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gecko-dev/layout/generic/nsBlockReflowContext.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:
/* ***** 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 ***** */
#include "nsBlockReflowContext.h"
#include "nsLineLayout.h"
#include "nsSpaceManager.h"
#include "nsIFontMetrics.h"
#include "nsPresContext.h"
#include "nsFrameManager.h"
#include "nsIContent.h"
#include "nsStyleContext.h"
#include "nsHTMLReflowCommand.h"
#include "nsHTMLContainerFrame.h"
#include "nsBlockFrame.h"
#include "nsLineBox.h"
#include "nsIDOMHTMLTableCellElement.h"
#include "nsIDOMHTMLBodyElement.h"
#include "nsLayoutAtoms.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,
PRBool aComputeMaxElementWidth,
PRBool aComputeMaximumWidth)
: mPresContext(aPresContext),
mOuterReflowState(aParentRS),
mMetrics(aComputeMaxElementWidth),
mComputeMaximumWidth(aComputeMaximumWidth)
{
mStyleBorder = nsnull;
mStyleMargin = nsnull;
mStylePadding = nsnull;
if (mComputeMaximumWidth)
mMetrics.mFlags |= NS_REFLOW_CALC_MAX_WIDTH;
}
PRBool
nsBlockReflowContext::ComputeCollapsedTopMargin(const nsHTMLReflowState& aRS,
nsCollapsingMargin* aMargin, nsIFrame* aClearanceFrame, PRBool* aMayNeedRetry)
{
// 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;
// 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.
void* bf;
if (0 == aRS.mComputedBorderPadding.top &&
!(aRS.frame->GetStateBits() & NS_BLOCK_MARGIN_ROOT) &&
NS_SUCCEEDED(aRS.frame->QueryInterface(kBlockFrameCID, &bf))) {
nsBlockFrame* block = NS_STATIC_CAST(nsBlockFrame*, aRS.frame);
for (nsBlockFrame::line_iterator line = block->begin_lines(),
line_end = block->end_lines();
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 = line->IsEmpty();
if (line->IsBlock()) {
nsBlockFrame* kidBlock = NS_STATIC_CAST(nsBlockFrame*, line->mFirstChild);
if (kidBlock == aClearanceFrame) {
line->SetHasClearance();
line->MarkDirty();
dirtiedLine = PR_TRUE;
break;
}
// 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. Since the reflow reason is irrelevant, we'll
// arbitrarily make it a `resize' to avoid the path-plucking
// behavior if we're in an incremental reflow.
nsSize availSpace(aRS.mComputedWidth, aRS.mComputedHeight);
nsHTMLReflowState reflowState(kidBlock->GetPresContext(),
aRS, kidBlock,
availSpace, eReflowReason_Resize);
// Record that we're being optimistic by assuming the kid
// has no clearance
if (kidBlock->GetStyleDisplay()->mBreakType != NS_STYLE_CLEAR_NONE) {
*aMayNeedRetry = PR_TRUE;
}
if (ComputeCollapsedTopMargin(reflowState, aMargin, aClearanceFrame, aMayNeedRetry)) {
line->MarkDirty();
dirtiedLine = PR_TRUE;
}
if (isEmpty)
aMargin->Include(reflowState.mComputedMargin.bottom);
}
if (!isEmpty)
break;
}
}
#ifdef NOISY_VERTICAL_MARGINS
nsFrame::ListTag(stdout, aRS.frame);
printf(": => %d\n", aMargin->get());
#endif
return dirtiedLine;
}
struct nsBlockHorizontalAlign {
nscoord mXOffset; // left edge
nscoord mLeftMargin;
nscoord mRightMargin;
};
// Given the width of the block frame and a suggested x-offset calculate
// the actual x-offset taking into account horizontal alignment. Also returns
// the actual left and right margin
void
nsBlockReflowContext::AlignBlockHorizontally(nscoord aWidth,
nsBlockHorizontalAlign &aAlign)
{
// Initialize OUT parameters
aAlign.mLeftMargin = mMargin.left;
aAlign.mRightMargin = mMargin.right;
// Get style unit associated with the left and right margins
nsStyleUnit leftUnit = mStyleMargin->mMargin.GetLeftUnit();
nsStyleUnit rightUnit = mStyleMargin->mMargin.GetRightUnit();
// Apply post-reflow horizontal alignment. When a block element
// doesn't use it all of the available width then we need to
// align it using the text-align property.
