Example #1
0
/* static */ void
nsMathMLFrame::GetAxisHeight(nsIRenderingContext& aRenderingContext,
                             nsIFontMetrics*      aFontMetrics,
                             nscoord&             aAxisHeight)
{
  // get the bounding metrics of the minus sign, the rendering context
  // is assumed to have been set with the font of the current style context
#ifdef NS_DEBUG
  nsCOMPtr<nsIFontMetrics> currFontMetrics;
  aRenderingContext.GetFontMetrics(*getter_AddRefs(currFontMetrics));
  NS_ASSERTION(currFontMetrics->Font().Equals(aFontMetrics->Font()),
	"unexpected state");
#endif
  nscoord xHeight;
  aFontMetrics->GetXHeight(xHeight);
  PRUnichar minus = 0x2212; // not '-', but official Unicode minus sign
  nsBoundingMetrics bm;
  nsresult rv = aRenderingContext.GetBoundingMetrics(&minus, PRUint32(1), bm);
  if (NS_SUCCEEDED(rv)) {
    aAxisHeight = bm.ascent - (bm.ascent + bm.descent)/2;
  }
  if (NS_FAILED(rv) || aAxisHeight <= 0 || aAxisHeight >= xHeight) {
    // fall-back to the other version
    GetAxisHeight(aFontMetrics, aAxisHeight);
  }
}
Example #2
0
/* static */ void
nsMathMLFrame::GetAxisHeight(nsRenderingContext& aRenderingContext,
                             nsFontMetrics*      aFontMetrics,
                             nscoord&             aAxisHeight)
{
  // get the bounding metrics of the minus sign, the rendering context
  // is assumed to have been set with the font of the current style context
  NS_ASSERTION(aRenderingContext.FontMetrics()->Font().
               Equals(aFontMetrics->Font()),
               "unexpected state");

  nscoord xHeight = aFontMetrics->XHeight();
  PRUnichar minus = 0x2212; // not '-', but official Unicode minus sign
  nsBoundingMetrics bm = aRenderingContext.GetBoundingMetrics(&minus, 1);
  aAxisHeight = bm.ascent - (bm.ascent + bm.descent)/2;
  if (aAxisHeight <= 0 || aAxisHeight >= xHeight) {
    // fall-back to the other version
    GetAxisHeight(aFontMetrics, aAxisHeight);
  }
}
NS_IMETHODIMP
nsMathMLmfencedFrame::Reflow(nsPresContext*          aPresContext,
                             nsHTMLReflowMetrics&     aDesiredSize,
                             const nsHTMLReflowState& aReflowState,
                             nsReflowStatus&          aStatus)
{
  nsresult rv;
  aDesiredSize.width = aDesiredSize.height = 0;
  aDesiredSize.ascent = 0;
  aDesiredSize.mBoundingMetrics = nsBoundingMetrics();

  PRInt32 i;
  const nsStyleFont* font = GetStyleFont();
  nsRefPtr<nsFontMetrics> fm;
  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm));
  aReflowState.rendContext->SetFont(fm);
  nscoord axisHeight, em;
  GetAxisHeight(*aReflowState.rendContext, fm, axisHeight);
  GetEmHeight(fm, em);
  // leading to be left at the top and the bottom of stretched chars
  nscoord leading = NSToCoordRound(0.2f * em); 

  /////////////
  // Reflow children
  // Asking each child to cache its bounding metrics

  // Note that we don't use the base method nsMathMLContainerFrame::Reflow()
  // because we want to stretch our fences, separators and stretchy frames using
  // the *same* initial aDesiredSize.mBoundingMetrics. If we were to use the base
  // method here, our stretchy frames will be stretched and placed, and we may
  // end up stretching our fences/separators with a different aDesiredSize.
  // XXX The above decision was revisited in bug 121748 and this code can be
  // refactored to use nsMathMLContainerFrame::Reflow() at some stage.

  nsReflowStatus childStatus;
  nsSize availSize(aReflowState.ComputedWidth(), NS_UNCONSTRAINEDSIZE);
  nsIFrame* firstChild = GetFirstChild(nsnull);
  nsIFrame* childFrame = firstChild;
  nscoord ascent = 0, descent = 0;
  if (firstChild || mOpenChar || mCloseChar || mSeparatorsCount > 0) {
    // We use the ASCII metrics to get our minimum height. This way,
    // if we have borders or a background, they will fit better with
    // other elements on the line.
    ascent = fm->MaxAscent();
    descent = fm->MaxDescent();
  }
  while (childFrame) {
    nsHTMLReflowMetrics childDesiredSize(aDesiredSize.mFlags
                                         | NS_REFLOW_CALC_BOUNDING_METRICS);
    nsHTMLReflowState childReflowState(aPresContext, aReflowState,
                                       childFrame, availSize);
    rv = ReflowChild(childFrame, aPresContext, childDesiredSize,
                     childReflowState, childStatus);
    //NS_ASSERTION(NS_FRAME_IS_COMPLETE(childStatus), "bad status");
    if (NS_FAILED(rv)) {
      // Call DidReflow() for the child frames we successfully did reflow.
      DidReflowChildren(firstChild, childFrame);
      return rv;
    }

    SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                    childDesiredSize.mBoundingMetrics);

    nscoord childDescent = childDesiredSize.height - childDesiredSize.ascent;
    if (descent < childDescent)
      descent = childDescent;
    if (ascent < childDesiredSize.ascent)
      ascent = childDesiredSize.ascent;

    childFrame = childFrame->GetNextSibling();
  }

  /////////////
  // Ask stretchy children to stretch themselves

  nsBoundingMetrics containerSize;
  nsStretchDirection stretchDir = NS_STRETCH_DIRECTION_VERTICAL;

