pjs/layout/generic/nsHTMLReflowMetrics.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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*
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* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
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* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
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* Contributor(s):
*
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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 nsHTMLReflowMetrics_h___
#define nsHTMLReflowMetrics_h___
#include <stdio.h>
#include "nsISupports.h"
#include "nsMargin.h"
#include "nsRect.h"
// for MOZ_MATHML
#include "nsIRenderingContext.h" //to get struct nsBoundingMetrics
//----------------------------------------------------------------------
// Option flags
#define NS_REFLOW_CALC_MAX_WIDTH 0x0001
#ifdef MOZ_MATHML
#define NS_REFLOW_CALC_BOUNDING_METRICS 0x0002
#endif
/**
* An nsCollapsingMargin represents a vertical collapsing margin between
* blocks as described in section 8.3.1 of CSS2,
* <URL: http://www.w3.org/TR/REC-CSS2/box.html#collapsing-margins >.
*
* All adjacent vertical margins collapse, and the resulting margin is
* the sum of the largest positive margin included and the smallest (most
* negative) negative margin included.
*/
struct nsCollapsingMargin {
private:
nscoord mMostPos; // the largest positive margin included
nscoord mMostNeg; // the smallest negative margin included
public:
nsCollapsingMargin()
: mMostPos(0),
mMostNeg(0)
{
}
nsCollapsingMargin(const nsCollapsingMargin& aOther)
: mMostPos(aOther.mMostPos),
mMostNeg(aOther.mMostNeg)
{
}
nsCollapsingMargin& operator=(const nsCollapsingMargin& aOther)
{
mMostPos = aOther.mMostPos;
mMostNeg = aOther.mMostNeg;
return *this;
}
void Include(nscoord aCoord)
{
if (aCoord > mMostPos)
mMostPos = aCoord;
else if (aCoord < mMostNeg)
mMostNeg = aCoord;
}
void Include(const nsCollapsingMargin& aOther)
{
if (aOther.mMostPos > mMostPos)
mMostPos = aOther.mMostPos;
if (aOther.mMostNeg < mMostNeg)
mMostNeg = aOther.mMostNeg;
}
void Zero()
{
mMostPos = 0;
mMostNeg = 0;
}
PRBool IsZero() const
{
return (mMostPos == 0) && (mMostNeg == 0);
}
nscoord get() const
{
return mMostPos + mMostNeg;
}
};
/**
* Reflow metrics used to return the frame's desired size and alignment
* information.
*
* @see #Reflow()
*/
struct nsHTMLReflowMetrics {
nscoord width, height; // [OUT] desired width and height
nscoord ascent, descent; // [OUT] ascent and descent information
nscoord mMaxElementWidth; // [OUT]
// Used for incremental reflow. If the NS_REFLOW_CALC_MAX_WIDTH flag is set,
// then the caller is requesting that you update and return your maximum width
nscoord mMaximumWidth; // [OUT]
#ifdef MOZ_MATHML
// Metrics that _exactly_ enclose the text to allow precise MathML placements.
// If the NS_REFLOW_CALC_BOUNDING_METRICS flag is set, then the caller is
// requesting that you also compute additional details about your inner
// bounding box and italic correction. For example, the bounding box of
// msup is the smallest rectangle that _exactly_ encloses both the text
// of the base and the text of the superscript.
nsBoundingMetrics mBoundingMetrics; // [OUT]
#endif
// Carried out bottom margin values. This is the collapsed
// (generational) bottom margin value.
nsCollapsingMargin mCarriedOutBottomMargin;
// For frames that have content that overflow their content area
// (NS_FRAME_OUTSIDE_CHILDREN) this rectangle represents the total area
// of the frame including visible overflow, i.e., don't include overflowing
// content that is hidden.
// The rect is in the local coordinate space of the frame, and should be at
// least as big as the desired size. If there is no content that overflows,
// then the overflow area is identical to the desired size and should be
// {0, 0, mWidth, mHeight}.
nsRect mOverflowArea;
PRUint32 mFlags;
// used by tables to optimize common cases
PRPackedBool mNothingChanged;
// Should we compute mMaxElementWidth?
PRPackedBool mComputeMEW;
nsHTMLReflowMetrics(PRBool aComputeMEW, PRUint32 aFlags = 0) {
mComputeMEW = aComputeMEW;
mMaxElementWidth = 0;
mMaximumWidth = 0;
mFlags = aFlags;
mOverflowArea.x = 0;
mOverflowArea.y = 0;
mOverflowArea.width = 0;
mOverflowArea.height = 0;
mNothingChanged = PR_FALSE;
#ifdef MOZ_MATHML
mBoundingMetrics.Clear();
#endif
// XXX These are OUT parameters and so they shouldn't have to be
// initialized, but there are some bad frame classes that aren't
// properly setting them when returning from Reflow()...
width = height = 0;
ascent = descent = 0;
}
nsHTMLReflowMetrics& operator=(const nsHTMLReflowMetrics& aOther)
{
mMaxElementWidth = aOther.mMaxElementWidth;
mMaximumWidth = aOther.mMaximumWidth;
mFlags = aOther.mFlags;
mCarriedOutBottomMargin = aOther.mCarriedOutBottomMargin;
mOverflowArea.x = aOther.mOverflowArea.x;
mOverflowArea.y = aOther.mOverflowArea.y;
mOverflowArea.width = aOther.mOverflowArea.width;
mOverflowArea.height = aOther.mOverflowArea.height;
mNothingChanged = aOther.mNothingChanged;
#ifdef MOZ_MATHML
mBoundingMetrics = aOther.mBoundingMetrics;
#endif
width = aOther.width;
height = aOther.height;
ascent = aOther.ascent;
descent = aOther.descent;
return *this;
}
};
#endif /* nsHTMLReflowMetrics_h___ */