michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsMathMLmfracFrame_h___
michael@0: #define nsMathMLmfracFrame_h___
michael@0: 
michael@0: #include "mozilla/Attributes.h"
michael@0: #include "nsMathMLContainerFrame.h"
michael@0: 
michael@0: //
michael@0: // <mfrac> -- form a fraction from two subexpressions 
michael@0: //
michael@0: 
michael@0: /*
michael@0: The MathML REC describes:
michael@0: 
michael@0: The <mfrac> element is used for fractions. It can also be used to mark up 
michael@0: fraction-like objects such as binomial coefficients and Legendre symbols. 
michael@0: The syntax for <mfrac> is:
michael@0:   <mfrac> numerator denominator </mfrac>
michael@0: 
michael@0: Attributes of <mfrac>:
michael@0:      Name                      values                     default 
michael@0:   linethickness  number [ v-unit ] | thin | medium | thick  1 
michael@0: 
michael@0: E.g., 
michael@0: linethickness=2 actually means that linethickness=2*DEFAULT_THICKNESS
michael@0: (DEFAULT_THICKNESS is not specified by MathML, see below.)
michael@0: 
michael@0: The linethickness attribute indicates the thickness of the horizontal
michael@0: "fraction bar", or "rule", typically used to render fractions. A fraction
michael@0: with linethickness="0" renders without the bar, and might be used within
michael@0: binomial coefficients. A linethickness greater than one might be used with
michael@0: nested fractions. 
michael@0: 
michael@0: In general, the value of linethickness can be a number, as a multiplier
michael@0: of the default thickness of the fraction bar (the default thickness is
michael@0: not specified by MathML), or a number with a unit of vertical length (see
michael@0: Section 2.3.3), or one of the keywords medium (same as 1), thin (thinner
michael@0: than 1, otherwise up to the renderer), or thick (thicker than 1, otherwise
michael@0: up to the renderer). 
michael@0: 
michael@0: The <mfrac> element sets displaystyle to "false", or if it was already
michael@0: false increments scriptlevel by 1, within numerator and denominator.
michael@0: These attributes are inherited by every element from its rendering 
michael@0: environment, but can be set explicitly only on the <mstyle> 
michael@0: element. 
michael@0: */
michael@0: 
michael@0: class nsMathMLmfracFrame : public nsMathMLContainerFrame {
michael@0: public:
michael@0:   NS_DECL_FRAMEARENA_HELPERS
michael@0: 
michael@0:   friend nsIFrame* NS_NewMathMLmfracFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
michael@0: 
michael@0:   virtual eMathMLFrameType GetMathMLFrameType() MOZ_OVERRIDE;
michael@0: 
michael@0:   virtual nsresult
michael@0:   MeasureForWidth(nsRenderingContext& aRenderingContext,
michael@0:                   nsHTMLReflowMetrics& aDesiredSize) MOZ_OVERRIDE;
michael@0: 
michael@0:   virtual nsresult
michael@0:   Place(nsRenderingContext& aRenderingContext,
michael@0:         bool                 aPlaceOrigin,
michael@0:         nsHTMLReflowMetrics& aDesiredSize) MOZ_OVERRIDE;
michael@0: 
michael@0:   virtual void BuildDisplayList(nsDisplayListBuilder*   aBuilder,
michael@0:                                 const nsRect&           aDirtyRect,
michael@0:                                 const nsDisplayListSet& aLists) MOZ_OVERRIDE;
michael@0: 
michael@0:   NS_IMETHOD
michael@0:   TransmitAutomaticData() MOZ_OVERRIDE;
michael@0: 
michael@0:   // override the base method so that we can deal with the fraction line
michael@0:   virtual nscoord
michael@0:   FixInterFrameSpacing(nsHTMLReflowMetrics& aDesiredSize) MOZ_OVERRIDE;
michael@0: 
michael@0:   // helper to translate the thickness attribute into a usable form
michael@0:   static nscoord 
michael@0:   CalcLineThickness(nsPresContext*  aPresContext,
michael@0:                     nsStyleContext*  aStyleContext,
michael@0:                     nsString&        aThicknessAttribute,
michael@0:                     nscoord          onePixel,
michael@0:                     nscoord          aDefaultRuleThickness);
michael@0: 
michael@0:   uint8_t
michael@0:   ScriptIncrement(nsIFrame* aFrame) MOZ_OVERRIDE;
michael@0: 
michael@0: protected:
michael@0:   nsMathMLmfracFrame(nsStyleContext* aContext) : nsMathMLContainerFrame(aContext) {}
michael@0:   virtual ~nsMathMLmfracFrame();
michael@0:   
michael@0:   nsresult PlaceInternal(nsRenderingContext& aRenderingContext,
michael@0:                          bool                 aPlaceOrigin,
michael@0:                          nsHTMLReflowMetrics& aDesiredSize,
michael@0:                          bool                 aWidthOnly);
michael@0: 
michael@0:   // Display a slash
michael@0:   void DisplaySlash(nsDisplayListBuilder* aBuilder,
michael@0:                     nsIFrame* aFrame, const nsRect& aRect,
michael@0:                     nscoord aThickness,
michael@0:                     const nsDisplayListSet& aLists);
michael@0: 
michael@0:   nsRect        mLineRect;
michael@0:   nsMathMLChar* mSlashChar;
michael@0:   nscoord       mLineThickness;
michael@0:   bool          mIsBevelled;
michael@0: };
michael@0: 
michael@0: #endif /* nsMathMLmfracFrame_h___ */