  GetPreferredStretchSize(*aReflowState.rendContext,
                          0, /* i.e., without embellishments */
                          stretchDir, containerSize);
  childFrame = firstChild;
  while (childFrame) {
    nsIMathMLFrame* mathmlChild = do_QueryFrame(childFrame);
    if (mathmlChild) {
      nsHTMLReflowMetrics childDesiredSize;
      // retrieve the metrics that was stored at the previous pass
      GetReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                     childDesiredSize.mBoundingMetrics);
      
      mathmlChild->Stretch(*aReflowState.rendContext, 
                           stretchDir, containerSize, childDesiredSize);
      // store the updated metrics
      SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                      childDesiredSize.mBoundingMetrics);
      
      nscoord childDescent = childDesiredSize.height - childDesiredSize.ascent;
      if (descent < childDescent)
        descent = childDescent;
      if (ascent < childDesiredSize.ascent)
        ascent = childDesiredSize.ascent;
    }
    childFrame = childFrame->GetNextSibling();
  }

  // bug 121748: for surrounding fences & separators, use a size that covers everything
  GetPreferredStretchSize(*aReflowState.rendContext,
                          STRETCH_CONSIDER_EMBELLISHMENTS,
                          stretchDir, containerSize);

  //////////////////////////////////////////
  // Prepare the opening fence, separators, and closing fence, and
  // adjust the origin of children.

  // we need to center around the axis
  nscoord delta = NS_MAX(containerSize.ascent - axisHeight, 
                         containerSize.descent + axisHeight);
  containerSize.ascent = delta + axisHeight;
  containerSize.descent = delta - axisHeight;

  /////////////////
  // opening fence ...
  ReflowChar(aPresContext, *aReflowState.rendContext, mOpenChar,
             NS_MATHML_OPERATOR_FORM_PREFIX, font->mScriptLevel, 
             axisHeight, leading, em, containerSize, ascent, descent);
  /////////////////
  // separators ...
  for (i = 0; i < mSeparatorsCount; i++) {
    ReflowChar(aPresContext, *aReflowState.rendContext, &mSeparatorsChar[i],
               NS_MATHML_OPERATOR_FORM_INFIX, font->mScriptLevel,
               axisHeight, leading, em, containerSize, ascent, descent);
  }
  /////////////////
  // closing fence ...
  ReflowChar(aPresContext, *aReflowState.rendContext, mCloseChar,
             NS_MATHML_OPERATOR_FORM_POSTFIX, font->mScriptLevel,
             axisHeight, leading, em, containerSize, ascent, descent);

  //////////////////
  // Adjust the origins of each child.
  // and update our bounding metrics

  i = 0;
  nscoord dx = 0;
  nsBoundingMetrics bm;
  PRBool firstTime = PR_TRUE;
  if (mOpenChar) {
    PlaceChar(mOpenChar, ascent, bm, dx);
    aDesiredSize.mBoundingMetrics = bm;
    firstTime = PR_FALSE;
  }

  childFrame = firstChild;
  while (childFrame) {
    nsHTMLReflowMetrics childSize;
    GetReflowAndBoundingMetricsFor(childFrame, childSize, bm);
    if (firstTime) {
      firstTime = PR_FALSE;
      aDesiredSize.mBoundingMetrics  = bm;
    }
    else  
      aDesiredSize.mBoundingMetrics += bm;

    FinishReflowChild(childFrame, aPresContext, nsnull, childSize, 
                      dx, ascent - childSize.ascent, 0);
    dx += childSize.width;

    if (i < mSeparatorsCount) {
      PlaceChar(&mSeparatorsChar[i], ascent, bm, dx);
      aDesiredSize.mBoundingMetrics += bm;
    }
    i++;

    childFrame = childFrame->GetNextSibling();
  }

  if (mCloseChar) {
    PlaceChar(mCloseChar, ascent, bm, dx);
    if (firstTime)
      aDesiredSize.mBoundingMetrics  = bm;
    else  
      aDesiredSize.mBoundingMetrics += bm;
  }

  aDesiredSize.width = aDesiredSize.mBoundingMetrics.width;
  aDesiredSize.height = ascent + descent;
  aDesiredSize.ascent = ascent;

  SetBoundingMetrics(aDesiredSize.mBoundingMetrics);
  SetReference(nsPoint(0, aDesiredSize.ascent));

  // see if we should fix the spacing
  FixInterFrameSpacing(aDesiredSize);

  // Finished with these:
  ClearSavedChildMetrics();

  // Set our overflow area
  GatherAndStoreOverflow(&aDesiredSize);

  aStatus = NS_FRAME_COMPLETE;
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
  return NS_OK;
}
// NOTE: aDesiredStretchSize is an IN/OUT parameter
//       On input  - it contains our current size
//       On output - the same size or the new size that we want
NS_IMETHODIMP
nsMathMLmoFrame::Stretch(nsRenderingContext& aRenderingContext,
                         nsStretchDirection   aStretchDirection,
                         nsBoundingMetrics&   aContainerSize,
                         nsHTMLReflowMetrics& aDesiredStretchSize)
{
  if (NS_MATHML_STRETCH_WAS_DONE(mPresentationData.flags)) {
    NS_WARNING("it is wrong to fire stretch more than once on a frame");
    return NS_OK;
  }
  mPresentationData.flags |= NS_MATHML_STRETCH_DONE;

  nsIFrame* firstChild = mFrames.FirstChild();

  // get the axis height;
  nsRefPtr<nsFontMetrics> fm;
  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm));
  aRenderingContext.SetFont(fm);
  nscoord axisHeight, height;
  GetAxisHeight(aRenderingContext, fm, axisHeight);

  // get the leading to be left at the top and the bottom of the stretched char
  // this seems more reliable than using fm->GetLeading() on suspicious fonts
  nscoord em;
  GetEmHeight(fm, em);
  nscoord leading = NSToCoordRound(0.2f * em);

