mozilla
/
pjs
зеркало из https://github.com/mozilla/pjs.git
1
0
Форкнуть 0
Код Задачи Пакеты Проекты Релизы Вики Активность
pjs/layout/generic/nsBlockReflowState.cpp

1068 строки
39 KiB
C++
Исходник Ответственный История

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
// vim:cindent:ts=2:et:sw=2:
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* 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 Communicator client code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Steve Clark <buster@netscape.com>
* Robert O'Callahan <roc+moz@cs.cmu.edu>
* L. David Baron <dbaron@dbaron.org>
* Mats Palmgren <mats.palmgren@bredband.net>
*
* Alternatively, the contents of this file may be used under the terms of
* either of 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"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/* state used in reflow of block frames */
#include "nsBlockReflowContext.h"
#include "nsBlockReflowState.h"
#include "nsBlockFrame.h"
#include "nsLineLayout.h"
#include "nsPresContext.h"
#include "nsGkAtoms.h"
#include "nsIFrame.h"
#include "nsFrameManager.h"
#include "nsINameSpaceManager.h"
#ifdef DEBUG
#include "nsBlockDebugFlags.h"
#endif
nsBlockReflowState::nsBlockReflowState(const nsHTMLReflowState& aReflowState,
nsPresContext* aPresContext,
nsBlockFrame* aFrame,
const nsHTMLReflowMetrics& aMetrics,
PRBool aTopMarginRoot,
PRBool aBottomMarginRoot,
PRBool aBlockNeedsSpaceManager)
: mBlock(aFrame),
mPresContext(aPresContext),
mReflowState(aReflowState),
mPrevBottomMargin(),
mLineNumber(0),
mFlags(0),
mFloatBreakType(NS_STYLE_CLEAR_NONE),
mOverflowTracker(aPresContext, aFrame, PR_FALSE)
{
SetFlag(BRS_ISFIRSTINFLOW, aFrame->GetPrevInFlow() == nsnull);
SetFlag(BRS_ISOVERFLOWCONTAINER,
IS_TRUE_OVERFLOW_CONTAINER(aFrame));
const nsMargin& borderPadding = BorderPadding();
if (aTopMarginRoot || 0 != aReflowState.mComputedBorderPadding.top) {
SetFlag(BRS_ISTOPMARGINROOT, PR_TRUE);
}
if (aBottomMarginRoot || 0 != aReflowState.mComputedBorderPadding.bottom) {
SetFlag(BRS_ISBOTTOMMARGINROOT, PR_TRUE);
}
if (GetFlag(BRS_ISTOPMARGINROOT)) {
SetFlag(BRS_APPLYTOPMARGIN, PR_TRUE);
}
if (aBlockNeedsSpaceManager) {
SetFlag(BRS_SPACE_MGR, PR_TRUE);
}
mSpaceManager = aReflowState.mSpaceManager;
NS_ASSERTION(mSpaceManager,
"SpaceManager should be set in nsBlockReflowState" );
if (mSpaceManager) {
// Translate into our content area and then save the
// coordinate system origin for later.
mSpaceManager->Translate(borderPadding.left, borderPadding.top);
mSpaceManager->GetTranslation(mSpaceManagerX, mSpaceManagerY);
}
mReflowStatus = NS_FRAME_COMPLETE;
mPresContext = aPresContext;
mNextInFlow = static_cast<nsBlockFrame*>(mBlock->GetNextInFlow());
NS_ASSERTION(NS_UNCONSTRAINEDSIZE != aReflowState.ComputedWidth(),
"no unconstrained widths should be present anymore");
mContentArea.width = aReflowState.ComputedWidth();
// Compute content area height. Unlike the width, if we have a
// specified style height we ignore it since extra content is
// managed by the "overflow" property. When we don't have a
// specified style height then we may end up limiting our height if
// the availableHeight is constrained (this situation occurs when we
// are paginated).
if (NS_UNCONSTRAINEDSIZE != aReflowState.availableHeight) {
// We are in a paginated situation. The bottom edge is just inside
// the bottom border and padding. The content area height doesn't
// include either border or padding edge.
mBottomEdge = aReflowState.availableHeight - borderPadding.bottom;
mContentArea.height = PR_MAX(0, mBottomEdge - borderPadding.top);
}
else {
// When we are not in a paginated situation then we always use
// an constrained height.
