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

1088 строки
41 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 aBlockNeedsFloatManager)
: mBlock(aFrame),
mPresContext(aPresContext),
mReflowState(aReflowState),
mOverflowTracker(nsnull),
mPrevBottomMargin(),
mLineNumber(0),
mFlags(0),
mFloatBreakType(NS_STYLE_CLEAR_NONE)
{
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 (aBlockNeedsFloatManager) {
SetFlag(BRS_FLOAT_MGR, PR_TRUE);
}
mFloatManager = aReflowState.mFloatManager;
NS_ASSERTION(mFloatManager,
"FloatManager should be set in nsBlockReflowState" );
if (mFloatManager) {
// Translate into our content area and then save the
// coordinate system origin for later.
mFloatManager->Translate(borderPadding.left, borderPadding.top);
mFloatManager->GetTranslation(mFloatManagerX, mFloatManagerY);
mFloatManager->PushState(&mFloatManagerStateBefore); // never popped
}
mReflowStatus = NS_FRAME_COMPLETE;
mPresContext = aPresContext;
mNextInFlow = static_cast<nsBlockFrame*>(mBlock->GetNextInFlow());
NS_WARN_IF_FALSE(NS_UNCONSTRAINEDSIZE != aReflowState.ComputedWidth(),
"have unconstrained width; this should only result from "
"very large sizes, not attempts at intrinsic width "
"calculation");
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 = NS_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;
mPrevChild = nsnull;
mCurrentLine = aFrame->end_lines();
mMinLineHeight = aReflowState.CalcLineHeight();
}
nsBlockReflowState::~nsBlockReflowState()
{
NS_ASSERTION(mFloatContinuations.IsEmpty(),
"Leaking float continuation frames");
// Restore the coordinate system, unless the float manager is null,
// which means it was just destroyed.
if (mFloatManager) {
const nsMargin& borderPadding = BorderPadding();
mFloatManager->Translate(-borderPadding.left, -borderPadding.top);
}
if (GetFlag(BRS_PROPTABLE_FLOATCLIST)) {
mPresContext->PropertyTable()->
Delete(mBlock, nsBlockFrame::FloatContinuationProperty());
}
}
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());
}
}
void
nsBlockReflowState::ComputeReplacedBlockOffsetsForFloats(nsIFrame* aFrame,
const nsRect& aFloatAvailableSpace,
nscoord& aLeftResult,
nscoord& aRightResult,
nsBlockFrame::
ReplacedElementWidthToClear
*aReplacedWidth)
{
// The frame is clueless about the float manager and therefore we
// only give it free space. An example is a table frame - the
// tables do not flow around floats.
// However, we can let its margins intersect floats.
NS_ASSERTION(aFloatAvailableSpace.x >= 0, "bad avail space rect x");
NS_ASSERTION(aFloatAvailableSpace.width == 0 ||
aFloatAvailableSpace.XMost() <= mContentArea.width,
"bad avail space rect width");
nscoord leftOffset, rightOffset;
if (aFloatAvailableSpace.width == mContentArea.width) {
// We don't need to compute margins when there are no floats around.
leftOffset = 0;
rightOffset = 0;
} else {
// We pass in aReplacedWidth to make handling outer table frames
// work correctly. For outer table frames, we need to subtract off
// the margin that's going to be at the edge of them, since we're
// dealing with margin that it's really the child's responsibility
// to place.