  // Operators that are stretchy, or those that are to be centered
  // to cater for fonts that are not math-aware, are handled by the MathMLChar
  // ('form' is reset if stretch fails -- i.e., we don't bother to stretch next time)
  bool useMathMLChar = UseMathMLChar();

  nsBoundingMetrics charSize;
  nsBoundingMetrics container = aDesiredStretchSize.mBoundingMetrics;
  bool isVertical = false;

  if (((aStretchDirection == NS_STRETCH_DIRECTION_VERTICAL) ||
       (aStretchDirection == NS_STRETCH_DIRECTION_DEFAULT))  &&
      (mEmbellishData.direction == NS_STRETCH_DIRECTION_VERTICAL)) {
    isVertical = true;
  }

  uint32_t stretchHint =
    GetStretchHint(mFlags, mPresentationData, isVertical);

  if (useMathMLChar) {
    nsBoundingMetrics initialSize = aDesiredStretchSize.mBoundingMetrics;

    if (stretchHint != NS_STRETCH_NONE) {

      container = aContainerSize;

      // some adjustments if the operator is symmetric and vertical

      if (isVertical && NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags)) {
        // we need to center about the axis
        nscoord delta = std::max(container.ascent - axisHeight,
                               container.descent + axisHeight);
        container.ascent = delta + axisHeight;
        container.descent = delta - axisHeight;

        // get ready in case we encounter user-desired min-max size
        delta = std::max(initialSize.ascent - axisHeight,
                       initialSize.descent + axisHeight);
        initialSize.ascent = delta + axisHeight;
        initialSize.descent = delta - axisHeight;
      }

      // check for user-desired min-max size

      if (mMaxSize != NS_MATHML_OPERATOR_SIZE_INFINITY && mMaxSize > 0.0f) {
        // if we are here, there is a user defined maxsize ...
        //XXX Set stretchHint = NS_STRETCH_NORMAL? to honor the maxsize as close as possible?
        if (NS_MATHML_OPERATOR_MAXSIZE_IS_ABSOLUTE(mFlags)) {
          // there is an explicit value like maxsize="20pt"
          // try to maintain the aspect ratio of the char
          float aspect = mMaxSize / float(initialSize.ascent + initialSize.descent);
          container.ascent =
            std::min(container.ascent, nscoord(initialSize.ascent * aspect));
          container.descent =
            std::min(container.descent, nscoord(initialSize.descent * aspect));
          // below we use a type cast instead of a conversion to avoid a VC++ bug
          // see http://support.microsoft.com/support/kb/articles/Q115/7/05.ASP
          container.width =
            std::min(container.width, (nscoord)mMaxSize);
        }
        else { // multiplicative value
          container.ascent =
            std::min(container.ascent, nscoord(initialSize.ascent * mMaxSize));
          container.descent =
            std::min(container.descent, nscoord(initialSize.descent * mMaxSize));
          container.width =
            std::min(container.width, nscoord(initialSize.width * mMaxSize));
        }

        if (isVertical && !NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags)) {
          // re-adjust to align the char with the bottom of the initial container
          height = container.ascent + container.descent;
          container.descent = aContainerSize.descent;
          container.ascent = height - container.descent;
        }
      }

      if (mMinSize > 0.0f) {
        // if we are here, there is a user defined minsize ...
        // always allow the char to stretch in its natural direction,
        // even if it is different from the caller's direction 
        if (aStretchDirection != NS_STRETCH_DIRECTION_DEFAULT &&
            aStretchDirection != mEmbellishData.direction) {
          aStretchDirection = NS_STRETCH_DIRECTION_DEFAULT;
          // but when we are not honoring the requested direction
          // we should not use the caller's container size either
          container = initialSize;
        }
        if (NS_MATHML_OPERATOR_MINSIZE_IS_ABSOLUTE(mFlags)) {
          // there is an explicit value like minsize="20pt"
          // try to maintain the aspect ratio of the char
          float aspect = mMinSize / float(initialSize.ascent + initialSize.descent);
          container.ascent =
            std::max(container.ascent, nscoord(initialSize.ascent * aspect));
          container.descent =
            std::max(container.descent, nscoord(initialSize.descent * aspect));
          container.width =
            std::max(container.width, (nscoord)mMinSize);
        }
        else { // multiplicative value
          container.ascent =
            std::max(container.ascent, nscoord(initialSize.ascent * mMinSize));
          container.descent =
            std::max(container.descent, nscoord(initialSize.descent * mMinSize));
          container.width =
            std::max(container.width, nscoord(initialSize.width * mMinSize));
        }

        if (isVertical && !NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags)) {
          // re-adjust to align the char with the bottom of the initial container
          height = container.ascent + container.descent;
          container.descent = aContainerSize.descent;
          container.ascent = height - container.descent;
        }
      }
    }

    // let the MathMLChar stretch itself...
    nsresult res = mMathMLChar.Stretch(PresContext(), aRenderingContext,
                                       aStretchDirection, container, charSize,
                                       stretchHint,
                                       StyleVisibility()->mDirection);
    if (NS_FAILED(res)) {
      // gracefully handle cases where stretching the char failed (i.e., GetBoundingMetrics failed)
      // clear our 'form' to behave as if the operator wasn't in the dictionary
      mFlags &= ~NS_MATHML_OPERATOR_FORM;
      useMathMLChar = false;
    }
  }

  // Child frames of invisble operators are not reflowed
  if (!NS_MATHML_OPERATOR_IS_INVISIBLE(mFlags)) {
    // Place our children using the default method
    // This will allow our child text frame to get its DidReflow()
    nsresult rv = Place(aRenderingContext, true, aDesiredStretchSize);
    if (NS_MATHML_HAS_ERROR(mPresentationData.flags) || NS_FAILED(rv)) {
      // Make sure the child frames get their DidReflow() calls.
      DidReflowChildren(mFrames.FirstChild());
    }
  }

  if (useMathMLChar) {
    // update our bounding metrics... it becomes that of our MathML char
    mBoundingMetrics = charSize;