SetFlag(BRS_UNCONSTRAINEDHEIGHT, PR_TRUE);
mContentArea.height = mBottomEdge = NS_UNCONSTRAINEDSIZE;
}
mY = borderPadding.top;
mBand.Init(mSpaceManager, mContentArea);
mPrevChild = nsnull;
mCurrentLine = aFrame->end_lines();
mMinLineHeight = nsHTMLReflowState::CalcLineHeight(aReflowState.rendContext,
aReflowState.frame);
}
void
nsBlockReflowState::SetupOverflowPlaceholdersProperty()
{
if (mReflowState.availableHeight != NS_UNCONSTRAINEDSIZE ||
!mOverflowPlaceholders.IsEmpty()) {
mBlock->SetProperty(nsGkAtoms::overflowPlaceholdersProperty,
&mOverflowPlaceholders, nsnull);
mBlock->AddStateBits(NS_BLOCK_HAS_OVERFLOW_PLACEHOLDERS);
}
}
nsBlockReflowState::~nsBlockReflowState()
{
NS_ASSERTION(mOverflowPlaceholders.IsEmpty(),
"Leaking overflow placeholder frames");
// Restore the coordinate system, unless the space manager is null,
// which means it was just destroyed.
if (mSpaceManager) {
const nsMargin& borderPadding = BorderPadding();
mSpaceManager->Translate(-borderPadding.left, -borderPadding.top);
}
if (mBlock->GetStateBits() & NS_BLOCK_HAS_OVERFLOW_PLACEHOLDERS) {
mBlock->UnsetProperty(nsGkAtoms::overflowPlaceholdersProperty);
mBlock->RemoveStateBits(NS_BLOCK_HAS_OVERFLOW_PLACEHOLDERS);
}
}
nsLineBox*
nsBlockReflowState::NewLineBox(nsIFrame* aFrame,
PRInt32 aCount,
PRBool aIsBlock)
{
return NS_NewLineBox(mPresContext->PresShell(), aFrame, aCount, aIsBlock);
}
void
nsBlockReflowState::FreeLineBox(nsLineBox* aLine)
{
if (aLine) {
aLine->Destroy(mPresContext->PresShell());
}
}
// Compute the amount of available space for reflowing a block frame
// at the current Y coordinate. This method assumes that
// GetAvailableSpace has already been called.
void
nsBlockReflowState::ComputeBlockAvailSpace(nsIFrame* aFrame,
const nsStyleDisplay* aDisplay,
nsRect& aResult)
{
#ifdef REALLY_NOISY_REFLOW
printf("CBAS frame=%p has float count %d\n", aFrame, mBand.GetFloatCount());
mBand.List();
#endif
aResult.y = mY;
aResult.height = GetFlag(BRS_UNCONSTRAINEDHEIGHT)
? NS_UNCONSTRAINEDSIZE
: PR_MAX(0, mBottomEdge - mY);
// mY might be greater than mBottomEdge if the block's top margin pushes
// it off the page/column. Negative available height can confuse other code
// and is nonsense in principle.
const nsMargin& borderPadding = BorderPadding();
// text controls are not splittable
// XXXldb Why not just set the frame state bit?
nsSplittableType splitType = aFrame->GetSplittableType();
if ((NS_FRAME_SPLITTABLE_NON_RECTANGULAR == splitType || // normal blocks
NS_FRAME_NOT_SPLITTABLE == splitType) && // things like images mapped to display: block
!(aFrame->IsFrameOfType(nsIFrame::eReplaced)) && // but not replaced elements
aFrame->GetType() != nsGkAtoms::scrollFrame) // or scroll frames
{
if (mBand.GetFloatCount()) {
// Use the float-edge property to determine how the child block
// will interact with the float.
const nsStyleBorder* borderStyle = aFrame->GetStyleBorder();
switch (borderStyle->mFloatEdge) {
default:
case NS_STYLE_FLOAT_EDGE_CONTENT: // content and only content does runaround of floats
// The child block will flow around the float. Therefore
// give it all of the available space.
aResult.x = borderPadding.left;
aResult.width = mContentArea.width;
break;
case NS_STYLE_FLOAT_EDGE_BORDER:
case NS_STYLE_FLOAT_EDGE_PADDING:
{
// The child block's border should be placed adjacent to,
// but not overlap the float(s).
nsMargin m(0, 0, 0, 0);
const nsStyleMargin* styleMargin = aFrame->GetStyleMargin();
styleMargin->GetMargin(m); // XXX percentage margins
if (NS_STYLE_FLOAT_EDGE_PADDING == borderStyle->mFloatEdge) {
// Add in border too
m += borderStyle->GetBorder();
}
// determine left edge
if (mBand.GetLeftFloatCount()) {
aResult.x = mAvailSpaceRect.x + borderPadding.left - m.left;
}
else {
aResult.x = borderPadding.left;
}
// determine width
if (mBand.GetRightFloatCount()) {
if (mBand.GetLeftFloatCount()) {
aResult.width = mAvailSpaceRect.width + m.left + m.right;
}
else {
aResult.width = mAvailSpaceRect.width + m.right;
}
}
else {
aResult.width = mAvailSpaceRect.width + m.left;
}
}
break;
case NS_STYLE_FLOAT_EDGE_MARGIN:
{
// The child block's margins should be placed adjacent to,
// but not overlap the float.
