gecko-dev/layout/generic/nsILineIterator.h

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/* -*- 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 ***** */
#ifndef nsILineIterator_h___
#define nsILineIterator_h___
#include "nscore.h"
#include "nsCoord.h"
class nsIFrame;
struct nsRect;
// Line Flags (see GetLine below)
// This bit is set when the line is wrapping up a block frame. When
// clear, it means that the line contains inline elements.
#define NS_LINE_FLAG_IS_BLOCK 0x1
// This bit is set when the line ends in some sort of break.
#define NS_LINE_FLAG_ENDS_IN_BREAK 0x4
/**
* Line iterator API.
*
* Lines are numbered from 0 to N, where 0 is the top line and N is
* the bottom line.
*
* Obtain this interface from frames via nsIFrame::GetLineIterator.
* When you are finished using the iterator, call DisposeLineIterator()
* to destroy the iterator if appropriate.
*/
class nsILineIterator
{
protected:
~nsILineIterator() { }
public:
virtual void DisposeLineIterator() = 0;
/**
* The number of lines in the block
*/
virtual PRInt32 GetNumLines() = 0;
/**
* The prevailing direction of lines.
*
* @return true if the CSS direction property for the block is
* "rtl", otherwise false
*/
virtual bool GetDirection() = 0;
// Return structural information about a line. aFirstFrameOnLine is
// the first frame on the line and aNumFramesOnLine is the number of
// frames that are on the line. If the line-number is invalid then
// aFirstFrameOnLine will be nsnull and aNumFramesOnLine will be
// zero.
//
// For valid line numbers, aLineBounds is set to the bounding box of
// the line (which is based on the in-flow position of the frames on
// the line; if a frame was moved because of relative positioning
// then its coordinates may be outside the line bounds).
//
// In addition, aLineFlags will contain flag information about the
// line.
NS_IMETHOD GetLine(PRInt32 aLineNumber,
nsIFrame** aFirstFrameOnLine,
PRInt32* aNumFramesOnLine,
nsRect& aLineBounds,
PRUint32* aLineFlags) = 0;
/**
* Given a frame that's a child of the block, find which line its on
* and return that line index, as long as it's at least as big as
* aStartLine. Returns -1 if the frame cannot be found on lines
* starting with aStartLine.
*/
virtual PRInt32 FindLineContaining(nsIFrame* aFrame,
PRInt32 aStartLine = 0) = 0;
// Given a line number and an X coordinate, find the frame on the
// line that is nearest to the X coordinate. The
// aXIsBeforeFirstFrame and aXIsAfterLastFrame flags are updated
// appropriately.
NS_IMETHOD FindFrameAt(PRInt32 aLineNumber,
nscoord aX,
nsIFrame** aFrameFound,
bool* aXIsBeforeFirstFrame,
bool* aXIsAfterLastFrame) = 0;
// Give the line iterator implementor a chance todo something more complicated than
// nsIFrame::GetNextSibling()
NS_IMETHOD GetNextSiblingOnLine(nsIFrame*& aFrame, PRInt32 aLineNumber) = 0;
#ifdef IBMBIDI
// Check whether visual and logical order of frames within a line are identical.
// If not, return the first and last visual frames
NS_IMETHOD CheckLineOrder(PRInt32 aLine,
bool *aIsReordered,
nsIFrame **aFirstVisual,
nsIFrame **aLastVisual) = 0;
#endif
};
class nsAutoLineIterator
{
public:
nsAutoLineIterator() : mRawPtr(nsnull) { }
nsAutoLineIterator(nsILineIterator *i) : mRawPtr(i) { }
~nsAutoLineIterator() {
if (mRawPtr)
mRawPtr->DisposeLineIterator();
}
operator nsILineIterator*() { return mRawPtr; }
nsILineIterator* operator->() { return mRawPtr; }
nsILineIterator* operator=(nsILineIterator* i) {
if (i == mRawPtr)
return i;
if (mRawPtr)
mRawPtr->DisposeLineIterator();
mRawPtr = i;
return i;
}
private:
nsILineIterator* mRawPtr;
};
#endif /* nsILineIterator_h___ */