nsCSSOffsetState os(aFrame, mReflowState.rendContext, mContentArea.width);
NS_ASSERTION(!aReplacedWidth ||
aFrame->GetType() == nsGkAtoms::tableOuterFrame ||
(aReplacedWidth->marginLeft == os.mComputedMargin.left &&
aReplacedWidth->marginRight == os.mComputedMargin.right),
"unexpected aReplacedWidth");
nscoord leftFloatXOffset = aFloatAvailableSpace.x;
leftOffset = NS_MAX(leftFloatXOffset, os.mComputedMargin.left) -
(aReplacedWidth ? aReplacedWidth->marginLeft
: os.mComputedMargin.left);
leftOffset = NS_MAX(leftOffset, 0); // in case of negative margin
nscoord rightFloatXOffset =
mContentArea.width - aFloatAvailableSpace.XMost();
rightOffset = NS_MAX(rightFloatXOffset, os.mComputedMargin.right) -
(aReplacedWidth ? aReplacedWidth->marginRight
: os.mComputedMargin.right);
rightOffset = NS_MAX(rightOffset, 0); // in case of negative margin
}
aLeftResult = leftOffset;
aRightResult = rightOffset;
}
// 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,
const nsFlowAreaRect& aFloatAvailableSpace,
PRBool aBlockAvoidsFloats,
nsRect& aResult)
{
#ifdef REALLY_NOISY_REFLOW
printf("CBAS frame=%p has floats %d\n",
aFrame, aFloatAvailableSpace.mHasFloats);
#endif
aResult.y = mY;
aResult.height = GetFlag(BRS_UNCONSTRAINEDHEIGHT)
? NS_UNCONSTRAINEDSIZE
: NS_MAX(0, mReflowState.availableHeight - 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();
// XXX Do we really want this condition to be this restrictive (i.e.,
// more restrictive than it used to be)? The |else| here is allowed
// by the CSS spec, but only out of desperation given implementations,
// and the behavior it leads to is quite undesirable (it can cause
// things to become extremely narrow when they'd fit quite well a
// little bit lower). Should the else be a quirk or something that
// applies to a specific set of frame classes and no new ones?
// If we did that, then for those frames where the condition below is
// true but nsBlockFrame::BlockCanIntersectFloats is false,
// nsBlockFrame::WidthToClearPastFloats would need to use the
// shrink-wrap formula, max(MIN_WIDTH, min(avail width, PREF_WIDTH))
// rather than just using MIN_WIDTH.
NS_ASSERTION(nsBlockFrame::BlockCanIntersectFloats(aFrame) ==
!aBlockAvoidsFloats,
"unexpected replaced width");
if (!aBlockAvoidsFloats) {
if (aFloatAvailableSpace.mHasFloats) {
// 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_MARGIN:
{
// The child block's margins should be placed adjacent to,
// but not overlap the float.
aResult.x = aFloatAvailableSpace.mRect.x + borderPadding.left;
aResult.width = aFloatAvailableSpace.mRect.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 {
nsBlockFrame::ReplacedElementWidthToClear replacedWidthStruct;
nsBlockFrame::ReplacedElementWidthToClear *replacedWidth = nsnull;
if (aFrame->GetType() == nsGkAtoms::tableOuterFrame) {
replacedWidth = &replacedWidthStruct;
replacedWidthStruct =
nsBlockFrame::WidthToClearPastFloats(*this, aFloatAvailableSpace.mRect,
aFrame);
}
nscoord leftOffset, rightOffset;
ComputeReplacedBlockOffsetsForFloats(aFrame, aFloatAvailableSpace.mRect,
leftOffset, rightOffset,
replacedWidth);
aResult.x = borderPadding.left + leftOffset;
aResult.width = mContentArea.width - leftOffset - rightOffset;
}
#ifdef REALLY_NOISY_REFLOW
printf(" CBAS: result %d %d %d %d\n", aResult.x, aResult.y, aResult.width, aResult.height);
#endif
}
nsFlowAreaRect
nsBlockReflowState::GetFloatAvailableSpaceWithState(
nscoord aY, PRBool aRelaxHeightConstraint,
nsFloatManager::SavedState *aState) const
{
#ifdef DEBUG
// Verify that the caller setup the coordinate system properly
nscoord wx, wy;
mFloatManager->GetTranslation(wx, wy);
NS_ASSERTION((wx == mFloatManagerX) && (wy == mFloatManagerY),
"bad coord system");
#endif
nsFlowAreaRect result =
mFloatManager->GetFlowArea(aY - BorderPadding().top,
nsFloatManager::BAND_FROM_POINT,
aRelaxHeightConstraint ? nscoord_MAX
: mContentArea.height,
mContentArea.width, aState);
// Keep the width >= 0 for compatibility with nsSpaceManager.
if (result.mRect.width < 0)
result.mRect.width = 0;
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("GetAvailableSpace: band=%d,%d,%d,%d hasfloats=%d\n",
result.mRect.x, result.mRect.y, result.mRect.width,
result.mRect.height, result.mHasFloats);
}
#endif
return result;
}
nsFlowAreaRect
nsBlockReflowState::GetFloatAvailableSpaceForHeight(
nscoord aY, nscoord aHeight,
nsFloatManager::SavedState *aState) const
{
#ifdef DEBUG
// Verify that the caller setup the coordinate system properly
nscoord wx, wy;
mFloatManager->GetTranslation(wx, wy);
NS_ASSERTION((wx == mFloatManagerX) && (wy == mFloatManagerY),
"bad coord system");
#endif
nsFlowAreaRect result =
mFloatManager->GetFlowArea(aY - BorderPadding().top,
nsFloatManager::WIDTH_WITHIN_HEIGHT,
aHeight, mContentArea.width, aState);
// Keep the width >= 0 for compatibility with nsSpaceManager.