aResult.x = mAvailSpaceRect.x + borderPadding.left;
aResult.width = mAvailSpaceRect.width;
}
break;
}
}
else {
// Since there are no floats present the float-edge property
// doesn't matter therefore give the block element all of the
// available space since it will flow around the float itself.
aResult.x = borderPadding.left;
aResult.width = mContentArea.width;
}
}
else {
// The frame is clueless about the space manager and therefore we
// only give it free space. An example is a table frame - the
// tables do not flow around floats.
aResult.x = mAvailSpaceRect.x + borderPadding.left;
aResult.width = mAvailSpaceRect.width;
}
#ifdef REALLY_NOISY_REFLOW
printf(" CBAS: result %d %d %d %d\n", aResult.x, aResult.y, aResult.width, aResult.height);
#endif
}
void
nsBlockReflowState::GetAvailableSpace(nscoord aY, PRBool aRelaxHeightConstraint)
{
#ifdef DEBUG
// Verify that the caller setup the coordinate system properly
nscoord wx, wy;
mSpaceManager->GetTranslation(wx, wy);
NS_ASSERTION((wx == mSpaceManagerX) && (wy == mSpaceManagerY),
"bad coord system");
#endif
mBand.GetAvailableSpace(aY - BorderPadding().top, aRelaxHeightConstraint,
mAvailSpaceRect);
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("GetAvailableSpace: band=%d,%d,%d,%d count=%d\n",
mAvailSpaceRect.x, mAvailSpaceRect.y,
mAvailSpaceRect.width, mAvailSpaceRect.height,
mBand.GetTrapezoidCount());
}
#endif
}
/*
* Reconstruct the vertical margin before the line |aLine| in order to
* do an incremental reflow that begins with |aLine| without reflowing
* the line before it. |aLine| may point to the fencepost at the end of
* the line list, and it is used this way since we (for now, anyway)
* always need to recover margins at the end of a block.
*
* The reconstruction involves walking backward through the line list to
* find any collapsed margins preceding the line that would have been in
* the reflow state's |mPrevBottomMargin| when we reflowed that line in
* a full reflow (under the rule in CSS2 that all adjacent vertical
* margins of blocks collapse).
*/
void
nsBlockReflowState::ReconstructMarginAbove(nsLineList::iterator aLine)
{
mPrevBottomMargin.Zero();
nsBlockFrame *block = mBlock;
nsLineList::iterator firstLine = block->begin_lines();
for (;;) {
--aLine;
if (aLine->IsBlock()) {
mPrevBottomMargin = aLine->GetCarriedOutBottomMargin();
break;
}
if (!aLine->IsEmpty()) {
break;
}
if (aLine == firstLine) {
// If the top margin was carried out (and thus already applied),
// set it to zero. Either way, we're done.
if (!GetFlag(BRS_ISTOPMARGINROOT)) {
mPrevBottomMargin.Zero();
}
break;
}
}
}
/**
* Restore information about floats into the space manager for an
* incremental reflow, and simultaneously push the floats by
* |aDeltaY|, which is the amount |aLine| was pushed relative to its
* parent. The recovery of state is one of the things that makes
* incremental reflow O(N^2) and this state should really be kept
* around, attached to the frame tree.
*/
void
nsBlockReflowState::RecoverFloats(nsLineList::iterator aLine,
nscoord aDeltaY)
{
if (aLine->HasFloats()) {
// Place the floats into the space-manager again. Also slide
// them, just like the regular frames on the line.
nsFloatCache* fc = aLine->GetFirstFloat();
while (fc) {
nsIFrame* floatFrame = fc->mPlaceholder->GetOutOfFlowFrame();
if (aDeltaY != 0) {
fc->mRegion.y += aDeltaY;
nsPoint p = floatFrame->GetPosition();
floatFrame->SetPosition(nsPoint(p.x, p.y + aDeltaY));
nsContainerFrame::PositionFrameView(floatFrame);
nsContainerFrame::PositionChildViews(floatFrame);
}
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow || nsBlockFrame::gNoisySpaceManager) {
nscoord tx, ty;
mSpaceManager->GetTranslation(tx, ty);
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("RecoverFloats: txy=%d,%d (%d,%d) ",
tx, ty, mSpaceManagerX, mSpaceManagerY);
nsFrame::ListTag(stdout, floatFrame);
printf(" aDeltaY=%d region={%d,%d,%d,%d}\n",
aDeltaY, fc->mRegion.x, fc->mRegion.y,
fc->mRegion.width, fc->mRegion.height);
}
#endif
mSpaceManager->AddRectRegion(floatFrame, fc->mRegion);
fc = fc->Next();
}
} else if (aLine->IsBlock()) {
nsBlockFrame *kid = nsnull;
aLine->mFirstChild->QueryInterface(kBlockFrameCID, (void**)&kid);
// don't recover any state inside a block that has its own space
// manager (we don't currently have any blocks like this, though,
// thanks to our use of extra frames for 'overflow')
if (kid && !nsBlockFrame::BlockNeedsSpaceManager(kid)) {
nscoord tx = kid->mRect.x, ty = kid->mRect.y;
// If the element is relatively positioned, then adjust x and y
// accordingly so that we consider relatively positioned frames
// at their original position.
