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pjs/layout/generic/nsBlockReflowContext.cpp

445 строки
18 KiB
C++
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/* -*- 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):
* David Baron <dbaron@dbaron.org>
*
* 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 ***** */
/* class that a parent frame uses to reflow a block frame */
#include "nsBlockReflowContext.h"
#include "nsLineLayout.h"
#include "nsFloatManager.h"
#include "nsIFontMetrics.h"
#include "nsPresContext.h"
#include "nsFrameManager.h"
#include "nsIContent.h"
#include "nsStyleContext.h"
#include "nsHTMLContainerFrame.h"
#include "nsBlockFrame.h"
#include "nsLineBox.h"
#include "nsIDOMHTMLTableCellElement.h"
#include "nsIDOMHTMLBodyElement.h"
#include "nsGkAtoms.h"
#include "nsCOMPtr.h"
#include "nsLayoutUtils.h"
#ifdef NS_DEBUG
#undef NOISY_MAX_ELEMENT_SIZE
#undef REALLY_NOISY_MAX_ELEMENT_SIZE
#undef NOISY_VERTICAL_MARGINS
#else
#undef NOISY_MAX_ELEMENT_SIZE
#undef REALLY_NOISY_MAX_ELEMENT_SIZE
#undef NOISY_VERTICAL_MARGINS
#endif
nsBlockReflowContext::nsBlockReflowContext(nsPresContext* aPresContext,
const nsHTMLReflowState& aParentRS)
: mPresContext(aPresContext),
mOuterReflowState(aParentRS),
mMetrics()
{
}
static nsIFrame* DescendIntoBlockLevelFrame(nsIFrame* aFrame)
{
nsIAtom* type = aFrame->GetType();
if (type == nsGkAtoms::columnSetFrame)
return DescendIntoBlockLevelFrame(aFrame->GetFirstChild(nsnull));
return aFrame;
}
PRBool
nsBlockReflowContext::ComputeCollapsedTopMargin(const nsHTMLReflowState& aRS,
nsCollapsingMargin* aMargin, nsIFrame* aClearanceFrame,
PRBool* aMayNeedRetry, PRBool* aBlockIsEmpty)
{
// Include frame's top margin
aMargin->Include(aRS.mComputedMargin.top);
// The inclusion of the bottom margin when empty is done by the caller
// since it doesn't need to be done by the top-level (non-recursive)
// caller.
#ifdef NOISY_VERTICAL_MARGINS
nsFrame::ListTag(stdout, aRS.frame);
printf(": %d => %d\n", aRS.mComputedMargin.top, aMargin->get());
#endif
PRBool dirtiedLine = PR_FALSE;
PRBool setBlockIsEmpty = PR_FALSE;
// Calculate the frame's generational top-margin from its child
// blocks. Note that if the frame has a non-zero top-border or
// top-padding then this step is skipped because it will be a margin
// root. It is also skipped if the frame is a margin root for other
// reasons.
nsIFrame* frame = DescendIntoBlockLevelFrame(aRS.frame);
nsPresContext* prescontext = frame->PresContext();
if (0 == aRS.mComputedBorderPadding.top &&
nsLayoutUtils::GetAsBlock(frame) &&
!nsBlockFrame::BlockIsMarginRoot(frame)) {
// iterate not just through the lines of 'block' but also its
// overflow lines and the normal and overflow lines of its next in
// flows. Note that this will traverse some frames more than once:
// for example, if A contains B and A->nextinflow contains
// B->nextinflow, we'll traverse B->nextinflow twice. But this is
// OK because our traversal is idempotent.
for (nsBlockFrame* block = static_cast<nsBlockFrame*>(frame);
block; block = static_cast<nsBlockFrame*>(block->GetNextInFlow())) {
for (PRBool overflowLines = PR_FALSE; overflowLines <= PR_TRUE; ++overflowLines) {
nsBlockFrame::line_iterator line;
nsBlockFrame::line_iterator line_end;
PRBool anyLines = PR_TRUE;
if (overflowLines) {
nsLineList* lines = block->GetOverflowLines();
if (!lines) {
anyLines = PR_FALSE;
} else {
line = lines->begin();
line_end = lines->end();
}
} else {
line = block->begin_lines();
line_end = block->end_lines();
}
for (; anyLines && line != line_end; ++line) {
if (!aClearanceFrame && line->HasClearance()) {
// If we don't have a clearance frame, then we're computing
// the collapsed margin in the first pass, assuming that all
// lines have no clearance. So clear their clearance flags.
