gecko-dev/layout/generic/nsBlockReflowContext.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (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/NPL/
*
* 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 Netscape are Copyright (C) 1998
* Netscape Communications Corporation. All Rights Reserved.
*/
#include "nsBlockReflowContext.h"
#include "nsLineLayout.h"
#include "nsHTMLIIDs.h"
#include "nsISpaceManager.h"
#include "nsIFontMetrics.h"
#include "nsIPresContext.h"
#include "nsIContent.h"
#include "nsIStyleContext.h"
#include "nsHTMLContainerFrame.h"
#include "nsBlockFrame.h"
#include "nsIDOMHTMLParagraphElement.h"
#include "nsCOMPtr.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(nsIPresContext* aPresContext,
const nsHTMLReflowState& aParentRS,
PRBool aComputeMaxElementSize)
: mPresContext(aPresContext),
mOuterReflowState(aParentRS),
mMetrics(aComputeMaxElementSize ? &mMaxElementSize : nsnull),
mMaxElementSize(0, 0)
{
mStyleSpacing = nsnull;
}
PRBool
nsBlockReflowContext::IsHTMLParagraph(nsIFrame* aFrame)
{
PRBool result = PR_FALSE;
nsCOMPtr<nsIContent> content;
nsresult rv = aFrame->GetContent(getter_AddRefs(content));
if (NS_SUCCEEDED(rv) && content) {
nsCOMPtr<nsIDOMHTMLParagraphElement> p(do_QueryInterface(content));
if (p) {
result = PR_TRUE;
}
}
return result;
}
nscoord
nsBlockReflowContext::ComputeCollapsedTopMargin(nsIPresContext* aPresContext,
nsHTMLReflowState& aRS)
{
// Get aFrame's top margin
nscoord topMargin = aRS.mComputedMargin.top;
// Calculate aFrame's generational top-margin from its child
// blocks. Note that if aFrame has a non-zero top-border or
// top-padding then this step is skipped because it will be a margin
// root.
nscoord generationalTopMargin = 0;
if (0 == aRS.mComputedBorderPadding.top) {
nsBlockFrame* bf;
if (NS_SUCCEEDED(aRS.frame->QueryInterface(kBlockFrameCID, (void**)&bf))) {
// Ask the block frame for the top block child that we should
// try to collapse the top margin with.
nsIFrame* childFrame = bf->GetTopBlockChild();
if (nsnull != childFrame) {
// Here is where we recurse. 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.
nsSize availSpace(aRS.mComputedWidth, aRS.mComputedHeight);
nsHTMLReflowState reflowState(*aPresContext, aRS, childFrame,
availSpace);
generationalTopMargin =
ComputeCollapsedTopMargin(aPresContext, reflowState);
}
}
}
// Now compute the collapsed top-margin value. At this point we have
// the child frames effective top margin value.
nscoord collapsedTopMargin = MaxMargin(topMargin, generationalTopMargin);
#ifdef NOISY_VERTICAL_MARGINS
nsFrame::ListTag(stdout, aRS.frame);
printf(": topMargin=%d generationalTopMargin=%d => %d\n",
topMargin, generationalTopMargin, collapsedTopMargin);
#endif
return collapsedTopMargin;
}
nsresult
nsBlockReflowContext::ReflowBlock(nsIFrame* aFrame,
const nsRect& aSpace,
PRBool aApplyTopMargin,
nscoord aPrevBottomMargin,
PRBool aIsAdjacentWithTop,
nsMargin& aComputedOffsets,
nsReflowStatus& aFrameReflowStatus)
{
nsresult rv = NS_OK;
mFrame = aFrame;
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.
nsReflowReason reason = eReflowReason_Resize;
nsFrameState state;
aFrame->GetFrameState(&state);
if (NS_FRAME_FIRST_REFLOW & state) {
reason = eReflowReason_Initial;
}
else if (mNextRCFrame == aFrame) {
reason = eReflowReason_Incremental;
// Make sure we only incrementally reflow once
mNextRCFrame = nsnull;
}
// Setup reflow state for reflowing the frame
// XXX subtract out vertical margin?
nsSize availSpace(aSpace.width, aSpace.height);
nsHTMLReflowState reflowState(*mPresContext, mOuterReflowState, aFrame,
availSpace, reason);
aComputedOffsets = reflowState.mComputedOffsets;
reflowState.mLineLayout = nsnull;
if (!aIsAdjacentWithTop) {
reflowState.isTopOfPage = PR_FALSE; // make sure this is cleared
}
mIsTable = NS_STYLE_DISPLAY_TABLE == reflowState.mStyleDisplay->mDisplay;
mComputedWidth = reflowState.mComputedWidth;
nscoord topMargin = 0;
if (aApplyTopMargin) {
// Compute the childs collapsed top margin (its margin collpased
// with its first childs top-margin -- recursively).