if (NS_STYLE_POSITION_RELATIVE == kid->GetStyleDisplay()->mPosition) {
nsPoint *offsets = static_cast<nsPoint*>
(mPresContext->PropertyTable()->GetProperty(kid,
nsGkAtoms::computedOffsetProperty));
if (offsets) {
tx -= offsets->x;
ty -= offsets->y;
}
}
mSpaceManager->Translate(tx, ty);
for (nsBlockFrame::line_iterator line = kid->begin_lines(),
line_end = kid->end_lines();
line != line_end;
++line)
// Pass 0, not the real DeltaY, since these floats aren't
// moving relative to their parent block, only relative to
// the space manager.
RecoverFloats(line, 0);
mSpaceManager->Translate(-tx, -ty);
}
}
}
/**
* Everything done in this function is done O(N) times for each pass of
* reflow so it is O(N*M) where M is the number of incremental reflow
* passes. That's bad. Don't do stuff here.
*
* When this function is called, |aLine| has just been slid by |aDeltaY|
* and the purpose of RecoverStateFrom is to ensure that the
* nsBlockReflowState is in the same state that it would have been in
* had the line just been reflowed.
*
* Most of the state recovery that we have to do involves floats.
*/
void
nsBlockReflowState::RecoverStateFrom(nsLineList::iterator aLine,
nscoord aDeltaY)
{
// Make the line being recovered the current line
mCurrentLine = aLine;
// Place floats for this line into the space manager
if (aLine->HasFloats() || aLine->IsBlock()) {
// Undo border/padding translation since the nsFloatCache's
// coordinates are relative to the frame not relative to the
// border/padding.
const nsMargin& bp = BorderPadding();
mSpaceManager->Translate(-bp.left, -bp.top);
RecoverFloats(aLine, aDeltaY);
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow || nsBlockFrame::gNoisySpaceManager) {
mSpaceManager->List(stdout);
}
#endif
// And then put the translation back again
mSpaceManager->Translate(bp.left, bp.top);
}
}
PRBool
nsBlockReflowState::IsImpactedByFloat() const
{
#ifdef REALLY_NOISY_REFLOW
printf("nsBlockReflowState::IsImpactedByFloat %p returned %d\n",
this, mBand.GetFloatCount());
#endif
return mBand.GetFloatCount() > 0;
}
PRBool
nsBlockReflowState::InitFloat(nsLineLayout& aLineLayout,
nsPlaceholderFrame* aPlaceholder,
nsReflowStatus& aReflowStatus)
{
// Set the geometric parent of the float
nsIFrame* floatFrame = aPlaceholder->GetOutOfFlowFrame();
floatFrame->SetParent(mBlock);
// Then add the float to the current line and place it when
// appropriate
return AddFloat(aLineLayout, aPlaceholder, PR_TRUE, aReflowStatus);
}
// This is called by the line layout's AddFloat method when a
// place-holder frame is reflowed in a line. If the float is a
// left-most child (it's x coordinate is at the line's left margin)
// then the float is place immediately, otherwise the float
// placement is deferred until the line has been reflowed.
// XXXldb This behavior doesn't quite fit with CSS1 and CSS2 --
// technically we're supposed let the current line flow around the
// float as well unless it won't fit next to what we already have.
// But nobody else implements it that way...
PRBool
nsBlockReflowState::AddFloat(nsLineLayout& aLineLayout,
nsPlaceholderFrame* aPlaceholder,
PRBool aInitialReflow,
nsReflowStatus& aReflowStatus)
{
NS_PRECONDITION(mBlock->end_lines() != mCurrentLine, "null ptr");
aReflowStatus = NS_FRAME_COMPLETE;
// Allocate a nsFloatCache for the float
nsFloatCache* fc = mFloatCacheFreeList.Alloc();
fc->mPlaceholder = aPlaceholder;
PRBool placed;
// Now place the float immediately if possible. Otherwise stash it
// away in mPendingFloats and place it later.