    // if the returned direction is 'unsupported', the char didn't actually change. 
    // So we do the centering only if necessary
    if (mMathMLChar.GetStretchDirection() != NS_STRETCH_DIRECTION_UNSUPPORTED ||
        NS_MATHML_OPERATOR_IS_CENTERED(mFlags)) {

      bool largeopOnly =
        (NS_STRETCH_LARGEOP & stretchHint) != 0 &&
        (NS_STRETCH_VARIABLE_MASK & stretchHint) == 0;

      if (isVertical || NS_MATHML_OPERATOR_IS_CENTERED(mFlags)) {
        // the desired size returned by mMathMLChar maybe different
        // from the size of the container.
        // the mMathMLChar.mRect.y calculation is subtle, watch out!!!

        height = mBoundingMetrics.ascent + mBoundingMetrics.descent;
        if (NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags) ||
            NS_MATHML_OPERATOR_IS_CENTERED(mFlags)) {
          // For symmetric and vertical operators, or for operators that are always
          // centered ('+', '*', etc) we want to center about the axis of the container
          mBoundingMetrics.descent = height/2 - axisHeight;
        } else if (!largeopOnly) {
          // Align the center of the char with the center of the container
          mBoundingMetrics.descent = height/2 +
            (container.ascent + container.descent)/2 - container.ascent;
        } // else align the baselines
        mBoundingMetrics.ascent = height - mBoundingMetrics.descent;
      }
    }
  }

  // Fixup for the final height.
  // On one hand, our stretchy height can sometimes be shorter than surrounding
  // ASCII chars, e.g., arrow symbols have |mBoundingMetrics.ascent + leading|
  // that is smaller than the ASCII's ascent, hence when painting the background
  // later, it won't look uniform along the line.
  // On the other hand, sometimes we may leave too much gap when our glyph happens
  // to come from a font with tall glyphs. For example, since CMEX10 has very tall
  // glyphs, its natural font metrics are large, even if we pick a small glyph
  // whose size is comparable to the size of a normal ASCII glyph.
  // So to avoid uneven spacing in either of these two cases, we use the height
  // of the ASCII font as a reference and try to match it if possible.

  // special case for accents... keep them short to improve mouse operations...
  // an accent can only be the non-first child of <mover>, <munder>, <munderover>
  bool isAccent =
    NS_MATHML_EMBELLISH_IS_ACCENT(mEmbellishData.flags);
  if (isAccent) {
    nsEmbellishData parentData;
    GetEmbellishDataFrom(mParent, parentData);
    isAccent =
       (NS_MATHML_EMBELLISH_IS_ACCENTOVER(parentData.flags) ||
        NS_MATHML_EMBELLISH_IS_ACCENTUNDER(parentData.flags)) &&
       parentData.coreFrame != this;
  }
  if (isAccent && firstChild) {
    // see bug 188467 for what is going on here
    nscoord dy = aDesiredStretchSize.ascent - (mBoundingMetrics.ascent + leading);
    aDesiredStretchSize.ascent = mBoundingMetrics.ascent + leading;
    aDesiredStretchSize.height = aDesiredStretchSize.ascent + mBoundingMetrics.descent;

    firstChild->SetPosition(firstChild->GetPosition() - nsPoint(0, dy));
  }
  else if (useMathMLChar) {
    nscoord ascent = fm->MaxAscent();
    nscoord descent = fm->MaxDescent();
    aDesiredStretchSize.ascent = std::max(mBoundingMetrics.ascent + leading, ascent);
    aDesiredStretchSize.height = aDesiredStretchSize.ascent +
                                 std::max(mBoundingMetrics.descent + leading, descent);
  }
  aDesiredStretchSize.width = mBoundingMetrics.width;
  aDesiredStretchSize.mBoundingMetrics = mBoundingMetrics;
  mReference.x = 0;
  mReference.y = aDesiredStretchSize.ascent;
  // Place our mMathMLChar, its origin is in our coordinate system
  if (useMathMLChar) {
    nscoord dy = aDesiredStretchSize.ascent - mBoundingMetrics.ascent;
    mMathMLChar.SetRect(nsRect(0, dy, charSize.width, charSize.ascent + charSize.descent));
  }

  // Before we leave... there is a last item in the check-list:
  // If our parent is not embellished, it means we are the outermost embellished
  // container and so we put the spacing, otherwise we don't include the spacing,
  // the outermost embellished container will take care of it.

  if (!NS_MATHML_OPERATOR_HAS_EMBELLISH_ANCESTOR(mFlags)) {

    // Account the spacing if we are not an accent with explicit attributes
    nscoord leadingSpace = mEmbellishData.leadingSpace;
    if (isAccent && !NS_MATHML_OPERATOR_HAS_LSPACE_ATTR(mFlags)) {
      leadingSpace = 0;
    }
    nscoord trailingSpace = mEmbellishData.trailingSpace;
    if (isAccent && !NS_MATHML_OPERATOR_HAS_RSPACE_ATTR(mFlags)) {
      trailingSpace = 0;
    }

    mBoundingMetrics.width += leadingSpace + trailingSpace;
    aDesiredStretchSize.width = mBoundingMetrics.width;
    aDesiredStretchSize.mBoundingMetrics.width = mBoundingMetrics.width;

    nscoord dx = (StyleVisibility()->mDirection ?
                  trailingSpace : leadingSpace);
    if (dx) {
      // adjust the offsets
      mBoundingMetrics.leftBearing += dx;
      mBoundingMetrics.rightBearing += dx;
      aDesiredStretchSize.mBoundingMetrics.leftBearing += dx;
      aDesiredStretchSize.mBoundingMetrics.rightBearing += dx;

      if (useMathMLChar) {
        nsRect rect;
        mMathMLChar.GetRect(rect);
        mMathMLChar.SetRect(nsRect(rect.x + dx, rect.y,
                                   rect.width, rect.height));
      }
      else {
        nsIFrame* childFrame = firstChild;
        while (childFrame) {
          childFrame->SetPosition(childFrame->GetPosition() +
                                  nsPoint(dx, 0));
          childFrame = childFrame->GetNextSibling();
        }
      }
    }
  }