if (result.mRect.width < 0)
result.mRect.width = 0;
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("GetAvailableSpaceForHeight: space=%d,%d,%d,%d hasfloats=%d\n",
result.mRect.x, result.mRect.y, result.mRect.width,
result.mRect.height, result.mHasFloats);
}
#endif
return result;
}
/*
* 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;
}
}
}
void
nsBlockReflowState::SetupFloatContinuationList()
{
if (!GetFlag(BRS_PROPTABLE_FLOATCLIST)) {
mPresContext->PropertyTable()->
Set(mBlock, nsBlockFrame::FloatContinuationProperty(),
&mFloatContinuations);
SetFlag(BRS_PROPTABLE_FLOATCLIST, PR_TRUE);
}
}
/**
* Restore information about floats into the float 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->mFloat;
if (aDeltaY != 0) {
nsPoint p = floatFrame->GetPosition();
floatFrame->SetPosition(nsPoint(p.x, p.y + aDeltaY));
nsContainerFrame::PositionFrameView(floatFrame);
nsContainerFrame::PositionChildViews(floatFrame);
}
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow || nsBlockFrame::gNoisyFloatManager) {
nscoord tx, ty;
mFloatManager->GetTranslation(tx, ty);
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("RecoverFloats: txy=%d,%d (%d,%d) ",
tx, ty, mFloatManagerX, mFloatManagerY);
nsFrame::ListTag(stdout, floatFrame);
nsRect region = nsFloatManager::GetRegionFor(floatFrame);
printf(" aDeltaY=%d region={%d,%d,%d,%d}\n",
aDeltaY, region.x, region.y, region.width, region.height);
}
#endif
mFloatManager->AddFloat(floatFrame,
nsFloatManager::GetRegionFor(floatFrame));
fc = fc->Next();
}
} else if (aLine->IsBlock()) {
nsBlockFrame::RecoverFloatsFor(aLine->mFirstChild, *mFloatManager);
}
}
/**
* 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 float 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();
mFloatManager->Translate(-bp.left, -bp.top);
RecoverFloats(aLine, aDeltaY);
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow || nsBlockFrame::gNoisyFloatManager) {
mFloatManager->List(stdout);
}
#endif
// And then put the translation back again
mFloatManager->Translate(bp.left, bp.top);
}
}
// 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,
nsIFrame* aFloat,
nscoord aAvailableWidth,
nsReflowStatus& aReflowStatus)
{
NS_PRECONDITION(!aLineLayout || mBlock->end_lines() != mCurrentLine, "null ptr");
NS_PRECONDITION(aFloat->GetStateBits() & NS_FRAME_OUT_OF_FLOW,
"aFloat must be an out-of-flow frame");
// Set the geometric parent of the float
aFloat->SetParent(mBlock);
aReflowStatus = NS_FRAME_COMPLETE;
// 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;
mFloatManager->GetTranslation(ox, oy);
nscoord dx = ox - mFloatManagerX;
nscoord dy = oy - mFloatManagerY;
mFloatManager->Translate(-dx, -dy);
PRBool placed;
// Now place the float immediately if possible. Otherwise stash it
// away in mPendingFloats and place it later.
// If one or more floats has already been pushed to the next line,
// don't let this one go on the current line, since that would violate
// float ordering.
nsRect floatAvailableSpace = GetFloatAvailableSpace().mRect;
if (!aLineLayout ||
(mBelowCurrentLineFloats.IsEmpty() &&
(aLineLayout->LineIsEmpty() ||
mBlock->ComputeFloatWidth(*this, floatAvailableSpace, aFloat)
<= aAvailableWidth))) {
// And then place it
// force it to fit if we're at the top of the block and we can't
// break before this
PRBool forceFit = !aLineLayout ||
(IsAdjacentWithTop() && !aLineLayout->LineIsBreakable());
placed = FlowAndPlaceFloat(aFloat, 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
nsFlowAreaRect floatAvailSpace =
GetFloatAvailableSpace(mY, forceFit);
nsRect availSpace(nsPoint(floatAvailSpace.mRect.x + BorderPadding().left,
mY),
floatAvailSpace.mRect.Size());
if (aLineLayout) {
aLineLayout->UpdateBand(availSpace, aFloat);
// Record this float in the current-line list
mCurrentLineFloats.Append(mFloatCacheFreeList.Alloc(aFloat));
}
// 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;
}
}
}
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(mFloatCacheFreeList.Alloc(aFloat));
}
// Restore coordinate system
mFloatManager->Translate(dx, dy);
return placed;
}
PRBool
nsBlockReflowState::CanPlaceFloat(const nsSize& aFloatSize, PRUint8 aFloats,
const nsFlowAreaRect& aFloatAvailableSpace,
PRBool aForceFit)
{
// If the current Y coordinate is not impacted by any floats
// then by definition the float fits.
