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Diffstat (limited to 'layout/generic/nsILineIterator.h')
-rw-r--r-- | layout/generic/nsILineIterator.h | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/layout/generic/nsILineIterator.h b/layout/generic/nsILineIterator.h new file mode 100644 index 000000000..7d20691f4 --- /dev/null +++ b/layout/generic/nsILineIterator.h @@ -0,0 +1,124 @@ +/* -*- 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___ */ |