if (aLineLayout.CanPlaceFloatNow()) {
// Because we are in the middle of reflowing a placeholder frame
// within a line (and possibly nested in an inline frame or two
// that's a child of our block) we need to restore the space
// manager's translation to the space that the block resides in
// before placing the float.
nscoord ox, oy;
mSpaceManager->GetTranslation(ox, oy);
nscoord dx = ox - mSpaceManagerX;
nscoord dy = oy - mSpaceManagerY;
mSpaceManager->Translate(-dx, -dy);
// And then place it
PRBool isLeftFloat;
// force it to fit if we're at the top of the block and we can't
// break before this
PRBool forceFit = IsAdjacentWithTop() && !aLineLayout.LineIsBreakable();
placed = FlowAndPlaceFloat(fc, &isLeftFloat, aReflowStatus, forceFit);
NS_ASSERTION(placed || !forceFit,
"If we asked for force-fit, it should have been placed");
if (forceFit || (placed && !NS_FRAME_IS_TRUNCATED(aReflowStatus))) {
// Pass on updated available space to the current inline reflow engine
GetAvailableSpace(mY, forceFit);
aLineLayout.UpdateBand(mAvailSpaceRect.x + BorderPadding().left, mY,
mAvailSpaceRect.width,
mAvailSpaceRect.height,
isLeftFloat,
aPlaceholder->GetOutOfFlowFrame());
// Record this float in the current-line list
mCurrentLineFloats.Append(fc);
// If we can't break here, hide the fact that it's truncated
// XXX We can probably do this more cleanly
aReflowStatus &= ~NS_FRAME_TRUNCATED;
}
else {
if (IsAdjacentWithTop()) {
// Pushing the line to the next page won't give us any more space;
// therefore, we break.
NS_ASSERTION(aLineLayout.LineIsBreakable(),
"We can't get here unless forceFit is false");
aReflowStatus = NS_INLINE_LINE_BREAK_BEFORE();
} else {
// Make sure we propagate the truncated status; this signals the
// block to push the line to the next page.
aReflowStatus |= NS_FRAME_TRUNCATED;
}
delete fc;
}
// Restore coordinate system
mSpaceManager->Translate(dx, dy);
}
else {
// Always claim to be placed; we don't know whether we fit yet, so we
// deal with this in PlaceBelowCurrentLineFloats
placed = PR_TRUE;
// This float will be placed after the line is done (it is a
// below-current-line float).
mBelowCurrentLineFloats.Append(fc);
if (mReflowState.availableHeight != NS_UNCONSTRAINEDSIZE ||
aPlaceholder->GetNextInFlow()) {
// If the float might not be complete, mark it incomplete now to
// prevent the placeholders being torn down. We will destroy any
// placeholders later if PlaceBelowCurrentLineFloats finds the
// float is complete.
// Note that we could have unconstrained height and yet have
// a next-in-flow placeholder --- for example columns can switch
// from constrained height to unconstrained height.
if (aPlaceholder->GetSplittableType() != NS_FRAME_NOT_SPLITTABLE) {
aReflowStatus = NS_FRAME_NOT_COMPLETE;
}
}
}
return placed;
}
PRBool
nsBlockReflowState::CanPlaceFloat(const nsSize& aFloatSize,
PRUint8 aFloats, PRBool aForceFit)
{
// If the current Y coordinate is not impacted by any floats
// then by definition the float fits.
PRBool result = PR_TRUE;
if (0 != mBand.GetFloatCount()) {
// XXX We should allow overflow by up to half a pixel here (bug 21193).
if (mAvailSpaceRect.width < aFloatSize.width) {
// The available width is too narrow (and its been impacted by a
// prior float)
result = PR_FALSE;
}
}
if (!result)
return result;
// At this point we know that there is enough horizontal space for
// the float (somewhere). Lets see if there is enough vertical
// space.
if (mAvailSpaceRect.height < aFloatSize.height) {
// The available height is too short. However, its possible that
// there is enough open space below which is not impacted by a
// float.
//
// Compute the X coordinate for the float based on its float
// type, assuming its placed on the current line. This is
// where the float will be placed horizontally if it can go
// here.
nscoord xa;
if (NS_STYLE_FLOAT_LEFT == aFloats) {
xa = mAvailSpaceRect.x;
}
else {
xa = mAvailSpaceRect.XMost() - aFloatSize.width;
// In case the float is too big, don't go past the left edge
// XXXldb This seems wrong, but we might want to fix bug 6976
// first.
if (xa < mAvailSpaceRect.x) {
xa = mAvailSpaceRect.x;
}
}
nscoord xb = xa + aFloatSize.width;
// Calculate the top and bottom y coordinates, again assuming
// that the float is placed on the current line.
