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gecko-dev/layout/generic/nsBlockReflowState.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
// vim:cindent:ts=2:et:sw=2:
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* state used in reflow of block frames */
#include "nsBlockReflowState.h"
#include "mozilla/DebugOnly.h"
#include "nsBlockReflowContext.h"
#include "nsBlockFrame.h"
#include "nsLineLayout.h"
#include "nsPresContext.h"
#include "nsGkAtoms.h"
#include "nsIFrame.h"
#include "nsFrameManager.h"
#include "mozilla/AutoRestore.h"
#include "FrameLayerBuilder.h"
#include "nsINameSpaceManager.h"
#include <algorithm>
#ifdef DEBUG
#include "nsBlockDebugFlags.h"
#endif
using namespace mozilla;
using namespace mozilla::layout;
nsBlockReflowState::nsBlockReflowState(const nsHTMLReflowState& aReflowState,
nsPresContext* aPresContext,
nsBlockFrame* aFrame,
bool aTopMarginRoot,
bool aBottomMarginRoot,
bool aBlockNeedsFloatManager,
nscoord aConsumedHeight)
: mBlock(aFrame),
mPresContext(aPresContext),
mReflowState(aReflowState),
mPushedFloats(nullptr),
mOverflowTracker(nullptr),
mPrevBottomMargin(),
mLineNumber(0),
mFlags(0),
mFloatBreakType(NS_STYLE_CLEAR_NONE),
mConsumedHeight(aConsumedHeight)
{
SetFlag(BRS_ISFIRSTINFLOW, aFrame->GetPrevInFlow() == nullptr);
SetFlag(BRS_ISOVERFLOWCONTAINER,
IS_TRUE_OVERFLOW_CONTAINER(aFrame));
const nsMargin& borderPadding = BorderPadding();
if (aTopMarginRoot || 0 != aReflowState.mComputedBorderPadding.top) {
SetFlag(BRS_ISTOPMARGINROOT, true);
}
if (aBottomMarginRoot || 0 != aReflowState.mComputedBorderPadding.bottom) {
SetFlag(BRS_ISBOTTOMMARGINROOT, true);
}
if (GetFlag(BRS_ISTOPMARGINROOT)) {
SetFlag(BRS_APPLYTOPMARGIN, true);
}
if (aBlockNeedsFloatManager) {
SetFlag(BRS_FLOAT_MGR, true);
}
mFloatManager = aReflowState.mFloatManager;
NS_ASSERTION(mFloatManager,
"FloatManager should be set in nsBlockReflowState" );
if (mFloatManager) {
// Save the coordinate system origin for later.
mFloatManager->GetTranslation(mFloatManagerX, mFloatManagerY);
mFloatManager->PushState(&mFloatManagerStateBefore); // never popped
}
mReflowStatus = NS_FRAME_COMPLETE;
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 = std::max(0, mBottomEdge - borderPadding.top);
}
else {
// When we are not in a paginated situation then we always use
// an constrained height.
SetFlag(BRS_UNCONSTRAINEDHEIGHT, true);
mContentArea.height = mBottomEdge = NS_UNCONSTRAINEDSIZE;
}
mContentArea.x = borderPadding.left;
mY = mContentArea.y = borderPadding.top;
mPrevChild = nullptr;
mCurrentLine = aFrame->end_lines();
mMinLineHeight = aReflowState.CalcLineHeight();
}
nscoord
nsBlockReflowState::GetConsumedHeight()
{
if (mConsumedHeight == NS_INTRINSICSIZE) {
mConsumedHeight = mBlock->GetConsumedHeight();
}
return mConsumedHeight;
}
void
nsBlockReflowState::ComputeReplacedBlockOffsetsForFloats(nsIFrame* aFrame,
const nsRect& aFloatAvailableSpace,
nscoord& aLeftResult,
nscoord& aRightResult)
{
// 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 >= mContentArea.x, "bad avail space rect x");
NS_ASSERTION(aFloatAvailableSpace.width == 0 ||
aFloatAvailableSpace.XMost() <= mContentArea.XMost(),
"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 {
nsMargin frameMargin;
nsCSSOffsetState os(aFrame, mReflowState.rendContext, mContentArea.width);
frameMargin = os.mComputedMargin;
nscoord leftFloatXOffset = aFloatAvailableSpace.x - mContentArea.x;
leftOffset = std::max(leftFloatXOffset, frameMargin.left) -
frameMargin.left;
leftOffset = std::max(leftOffset, 0); // in case of negative margin
nscoord rightFloatXOffset =
mContentArea.XMost() - aFloatAvailableSpace.XMost();
rightOffset = std::max(rightFloatXOffset, frameMargin.right) -
frameMargin.right;
rightOffset = std::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,
bool 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
: 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.
