gecko-dev/layout/generic/nsBRFrame.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* rendering object for HTML <br> elements */
#include "nsCOMPtr.h"
#include "nsFrame.h"
#include "nsHTMLParts.h"
#include "nsPresContext.h"
#include "nsLineLayout.h"
#include "nsStyleConsts.h"
#include "nsHTMLAtoms.h"
#include "nsIFontMetrics.h"
#include "nsIRenderingContext.h"
#include "nsLayoutAtoms.h"
#include "nsTextTransformer.h"
#ifdef ACCESSIBILITY
#include "nsIServiceManager.h"
#include "nsIAccessible.h"
#include "nsIAccessibilityService.h"
#endif
//FOR SELECTION
#include "nsIContent.h"
#include "nsFrameSelection.h"
//END INCLUDES FOR SELECTION
class BRFrame : public nsFrame {
public:
friend nsIFrame* NS_NewBRFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
virtual ContentOffsets CalcContentOffsetsFromFramePoint(nsPoint aPoint);
virtual PRBool PeekOffsetNoAmount(PRBool aForward, PRInt32* aOffset);
virtual PRBool PeekOffsetCharacter(PRBool aForward, PRInt32* aOffset);
virtual PRBool PeekOffsetWord(PRBool aForward, PRBool aWordSelectEatSpace, PRBool aIsKeyboardSelect,
PRInt32* aOffset, PRBool* aSawBeforeType);
NS_IMETHOD Reflow(nsPresContext* aPresContext,
nsHTMLReflowMetrics& aDesiredSize,
const nsHTMLReflowState& aReflowState,
nsReflowStatus& aStatus);
virtual nsIAtom* GetType() const;
#ifdef ACCESSIBILITY
NS_IMETHOD GetAccessible(nsIAccessible** aAccessible);
#endif
protected:
BRFrame(nsStyleContext* aContext) : nsFrame(aContext) {}
virtual ~BRFrame();
};
nsIFrame*
NS_NewBRFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
{
return new (aPresShell) BRFrame(aContext);
}
BRFrame::~BRFrame()
{
}
NS_IMETHODIMP
BRFrame::Reflow(nsPresContext* aPresContext,
nsHTMLReflowMetrics& aMetrics,
const nsHTMLReflowState& aReflowState,
nsReflowStatus& aStatus)
{
DO_GLOBAL_REFLOW_COUNT("BRFrame", aReflowState.reason);
DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aStatus);
if (aMetrics.mComputeMEW) {
aMetrics.mMaxElementWidth = 0;
}
aMetrics.height = 0; // BR frames with height 0 are ignored in quirks
// mode by nsLineLayout::VerticalAlignFrames .
// However, it's not always 0. See below.
aMetrics.width = 0;
aMetrics.ascent = 0;
aMetrics.descent = 0;
// Only when the BR is operating in a line-layout situation will it
// behave like a BR.
nsLineLayout* ll = aReflowState.mLineLayout;
if (ll) {
// Note that the compatibility mode check excludes AlmostStandards
// mode, since this is the inline box model. See bug 161691.
if ( ll->CanPlaceFloatNow() ||
ll->GetCompatMode() == eCompatibility_FullStandards ) {
// If we can place a float on the line now it means that the
// line is effectively empty (there may be zero sized compressed
// white-space frames on the line, but they are to be ignored).
//
// If this frame is going to terminate the line we know
// that nothing else will go on the line. Therefore, in this
// case, we provide some height for the BR frame so that it
// creates some vertical whitespace. It's necessary to use the
// line-height rather than the font size because the
// quirks-mode fix that doesn't apply the block's min
// line-height makes this necessary to make BR cause a line
// of the full line-height
// We also do this in strict mode because BR should act like a
// normal inline frame. That line-height is used is important
// here for cases where the line-height is less that 1.