line->ClearHasClearance();
line->MarkDirty();
dirtiedLine = PR_TRUE;
}
PRBool isEmpty;
if (line->IsInline()) {
isEmpty = line->IsEmpty();
} else {
nsIFrame* kid = line->mFirstChild;
if (kid == aClearanceFrame) {
line->SetHasClearance();
line->MarkDirty();
dirtiedLine = PR_TRUE;
goto done;
}
// Here is where we recur. Now that we have determined that a
// generational collapse is required we need to compute the
// child blocks margin and so in so that we can look into
// it. For its margins to be computed we need to have a reflow
// state for it.
// We may have to construct an extra reflow state here if
// we drilled down through a block wrapper. At the moment
// we can only drill down one level so we only have to support
// one extra reflow state.
const nsHTMLReflowState* outerReflowState = &aRS;
if (frame != aRS.frame) {
NS_ASSERTION(frame->GetParent() == aRS.frame,
"Can only drill through one level of block wrapper");
nsSize availSpace(aRS.ComputedWidth(), aRS.ComputedHeight());
outerReflowState = new nsHTMLReflowState(prescontext,
aRS, frame, availSpace);
if (!outerReflowState)
goto done;
}
{
nsSize availSpace(outerReflowState->ComputedWidth(),
outerReflowState->ComputedHeight());
nsHTMLReflowState innerReflowState(prescontext,
*outerReflowState, kid,
availSpace);
// Record that we're being optimistic by assuming the kid
// has no clearance
if (kid->GetStyleDisplay()->mBreakType != NS_STYLE_CLEAR_NONE) {
*aMayNeedRetry = PR_TRUE;
}
if (ComputeCollapsedTopMargin(innerReflowState, aMargin, aClearanceFrame, aMayNeedRetry, &isEmpty)) {
line->MarkDirty();
dirtiedLine = PR_TRUE;
}
if (isEmpty)
aMargin->Include(innerReflowState.mComputedMargin.bottom);
}
if (outerReflowState != &aRS) {
delete const_cast<nsHTMLReflowState*>(outerReflowState);
}
}
if (!isEmpty) {
if (!setBlockIsEmpty && aBlockIsEmpty) {
setBlockIsEmpty = PR_TRUE;
*aBlockIsEmpty = PR_FALSE;
}
goto done;
}
}
if (!setBlockIsEmpty && aBlockIsEmpty) {
// The first time we reach here is when this is the first block
// and we have processed all its normal lines.
setBlockIsEmpty = PR_TRUE;
// All lines are empty, or we wouldn't be here!
*aBlockIsEmpty = aRS.frame->IsSelfEmpty();
}
}
}
done:
;
}
if (!setBlockIsEmpty && aBlockIsEmpty) {
*aBlockIsEmpty = aRS.frame->IsEmpty();
}
#ifdef NOISY_VERTICAL_MARGINS
nsFrame::ListTag(stdout, aRS.frame);
printf(": => %d\n", aMargin->get());
#endif
return dirtiedLine;
}
nsresult
nsBlockReflowContext::ReflowBlock(const nsRect& aSpace,
PRBool aApplyTopMargin,
nsCollapsingMargin& aPrevMargin,
nscoord aClearance,
PRBool aIsAdjacentWithTop,
nsLineBox* aLine,
nsHTMLReflowState& aFrameRS,
nsReflowStatus& aFrameReflowStatus,
nsBlockReflowState& aState)
{
nsresult rv = NS_OK;
mFrame = aFrameRS.frame;
mSpace = aSpace;
if (!aIsAdjacentWithTop) {
aFrameRS.mFlags.mIsTopOfPage = PR_FALSE; // make sure this is cleared
}
if (aApplyTopMargin) {
mTopMargin = aPrevMargin;
#ifdef NOISY_VERTICAL_MARGINS
nsFrame::ListTag(stdout, mOuterReflowState.frame);
printf(": reflowing ");
nsFrame::ListTag(stdout, mFrame);
printf(" margin => %d, clearance => %d\n", mTopMargin.get(), aClearance);
#endif
// Adjust the available height if its constrained so that the
// child frame doesn't think it can reflow into its margin area.
