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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsILineIterator_h___
#define nsILineIterator_h___
#include "nscore.h"
#include "nsPoint.h"
#include "mozilla/Attributes.h"
class nsIFrame;
struct nsRect;
/**
* 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 int32_t GetNumLines() = 0;
/**
* The prevailing direction of lines.
*
* @return true if the CSS direction property for the block is
* "rtl", otherwise false
*
*XXX after bug 924851 change this to return a UBiDiDirection
*/
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 nullptr 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).
NS_IMETHOD GetLine(int32_t aLineNumber,
nsIFrame** aFirstFrameOnLine,
int32_t* aNumFramesOnLine,
nsRect& aLineBounds) = 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 int32_t FindLineContaining(nsIFrame* aFrame,
int32_t aStartLine = 0) = 0;
// Given a line number and a coordinate, find the frame on the line
// that is nearest to aPos along the inline axis. (The block-axis coord
// of aPos is irrelevant.)
// The aPosIsBeforeFirstFrame and aPosIsAfterLastFrame flags are updated
// appropriately.
NS_IMETHOD FindFrameAt(int32_t aLineNumber,
nsPoint aPos,
nsIFrame** aFrameFound,
bool* aPosIsBeforeFirstFrame,
bool* aPosIsAfterLastFrame) = 0;
// Give the line iterator implementor a chance todo something more complicated than
// nsIFrame::GetNextSibling()
NS_IMETHOD GetNextSiblingOnLine(nsIFrame*& aFrame, int32_t aLineNumber) = 0;
// 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(int32_t aLine,
bool *aIsReordered,
nsIFrame **aFirstVisual,
nsIFrame **aLastVisual) = 0;
};
class nsAutoLineIterator
{
public:
nsAutoLineIterator() : mRawPtr(nullptr) { }
MOZ_IMPLICIT 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___ */
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