PRBool result = PR_TRUE;
if (aFloatAvailableSpace.mHasFloats) {
// XXX We should allow overflow by up to half a pixel here (bug 21193).
if (aFloatAvailableSpace.mRect.width < aFloatSize.width) {
// The available width is too narrow (and it's 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 (NSCoordGreaterThan(aFloatSize.height,
aFloatAvailableSpace.mRect.height)) {
// The available height is too short. However, it's 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 it's 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 = aFloatAvailableSpace.mRect.x;
}
else {
xa = aFloatAvailableSpace.mRect.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 < aFloatAvailableSpace.mRect.x) {
xa = aFloatAvailableSpace.mRect.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;
nsFlowAreaRect floatAvailableSpace(aFloatAvailableSpace);
for (;;) {
// Get the available space at the new Y coordinate
if (floatAvailableSpace.mRect.height <= 0) {
// there is no more available space. We lose.
result = PR_FALSE;
break;
}
mY += floatAvailableSpace.mRect.height;
floatAvailableSpace = GetFloatAvailableSpace(mY, aForceFit);
if (floatAvailableSpace.mHasFloats) {
if (xa < floatAvailableSpace.mRect.x ||
xb > floatAvailableSpace.mRect.XMost()) {
// The float can't go here.
result = PR_FALSE;
break;
}
}
// See if there is now enough height for the float.
if (yb <= mY + floatAvailableSpace.mRect.height) {
// Winner. The bottom Y coordinate of the float is in
// this band.
break;
}
}
// Restore Y coordinate
mY = saveY;
}
return result;
}
PRBool
nsBlockReflowState::FlowAndPlaceFloat(nsIFrame* aFloat,
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;
// Grab the float's display information
const nsStyleDisplay* floatDisplay = aFloat->GetStyleDisplay();
// The float's old region, so we can propagate damage.
nsRect oldRegion = nsFloatManager::GetRegionFor(aFloat);
// 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(mFloatManager->GetLowestFloatTop() + 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
nsFlowAreaRect floatAvailableSpace = GetFloatAvailableSpace(mY, aForceFit);
NS_ASSERTION(aFloat->GetParent() == mBlock,
"Float frame has wrong parent");
// Reflow the float
nsMargin floatMargin; // computed margin
mBlock->ReflowFloat(*this, floatAvailableSpace.mRect, aFloat,
floatMargin, aReflowStatus);
if (aFloat->GetPrevInFlow())
floatMargin.top = 0;
if (NS_FRAME_IS_NOT_COMPLETE(aReflowStatus))
floatMargin.bottom = 0;
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsRect region = aFloat->GetRect();
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("flowed float: ");
nsFrame::ListTag(stdout, aFloat);
printf(" (%d,%d,%d,%d)\n",
region.x, region.y, region.width, region.height);
}
#endif
nsSize floatSize = aFloat->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, floatAvailableSpace,
aForceFit)) {
if (floatAvailableSpace.mRect.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 += floatAvailableSpace.mRect.height;
floatAvailableSpace = GetFloatAvailableSpace(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->mFloat == aFloat) {
break;
}
prevFrame = fc->mFloat;
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 += floatAvailableSpace.mRect.height;
floatAvailableSpace = GetFloatAvailableSpace(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, floatAvailableSpace.mRect, aFloat,
floatMargin, aReflowStatus);
// Get the floats bounding box and margin information
floatSize = aFloat->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.
nscoord floatX, floatY;
if (NS_STYLE_FLOAT_LEFT == floatDisplay->mFloats) {
floatX = floatAvailableSpace.mRect.x;
}
else {
if (!keepFloatOnSameLine) {
floatX = floatAvailableSpace.mRect.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 = floatAvailableSpace.mRect.x;
}
}
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;
}
// 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
origin += aFloat->GetRelativeOffset(floatDisplay);
// 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.