const nsMargin& borderPadding = BorderPadding();
nscoord ya = mY - borderPadding.top;
if (ya < 0) {
// CSS2 spec, 9.5.1 rule [4]: "A floating box's outer top may not
// be higher than the top of its containing block." (Since the
// containing block is the content edge of the block box, this
// means the margin edge of the float can't be higher than the
// content edge of the block that contains it.)
ya = 0;
}
nscoord yb = ya + aFloatSize.height;
nscoord saveY = mY;
for (;;) {
// Get the available space at the new Y coordinate
if (mAvailSpaceRect.height <= 0) {
// there is no more available space. We lose.
result = PR_FALSE;
break;
}
mY += mAvailSpaceRect.height;
GetAvailableSpace(mY, aForceFit);
if (0 != mBand.GetFloatCount()) {
if ((xa < mAvailSpaceRect.x) || (xb > mAvailSpaceRect.XMost())) {
// The float can't go here.
result = PR_FALSE;
break;
}
}
// See if there is now enough height for the float.
if (yb <= mY + mAvailSpaceRect.height) {
// Winner. The bottom Y coordinate of the float is in
// this band.
break;
}
}
// Restore Y coordinate and available space information
// regardless of the outcome.
mY = saveY;
GetAvailableSpace(mY, aForceFit);
}
return result;
}
PRBool
nsBlockReflowState::FlowAndPlaceFloat(nsFloatCache* aFloatCache,
PRBool* aIsLeftFloat,
nsReflowStatus& aReflowStatus,
PRBool aForceFit)
{
aReflowStatus = NS_FRAME_COMPLETE;
// Save away the Y coordinate before placing the float. We will
// restore mY at the end after placing the float. This is
// necessary because any adjustments to mY during the float
// placement are for the float only, not for any non-floating
// content.
nscoord saveY = mY;
nsPlaceholderFrame* placeholder = aFloatCache->mPlaceholder;
nsIFrame* floatFrame = placeholder->GetOutOfFlowFrame();
// Grab the float's display information
const nsStyleDisplay* floatDisplay = floatFrame->GetStyleDisplay();
// The float's old region, so we can propagate damage.
nsRect oldRegion = aFloatCache->mRegion;
// Enforce CSS2 9.5.1 rule [2], i.e., make sure that a float isn't
// ``above'' another float that preceded it in the flow.
mY = NS_MAX(mSpaceManager->GetLowestRegionTop() + BorderPadding().top, mY);
// See if the float should clear any preceding floats...
// XXX We need to mark this float somehow so that it gets reflowed
// when floats are inserted before it.
if (NS_STYLE_CLEAR_NONE != floatDisplay->mBreakType) {
// XXXldb Does this handle vertical margins correctly?
mY = ClearFloats(mY, floatDisplay->mBreakType);
}
// Get the band of available space
GetAvailableSpace(mY, aForceFit);
NS_ASSERTION(floatFrame->GetParent() == mBlock,
"Float frame has wrong parent");
// Reflow the float
nsMargin floatMargin;
mBlock->ReflowFloat(*this, placeholder, floatMargin, aReflowStatus);
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsRect region = floatFrame->GetRect();
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("flowed float: ");
nsFrame::ListTag(stdout, floatFrame);
printf(" (%d,%d,%d,%d)\n",
region.x, region.y, region.width, region.height);
}
#endif
nsSize floatSize = floatFrame->GetSize() +
nsSize(floatMargin.LeftRight(), floatMargin.TopBottom());
// Find a place to place the float. The CSS2 spec doesn't want
// floats overlapping each other or sticking out of the containing
// block if possible (CSS2 spec section 9.5.1, see the rule list).
NS_ASSERTION((NS_STYLE_FLOAT_LEFT == floatDisplay->mFloats) ||
(NS_STYLE_FLOAT_RIGHT == floatDisplay->mFloats),
"invalid float type");
// Can the float fit here?
PRBool keepFloatOnSameLine = PR_FALSE;
while (!CanPlaceFloat(floatSize, floatDisplay->mFloats, aForceFit)) {
if (mAvailSpaceRect.height <= 0) {
// No space, nowhere to put anything.
mY = saveY;
return PR_FALSE;
}
// Nope. try to advance to the next band.