  // Finished with these:
  ClearSavedChildMetrics();
  // Set our overflow area
  GatherAndStoreOverflow(&aDesiredStretchSize);

  // There used to be code here to change the height of the child frame to
  // change the caret height, but the text frame that manages the caret is now
  // not a direct child but wrapped in a block frame.  See also bug 412033.

  return NS_OK;
}
Example #5
0
nsresult
nsMathMLmfracFrame::PlaceInternal(nsRenderingContext& aRenderingContext,
                                  bool                 aPlaceOrigin,
                                  nsHTMLReflowMetrics& aDesiredSize,
                                  bool                 aWidthOnly)
{
  ////////////////////////////////////
  // Get the children's desired sizes
  nsBoundingMetrics bmNum, bmDen;
  nsHTMLReflowMetrics sizeNum;
  nsHTMLReflowMetrics sizeDen;
  nsIFrame* frameDen = nsnull;
  nsIFrame* frameNum = mFrames.FirstChild();
  if (frameNum) 
    frameDen = frameNum->GetNextSibling();
  if (!frameNum || !frameDen || frameDen->GetNextSibling()) {
    // report an error, encourage people to get their markups in order
    return ReflowError(aRenderingContext, aDesiredSize);
  }
  GetReflowAndBoundingMetricsFor(frameNum, sizeNum, bmNum);
  GetReflowAndBoundingMetricsFor(frameDen, sizeDen, bmDen);

  nsPresContext* presContext = PresContext();
  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);

  nsRefPtr<nsFontMetrics> fm;
  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm));
  aRenderingContext.SetFont(fm);

  nscoord defaultRuleThickness, axisHeight;
  GetRuleThickness(aRenderingContext, fm, defaultRuleThickness);
  GetAxisHeight(aRenderingContext, fm, axisHeight);

  nsEmbellishData coreData;
  GetEmbellishDataFrom(mEmbellishData.coreFrame, coreData);

  // see if the linethickness attribute is there 
  nsAutoString value;
  GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::linethickness_,
               value);

  mLineThickness = CalcLineThickness(presContext, mStyleContext, value,
                                     onePixel, defaultRuleThickness);

  // bevelled attribute
  GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::bevelled_,
               value);
  mIsBevelled = value.EqualsLiteral("true");

  if (!mIsBevelled) {
    mLineRect.height = mLineThickness;
    
    // by default, leave at least one-pixel padding at either end, or use
    // lspace & rspace that may come from <mo> if we are an embellished
    // container (we fetch values from the core since they may use units that
    // depend on style data, and style changes could have occurred in the
    // core since our last visit there)
    nscoord leftSpace = NS_MAX(onePixel, coreData.leftSpace);
    nscoord rightSpace = NS_MAX(onePixel, coreData.rightSpace);

    //////////////////
    // Get shifts
    nscoord numShift = 0;
    nscoord denShift = 0;

    // Rule 15b, App. G, TeXbook
    nscoord numShift1, numShift2, numShift3;
    nscoord denShift1, denShift2;

    GetNumeratorShifts(fm, numShift1, numShift2, numShift3);
    GetDenominatorShifts(fm, denShift1, denShift2);
    if (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
      // C > T
      numShift = numShift1;
      denShift = denShift1;
    }
    else {
      numShift = (0 < mLineRect.height) ? numShift2 : numShift3;
      denShift = denShift2;
    }

    nscoord minClearance = 0;
    nscoord actualClearance = 0;

    nscoord actualRuleThickness =  mLineThickness;

    if (0 == actualRuleThickness) {
      // Rule 15c, App. G, TeXbook

      // min clearance between numerator and denominator
      minClearance = (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) ?
        7 * defaultRuleThickness : 3 * defaultRuleThickness;
      actualClearance =
        (numShift - bmNum.descent) - (bmDen.ascent - denShift);
      // actualClearance should be >= minClearance
      if (actualClearance < minClearance) {
        nscoord halfGap = (minClearance - actualClearance)/2;
        numShift += halfGap;
        denShift += halfGap;
      }
    }
    else {
    // Rule 15d, App. G, TeXbook

    // min clearance between numerator or denominator and middle of bar

    // TeX has a different interpretation of the thickness.
    // Try $a \above10pt b$ to see. Here is what TeX does:
//     minClearance = (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) ?
//      3 * actualRuleThickness : actualRuleThickness;
 
    // we slightly depart from TeX here. We use the defaultRuleThickness instead
    // of the value coming from the linethickness attribute, i.e., we recover what
    // TeX does if the user hasn't set linethickness. But when the linethickness
    // is set, we avoid the wide gap problem.
     minClearance = (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) ?
      3 * defaultRuleThickness : defaultRuleThickness + onePixel;

      // adjust numShift to maintain minClearance if needed
      actualClearance =
        (numShift - bmNum.descent) - (axisHeight + actualRuleThickness/2);
      if (actualClearance < minClearance) {
        numShift += (minClearance - actualClearance);
      }
      // adjust denShift to maintain minClearance if needed
      actualClearance =
        (axisHeight - actualRuleThickness/2) - (bmDen.ascent - denShift);
      if (actualClearance < minClearance) {
        denShift += (minClearance - actualClearance);
      }
    }

    //////////////////
    // Place Children

    // XXX Need revisiting the width. TeX uses the exact width
    // e.g. in $$\huge\frac{\displaystyle\int}{i}$$
    nscoord width = NS_MAX(bmNum.width, bmDen.width);
    nscoord dxNum = leftSpace + (width - sizeNum.width)/2;
    nscoord dxDen = leftSpace + (width - sizeDen.width)/2;
    width += leftSpace + rightSpace;

    // see if the numalign attribute is there 
    GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::numalign_,
                 value);
    if (value.EqualsLiteral("left"))
      dxNum = leftSpace;
    else if (value.EqualsLiteral("right"))
      dxNum = width - rightSpace - sizeNum.width;