// 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->StyleBorder();
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 = mContentArea.x;
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;
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 = mContentArea.x;
aResult.width = mContentArea.width;
}
}
else {
nscoord leftOffset, rightOffset;
ComputeReplacedBlockOffsetsForFloats(aFrame, aFloatAvailableSpace.mRect,
leftOffset, rightOffset);
aResult.x = mContentArea.x + 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,
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
nscoord height = (mContentArea.height == nscoord_MAX)
? nscoord_MAX : std::max(mContentArea.YMost() - aY, 0);
nsFlowAreaRect result =
mFloatManager->GetFlowArea(aY, nsFloatManager::BAND_FROM_POINT,
height, mContentArea, 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, nsFloatManager::WIDTH_WITHIN_HEIGHT,
aHeight, mContentArea, 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::SetupPushedFloatList()
{
NS_ABORT_IF_FALSE(!GetFlag(BRS_PROPTABLE_FLOATCLIST) == !mPushedFloats,
"flag mismatch");
if (!GetFlag(BRS_PROPTABLE_FLOATCLIST)) {
// If we're being re-Reflow'd without our next-in-flow having been
// reflowed, some pushed floats from our previous reflow might
// still be on our pushed floats list. However, that's
// actually fine, since they'll all end up being stolen and
// reordered into the correct order again.
// (nsBlockFrame::ReflowDirtyLines ensures that any lines with
// pushed floats are reflowed.)
mPushedFloats = mBlock->EnsurePushedFloats();
SetFlag(BRS_PROPTABLE_FLOATCLIST, true);
}
}
void
nsBlockReflowState::AppendPushedFloat(nsIFrame* aFloatCont)
{
SetupPushedFloatList();
aFloatCont->AddStateBits(NS_FRAME_IS_PUSHED_FLOAT);
mPushedFloats->AppendFrame(mBlock, aFloatCont);
}
/**
* 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()) {
RecoverFloats(aLine, aDeltaY);
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow || nsBlockFrame::gNoisyFloatManager) {
mFloatManager->List(stdout);
}
#endif
}
}
// 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...
bool
nsBlockReflowState::AddFloat(nsLineLayout* aLineLayout,
nsIFrame* aFloat,
nscoord aAvailableWidth)
{
NS_PRECONDITION(aLineLayout, "must have line layout");
NS_PRECONDITION(mBlock->end_lines() != mCurrentLine, "null ptr");
NS_PRECONDITION(aFloat->GetStateBits() & NS_FRAME_OUT_OF_FLOW,
"aFloat must be an out-of-flow frame");
NS_ABORT_IF_FALSE(aFloat->GetParent(), "float must have parent");
NS_ABORT_IF_FALSE(aFloat->GetParent()->IsFrameOfType(nsIFrame::eBlockFrame),
"float's parent must be block");
NS_ABORT_IF_FALSE(aFloat->GetParent() == mBlock ||
(aFloat->GetStateBits() & NS_FRAME_IS_PUSHED_FLOAT),
"float should be in this block unless it was marked as "
"pushed float");
if (aFloat->GetStateBits() & NS_FRAME_IS_PUSHED_FLOAT) {
// If, in a previous reflow, the float was pushed entirely to
// another column/page, we need to steal it back. (We might just
// push it again, though.) Likewise, if that previous reflow
// reflowed this block but not its next continuation, we might need
// to steal it from our own float-continuations list.
//
// For more about pushed floats, see the comment above
// nsBlockFrame::DrainPushedFloats.
nsBlockFrame *floatParent =
static_cast<nsBlockFrame*>(aFloat->GetParent());
floatParent->StealFrame(mPresContext, aFloat);
aFloat->RemoveStateBits(NS_FRAME_IS_PUSHED_FLOAT);
// Appending is fine, since if a float was pushed to the next
// page/column, all later floats were also pushed.