topMargin = ComputeCollapsedTopMargin(mPresContext, reflowState);
#ifdef NOISY_VERTICAL_MARGINS
nsFrame::ListTag(stdout, mOuterReflowState.frame);
printf(": reflowing ");
nsFrame::ListTag(stdout, aFrame);
printf(" prevBottomMargin=%d, collapsedTopMargin=%d => %d\n",
aPrevBottomMargin, topMargin,
MaxMargin(topMargin, aPrevBottomMargin));
#endif
// Collapse that value with the previous bottom margin to perform
// the sibling to sibling collaspe.
topMargin = MaxMargin(topMargin, aPrevBottomMargin);
// Adjust the available height if its constrained so that the
// child frame doesn't think it can reflow into its margin area.
// XXX write me
#if 0
availSpace.y += topMargin;
if (NS_UNCONSTRAINEDSIZE != availHeight) {
availSpace.height -= topMargin;
}
#endif
}
mTopMargin = topMargin;
// 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 = reflowState.mComputedMargin;
mStyleSpacing = reflowState.mStyleSpacing;
nscoord x = aSpace.x + mMargin.left;
nscoord y = aSpace.y + topMargin;
mX = x;
mY = y;
// Let frame know that we are reflowing it
nsIHTMLReflow* htmlReflow;
rv = aFrame->QueryInterface(kIHTMLReflowIID, (void**)&htmlReflow);
if (NS_FAILED(rv)) {
return rv;
}
htmlReflow->WillReflow(*mPresContext);
#ifdef DEBUG
mMetrics.width = nscoord(0xdeadbeef);
mMetrics.height = nscoord(0xdeadbeef);
mMetrics.ascent = nscoord(0xdeadbeef);
mMetrics.descent = nscoord(0xdeadbeef);
if (nsnull != mMetrics.maxElementSize) {
mMetrics.maxElementSize->width = nscoord(0xdeadbeef);
mMetrics.maxElementSize->height = nscoord(0xdeadbeef);
}
#endif
// Adjust spacemanager 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;
mOuterReflowState.mSpaceManager->Translate(tx, ty);
rv = htmlReflow->Reflow(*mPresContext, mMetrics, reflowState,
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, aFrame);
printf(" metrics=%d,%d!\n", mMetrics.width, mMetrics.height);
}
if ((nsnull != mMetrics.maxElementSize) &&
((nscoord(0xdeadbeef) == mMetrics.maxElementSize->width) ||
(nscoord(0xdeadbeef) == mMetrics.maxElementSize->height))) {
printf("nsBlockReflowContext: ");
nsFrame::ListTag(stdout, aFrame);
printf(" didn't set max-element-size!\n");
mMetrics.maxElementSize->width = 0;
mMetrics.maxElementSize->height = 0;
}
#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 ((nsnull != mMetrics.maxElementSize) &&
((mMetrics.maxElementSize->width > mMetrics.width) ||
(mMetrics.maxElementSize->height > mMetrics.height))) {
printf("nsBlockReflowContext: ");
nsFrame::ListTag(stdout, aFrame);
printf(": WARNING: maxElementSize=%d,%d > metrics=%d,%d\n",
mMetrics.maxElementSize->width,
mMetrics.maxElementSize->height,
mMetrics.width, mMetrics.height);
}
#endif
if ((mMetrics.width == nscoord(0xdeadbeef)) ||
(mMetrics.height == nscoord(0xdeadbeef)) ||
(mMetrics.ascent == nscoord(0xdeadbeef)) ||
(mMetrics.descent == nscoord(0xdeadbeef))) {
printf("nsBlockReflowContext: ");
nsFrame::ListTag(stdout, aFrame);
printf(" didn't set whad %d,%d,%d,%d!\n",
mMetrics.width, mMetrics.height,
mMetrics.ascent, mMetrics.descent);
}
}
#endif
#ifdef NOISY_MAX_ELEMENT_SIZE
if (!NS_INLINE_IS_BREAK_BEFORE(aFrameReflowStatus)) {
if (nsnull != mMetrics.maxElementSize) {
printf(" ");
nsFrame::ListTag(stdout, aFrame);
printf(": maxElementSize=%d,%d wh=%d,%d\n",
mMetrics.maxElementSize->width,
mMetrics.maxElementSize->height,
mMetrics.width, mMetrics.height);
}
}
#endif
aFrame->GetFrameState(&state);
if (0 == (NS_FRAME_OUTSIDE_CHILDREN & state)) {
// Provide combined area for child that doesn't have any
mMetrics.mCombinedArea.x = 0;
mMetrics.mCombinedArea.y = 0;
mMetrics.mCombinedArea.width = mMetrics.width;
mMetrics.mCombinedArea.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 == reason) {
aFrame->SetFrameState(state & ~NS_FRAME_FIRST_REFLOW);
}
if (!NS_INLINE_IS_BREAK_BEFORE(aFrameReflowStatus)) {
// 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).