if (NS_UNCONSTRAINEDSIZE != mSpace.width &&
NS_UNCONSTRAINEDSIZE != mOuterReflowState.mComputedWidth) {
// It is possible that the object reflowed was given a
// constrained width and ended up picking a different width
// (e.g. a table width a set width that ended up larger
// because its contents required it). When this happens we
// need to recompute auto margins because the reflow state's
// computations are no longer valid.
if (aWidth != mComputedWidth) {
if (eStyleUnit_Auto == leftUnit) {
aAlign.mXOffset = mSpace.x;
aAlign.mLeftMargin = 0;
}
if (eStyleUnit_Auto == rightUnit) {
aAlign.mRightMargin = 0;
}
}
// Compute how much remaining space there is, and in special
// cases apply it (normally we should get zero here because of
// the logic in nsHTMLReflowState).
nscoord remainingSpace = mSpace.XMost() - (aAlign.mXOffset + aWidth +
aAlign.mRightMargin);
if (remainingSpace > 0) {
// The block/table frame didn't use all of the available
// space. Synthesize margins for its horizontal placement.
if (eStyleUnit_Auto == leftUnit) {
if (eStyleUnit_Auto == rightUnit) {
// When both margins are auto, we center the block
aAlign.mXOffset += remainingSpace / 2;
}
else {
// When the left margin is auto we right align the block
aAlign.mXOffset += remainingSpace;
}
}
else if (eStyleUnit_Auto != rightUnit) {
// The block/table doesn't have auto margins.
// For normal (non-table) blocks we don't get here because
// nsHTMLReflowState::CalculateBlockSideMargins handles this.
// (I think there may be an exception to that, though...)
// We use a special value of the text-align property for
// HTML alignment (the CENTER element and DIV ALIGN=...)
// since it acts on blocks and tables rather than just
// being a text-align.
// So, check the text-align value from the parent to see if
// it has one of these special values.
const nsStyleText* styleText = mOuterReflowState.mStyleText;
if (styleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_RIGHT) {
aAlign.mXOffset += remainingSpace;
} else if (styleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER) {
aAlign.mXOffset += remainingSpace / 2;
} else {
// If we don't have a special text-align value indicating
// HTML alignment, then use the CSS rules.
// When neither margin is auto then the block is said to
// be over constrained, Depending on the direction, choose
// which margin to treat as auto.
PRUint8 direction = mOuterReflowState.mStyleVisibility->mDirection;
if (NS_STYLE_DIRECTION_RTL == direction) {
// The left margin becomes auto
aAlign.mXOffset += remainingSpace;
}
//else {
// The right margin becomes auto which is a no-op
//}
}
}
}
}
}
static void
ComputeShrinkwrapMargins(const nsStyleMargin* aStyleMargin, nscoord aWidth,
nsMargin& aMargin, nscoord& aXToUpdate)
{
nscoord boxWidth = aWidth;
float leftPct = 0.0, rightPct = 0.0;
const nsStyleSides& margin = aStyleMargin->mMargin;
if (eStyleUnit_Percent == margin.GetLeftUnit()) {
nsStyleCoord coord;
leftPct = margin.GetLeft(coord).GetPercentValue();
} else {
boxWidth += aMargin.left;
}
if (eStyleUnit_Percent == margin.GetRightUnit()) {
nsStyleCoord coord;
rightPct = margin.GetRight(coord).GetPercentValue();
} else {
boxWidth += aMargin.right;
}
// The total shrink wrap width "sww" (i.e., the width that the
// containing block needs to be to shrink-wrap this block) is
// calculated by the expression:
// sww = bw + (mp * sww)
// where "bw" is the box width (frame width plus margins that aren't
// percentage based) and "mp" are the total margin percentages (i.e.,
// the left percentage value plus the right percentage value).
