gecko-dev/layout/generic/nsBlockBandData.cpp

271 lines
9.1 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 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):
*
* 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 ***** */
/* code for management of floats that implements space manager interfaces */
#include "nsCOMPtr.h"
#include "nsBlockBandData.h"
#include "nsIFrame.h"
#include "nsHTMLReflowState.h"
#include "nsPresContext.h"
#include "nsIPresShell.h"
nsBlockBandData::nsBlockBandData()
: mSpaceManager(nsnull),
mSpaceManagerX(0),
mSpaceManagerY(0),
mSpace(0, 0)
{
mSize = NS_BLOCK_BAND_DATA_TRAPS;
mTrapezoids = mData;
}
nsBlockBandData::~nsBlockBandData()
{
if (mTrapezoids != mData) {
delete [] mTrapezoids;
}
}
nsresult
nsBlockBandData::Init(nsSpaceManager* aSpaceManager,
const nsSize& aSpace)
{
NS_PRECONDITION(aSpaceManager, "null pointer");
mSpaceManager = aSpaceManager;
aSpaceManager->GetTranslation(mSpaceManagerX, mSpaceManagerY);
mSpace = aSpace;
mLeftFloats = 0;
mRightFloats = 0;
return NS_OK;
}
// Get the available reflow space for the current y coordinate. The
// available space is relative to our coordinate system (0,0) is our
// upper left corner.
nsresult
nsBlockBandData::GetAvailableSpace(nscoord aY, PRBool aRelaxHeightConstraint,
nsRect& aResult)
{
// Get the raw band data for the given Y coordinate
nsresult rv = GetBandData(aY, aRelaxHeightConstraint);
if (NS_FAILED(rv)) { return rv; }
// Compute the bounding rect of the available space, i.e. space
// between any left and right floats.
ComputeAvailSpaceRect();
aResult = mAvailSpace;
#ifdef REALLY_NOISY_COMPUTEAVAILSPACERECT
printf("nsBBD %p GetAvailableSpace(%d) returning (%d, %d, %d, %d)\n",
this, aY, aResult.x, aResult.y, aResult.width, aResult.height);
#endif
return NS_OK;
}
// the code below should never loop more than a very few times.
// this is a safety valve to see if we've gone off the deep end
#define ERROR_TOO_MANY_ITERATIONS 1000
/* nsBlockBandData methods should never call mSpaceManager->GetBandData directly.
* They should always call nsBlockBandData::GetBandData() instead.
*/
nsresult
nsBlockBandData::GetBandData(nscoord aY, PRBool aRelaxHeightConstraint)
{
NS_ASSERTION(mSpaceManager, "bad state, no space manager");
PRInt32 iterations =0;
nsSize space = mSpace;
if (aRelaxHeightConstraint) {
space.height = NS_UNCONSTRAINEDSIZE;
}
nsresult rv = mSpaceManager->GetBandData(aY, space, *this);
while (NS_FAILED(rv)) {
iterations++;
if (iterations>ERROR_TOO_MANY_ITERATIONS)
{
NS_ASSERTION(PR_FALSE, "too many iterations in nsBlockBandData::GetBandData");
return NS_ERROR_FAILURE;
}
// We need more space for our bands
NS_ASSERTION(mTrapezoids, "bad state, no mTrapezoids");
if (mTrapezoids && (mTrapezoids != mData)) {
delete [] mTrapezoids;
}
PRInt32 newSize = mSize * 2;
if (newSize<mCount) {
newSize = mCount;
}
mTrapezoids = new nsBandTrapezoid[newSize];
NS_POSTCONDITION(mTrapezoids, "failure allocating mTrapezoids");
if (!mTrapezoids) {
return NS_ERROR_OUT_OF_MEMORY;
}
mSize = newSize;
rv = mSpaceManager->GetBandData(aY, space, *this);
}
NS_POSTCONDITION(mCount<=mSize, "bad state, count > size");
return NS_OK;
}
/**
* Computes the bounding rect of the available space, i.e. space
* between any left and right floats. Uses the current trapezoid
* data, see nsISpaceManager::GetBandData(). Also updates member
* data "availSpace".