    // see if the denomalign attribute is there 
    GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::denomalign_,
                 value);
    if (value.EqualsLiteral("left"))
      dxDen = leftSpace;
    else if (value.EqualsLiteral("right"))
      dxDen = width - rightSpace - sizeDen.width;

    mBoundingMetrics.rightBearing =
      NS_MAX(dxNum + bmNum.rightBearing, dxDen + bmDen.rightBearing);
    if (mBoundingMetrics.rightBearing < width - rightSpace)
      mBoundingMetrics.rightBearing = width - rightSpace;
    mBoundingMetrics.leftBearing =
      NS_MIN(dxNum + bmNum.leftBearing, dxDen + bmDen.leftBearing);
    if (mBoundingMetrics.leftBearing > leftSpace)
      mBoundingMetrics.leftBearing = leftSpace;
    mBoundingMetrics.ascent = bmNum.ascent + numShift;
    mBoundingMetrics.descent = bmDen.descent + denShift;
    mBoundingMetrics.width = width;

    aDesiredSize.ascent = sizeNum.ascent + numShift;
    aDesiredSize.height = aDesiredSize.ascent +
      sizeDen.height - sizeDen.ascent + denShift;
    aDesiredSize.width = mBoundingMetrics.width;
    aDesiredSize.mBoundingMetrics = mBoundingMetrics;

    mReference.x = 0;
    mReference.y = aDesiredSize.ascent;

    if (aPlaceOrigin) {
      nscoord dy;
      // place numerator
      dy = 0;
      FinishReflowChild(frameNum, presContext, nsnull, sizeNum, dxNum, dy, 0);
      // place denominator
      dy = aDesiredSize.height - sizeDen.height;
      FinishReflowChild(frameDen, presContext, nsnull, sizeDen, dxDen, dy, 0);
      // place the fraction bar - dy is top of bar
      dy = aDesiredSize.ascent - (axisHeight + actualRuleThickness/2);
      mLineRect.SetRect(leftSpace, dy, width - (leftSpace + rightSpace),
                        actualRuleThickness);
    }
  } else {
    nscoord numShift = 0.0;
    nscoord denShift = 0.0;
    nscoord padding = 3 * defaultRuleThickness;
    nscoord slashRatio = 3;

    // Define the constant used in the expression of the maximum width
    nscoord em = fm->EmHeight();
    nscoord slashMaxWidthConstant = 2 * em;

    // For large line thicknesses the minimum slash height is limited to the
    // largest expected height of a fraction
    nscoord slashMinHeight = slashRatio *
      NS_MIN(2 * mLineThickness, slashMaxWidthConstant);

    nscoord leftSpace = NS_MAX(padding, coreData.leftSpace);
    nscoord rightSpace = NS_MAX(padding, coreData.rightSpace);
    nscoord delta;
    
    //           ___________
    //          |           |    /
    //         {|-NUMERATOR-|   /
    //         {|___________|  S
    //         {               L
    // numShift{               A
    // ------------------------------------------------------- baseline
    //                         S   _____________ } denShift
    //                         H  |             |}
    //                        /   |-DENOMINATOR-|}
    //                       /    |_____________| 
    //

    // first, ensure that the top of the numerator is at least as high as the
    // top of the denominator (and the reverse for the bottoms)
    delta = NS_MAX(bmDen.ascent - bmNum.ascent,
                   bmNum.descent - bmDen.descent) / 2;
    if (delta > 0) {
      numShift += delta;
      denShift += delta;
    }

    if (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
      delta = NS_MIN(bmDen.ascent + bmDen.descent,
                     bmNum.ascent + bmNum.descent) / 2;
      numShift += delta;
      denShift += delta;
    } else {
      nscoord xHeight = fm->XHeight();
      numShift += xHeight / 2;
      denShift += xHeight / 4;
    }
   
    // Set the ascent/descent of our BoundingMetrics.
    mBoundingMetrics.ascent = bmNum.ascent + numShift;
    mBoundingMetrics.descent = bmDen.descent + denShift;

    // At this point the height of the slash is
    // mBoundingMetrics.ascent + mBoundingMetrics.descent
    // Ensure that it is greater than slashMinHeight
    delta = (slashMinHeight -
             (mBoundingMetrics.ascent + mBoundingMetrics.descent)) / 2;
    if (delta > 0) {
      mBoundingMetrics.ascent += delta;
      mBoundingMetrics.descent += delta;
    }

    // Set the width of the slash
    if (aWidthOnly) {
      mLineRect.width = mLineThickness + slashMaxWidthConstant;
    } else {
      mLineRect.width = mLineThickness +
        NS_MIN(slashMaxWidthConstant,
               (mBoundingMetrics.ascent + mBoundingMetrics.descent) /
               slashRatio);
    }

    // Set horizontal bounding metrics
    mBoundingMetrics.leftBearing = leftSpace + bmNum.leftBearing;
    mBoundingMetrics.rightBearing =
      leftSpace + bmNum.width + mLineRect.width + bmDen.rightBearing;
    mBoundingMetrics.width =
      leftSpace + bmNum.width + mLineRect.width + bmDen.width + rightSpace;

    // Set aDesiredSize
    aDesiredSize.ascent = mBoundingMetrics.ascent + padding;
    aDesiredSize.height =
      mBoundingMetrics.ascent + mBoundingMetrics.descent + 2 * padding;
    aDesiredSize.width = mBoundingMetrics.width;
    aDesiredSize.mBoundingMetrics = mBoundingMetrics;

    mReference.x = 0;
    mReference.y = aDesiredSize.ascent;
    
    if (aPlaceOrigin) {
      FinishReflowChild(frameNum, presContext, nsnull, sizeNum,
                        leftSpace,
                        aDesiredSize.ascent - numShift - sizeNum.ascent, 0);

      mLineRect.SetRect(leftSpace + bmNum.width,
                        aDesiredSize.ascent - mBoundingMetrics.ascent,
                        mLineRect.width,
                        aDesiredSize.height - 2 * padding);

      FinishReflowChild(frameDen, presContext, nsnull, sizeDen,
                        leftSpace + bmNum.width + mLineRect.width,
                        aDesiredSize.ascent + denShift - sizeDen.ascent, 0);
    }