// Solving for "sww" gives:
// sww = bw / (1 - mp)
// Note that this is only well defined for "mp" less than 100% and
// greater than -100% (XXXldb but we only accept 0 to 100%).
float marginPct = leftPct + rightPct;
if (marginPct >= 1.0) {
// Ignore the right percentage and just use the left percentage
// XXX Pay attention to direction property...
marginPct = leftPct;
rightPct = 0.0;
}
if ((marginPct > 0.0) && (marginPct < 1.0)) {
double shrinkWrapWidth = float(boxWidth) / (1.0 - marginPct);
if (eStyleUnit_Percent == margin.GetLeftUnit()) {
aMargin.left = NSToCoordFloor((float)(shrinkWrapWidth * leftPct));
aXToUpdate += aMargin.left;
}
if (eStyleUnit_Percent == margin.GetRightUnit()) {
aMargin.right = NSToCoordFloor((float)(shrinkWrapWidth * rightPct));
}
}
}
static void
nsPointDtor(void *aFrame, nsIAtom *aPropertyName,
void *aPropertyValue, void *aDtorData)
{
nsPoint *point = NS_STATIC_CAST(nsPoint*, aPropertyValue);
delete point;
}
nsresult
nsBlockReflowContext::ReflowBlock(const nsRect& aSpace,
PRBool aApplyTopMargin,
nsCollapsingMargin& aPrevMargin,
nscoord aClearance,
PRBool aIsAdjacentWithTop,
nsMargin& aComputedOffsets,
nsHTMLReflowState& aFrameRS,
nsReflowStatus& aFrameReflowStatus)
{
nsresult rv = NS_OK;
mFrame = aFrameRS.frame;
mSpace = aSpace;
// Get reflow reason set correctly. It's possible that a child was
// created and then it was decided that it could not be reflowed
// (for example, a block frame that isn't at the start of a
// line). In this case the reason will be wrong so we need to check
// the frame state.
aFrameRS.reason = eReflowReason_Resize;
if (NS_FRAME_FIRST_REFLOW & mFrame->GetStateBits()) {
aFrameRS.reason = eReflowReason_Initial;
}
else if (mOuterReflowState.reason == eReflowReason_Incremental) {
// If the frame we're about to reflow is on the reflow path, then
// propagate the reflow as `incremental' so it unwinds correctly
// to the target frames below us.
PRBool frameIsOnReflowPath = mOuterReflowState.path->HasChild(mFrame);
if (frameIsOnReflowPath)
aFrameRS.reason = eReflowReason_Incremental;
// But...if the incremental reflow command is a StyleChanged
// reflow and its target is the current block, change the reason
// to `style change', so that it propagates through the entire
// subtree.
nsHTMLReflowCommand* rc = mOuterReflowState.path->mReflowCommand;
if (rc) {
nsReflowType type;
rc->GetType(type);
if (type == eReflowType_StyleChanged)
aFrameRS.reason = eReflowReason_StyleChange;
else if (type == eReflowType_ReflowDirty &&
(mFrame->GetStateBits() & NS_FRAME_IS_DIRTY) &&
!frameIsOnReflowPath) {
aFrameRS.reason = eReflowReason_Dirty;
}
}
}
else if (mOuterReflowState.reason == eReflowReason_StyleChange) {
aFrameRS.reason = eReflowReason_StyleChange;
}
else if (mOuterReflowState.reason == eReflowReason_Dirty) {
if (mFrame->GetStateBits() & NS_FRAME_IS_DIRTY)
aFrameRS.reason = eReflowReason_Dirty;
}
const nsStyleDisplay* display = mFrame->GetStyleDisplay();
aComputedOffsets = aFrameRS.mComputedOffsets;
if (NS_STYLE_POSITION_RELATIVE == display->mPosition) {
nsPropertyTable *propTable = mPresContext->PropertyTable();
nsPoint *offsets = NS_STATIC_CAST(nsPoint*,
propTable->GetProperty(mFrame, nsLayoutAtoms::computedOffsetProperty));
if (offsets)
offsets->MoveTo(aComputedOffsets.left, aComputedOffsets.top);
else {
offsets = new nsPoint(aComputedOffsets.left, aComputedOffsets.top);
if (offsets)
propTable->SetProperty(mFrame, nsLayoutAtoms::computedOffsetProperty,
offsets, nsPointDtor, nsnull);
}
}
aFrameRS.mLineLayout = nsnull;
if (!aIsAdjacentWithTop) {
aFrameRS.mFlags.mIsTopOfPage = PR_FALSE; // make sure this is cleared
}
mComputedWidth = aFrameRS.mComputedWidth;
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;
}
}
// 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.