mBlock->mFloats.AppendFrame(mBlock, aFloat);
}
// 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);
bool 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 (mBelowCurrentLineFloats.IsEmpty() &&
(aLineLayout->LineIsEmpty() ||
mBlock->ComputeFloatWidth(*this, floatAvailableSpace, aFloat)
<= aAvailableWidth)) {
// And then place it
placed = FlowAndPlaceFloat(aFloat);
if (placed) {
// Pass on updated available space to the current inline reflow engine
nsFlowAreaRect floatAvailSpace = GetFloatAvailableSpace(mY);
nsRect availSpace(nsPoint(floatAvailSpace.mRect.x, mY),
floatAvailSpace.mRect.Size());
aLineLayout->UpdateBand(availSpace, aFloat);
// Record this float in the current-line list
mCurrentLineFloats.Append(mFloatCacheFreeList.Alloc(aFloat));
} else {
(*aLineLayout->GetLine())->SetHadFloatPushed();
}
}
else {
// Always claim to be placed; we don't know whether we fit yet, so we
// deal with this in PlaceBelowCurrentLineFloats
placed = 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;
}
bool
nsBlockReflowState::CanPlaceFloat(nscoord aFloatWidth,
const nsFlowAreaRect& aFloatAvailableSpace)
{
// A float fits at a given vertical position if there are no floats at
// its horizontal position (no matter what its width) or if its width
// fits in the space remaining after prior floats have been placed.
// FIXME: We should allow overflow by up to half a pixel here (bug 21193).
return !aFloatAvailableSpace.mHasFloats ||
aFloatAvailableSpace.mRect.width >= aFloatWidth;
}
static nscoord
FloatMarginWidth(const nsHTMLReflowState& aCBReflowState,
nscoord aFloatAvailableWidth,
nsIFrame *aFloat,
const nsCSSOffsetState& aFloatOffsetState)
{
AutoMaybeDisableFontInflation an(aFloat);
return aFloat->ComputeSize(
aCBReflowState.rendContext,
nsSize(aCBReflowState.ComputedWidth(),
aCBReflowState.ComputedHeight()),
aFloatAvailableWidth,
nsSize(aFloatOffsetState.mComputedMargin.LeftRight(),
aFloatOffsetState.mComputedMargin.TopBottom()),
nsSize(aFloatOffsetState.mComputedBorderPadding.LeftRight() -
aFloatOffsetState.mComputedPadding.LeftRight(),
aFloatOffsetState.mComputedBorderPadding.TopBottom() -
aFloatOffsetState.mComputedPadding.TopBottom()),
nsSize(aFloatOffsetState.mComputedPadding.LeftRight(),
aFloatOffsetState.mComputedPadding.TopBottom()),
true).width +
aFloatOffsetState.mComputedMargin.LeftRight() +
aFloatOffsetState.mComputedBorderPadding.LeftRight();
}
bool
nsBlockReflowState::FlowAndPlaceFloat(nsIFrame* aFloat)
{
// 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.
AutoRestore<nscoord> restoreY(mY);
// FIXME: Should give AutoRestore a getter for the value to avoid this.
const nscoord saveY = mY;
// Grab the float's display information
const nsStyleDisplay* floatDisplay = aFloat->StyleDisplay();
// 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 = std::max(mFloatManager->GetLowestFloatTop(), 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);
nsRect adjustedAvailableSpace = mBlock->AdjustFloatAvailableSpace(*this,
floatAvailableSpace.mRect, aFloat);
NS_ASSERTION(aFloat->GetParent() == mBlock,
"Float frame has wrong parent");
nsCSSOffsetState offsets(aFloat, mReflowState.rendContext,
mReflowState.ComputedWidth());
nscoord floatMarginWidth = FloatMarginWidth(mReflowState,
adjustedAvailableSpace.width,
aFloat, offsets);
nsMargin floatMargin; // computed margin
nsReflowStatus reflowStatus;
// If it's a floating first-letter, we need to reflow it before we
// know how wide it is (since we don't compute which letters are part
// of the first letter until reflow!).
bool isLetter = aFloat->GetType() == nsGkAtoms::letterFrame;
if (isLetter) {
mBlock->ReflowFloat(*this, adjustedAvailableSpace, aFloat,
floatMargin, false, reflowStatus);
floatMarginWidth = aFloat->GetSize().width + floatMargin.LeftRight();
NS_ASSERTION(NS_FRAME_IS_COMPLETE(reflowStatus),
"letter frames shouldn't break, and if they do now, "
"then they're breaking at the wrong point");
}
// 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?
bool keepFloatOnSameLine = false;
// Are we required to place at least part of the float because we're
// at the top of the page (to avoid an infinite loop of pushing and
// breaking).
bool mustPlaceFloat =
mReflowState.mFlags.mIsTopOfPage && IsAdjacentWithTop();
for (;;) {
if (mReflowState.availableHeight != NS_UNCONSTRAINEDSIZE &&
floatAvailableSpace.mRect.height <= 0 &&
!mustPlaceFloat) {
// No space, nowhere to put anything.