  }

  return NS_OK;
}
Example #6
0
/* virtual */ nsresult
nsMathMLmfracFrame::Place(nsIRenderingContext& aRenderingContext,
                          PRBool               aPlaceOrigin,
                          nsHTMLReflowMetrics& aDesiredSize)
{
  ////////////////////////////////////
  // Get the children's desired sizes
  nsBoundingMetrics bmNum, bmDen;
  nsHTMLReflowMetrics sizeNum;
  nsHTMLReflowMetrics sizeDen;
  nsIFrame* frameDen = nsnull;
  nsIFrame* frameNum = mFrames.FirstChild();
  if (frameNum) 
    frameDen = frameNum->GetNextSibling();
  if (!frameNum || !frameDen || frameDen->GetNextSibling()) {
    // report an error, encourage people to get their markups in order
    NS_WARNING("invalid markup");
    return ReflowError(aRenderingContext, aDesiredSize);
  }
  GetReflowAndBoundingMetricsFor(frameNum, sizeNum, bmNum);
  GetReflowAndBoundingMetricsFor(frameDen, sizeDen, bmDen);

  //////////////////
  // Get shifts

  nsPresContext* presContext = PresContext();
  nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);

  aRenderingContext.SetFont(GetStyleFont()->mFont, nsnull);
  nsCOMPtr<nsIFontMetrics> fm;
  aRenderingContext.GetFontMetrics(*getter_AddRefs(fm));

  nscoord defaultRuleThickness, axisHeight;
  GetRuleThickness(aRenderingContext, fm, defaultRuleThickness);
  GetAxisHeight(aRenderingContext, fm, axisHeight);

  // by default, leave at least one-pixel padding at either end, or use
  // lspace & rspace that may come from <mo> if we are an embellished container
  // (we fetch values from the core since they may use units that depend
  // on style data, and style changes could have occurred in the core since
  // our last visit there)
  nsEmbellishData coreData;
  GetEmbellishDataFrom(mEmbellishData.coreFrame, coreData);
  nscoord leftSpace = PR_MAX(onePixel, coreData.leftSpace);
  nscoord rightSpace = PR_MAX(onePixel, coreData.rightSpace);

  // see if the linethickness attribute is there 
  nsAutoString value;
  GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::linethickness_, value);
  mLineRect.height = CalcLineThickness(presContext, mStyleContext, value,
                                       onePixel, defaultRuleThickness);
  nscoord numShift = 0;
  nscoord denShift = 0;

  // Rule 15b, App. G, TeXbook
  nscoord numShift1, numShift2, numShift3;
  nscoord denShift1, denShift2;

  GetNumeratorShifts(fm, numShift1, numShift2, numShift3);
  GetDenominatorShifts(fm, denShift1, denShift2);
  if (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) {
    // C > T
    numShift = numShift1;
    denShift = denShift1;
  }
  else {
    numShift = (0 < mLineRect.height) ? numShift2 : numShift3;
    denShift = denShift2;
  }

  nscoord minClearance = 0;
  nscoord actualClearance = 0;

  nscoord actualRuleThickness =  mLineRect.height;

  if (0 == actualRuleThickness) {
    // Rule 15c, App. G, TeXbook

    // min clearance between numerator and denominator
    minClearance = (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) ?
      7 * defaultRuleThickness : 3 * defaultRuleThickness;
    actualClearance =
      (numShift - bmNum.descent) - (bmDen.ascent - denShift);
    // actualClearance should be >= minClearance
    if (actualClearance < minClearance) {
      nscoord halfGap = (minClearance - actualClearance)/2;
      numShift += halfGap;
      denShift += halfGap;
    }
  }
  else {
    // Rule 15d, App. G, TeXbook

    // min clearance between numerator or denominator and middle of bar

    // TeX has a different interpretation of the thickness.
    // Try $a \above10pt b$ to see. Here is what TeX does:
//     minClearance = (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) ?
//      3 * actualRuleThickness : actualRuleThickness;
 
    // we slightly depart from TeX here. We use the defaultRuleThickness instead
    // of the value coming from the linethickness attribute, i.e., we recover what
    // TeX does if the user hasn't set linethickness. But when the linethickness
    // is set, we avoid the wide gap problem.
     minClearance = (NS_MATHML_IS_DISPLAYSTYLE(mPresentationData.flags)) ?
      3 * defaultRuleThickness : defaultRuleThickness + onePixel;

    // adjust numShift to maintain minClearance if needed
    actualClearance =
      (numShift - bmNum.descent) - (axisHeight + actualRuleThickness/2);
    if (actualClearance < minClearance) {
      numShift += (minClearance - actualClearance);
    }
    // adjust denShift to maintain minClearance if needed
    actualClearance =
      (axisHeight - actualRuleThickness/2) - (bmDen.ascent - denShift);
    if (actualClearance < minClearance) {
      denShift += (minClearance - actualClearance);
    }
  }

  //////////////////
  // Place Children

  // XXX Need revisiting the width. TeX uses the exact width
  // e.g. in $$\huge\frac{\displaystyle\int}{i}$$
  nscoord width = PR_MAX(bmNum.width, bmDen.width);
  nscoord dxNum = leftSpace + (width - sizeNum.width)/2;
  nscoord dxDen = leftSpace + (width - sizeDen.width)/2;
  width += leftSpace + rightSpace;

  // see if the numalign attribute is there 
  GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::numalign_,
               value);
  if (value.EqualsLiteral("left"))
    dxNum = leftSpace;
  else if (value.EqualsLiteral("right"))
    dxNum = width - rightSpace - sizeNum.width;