mMargin = aFrameRS.mComputedMargin;
mStyleBorder = aFrameRS.mStyleBorder;
mStyleMargin = aFrameRS.mStyleMargin;
mStylePadding = aFrameRS.mStylePadding;
nscoord x;
nscoord y = mSpace.y + mTopMargin.get() + aClearance;
// If it's a right floated element, then calculate the x-offset
// differently
if (NS_STYLE_FLOAT_RIGHT == aFrameRS.mStyleDisplay->mFloats) {
nscoord frameWidth;
if (NS_UNCONSTRAINEDSIZE == aFrameRS.mComputedWidth) {
// Use the current frame width
frameWidth = mFrame->GetSize().width;
} else {
frameWidth = aFrameRS.mComputedWidth +
aFrameRS.mComputedBorderPadding.left +
aFrameRS.mComputedBorderPadding.right;
}
// if this is an unconstrained width reflow, then just place the float at the left margin
if (NS_UNCONSTRAINEDSIZE == mSpace.width)
x = mSpace.x;
else
x = mSpace.XMost() - mMargin.right - frameWidth;
} else {
x = mSpace.x + mMargin.left;
}
mX = x;
mY = y;
// If it's an auto-width table, then it doesn't behave like other blocks
// XXX why not for a floating table too?
if (aFrameRS.mStyleDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE &&
!aFrameRS.mStyleDisplay->IsFloating()) {
// If this isn't the table's initial reflow, then use its existing
// width to determine where it will be placed horizontally
if (aFrameRS.reason != eReflowReason_Initial) {
nsBlockHorizontalAlign align;
align.mXOffset = x;
AlignBlockHorizontally(mFrame->GetSize().width, align);
// Don't reset "mX". because PlaceBlock() will recompute the
// x-offset and expects "mX" to be at the left margin edge
x = align.mXOffset;
}
}
// Compute the translation to be used for adjusting the spacemanagager
// coordinate system for the frame. The spacemanager coordinates are
// <b>inside</b> the callers border+padding, but the x/y coordinates
// are not (recall that frame coordinates are relative to the parents
// origin and that the parents border/padding is <b>inside</b> the
// parent frame. Therefore we have to subtract out the parents
// border+padding before translating.
nscoord tx = x - mOuterReflowState.mComputedBorderPadding.left;
nscoord ty = y - mOuterReflowState.mComputedBorderPadding.top;
// If the element is relatively positioned, then adjust x and y accordingly
if (NS_STYLE_POSITION_RELATIVE == aFrameRS.mStyleDisplay->mPosition) {
x += aFrameRS.mComputedOffsets.left;
y += aFrameRS.mComputedOffsets.top;
}
// Let frame know that we are reflowing it
mFrame->WillReflow(mPresContext);
// Position it and its view (if it has one)
// Note: Use "x" and "y" and not "mX" and "mY" because they more accurately
// represents where we think the block will be placed
mFrame->SetPosition(nsPoint(x, y));
nsContainerFrame::PositionFrameView(mFrame);
#ifdef DEBUG
mMetrics.width = nscoord(0xdeadbeef);
mMetrics.height = nscoord(0xdeadbeef);
mMetrics.ascent = nscoord(0xdeadbeef);
mMetrics.descent = nscoord(0xdeadbeef);
if (mMetrics.mComputeMEW) {
mMetrics.mMaxElementWidth = nscoord(0xdeadbeef);
}
#endif
mOuterReflowState.mSpaceManager->Translate(tx, ty);