PushFloatPastBreak(aFloat);
return false;
}
if (CanPlaceFloat(floatMarginWidth, floatAvailableSpace)) {
// We found an appropriate place.
break;
}
// Nope. try to advance to the next band.
if (NS_STYLE_DISPLAY_TABLE != floatDisplay->mDisplay ||
eCompatibility_NavQuirks != mPresContext->CompatibilityMode() ) {
mY += floatAvailableSpace.mRect.height;
if (adjustedAvailableSpace.height != NS_UNCONSTRAINEDSIZE) {
adjustedAvailableSpace.height -= floatAvailableSpace.mRect.height;
}
floatAvailableSpace = GetFloatAvailableSpace(mY);
} else {
// This quirk matches the one in nsBlockFrame::AdjustFloatAvailableSpace
// 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 = nullptr;
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 = 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;
// To match nsBlockFrame::AdjustFloatAvailableSpace, we have to
// get a new width for the new band.
floatAvailableSpace = GetFloatAvailableSpace(mY);
adjustedAvailableSpace = mBlock->AdjustFloatAvailableSpace(*this,
floatAvailableSpace.mRect, aFloat);
floatMarginWidth = FloatMarginWidth(mReflowState,
adjustedAvailableSpace.width,
aFloat, offsets);
}
mustPlaceFloat = false;
}
// 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.
nscoord floatX, floatY;
if (NS_STYLE_FLOAT_LEFT == floatDisplay->mFloats) {
floatX = floatAvailableSpace.mRect.x;
}
else {
if (!keepFloatOnSameLine) {
floatX = floatAvailableSpace.mRect.XMost() - floatMarginWidth;
}
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;
}
}
// 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 = std::max(mY, mContentArea.y);
// Reflow the float after computing its vertical position so it knows
// where to break.
if (!isLetter) {
bool pushedDown = mY != saveY;
mBlock->ReflowFloat(*this, adjustedAvailableSpace, aFloat,
floatMargin, pushedDown, reflowStatus);
}
if (aFloat->GetPrevInFlow())
floatMargin.top = 0;
if (NS_FRAME_IS_NOT_COMPLETE(reflowStatus))
floatMargin.bottom = 0;
// In the case that we're in columns and not splitting floats, we need
// to check here that the float's height fit, and if it didn't, bail.
// (This code is only for DISABLE_FLOAT_BREAKING_IN_COLUMNS .)
//
// Likewise, if none of the float fit, and it needs to be pushed in
// its entirety to the next page (NS_FRAME_IS_TRUNCATED or
// NS_INLINE_IS_BREAK_BEFORE), we need to do the same.
if ((mContentArea.height != NS_UNCONSTRAINEDSIZE &&
adjustedAvailableSpace.height == NS_UNCONSTRAINEDSIZE &&
!mustPlaceFloat &&
aFloat->GetSize().height + floatMargin.TopBottom() >
mContentArea.YMost() - floatY) ||
NS_FRAME_IS_TRUNCATED(reflowStatus) ||
NS_INLINE_IS_BREAK_BEFORE(reflowStatus)) {
PushFloatPastBreak(aFloat);
return false;
}
// We can't use aFloat->ShouldAvoidBreakInside(mReflowState) here since
// its mIsTopOfPage may be true even though the float isn't at the
// top when floatY > 0.
if (mContentArea.height != NS_UNCONSTRAINEDSIZE &&
!mustPlaceFloat && (!mReflowState.mFlags.mIsTopOfPage || floatY > 0) &&
NS_STYLE_PAGE_BREAK_AVOID == aFloat->StyleDisplay()->mBreakInside &&
(!NS_FRAME_IS_FULLY_COMPLETE(reflowStatus) ||
aFloat->GetSize().height + floatMargin.TopBottom() >
mContentArea.YMost() - floatY) &&
!aFloat->GetPrevInFlow()) {
PushFloatPastBreak(aFloat);
return false;
}
// Calculate the actual origin of the float frame's border rect
// relative to the parent block; the margin must be added in
// to get the border rect
nsPoint origin(floatMargin.left + floatX,
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.