SetFontFromStyle(aReflowState.rendContext, mStyleContext);
nsCOMPtr<nsIFontMetrics> fm;
aReflowState.rendContext->GetFontMetrics(*getter_AddRefs(fm));
if (fm) {
nscoord ascent, descent;
fm->GetMaxAscent(ascent);
fm->GetMaxDescent(descent);
nscoord logicalHeight =
aReflowState.CalcLineHeight(aPresContext,
aReflowState.rendContext,
this);
nscoord leading = logicalHeight - ascent - descent;
aMetrics.height = logicalHeight;
aMetrics.ascent = ascent + (leading/2);
aMetrics.descent = logicalHeight - aMetrics.ascent;
// = descent + (leading/2), but without rounding error
}
else {
aMetrics.ascent = aMetrics.height = 0;
}
// XXX temporary until I figure out a better solution; see the
// code in nsLineLayout::VerticalAlignFrames that zaps minY/maxY
// if the width is zero.
// XXX This also fixes bug 10036!
// Warning: nsTextControlFrame::CalculateSizeStandard depends on
// the following line, see bug 228752.
aMetrics.width = 1;
// Update max-element-width to keep us honest
if (aMetrics.mComputeMEW && aMetrics.width > aMetrics.mMaxElementWidth) {
aMetrics.mMaxElementWidth = aMetrics.width;
}
}
// Return our reflow status
PRUint32 breakType = aReflowState.mStyleDisplay->mBreakType;
if (NS_STYLE_CLEAR_NONE == breakType) {
breakType = NS_STYLE_CLEAR_LINE;
}
aStatus = NS_INLINE_BREAK | NS_INLINE_BREAK_AFTER |
NS_INLINE_MAKE_BREAK_TYPE(breakType);
ll->SetLineEndsInBR(PR_TRUE);
}
else {
aStatus = NS_FRAME_COMPLETE;
}
NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aMetrics);
return NS_OK;
}
nsIAtom*
BRFrame::GetType() const
{
return nsLayoutAtoms::brFrame;
}
nsIFrame::ContentOffsets BRFrame::CalcContentOffsetsFromFramePoint(nsPoint aPoint)
{
ContentOffsets offsets;
offsets.content = mContent->GetParent();
if (offsets.content) {
offsets.offset = offsets.content->IndexOf(mContent);
offsets.secondaryOffset = offsets.offset;
offsets.associateWithNext = PR_TRUE;
}
return offsets;
}
PRBool
BRFrame::PeekOffsetNoAmount(PRBool aForward, PRInt32* aOffset)
{
NS_ASSERTION (aOffset && *aOffset <= 1, "aOffset out of range");
PRInt32 startOffset = *aOffset;
// If we hit the end of a BR going backwards, go to its beginning and stay there.
if (!aForward && startOffset != 0) {
*aOffset = 0;
return PR_TRUE;
}
// Otherwise, stop if we hit the beginning, continue (forward) if we hit the end.
return (startOffset == 0);
}
PRBool
BRFrame::PeekOffsetCharacter(PRBool aForward, PRInt32* aOffset)
{
NS_ASSERTION (aOffset && *aOffset <= 1, "aOffset out of range");
// Keep going. The actual line jumping will stop us.
return PR_FALSE;
}
PRBool
BRFrame::PeekOffsetWord(PRBool aForward, PRBool aWordSelectEatSpace, PRBool aIsKeyboardSelect,
PRInt32* aOffset, PRBool* aSawBeforeType)
{
NS_ASSERTION (aOffset && *aOffset <= 1, "aOffset out of range");
// Keep going. The actual line jumping will stop us.
return PR_FALSE;
}
#ifdef ACCESSIBILITY
NS_IMETHODIMP BRFrame::GetAccessible(nsIAccessible** aAccessible)
{
nsCOMPtr<nsIAccessibilityService> accService = do_GetService("@mozilla.org/accessibilityService;1");
if (accService) {
return accService->CreateHTMLBRAccessible(NS_STATIC_CAST(nsIFrame*, this), aAccessible);
}
return NS_ERROR_FAILURE;
}
#endif