aFloat->SetPosition(origin);
nsContainerFrame::PositionFrameView(aFloat);
nsContainerFrame::PositionChildViews(aFloat);
// Update the float combined area state
nsRect combinedArea = aFloat->GetOverflowRect() + origin;
// XXX Floats should really just get invalidated here if necessary
mFloatCombinedArea.UnionRect(combinedArea, mFloatCombinedArea);
// Place the float in the float manager
// calculate region
nsRect region = nsFloatManager::CalculateRegionFor(aFloat, floatMargin);
// if the float split, then take up all of the vertical height
if (NS_FRAME_IS_NOT_COMPLETE(aReflowStatus) &&
(NS_UNCONSTRAINEDSIZE != mContentArea.height)) {
region.height = NS_MAX(region.height, mContentArea.height - floatY);
}
nsresult rv =
// spacemanager translation is inset by the border+padding.
mFloatManager->AddFloat(aFloat,
region - nsPoint(borderPadding.left, borderPadding.top));
NS_ABORT_IF_FALSE(NS_SUCCEEDED(rv), "bad float placement");
// store region
rv = nsFloatManager::StoreRegionFor(aFloat, region);
NS_ABORT_IF_FALSE(NS_SUCCEEDED(rv), "float region storage failed");
// If the float's dimensions have changed, note the damage in the
// float manager.
if (region != 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) - borderPadding.top;
nscoord bottom = NS_MAX(region.YMost(), oldRegion.YMost()) - borderPadding.top;
mFloatManager->IncludeInDamage(top, bottom);
}
#ifdef NOISY_FLOATMANAGER
nscoord tx, ty;
mFloatManager->GetTranslation(tx, ty);
nsFrame::ListTag(stdout, mBlock);
printf(": FlowAndPlaceFloat: AddFloat: txy=%d,%d (%d,%d) {%d,%d,%d,%d}\n",
tx, ty, mFloatManagerX, mFloatManagerY,
region.x, region.y, region.width, region.height);
#endif
// Now restore mY
mY = saveY;
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsRect r = aFloat->GetRect();
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("placed float: ");
nsFrame::ListTag(stdout, aFloat);
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->mFloat);
printf("\n");
}
#endif
// Place the float
nsReflowStatus reflowStatus;
PRBool placed = FlowAndPlaceFloat(fc->mFloat, 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_FULLY_COMPLETE(reflowStatus)) {
// Create a continuation for the incomplete float
nsresult rv = mBlock->SplitFloat(*this, fc->mFloat, reflowStatus);
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.
}
}
fc = fc->Next();
}
return PR_TRUE;
}
nscoord
nsBlockReflowState::ClearFloats(nscoord aY, PRUint8 aBreakType,
nsIFrame *aReplacedBlock)
{
#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);
mFloatManager->List(stdout);
#endif
const nsMargin& bp = BorderPadding();
nscoord newY = aY;
if (aBreakType != NS_STYLE_CLEAR_NONE) {
newY = bp.top + mFloatManager->ClearFloats(newY - bp.top, aBreakType);
}
if (aReplacedBlock) {
for (;;) {
nsFlowAreaRect floatAvailableSpace =
GetFloatAvailableSpace(newY, PR_FALSE);
nsBlockFrame::ReplacedElementWidthToClear replacedWidth =
nsBlockFrame::WidthToClearPastFloats(*this, floatAvailableSpace.mRect,
aReplacedBlock);
if (!floatAvailableSpace.mHasFloats ||
NS_MAX(floatAvailableSpace.mRect.x, replacedWidth.marginLeft) +
replacedWidth.borderBoxWidth +
NS_MAX(mContentArea.width -
NS_MIN(mContentArea.width,
floatAvailableSpace.mRect.XMost()),
replacedWidth.marginRight) <=
mContentArea.width) {
break;
}
// See the analogous code for inlines in nsBlockFrame::DoReflowInlineFrames
if (floatAvailableSpace.mRect.height > 0) {
// See if there's room in the next band.
newY += floatAvailableSpace.mRect.height;
} else {
if (mReflowState.availableHeight != NS_UNCONSTRAINEDSIZE) {
// Stop trying to clear here; we'll just get pushed to the
// next column or page and try again there.
break;
}
NS_NOTREACHED("avail space rect with zero height!");
newY += 1;
}
}
}
#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