if (NS_STYLE_DISPLAY_TABLE != floatDisplay->mDisplay ||
eCompatibility_NavQuirks != mPresContext->CompatibilityMode() ) {
mY += mAvailSpaceRect.height;
GetAvailableSpace(mY, aForceFit);
} else {
// This quirk matches the one in nsBlockFrame::ReflowFloat
// IE handles float tables in a very special way
// see if the previous float is also a table and has "align"
nsFloatCache* fc = mCurrentLineFloats.Head();
nsIFrame* prevFrame = nsnull;
while (fc) {
if (fc->mPlaceholder->GetOutOfFlowFrame() == floatFrame) {
break;
}
prevFrame = fc->mPlaceholder->GetOutOfFlowFrame();
fc = fc->Next();
}
if(prevFrame) {
//get the frame type
if (nsGkAtoms::tableOuterFrame == prevFrame->GetType()) {
//see if it has "align="
// IE makes a difference between align and he float property
nsIContent* content = prevFrame->GetContent();
if (content) {
// we're interested only if previous frame is align=left
// IE messes things up when "right" (overlapping frames)
if (content->AttrValueIs(kNameSpaceID_None, nsGkAtoms::align,
NS_LITERAL_STRING("left"), eIgnoreCase)) {
keepFloatOnSameLine = PR_TRUE;
// don't advance to next line (IE quirkie behaviour)
// it breaks rule CSS2/9.5.1/1, but what the hell
// since we cannot evangelize the world
break;
}
}
}
}
// the table does not fit anymore in this line so advance to next band
mY += mAvailSpaceRect.height;
GetAvailableSpace(mY, aForceFit);
// reflow the float again now since we have more space
// XXXldb We really don't need to Reflow in a loop, we just need
// to ComputeSize in a loop (once ComputeSize depends on
// availableWidth, which should make this work again).
mBlock->ReflowFloat(*this, placeholder, floatMargin, aReflowStatus);
// Get the floats bounding box and margin information
floatSize = floatFrame->GetSize() +
nsSize(floatMargin.LeftRight(), floatMargin.TopBottom());
}
}
// If the float is continued, it will get the same absolute x value as its prev-in-flow
// We don't worry about the geometry of the prev in flow, let the continuation
// place and size itself as required.
// Assign an x and y coordinate to the float. Note that the x,y
// coordinates are computed <b>relative to the translation in the
// spacemanager</b> which means that the impacted region will be
// <b>inside</b> the border/padding area.
PRBool isLeftFloat;
nscoord floatX, floatY;
if (NS_STYLE_FLOAT_LEFT == floatDisplay->mFloats) {
isLeftFloat = PR_TRUE;
floatX = mAvailSpaceRect.x;
}
else {
isLeftFloat = PR_FALSE;
if (!keepFloatOnSameLine) {
floatX = mAvailSpaceRect.XMost() - floatSize.width;
}
else {
// this is the IE quirk (see few lines above)
// the table is kept in the same line: don't let it overlap the
// previous float
floatX = mAvailSpaceRect.x;
}
}
*aIsLeftFloat = isLeftFloat;
const nsMargin& borderPadding = BorderPadding();
floatY = mY - borderPadding.top;
if (floatY < 0) {
// CSS2 spec, 9.5.1 rule [4]: "A floating box's outer top may not
// be higher than the top of its containing block." (Since the
// containing block is the content edge of the block box, this
// means the margin edge of the float can't be higher than the
// content edge of the block that contains it.)
floatY = 0;
}
// Place the float in the space manager
// if the float split, then take up all of the vertical height
if (NS_FRAME_IS_NOT_COMPLETE(aReflowStatus) &&
(NS_UNCONSTRAINEDSIZE != mContentArea.height)) {
floatSize.height = PR_MAX(floatSize.height, mContentArea.height - floatY);
}
nsRect region(floatX, floatY, floatSize.width, floatSize.height);
// Don't send rectangles with negative margin-box width or height to
// the space manager; it can't deal with them.
if (region.width < 0) {
// Preserve the right margin-edge for left floats and the left
// margin-edge for right floats
if (isLeftFloat) {
region.x = region.XMost();
}
region.width = 0;
}
if (region.height < 0) {
region.height = 0;
}
#ifdef DEBUG
nsresult rv =
#endif
mSpaceManager->AddRectRegion(floatFrame, region);
NS_ABORT_IF_FALSE(NS_SUCCEEDED(rv), "bad float placement");
// Save away the floats region in the spacemanager, after making
// it relative to the containing block's frame instead of relative
// to the spacemanager translation (which is inset by the
// border+padding).
// XXX Maybe RecoverFloats should calc/add in the borderPadding itself?