// See if this is the child's initial reflow and we are supposed to
// compute our maximum width
if (mComputeMaximumWidth && (eReflowReason_Initial == aFrameRS.reason)) {
mOuterReflowState.mSpaceManager->PushState();
nscoord oldAvailableWidth = aFrameRS.availableWidth;
nscoord oldComputedWidth = aFrameRS.mComputedWidth;
aFrameRS.availableWidth = NS_UNCONSTRAINEDSIZE;
aFrameRS.mComputedWidth = NS_UNCONSTRAINEDSIZE;
rv = mFrame->Reflow(mPresContext, mMetrics, aFrameRS, aFrameReflowStatus);
// Update the reflow metrics with the maximum width
mMetrics.mMaximumWidth = mMetrics.width;
#ifdef NOISY_REFLOW
printf("*** nsBlockReflowContext::ReflowBlock block %p returning max width %d\n",
mFrame, mMetrics.mMaximumWidth);
#endif
// The second reflow is just as a resize reflow with the constrained
// width
aFrameRS.availableWidth = oldAvailableWidth;
aFrameRS.mComputedWidth = oldComputedWidth;
aFrameRS.reason = eReflowReason_Resize;
mOuterReflowState.mSpaceManager->PopState();
}
rv = mFrame->Reflow(mPresContext, mMetrics, aFrameRS, aFrameReflowStatus);
mOuterReflowState.mSpaceManager->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.mComputeMEW &&
(nscoord(0xdeadbeef) == mMetrics.mMaxElementWidth)) {
printf("nsBlockReflowContext: ");
nsFrame::ListTag(stdout, mFrame);
printf(" didn't set max-element-size!\n");
}
#ifdef REALLY_NOISY_MAX_ELEMENT_SIZE
// Note: there are common reflow situations where this *correctly*
// occurs; so only enable this debug noise when you really need to
// analyze in detail.
if (mMetrics.mComputeMEW &&
(mMetrics.mMaxElementWidth > mMetrics.width)) {
printf("nsBlockReflowContext: ");
nsFrame::ListTag(stdout, mFrame);
printf(": WARNING: maxElementWidth=%d > metrics=%d\n",
mMetrics.mMaxElementWidth, mMetrics.width);
}
#endif
if ((mMetrics.width == nscoord(0xdeadbeef)) ||
(mMetrics.height == nscoord(0xdeadbeef)) ||
(mMetrics.ascent == nscoord(0xdeadbeef)) ||
(mMetrics.descent == nscoord(0xdeadbeef))) {
printf("nsBlockReflowContext: ");
nsFrame::ListTag(stdout, mFrame);
printf(" didn't set whad %d,%d,%d,%d!\n",
mMetrics.width, mMetrics.height,
mMetrics.ascent, mMetrics.descent);
}
}
#endif
#ifdef DEBUG
if (nsBlockFrame::gNoisyMaxElementWidth) {
nsFrame::IndentBy(stdout, nsBlockFrame::gNoiseIndent);
if (!NS_INLINE_IS_BREAK_BEFORE(aFrameReflowStatus)) {
if (mMetrics.mComputeMEW) {
printf(" ");
nsFrame::ListTag(stdout, mFrame);
printf(": maxElementSize=%d wh=%d,%d\n",
mMetrics.mMaxElementWidth,
mMetrics.width, mMetrics.height);
}
}
}
#endif
if (!(NS_FRAME_OUTSIDE_CHILDREN & mFrame->GetStateBits())) {
// Provide overflow area for child that doesn't have any
mMetrics.mOverflowArea.x = 0;
mMetrics.mOverflowArea.y = 0;
mMetrics.mOverflowArea.width = mMetrics.width;
mMetrics.mOverflowArea.height = mMetrics.height;
}
// Now that frame has been reflowed at least one time make sure that
// the NS_FRAME_FIRST_REFLOW bit is cleared so that never give it an
// initial reflow reason again.