if (NS_UNCONSTRAINEDSIZE != aFrameRS.availableHeight) {
aFrameRS.availableHeight -= mTopMargin.get() + aClearance;
}
}
nscoord tx = 0, ty = 0;
// The values of x and y do not matter for floats, so don't bother calculating
// them. Floats are guaranteed to have their own float manager, so tx and ty
// don't matter. mX and mY don't matter becacuse they are only used in
// PlaceBlock, which is not used for floats.
if (aLine) {
// Compute x/y coordinate where reflow will begin. Use the rules
// from 10.3.3 to determine what to apply. At this point in the
// reflow auto left/right margins will have a zero value.
mX = tx = mSpace.x + aFrameRS.mComputedMargin.left;
mY = ty = mSpace.y + mTopMargin.get() + aClearance;
if ((mFrame->GetStateBits() & NS_BLOCK_FLOAT_MGR) == 0)
aFrameRS.mBlockDelta = mOuterReflowState.mBlockDelta + ty - aLine->mBounds.y;
}
// Let frame know that we are reflowing it
mFrame->WillReflow(mPresContext);
#ifdef DEBUG
mMetrics.width = nscoord(0xdeadbeef);
mMetrics.height = nscoord(0xdeadbeef);
#endif
mOuterReflowState.mFloatManager->Translate(tx, ty);
rv = mFrame->Reflow(mPresContext, mMetrics, aFrameRS, aFrameReflowStatus);
mOuterReflowState.mFloatManager->Translate(-tx, -ty);
#ifdef DEBUG
if (!NS_INLINE_IS_BREAK_BEFORE(aFrameReflowStatus)) {
if (CRAZY_WIDTH(mMetrics.width) || CRAZY_HEIGHT(mMetrics.height)) {
printf("nsBlockReflowContext: ");
nsFrame::ListTag(stdout, mFrame);
printf(" metrics=%d,%d!\n", mMetrics.width, mMetrics.height);
}
if ((mMetrics.width == nscoord(0xdeadbeef)) ||
(mMetrics.height == nscoord(0xdeadbeef))) {
printf("nsBlockReflowContext: ");
nsFrame::ListTag(stdout, mFrame);
printf(" didn't set w/h %d,%d!\n", mMetrics.width, mMetrics.height);
}
}
#endif
if (!mFrame->HasOverflowAreas()) {
mMetrics.SetOverflowAreasToDesiredBounds();
}
if (!NS_INLINE_IS_BREAK_BEFORE(aFrameReflowStatus) ||
(mFrame->GetStateBits() & NS_FRAME_OUT_OF_FLOW)) {
// If frame is complete and has a next-in-flow, we need to delete
// them now. Do not do this when a break-before is signaled because
// the frame is going to get reflowed again (and may end up wanting
// a next-in-flow where it ends up), unless it is an out of flow frame.
if (NS_FRAME_IS_FULLY_COMPLETE(aFrameReflowStatus)) {
nsIFrame* kidNextInFlow = mFrame->GetNextInFlow();
if (nsnull != kidNextInFlow) {
// Remove all of the childs next-in-flows. Make sure that we ask
// the right parent to do the removal (it's possible that the
// parent is not this because we are executing pullup code).
// Floats will eventually be removed via nsBlockFrame::RemoveFloat
// which detaches the placeholder from the float.
/* XXX promote DeleteChildsNextInFlow to nsIFrame to elminate this cast */
aState.mOverflowTracker->Finish(mFrame);
static_cast<nsHTMLContainerFrame*>(kidNextInFlow->GetParent())
->DeleteNextInFlowChild(mPresContext, kidNextInFlow, PR_TRUE);
}
}
}
return rv;
}
/**
* Attempt to place the block frame within the available space. If
* it fits, apply horizontal positioning (CSS 10.3.3), collapse
* margins (CSS2 8.3.1). Also apply relative positioning.