// It's kind of confusing to have the spacemanager translation be different
// depending on what stage of reflow we're in.
aFloatCache->mRegion = region +
nsPoint(borderPadding.left, borderPadding.top);
// If the float's dimensions have changed, note the damage in the
// space manager.
if (aFloatCache->mRegion != oldRegion) {
// XXXwaterson conservative: we could probably get away with noting
// less damage; e.g., if only height has changed, then only note the
// area into which the float has grown or from which the float has
// shrunk.
nscoord top = NS_MIN(region.y, oldRegion.y);
nscoord bottom = NS_MAX(region.YMost(), oldRegion.YMost());
mSpaceManager->IncludeInDamage(top, bottom);
}
#ifdef NOISY_SPACEMANAGER
nscoord tx, ty;
mSpaceManager->GetTranslation(tx, ty);
nsFrame::ListTag(stdout, mBlock);
printf(": FlowAndPlaceFloat: AddRectRegion: txy=%d,%d (%d,%d) {%d,%d,%d,%d}\n",
tx, ty, mSpaceManagerX, mSpaceManagerY,
aFloatCache->mRegion.x, aFloatCache->mRegion.y,
aFloatCache->mRegion.width, aFloatCache->mRegion.height);
#endif
// Calculate the actual origin of the float frame's border rect
// relative to the parent block; floatX/Y must be converted from space-manager
// coordinates to parent coordinates, and the margin must be added in
// to get the border rect
nsPoint origin(borderPadding.left + floatMargin.left + floatX,
borderPadding.top + floatMargin.top + floatY);
// If float is relatively positioned, factor that in as well
if (NS_STYLE_POSITION_RELATIVE == floatDisplay->mPosition) {
nsPoint *offsets = static_cast<nsPoint*>
(floatFrame->GetProperty(nsGkAtoms::computedOffsetProperty));
if (offsets) {
origin += *offsets;
}
}
// Position the float and make sure and views are properly
// positioned. We need to explicitly position its child views as
// well, since we're moving the float after flowing it.
floatFrame->SetPosition(origin);
nsContainerFrame::PositionFrameView(floatFrame);
nsContainerFrame::PositionChildViews(floatFrame);
// Update the float combined area state
nsRect combinedArea = floatFrame->GetOverflowRect() + origin;
// XXX Floats should really just get invalidated here if necessary
mFloatCombinedArea.UnionRect(combinedArea, mFloatCombinedArea);
// Now restore mY
mY = saveY;
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsRect r = floatFrame->GetRect();
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("placed float: ");
nsFrame::ListTag(stdout, floatFrame);
printf(" %d,%d,%d,%d\n", r.x, r.y, r.width, r.height);
}
#endif
return PR_TRUE;
}
/**
* Place below-current-line floats.
*/
PRBool
nsBlockReflowState::PlaceBelowCurrentLineFloats(nsFloatCacheFreeList& aList, PRBool aForceFit)
{
nsFloatCache* fc = aList.Head();
while (fc) {
{
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("placing bcl float: ");
nsFrame::ListTag(stdout, fc->mPlaceholder->GetOutOfFlowFrame());
printf("\n");
}
#endif
// Place the float
PRBool isLeftFloat;
nsReflowStatus reflowStatus;
PRBool placed = FlowAndPlaceFloat(fc, &isLeftFloat, reflowStatus, aForceFit);
NS_ASSERTION(placed || !aForceFit,
"If we're in force-fit mode, we should have placed the float");
if (!placed || (NS_FRAME_IS_TRUNCATED(reflowStatus) && !aForceFit)) {
// return before processing all of the floats, since the line will be pushed.
return PR_FALSE;
}
else if (NS_FRAME_IS_NOT_COMPLETE(reflowStatus)) {
// Create a continuation for the incomplete float and its placeholder.
nsresult rv = mBlock->SplitPlaceholder(*this, fc->mPlaceholder);
if (NS_FAILED(rv))
return PR_FALSE;
} else {
// XXX We could deal with truncated frames better by breaking before
// the associated placeholder
NS_WARN_IF_FALSE(!NS_FRAME_IS_TRUNCATED(reflowStatus),
"This situation currently leads to data not printing");
// Float is complete. We need to delete any leftover placeholders now.
nsIFrame* nextPlaceholder = fc->mPlaceholder->GetNextInFlow();
if (nextPlaceholder) {
nsHTMLContainerFrame* parent =
static_cast<nsHTMLContainerFrame*>(nextPlaceholder->GetParent());
parent->DeleteNextInFlowChild(mPresContext, nextPlaceholder);
}
}
}
fc = fc->Next();
}
return PR_TRUE;
}
nscoord
nsBlockReflowState::ClearFloats(nscoord aY, PRUint8 aBreakType)
{
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("clear floats: in: aY=%d(%d)\n",
aY, aY - BorderPadding().top);
}
#endif
#ifdef NOISY_FLOAT_CLEARING
printf("nsBlockReflowState::ClearFloats: aY=%d breakType=%d\n",
aY, aBreakType);
mSpaceManager->List(stdout);
#endif
const nsMargin& bp = BorderPadding();
nscoord newY = mSpaceManager->ClearFloats(aY - bp.top, aBreakType);
newY += bp.top;
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("clear floats: out: y=%d(%d)\n", newY, newY - bp.top);
}
#endif
return newY;
}
Ссылка в новой задаче Показать git blame Копировать постоянную ссылку