if (eReflowReason_Initial == aFrameRS.reason) {
mFrame->RemoveStateBits(NS_FRAME_FIRST_REFLOW);
}
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_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)
/* XXX promote DeleteChildsNextInFlow to nsIFrame to elminate this cast */
NS_STATIC_CAST(nsHTMLContainerFrame*, kidNextInFlow->GetParent())
->DeleteNextInFlowChild(mPresContext, kidNextInFlow);
}
}
}
// If the block is shrink wrapping its width, then see if we have percentage
// based margins. If so, we can calculate them now that we know the shrink
// wrap width
if (NS_SHRINKWRAPWIDTH == aFrameRS.mComputedWidth) {
ComputeShrinkwrapMargins(aFrameRS.mStyleMargin, mMetrics.width, mMargin, mX);
}
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,
const nsMargin& aComputedOffsets,
nsCollapsingMargin& aBottomMarginResult,
nsRect& aInFlowBounds,
nsRect& aCombinedRect)
{
// Compute collapsed bottom margin value
aBottomMarginResult = mMetrics.mCarriedOutBottomMargin;
aBottomMarginResult.Include(mMargin.bottom);
// See if the block will fit in the available space
PRBool fits;
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.
if (0 == mMetrics.height && aLine->CachedIsEmpty())
{
// 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
// Empty blocks always fit
fits = PR_TRUE;
// 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();
}
else {
// See if the frame fit. If it's the first frame 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.
// XXX This is a bit of a hack. We really need to use floats in layout!
if (aForceFit ||
mSpace.height == NS_UNCONSTRAINEDSIZE ||
y + mMetrics.height <= mSpace.YMost())
{
fits = PR_TRUE;
// Adjust the max-element-size in the metrics to take into
// account the margins around the block element.
// Do not allow auto margins to impact the max-element size
// since they are springy and don't really count!
if (mMetrics.mComputeMEW) {
nsMargin maxElemMargin;
const nsStyleSides &styleMargin = mStyleMargin->mMargin;
nsStyleCoord coord;
if (styleMargin.GetLeftUnit() == eStyleUnit_Coord)
maxElemMargin.left = styleMargin.GetLeft(coord).GetCoordValue();
else
maxElemMargin.left = 0;
if (styleMargin.GetRightUnit() == eStyleUnit_Coord)
maxElemMargin.right = styleMargin.GetRight(coord).GetCoordValue();
else
maxElemMargin.right = 0;
nscoord dummyXOffset;
// Base the margins on the max-element size
ComputeShrinkwrapMargins(mStyleMargin, mMetrics.mMaxElementWidth,
maxElemMargin, dummyXOffset);
mMetrics.mMaxElementWidth += maxElemMargin.left + maxElemMargin.right;
}
// do the same for the maximum width
if (mComputeMaximumWidth) {
nsMargin maxWidthMargin;
const nsStyleSides &styleMargin = mStyleMargin->mMargin;
nsStyleCoord coord;
if (styleMargin.GetLeftUnit() == eStyleUnit_Coord)
maxWidthMargin.left = styleMargin.GetLeft(coord).GetCoordValue();
else
maxWidthMargin.left = 0;
if (styleMargin.GetRightUnit() == eStyleUnit_Coord)
maxWidthMargin.right = styleMargin.GetRight(coord).GetCoordValue();
else
maxWidthMargin.right = 0;
nscoord dummyXOffset;
// Base the margins on the maximum width
ComputeShrinkwrapMargins(mStyleMargin, mMetrics.mMaximumWidth,
maxWidthMargin, dummyXOffset);
mMetrics.mMaximumWidth += maxWidthMargin.left + maxWidthMargin.right;
}
}
else {
// Send the DidReflow() notification, but don't bother placing
// the frame
mFrame->DidReflow(mPresContext, &aReflowState, NS_FRAME_REFLOW_FINISHED);
fits = PR_FALSE;
}
}
if (fits) {
// Calculate the actual x-offset and left and right margin
nsBlockHorizontalAlign align;
align.mXOffset = x;
AlignBlockHorizontally(mMetrics.width, align);
x = align.mXOffset;
mMargin.left = align.mLeftMargin;
mMargin.right = align.mRightMargin;
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 += aComputedOffsets.left;
y += aComputedOffsets.top;
}
// Now place the frame and complete the reflow process
nsContainerFrame::FinishReflowChild(mFrame, mPresContext, &aReflowState, mMetrics, x, y, 0);
aCombinedRect = mMetrics.mOverflowArea + nsPoint(x, y);
}
return fits;
}
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