bool moved = aFloat->GetPosition() != origin;
if (moved) {
aFloat->SetPosition(origin);
nsContainerFrame::PositionFrameView(aFloat);
nsContainerFrame::PositionChildViews(aFloat);
}
// Update the float combined area state
// XXX Floats should really just get invalidated here if necessary
mFloatOverflowAreas.UnionWith(aFloat->GetOverflowAreas() + origin);
// 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(reflowStatus) &&
(NS_UNCONSTRAINEDSIZE != mContentArea.height)) {
region.height = std::max(region.height, mContentArea.height - floatY);
}
DebugOnly<nsresult> rv =
mFloatManager->AddFloat(aFloat, region);
NS_ABORT_IF_FALSE(NS_SUCCEEDED(rv), "bad float placement");
// store region
nsFloatManager::StoreRegionFor(aFloat, region);
// If the float's dimensions have changed, note the damage in the
// float manager.
if (!region.IsEqualEdges(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 = std::min(region.y, oldRegion.y);
nscoord bottom = std::max(region.YMost(), oldRegion.YMost());
mFloatManager->IncludeInDamage(top, bottom);
}
if (!NS_FRAME_IS_FULLY_COMPLETE(reflowStatus)) {
mBlock->SplitFloat(*this, aFloat, reflowStatus);
}
#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
#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 true;
}
void
nsBlockReflowState::PushFloatPastBreak(nsIFrame *aFloat)
{
// This ensures that we:
// * don't try to place later but smaller floats (which CSS says
// must have their tops below the top of this float)
// * don't waste much time trying to reflow this float again until
// after the break
if (aFloat->StyleDisplay()->mFloats == NS_STYLE_FLOAT_LEFT) {
mFloatManager->SetPushedLeftFloatPastBreak();
} else {
NS_ABORT_IF_FALSE(aFloat->StyleDisplay()->mFloats ==
NS_STYLE_FLOAT_RIGHT,
"unexpected float value");
mFloatManager->SetPushedRightFloatPastBreak();
}
// Put the float on the pushed floats list, even though it
// isn't actually a continuation.
DebugOnly<nsresult> rv = mBlock->StealFrame(mPresContext, aFloat);
NS_ASSERTION(NS_SUCCEEDED(rv), "StealFrame should succeed");
AppendPushedFloat(aFloat);
NS_FRAME_SET_OVERFLOW_INCOMPLETE(mReflowStatus);
}
/**
* Place below-current-line floats.
*/
void
nsBlockReflowState::PlaceBelowCurrentLineFloats(nsFloatCacheFreeList& aList,
nsLineBox* aLine)
{
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
bool placed = FlowAndPlaceFloat(fc->mFloat);
nsFloatCache *next = fc->Next();
if (!placed) {
aList.Remove(fc);
delete fc;
aLine->SetHadFloatPushed();
}
fc = next;
}
}
nscoord
nsBlockReflowState::ClearFloats(nscoord aY, uint8_t aBreakType,
nsIFrame *aReplacedBlock,
uint32_t aFlags)
{
#ifdef DEBUG
if (nsBlockFrame::gNoisyReflow) {
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
printf("clear floats: in: aY=%d\n", aY);
}
#endif
#ifdef NOISY_FLOAT_CLEARING
printf("nsBlockReflowState::ClearFloats: aY=%d breakType=%d\n",
aY, aBreakType);
mFloatManager->List(stdout);
#endif
if (!mFloatManager->HasAnyFloats()) {
return aY;
}
nscoord newY = aY;
if (aBreakType != NS_STYLE_CLEAR_NONE) {
newY = mFloatManager->ClearFloats(newY, aBreakType, aFlags);
}
if (aReplacedBlock) {
for (;;) {
nsFlowAreaRect floatAvailableSpace = GetFloatAvailableSpace(newY);
if (!floatAvailableSpace.mHasFloats) {
// If there aren't any floats here, then we always fit.
// We check this before calling WidthToClearPastFloats, which is
// somewhat expensive.
break;
}
nsBlockFrame::ReplacedElementWidthToClear replacedWidth =
nsBlockFrame::WidthToClearPastFloats(*this, floatAvailableSpace.mRect,
aReplacedBlock);
if (std::max(floatAvailableSpace.mRect.x - mContentArea.x,
replacedWidth.marginLeft) +
replacedWidth.borderBoxWidth +
std::max(mContentArea.XMost() - 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\n", newY);
}
#endif
return newY;
}
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