125 lines
4.0 KiB
C++
125 lines
4.0 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef nsILineIterator_h___
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#define nsILineIterator_h___
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#include "nscore.h"
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#include "nsPoint.h"
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#include "mozilla/Attributes.h"
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class nsIFrame;
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struct nsRect;
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/**
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* Line iterator API.
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*
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* Lines are numbered from 0 to N, where 0 is the top line and N is
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* the bottom line.
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*
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* Obtain this interface from frames via nsIFrame::GetLineIterator.
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* When you are finished using the iterator, call DisposeLineIterator()
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* to destroy the iterator if appropriate.
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*/
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class nsILineIterator
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{
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protected:
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~nsILineIterator() { }
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public:
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virtual void DisposeLineIterator() = 0;
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/**
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* The number of lines in the block
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*/
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virtual int32_t GetNumLines() = 0;
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/**
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* The prevailing direction of lines.
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*
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* @return true if the CSS direction property for the block is
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* "rtl", otherwise false
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*
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*XXX after bug 924851 change this to return a UBiDiDirection
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*/
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virtual bool GetDirection() = 0;
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// Return structural information about a line. aFirstFrameOnLine is
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// the first frame on the line and aNumFramesOnLine is the number of
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// frames that are on the line. If the line-number is invalid then
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// aFirstFrameOnLine will be nullptr and aNumFramesOnLine will be
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// zero.
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//
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// For valid line numbers, aLineBounds is set to the bounding box of
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// the line (which is based on the in-flow position of the frames on
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// the line; if a frame was moved because of relative positioning
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// then its coordinates may be outside the line bounds).
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NS_IMETHOD GetLine(int32_t aLineNumber,
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nsIFrame** aFirstFrameOnLine,
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int32_t* aNumFramesOnLine,
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nsRect& aLineBounds) = 0;
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/**
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* Given a frame that's a child of the block, find which line its on
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* and return that line index, as long as it's at least as big as
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* aStartLine. Returns -1 if the frame cannot be found on lines
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* starting with aStartLine.
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*/
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virtual int32_t FindLineContaining(nsIFrame* aFrame,
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int32_t aStartLine = 0) = 0;
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// Given a line number and a coordinate, find the frame on the line
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// that is nearest to aPos along the inline axis. (The block-axis coord
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// of aPos is irrelevant.)
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// The aPosIsBeforeFirstFrame and aPosIsAfterLastFrame flags are updated
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// appropriately.
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NS_IMETHOD FindFrameAt(int32_t aLineNumber,
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nsPoint aPos,
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nsIFrame** aFrameFound,
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bool* aPosIsBeforeFirstFrame,
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bool* aPosIsAfterLastFrame) = 0;
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// Give the line iterator implementor a chance todo something more complicated than
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// nsIFrame::GetNextSibling()
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NS_IMETHOD GetNextSiblingOnLine(nsIFrame*& aFrame, int32_t aLineNumber) = 0;
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// Check whether visual and logical order of frames within a line are identical.
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// If not, return the first and last visual frames
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NS_IMETHOD CheckLineOrder(int32_t aLine,
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bool *aIsReordered,
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nsIFrame **aFirstVisual,
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nsIFrame **aLastVisual) = 0;
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};
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class nsAutoLineIterator
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{
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public:
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nsAutoLineIterator() : mRawPtr(nullptr) { }
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MOZ_IMPLICIT nsAutoLineIterator(nsILineIterator *i) : mRawPtr(i) { }
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~nsAutoLineIterator() {
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if (mRawPtr)
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mRawPtr->DisposeLineIterator();
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}
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operator nsILineIterator*() { return mRawPtr; }
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nsILineIterator* operator->() { return mRawPtr; }
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nsILineIterator* operator=(nsILineIterator* i) {
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if (i == mRawPtr)
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return i;
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if (mRawPtr)
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mRawPtr->DisposeLineIterator();
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mRawPtr = i;
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return i;
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}
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private:
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nsILineIterator* mRawPtr;
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};
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#endif /* nsILineIterator_h___ */
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