* to set both the numerator and denominator to a small font size, whereas
* mrow does not have its own implementation of ReResolveStyleContext(),
* and instead uses the one in the base class nsHTMLContainerFrame.
*
* The advantage provided by the default ReResolveStyleContext() herein is
* that MathML tags that need scriptstyle switching can be derived from this
* base class with minimum footprint. For the few tags that need different
* style switching or that do not need style switching at all, you *should*
* override the default ReResolveStyleContext() method provided in this base.
* Do not use this nsMathMLContainerFrame::ReResolveStyleContext for a
* <tag>base arguments</tag> not needing 'arguments' in small font size.
* Instead, you should use nsHTMLContainerFrame::ReResolveStyleContext or
* provide your own.
*
* ReResolveStyleContext() implements nsIFrame::ReResolveStyleContext().
* See the documentation in nsIFrame.h for additional information on the
* frame API.
*/
class nsMathMLContainerFrame : public nsHTMLContainerFrame, public nsIMathMLFrame {
public:
// nsIMathMLFrame methods
NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr);
NS_IMETHOD_(nsrefcnt) AddRef(void);
NS_IMETHOD_(nsrefcnt) Release(void);
NS_IMETHOD Stretch(nsIPresContext& aPresContext,
nsStretchDirection aStretchDirection,
nsCharMetrics& aContainerSize,
nsCharMetrics& aDesiredStretchSize);
NS_IMETHOD
GetPresentationData(PRInt32* aScriptLevel,
PRBool* aDisplayStyle);
NS_IMETHOD
UpdatePresentationData(PRInt32 aScriptLevelIncrement,
PRBool aDisplayStyle);
NS_IMETHOD
UpdatePresentationDataFromChildAt(PRInt32 aIndex,
PRInt32 aScriptLevelIncrement,
PRBool aDisplayStyle);
// nsHTMLContainerFrame methods
NS_IMETHOD
Init(nsIPresContext& aPresContext,
nsIContent* aContent,
nsIFrame* aParent,
nsIStyleContext* aContext,
nsIFrame* aPrevInFlow);
NS_IMETHOD
Reflow(nsIPresContext& aPresContext,
nsHTMLReflowMetrics& aDesiredSize,
const nsHTMLReflowState& aReflowState,
nsReflowStatus& aStatus);
NS_IMETHOD
ReResolveStyleContext(nsIPresContext* aPresContext,
nsIStyleContext* aParentContext,
PRInt32 aParentChange,
nsStyleChangeList* aChangeList,
PRInt32* aLocalChange);
// helper methods for processing empty MathML frames (with whitespace only)
static PRBool
IsOnlyWhitespace(nsIFrame* aFrame);
static void
ReflowEmptyChild(nsIFrame* aFrame);
protected:
PRInt32 mScriptLevel; // Only relevant to nested frames within: msub, msup, msubsup,
// munder, mover, munderover, mmultiscripts, mfrac, mroot, mtable.
PRBool mDisplayStyle; // displaystyle="false" is intended to slightly alter how the
// rendering in done in inline mode.
virtual PRIntn GetSkipSides() const { return 0; }
};
#endif /* nsMathMLContainerFrame_h___ */