if (NS_FRAME_IS_COMPLETE(aFrameReflowStatus)) {
nsIFrame* kidNextInFlow;
aFrame->GetNextInFlow(&kidNextInFlow);
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 */
nsHTMLContainerFrame* parent;
aFrame->GetParent((nsIFrame**)&parent);
parent->DeleteChildsNextInFlow(*mPresContext, aFrame);
}
}
}
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(PRBool aForceFit,
const nsMargin& aComputedOffsets,
nscoord* aBottomMarginResult,
nsRect& aInFlowBounds,
nsRect& aCombinedRect)
{
// Compute collapsed bottom margin value
nscoord collapsedBottomMargin = MaxMargin(mMetrics.mCarriedOutBottomMargin,
mMargin.bottom);
*aBottomMarginResult = collapsedBottomMargin;
// See if the block will fit in the available space
PRBool fits = PR_TRUE;
nscoord x = mX;
nscoord y = mY;
// When deciding whether it's an empty paragraph we also need to take into
// account the combined area
if ((0 == mMetrics.height) && (0 == mMetrics.mCombinedArea.height)) {
if (IsHTMLParagraph(mFrame)) {
// Special "feature" for HTML compatability - empty paragraphs
// collapse into nothingness, including their margins. Signal
// the special nature here by returning -1.
*aBottomMarginResult = -1;
#ifdef NOISY_VERTICAL_MARGINS
printf(" ");
nsFrame::ListTag(stdout, mOuterReflowState.frame);
printf(": ");
nsFrame::ListTag(stdout, mFrame);
printf(" -- zapping top & bottom margin; y=%d spaceY=%d\n",
y, mSpace.y);
#endif
}
else {
// Collapse the bottom margin with the top margin that was already
// applied.
nscoord newBottomMargin = MaxMargin(collapsedBottomMargin, mTopMargin);
*aBottomMarginResult = newBottomMargin;
#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
}
// For empty blocks we revert the y coordinate back so that the
// top margin is no longer applied.
nsIHTMLReflow* htmlReflow;
nsresult rv = mFrame->QueryInterface(kIHTMLReflowIID, (void**)&htmlReflow);
if (NS_SUCCEEDED(rv)) {
// XXX This isn't good enough. What if the floater was placed
// downward, just below another floater?
nscoord dy = mSpace.y - mY;
htmlReflow->MoveInSpaceManager(mPresContext,
mOuterReflowState.mSpaceManager, 0, dy);
}
y = mSpace.y;
// Empty blocks do not have anything special done to them and they
// always fit. Note: don't force the width to 0
nsRect r(x, y, mMetrics.width, 0);
mFrame->SetRect(r);
aInFlowBounds = r;
// Retain combined area information in case we contain a floater
// and nothing else.
aCombinedRect = mMetrics.mCombinedArea;
aCombinedRect.x += x;
aCombinedRect.y += y;
}
else {
// See if the frame fit. If its the first frame then it always
// fits.
if (aForceFit || (y + mMetrics.height <= mSpace.YMost())) {
// Get style unit associated with the left and right margins
nsStyleUnit leftUnit = mStyleSpacing->mMargin.GetLeftUnit();
if (eStyleUnit_Inherit == leftUnit) {
leftUnit = GetRealMarginLeftUnit();
}
nsStyleUnit rightUnit = mStyleSpacing->mMargin.GetRightUnit();
if (eStyleUnit_Inherit == rightUnit) {
rightUnit = GetRealMarginRightUnit();
}
// 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) {
// 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 (mMetrics.width != mComputedWidth) {
if (eStyleUnit_Auto == leftUnit) {
x = 0;
mMargin.left = 0;
}
if (eStyleUnit_Auto == rightUnit) {
mMargin.right = 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() -
(x + mMetrics.width + mMargin.right);
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
x += remainingSpace / 2;
}
else {
// When the left margin is auto we right align the block
x += remainingSpace;
}
}
else if (eStyleUnit_Auto != rightUnit) {
// The block/table doesn't have auto margins.
PRBool doCSS = PR_TRUE;
if (mIsTable) {
const nsStyleText* styleText;
mOuterReflowState.frame->GetStyleData(eStyleStruct_Text,
(const nsStyleStruct*&)styleText);
// This is a navigator compatability case: tables are
// affected by the text alignment of the containing
// block. CSS doesn't do this, so we use special
// text-align attribute values to signal these
// compatability cases.
switch (styleText->mTextAlign) {
case NS_STYLE_TEXT_ALIGN_MOZ_RIGHT:
x += remainingSpace;
doCSS = PR_FALSE;
break;
case NS_STYLE_TEXT_ALIGN_MOZ_CENTER:
x += remainingSpace / 2;
doCSS = PR_FALSE;
break;
}
}
if (doCSS) {
// XXX It's not clear we can ever get here because for normal blocks,
// their size will be well defined by the nsHTMLReflowState logic
// (maybe width=0 cases get here?)