*/
void
nsBlockBandData::ComputeAvailSpaceRect()
{
#ifdef REALLY_NOISY_COMPUTEAVAILSPACERECT
printf("nsBlockBandData::ComputeAvailSpaceRect %p with count %d\n", this, mCount);
#endif
if (0 == mCount) {
mAvailSpace.x = 0;
mAvailSpace.y = 0;
mAvailSpace.width = 0;
mAvailSpace.height = 0;
mLeftFloats = 0;
mRightFloats = 0;
return;
}
nsBandTrapezoid* trapezoid = mTrapezoids;
// The trapezoid to the left of the first right-floated trapezoid.
nsBandTrapezoid* rightTrapezoid = nsnull;
PRInt32 leftFloats = 0;
PRInt32 rightFloats = 0;
if (mCount > 1) {
// If there's more than one trapezoid that means there are floats
PRInt32 i;
// Examine each trapezoid in the band, counting up the number of
// left and right floats. Use the right-most float to
// determine where the right edge of the available space is.
NS_PRECONDITION(mCount<=mSize, "bad state, count > size");
for (i = 0; i < mCount; i++) {
trapezoid = &mTrapezoids[i];
if (trapezoid->mFrames) {
#ifdef REALLY_NOISY_COMPUTEAVAILSPACERECT
printf("band %p checking !Avail trap %p with frame %p\n", this, trapezoid, trapezoid->mFrames);
#endif
const nsSmallVoidArray* frames = trapezoid->mFrames;
const PRInt32 numFrames = frames->Count();
NS_ASSERTION(numFrames > 0, "bad trapezoid frame list");
for (PRInt32 j = 0; j < numFrames; j++) {
nsIFrame* f = static_cast<nsIFrame*>(frames->ElementAt(j));
const nsStyleDisplay* display = f->GetStyleDisplay();
if (NS_STYLE_FLOAT_LEFT == display->mFloats) {
leftFloats++;
}
else if (NS_STYLE_FLOAT_RIGHT == display->mFloats) {
rightFloats++;
if ((nsnull == rightTrapezoid) && (i > 0)) {
rightTrapezoid = &mTrapezoids[i - 1];
}
}
}
}
}
}
else if (mTrapezoids[0].mFrames) {
// We have a float using up all the available space
leftFloats = 1;
}
#ifdef REALLY_NOISY_COMPUTEAVAILSPACERECT
printf("band %p has floats %d, %d\n", this, leftFloats, rightFloats);
#endif
mLeftFloats = leftFloats;
mRightFloats = rightFloats;
// We look for available space in the last trapezoid before the
// first right float, or in the last trapezoid if there is no right
// float or no trapezoid before the first right float.
if (nsnull != rightTrapezoid) {
trapezoid = rightTrapezoid;
}
trapezoid->GetRect(mAvailSpace);
// When there is no available space, we still need a proper X
// coordinate to place objects that end up here anyway.
const nsSmallVoidArray* frames = trapezoid->mFrames;
if (frames) {
// It's not clear what coordinate to use when there is no
// available space and the space is multiply occupied...So: If
// any of the floats that are a part of the trapezoid are left
// floats then we move over to the right edge of the
// unavaliable space.
const PRInt32 numFrames = frames->Count();
NS_ASSERTION(numFrames > 0, "bad trapezoid frame list");
for (PRInt32 j = 0; j < numFrames; j++) {
nsIFrame* f = static_cast<nsIFrame*>(frames->ElementAt(j));
const nsStyleDisplay* display = f->GetStyleDisplay();
if (NS_STYLE_FLOAT_LEFT == display->mFloats) {
mAvailSpace.x = mAvailSpace.XMost();
break;
}
}
mAvailSpace.width = 0;
}
// Fixup width
if (NS_UNCONSTRAINEDSIZE == mSpace.width) {
mAvailSpace.width = NS_UNCONSTRAINEDSIZE;
}
#ifdef REALLY_NOISY_COMPUTEAVAILSPACERECT
printf(" ComputeAvailSpaceRect settting state mAvailSpace (%d,%d,%d,%d)\n",
mAvailSpace.x, mAvailSpace.y, mAvailSpace.width, mAvailSpace.height);
#endif
}
#ifdef DEBUG
void nsBlockBandData::List()
{
printf("nsBlockBandData %p sm=%p, sm coord = (%d,%d), mSpace = (%d,%d)\n",
this, mSpaceManager, mSpaceManagerX, mSpaceManagerY,
mSpace.width, mSpace.height);
printf(" availSpace=(%d, %d, %d, %d), floats l=%d r=%d\n",
mAvailSpace.x, mAvailSpace.y, mAvailSpace.width, mAvailSpace.height,
mLeftFloats, mRightFloats);
}
#endif