*/
PRBool
nsBlockReflowContext::PlaceBlock(const nsHTMLReflowState& aReflowState,
PRBool aForceFit,
nsLineBox* aLine,
nsCollapsingMargin& aBottomMarginResult,
nsRect& aInFlowBounds,
nsOverflowAreas& aOverflowAreas,
nsReflowStatus aReflowStatus)
{
// Compute collapsed bottom margin value.
if (NS_FRAME_IS_COMPLETE(aReflowStatus)) {
aBottomMarginResult = mMetrics.mCarriedOutBottomMargin;
aBottomMarginResult.Include(aReflowState.mComputedMargin.bottom);
} else {
// The used bottom-margin is set to zero above a break.
aBottomMarginResult.Zero();
}
nscoord x = mX;
nscoord y = mY;
nscoord backupContainingBlockAdvance = 0;
// Check whether the block's bottom margin collapses with its top
// margin. See CSS 2.1 section 8.3.1; those rules seem to match
// nsBlockFrame::IsEmpty(). Any such block must have zero height so
// check that first. Note that a block can have clearance and still
// have adjoining top/bottom margins, because the clearance goes
// above the top margin.
// Mark the frame as non-dirty; it has been reflowed (or we wouldn't
// be here), and we don't want to assert in CachedIsEmpty()
mFrame->RemoveStateBits(NS_FRAME_IS_DIRTY);
PRBool empty = 0 == mMetrics.height && aLine->CachedIsEmpty();
if (empty) {
// Collapse the bottom margin with the top margin that was already
// applied.
aBottomMarginResult.Include(mTopMargin);
#ifdef NOISY_VERTICAL_MARGINS
printf(" ");
nsFrame::ListTag(stdout, mOuterReflowState.frame);
printf(": ");
nsFrame::ListTag(stdout, mFrame);
printf(" -- collapsing top & bottom margin together; y=%d spaceY=%d\n",
y, mSpace.y);
#endif
// Section 8.3.1 of CSS 2.1 says that blocks with adjoining
// top/bottom margins whose top margin collapses with their
// parent's top margin should have their top border-edge at the
// top border-edge of their parent. We actually don't have to do
// anything special to make this happen. In that situation,
// nsBlockFrame::ShouldApplyTopMargin will have returned PR_FALSE,
// and mTopMargin and aClearance will have been zero in
// ReflowBlock.
// If we did apply our top margin, but now we're collapsing it
// into the bottom margin, we need to back up the containing
// block's y-advance by our top margin so that it doesn't get
// counted twice. Note that here we're allowing the line's bounds
// to become different from the block's position; we do this
// because the containing block will place the next line at the
// line's YMost, and it must place the next line at a different
// point from where this empty block will be.
backupContainingBlockAdvance = mTopMargin.get();
}
// See if the frame fit. If it's the first frame or empty then it
// always fits. If the height is unconstrained then it always fits,
// even if there's some sort of integer overflow that makes y +
// mMetrics.height appear to go beyond the available height.
if (!empty && !aForceFit && mSpace.height != NS_UNCONSTRAINEDSIZE) {
nscoord yMost = y - backupContainingBlockAdvance + mMetrics.height;
if (yMost > mSpace.YMost()) {
// didn't fit, we must acquit.
mFrame->DidReflow(mPresContext, &aReflowState, NS_FRAME_REFLOW_FINISHED);
return PR_FALSE;
}
}
aInFlowBounds = nsRect(x, y - backupContainingBlockAdvance,
mMetrics.width, mMetrics.height);
// Apply CSS relative positioning
const nsStyleDisplay* styleDisp = mFrame->GetStyleDisplay();
if (NS_STYLE_POSITION_RELATIVE == styleDisp->mPosition) {
x += aReflowState.mComputedOffsets.left;
y += aReflowState.mComputedOffsets.top;
}
// Now place the frame and complete the reflow process
nsContainerFrame::FinishReflowChild(mFrame, mPresContext, &aReflowState, mMetrics, x, y, 0);
aOverflowAreas = mMetrics.mOverflowAreas + nsPoint(x, y);
return PR_TRUE;
}
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