// 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.mStyleDisplay->mDirection;
if (NS_STYLE_DIRECTION_RTL == direction) {
// The left margin becomes auto
x += remainingSpace;
}
else {
// The right margin becomes auto which is a no-op
}
}
}
}
}
// Update the in-flow bounding box's bounds. Include the margins.
aInFlowBounds.SetRect(x, y,
mMetrics.width + mMargin.right,
mMetrics.height);
// Apply CSS relative positioning to update x,y coordinates
const nsStylePosition* stylePos;
mFrame->GetStyleData(eStyleStruct_Position,
(const nsStyleStruct*&)stylePos);
if (NS_STYLE_POSITION_RELATIVE == stylePos->mPosition) {
x += aComputedOffsets.left;
y += aComputedOffsets.top;
}
// Compute combined-rect in callers coordinate system. The value
// returned in the reflow metrics is relative to the child
// frame.
aCombinedRect.x = mMetrics.mCombinedArea.x + x;
aCombinedRect.y = mMetrics.mCombinedArea.y + y;
aCombinedRect.width = mMetrics.mCombinedArea.width;
aCombinedRect.height = mMetrics.mCombinedArea.height;
// Now place the frame
mFrame->SetRect(nsRect(x, y, mMetrics.width, mMetrics.height));
// If the block frame ended up moving then we need to slide
// anything inside of it that impacts the space manager
// (otherwise the impacted space in the space manager will be
// out of sync with where the frames really are).
nscoord dx = x - mX;
nscoord dy = y - mY;
if ((0 != dx) || (0 != dy)) {
nsIHTMLReflow* htmlReflow;
nsresult rv;
rv = mFrame->QueryInterface(kIHTMLReflowIID, (void**)&htmlReflow);
if (NS_SUCCEEDED(rv)) {
// If the child has any floaters that impact the space manager,
// slide them now
htmlReflow->MoveInSpaceManager(mPresContext,
mOuterReflowState.mSpaceManager,
dx, dy);
}
}
// Adjust the max-element-size in the metrics to take into
// account the margins around the block element. Note that we
// use the collapsed top and bottom margin values.
if (nsnull != mMetrics.maxElementSize) {
nsSize* m = mMetrics.maxElementSize;
// Do not allow auto margins to impact the max-element size
// since they are springy and don't really count!
if (eStyleUnit_Auto != leftUnit) {
m->width += mMargin.left;
}
if (eStyleUnit_Auto != rightUnit) {
m->width += mMargin.right;
}
#if XXX_fix_me
// Margin height should affect the max-element height (since
// auto top/bottom margins are always zero)
m->height += mTopMargin + mBottomMargin;
#endif
}
}
else {
fits = PR_FALSE;
}
}
return fits;
}
// If we have an inherited margin its possible that its auto all the
// way up to the top of the tree. If that is the case, we need to know
// it.
nsStyleUnit
nsBlockReflowContext::GetRealMarginLeftUnit()
{
nsStyleUnit unit = eStyleUnit_Inherit;
nsIStyleContext* sc;
mFrame->GetStyleContext(&sc);
while ((nsnull != sc) && (eStyleUnit_Inherit == unit)) {
// Get parent style context
nsIStyleContext* psc;
psc = sc->GetParent();
NS_RELEASE(sc);
sc = psc;
if (nsnull != sc) {
const nsStyleSpacing* spacing = (const nsStyleSpacing*)
sc->GetStyleData(eStyleStruct_Spacing);
unit = spacing->mMargin.GetLeftUnit();
}
}
NS_IF_RELEASE(sc);
return unit;
}
// If we have an inherited margin its possible that its auto all the
// way up to the top of the tree. If that is the case, we need to know
// it.
nsStyleUnit
nsBlockReflowContext::GetRealMarginRightUnit()
{
nsStyleUnit unit = eStyleUnit_Inherit;
nsIStyleContext* sc;
mFrame->GetStyleContext(&sc);
while ((nsnull != sc) && (eStyleUnit_Inherit == unit)) {
// Get parent style context
nsIStyleContext* psc;
psc = sc->GetParent();
NS_RELEASE(sc);
sc = psc;
if (nsnull != sc) {
const nsStyleSpacing* spacing = (const nsStyleSpacing*)
sc->GetStyleData(eStyleStruct_Spacing);
unit = spacing->mMargin.GetRightUnit();
}
}
NS_IF_RELEASE(sc);
return unit;
}