  // see if the denomalign attribute is there 
  GetAttribute(mContent, mPresentationData.mstyle, nsGkAtoms::denomalign_,
               value);
  if (value.EqualsLiteral("left"))
    dxDen = leftSpace;
  else if (value.EqualsLiteral("right"))
    dxDen = width - rightSpace - sizeDen.width;

  mBoundingMetrics.rightBearing =
    PR_MAX(dxNum + bmNum.rightBearing, dxDen + bmDen.rightBearing);
  if (mBoundingMetrics.rightBearing < width - rightSpace)
    mBoundingMetrics.rightBearing = width - rightSpace;
  mBoundingMetrics.leftBearing =
    PR_MIN(dxNum + bmNum.leftBearing, dxDen + bmDen.leftBearing);
  if (mBoundingMetrics.leftBearing > leftSpace)
    mBoundingMetrics.leftBearing = leftSpace;
  mBoundingMetrics.ascent = bmNum.ascent + numShift;
  mBoundingMetrics.descent = bmDen.descent + denShift;
  mBoundingMetrics.width = width;

  aDesiredSize.ascent = sizeNum.ascent + numShift;
  aDesiredSize.height = aDesiredSize.ascent +
                        sizeDen.height - sizeDen.ascent + denShift;
  aDesiredSize.width = mBoundingMetrics.width;
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;

  mReference.x = 0;
  mReference.y = aDesiredSize.ascent;

  if (aPlaceOrigin) {
    nscoord dy;
    // place numerator
    dy = 0;
    FinishReflowChild(frameNum, presContext, nsnull, sizeNum, dxNum, dy, 0);
    // place denominator
    dy = aDesiredSize.height - sizeDen.height;
    FinishReflowChild(frameDen, presContext, nsnull, sizeDen, dxDen, dy, 0);
    // place the fraction bar - dy is top of bar
    dy = aDesiredSize.ascent - (axisHeight + actualRuleThickness/2);
    mLineRect.SetRect(leftSpace, dy, width - (leftSpace + rightSpace), actualRuleThickness);
  }

  return NS_OK;
}
NS_IMETHODIMP
nsMathMLmtableOuterFrame::Reflow(nsPresContext*          aPresContext,
                                 nsHTMLReflowMetrics&     aDesiredSize,
                                 const nsHTMLReflowState& aReflowState,
                                 nsReflowStatus&          aStatus)
{
  nsresult rv;
  nsAutoString value;
  // we want to return a table that is anchored according to the align attribute

  rv = nsTableOuterFrame::Reflow(aPresContext, aDesiredSize, aReflowState,
                                 aStatus);
  NS_ASSERTION(aDesiredSize.height >= 0, "illegal height for mtable");
  NS_ASSERTION(aDesiredSize.width >= 0, "illegal width for mtable");

  // see if the user has set the align attribute on the <mtable>
  // XXX should we also check <mstyle> ?
  PRInt32 rowIndex = 0;
  eAlign tableAlign = eAlign_axis;
  GetAttribute(mContent, nsnull, nsGkAtoms::align, value);
  if (!value.IsEmpty()) {
    ParseAlignAttribute(value, tableAlign, rowIndex);
  }

  // adjustments if there is a specified row from where to anchor the table
  // (conceptually: when there is no row of reference, picture the table as if
  // it is wrapped in a single big fictional row at dy = 0, this way of
  // doing so allows us to have a single code path for all cases).
  nscoord dy = 0;
  nscoord height = aDesiredSize.height;
  nsIFrame* rowFrame = nsnull;
  if (rowIndex) {
    rowFrame = GetRowFrameAt(aPresContext, rowIndex);
    if (rowFrame) {
      // translate the coordinates to be relative to us
      nsIFrame* frame = rowFrame;
      height = frame->GetSize().height;
      do {
        dy += frame->GetPosition().y;
        frame = frame->GetParent();
      } while (frame != this);
    }
  }
  switch (tableAlign) {
    case eAlign_top:
      aDesiredSize.ascent = dy;
      break;
    case eAlign_bottom:
      aDesiredSize.ascent = dy + height;
      break;
    case eAlign_center:
      aDesiredSize.ascent = dy + height/2;
      break;
    case eAlign_baseline:
      if (rowFrame) {
        // anchor the table on the baseline of the row of reference
        nscoord rowAscent = ((nsTableRowFrame*)rowFrame)->GetMaxCellAscent();
        if (rowAscent) { // the row has at least one cell with 'vertical-align: baseline'
          aDesiredSize.ascent = dy + rowAscent;
          break;
        }
      }
      // in other situations, fallback to center
      aDesiredSize.ascent = dy + height/2;
      break;
    case eAlign_axis:
    default: {
      // XXX should instead use style data from the row of reference here ?
      aReflowState.rendContext->SetFont(GetStyleFont()->mFont, nsnull,
                                        aPresContext->GetUserFontSet());
      nsCOMPtr<nsIFontMetrics> fm;
      aReflowState.rendContext->GetFontMetrics(*getter_AddRefs(fm));
      nscoord axisHeight;
      GetAxisHeight(*aReflowState.rendContext, fm, axisHeight);
      if (rowFrame) {
        // anchor the table on the axis of the row of reference
        // XXX fallback to baseline because it is a hard problem
        // XXX need to fetch the axis of the row; would need rowalign=axis to work better
        nscoord rowAscent = ((nsTableRowFrame*)rowFrame)->GetMaxCellAscent();
        if (rowAscent) { // the row has at least one cell with 'vertical-align: baseline'
          aDesiredSize.ascent = dy + rowAscent;
          break;
        }
      }
      // in other situations, fallback to using half of the height
      aDesiredSize.ascent = dy + height/2 + axisHeight;
    }
  }

  mReference.x = 0;
  mReference.y = aDesiredSize.ascent;

  // just make-up a bounding metrics
  mBoundingMetrics.Clear();
  mBoundingMetrics.ascent = aDesiredSize.ascent;
  mBoundingMetrics.descent = aDesiredSize.height - aDesiredSize.ascent;
  mBoundingMetrics.width = aDesiredSize.width;
  mBoundingMetrics.leftBearing = 0;
  mBoundingMetrics.rightBearing = aDesiredSize.width;

  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);

  return rv;
}