michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: #ifndef nsILineIterator_h___
michael@0: #define nsILineIterator_h___
michael@0: 
michael@0: #include "nscore.h"
michael@0: #include "nsCoord.h"
michael@0: 
michael@0: class nsIFrame;
michael@0: struct nsRect;
michael@0: 
michael@0: // Line Flags (see GetLine below)
michael@0: 
michael@0: // This bit is set when the line is wrapping up a block frame. When
michael@0: // clear, it means that the line contains inline elements.
michael@0: #define NS_LINE_FLAG_IS_BLOCK           0x1
michael@0: 
michael@0: // This bit is set when the line ends in some sort of break.
michael@0: #define NS_LINE_FLAG_ENDS_IN_BREAK      0x4
michael@0: 
michael@0: /**
michael@0:  * Line iterator API.
michael@0:  *
michael@0:  * Lines are numbered from 0 to N, where 0 is the top line and N is
michael@0:  * the bottom line.
michael@0:  *
michael@0:  * Obtain this interface from frames via nsIFrame::GetLineIterator.
michael@0:  * When you are finished using the iterator, call DisposeLineIterator()
michael@0:  * to destroy the iterator if appropriate.
michael@0:  */
michael@0: class nsILineIterator
michael@0: {
michael@0: protected:
michael@0:   ~nsILineIterator() { }
michael@0: 
michael@0: public:
michael@0:   virtual void DisposeLineIterator() = 0;
michael@0: 
michael@0:   /**
michael@0:    * The number of lines in the block
michael@0:    */
michael@0:   virtual int32_t GetNumLines() = 0;
michael@0: 
michael@0:   /**
michael@0:    * The prevailing direction of lines.
michael@0:    *
michael@0:    * @return true if the CSS direction property for the block is
michael@0:    *         "rtl", otherwise false
michael@0:    */
michael@0:   virtual bool GetDirection() = 0;
michael@0: 
michael@0:   // Return structural information about a line. aFirstFrameOnLine is
michael@0:   // the first frame on the line and aNumFramesOnLine is the number of
michael@0:   // frames that are on the line. If the line-number is invalid then
michael@0:   // aFirstFrameOnLine will be nullptr and aNumFramesOnLine will be
michael@0:   // zero.
michael@0:   //
michael@0:   // For valid line numbers, aLineBounds is set to the bounding box of
michael@0:   // the line (which is based on the in-flow position of the frames on
michael@0:   // the line; if a frame was moved because of relative positioning
michael@0:   // then its coordinates may be outside the line bounds).
michael@0:   //
michael@0:   // In addition, aLineFlags will contain flag information about the
michael@0:   // line.
michael@0:   NS_IMETHOD GetLine(int32_t aLineNumber,
michael@0:                      nsIFrame** aFirstFrameOnLine,
michael@0:                      int32_t* aNumFramesOnLine,
michael@0:                      nsRect& aLineBounds,
michael@0:                      uint32_t* aLineFlags) = 0;
michael@0: 
michael@0:   /**
michael@0:    * Given a frame that's a child of the block, find which line its on
michael@0:    * and return that line index, as long as it's at least as big as
michael@0:    * aStartLine.  Returns -1 if the frame cannot be found on lines
michael@0:    * starting with aStartLine.
michael@0:    */
michael@0:   virtual int32_t FindLineContaining(nsIFrame* aFrame,
michael@0:                                      int32_t aStartLine = 0) = 0;
michael@0: 
michael@0:   // Given a line number and an X coordinate, find the frame on the
michael@0:   // line that is nearest to the X coordinate. The
michael@0:   // aXIsBeforeFirstFrame and aXIsAfterLastFrame flags are updated
michael@0:   // appropriately.
michael@0:   NS_IMETHOD FindFrameAt(int32_t aLineNumber,
michael@0:                          nscoord aX,
michael@0:                          nsIFrame** aFrameFound,
michael@0:                          bool* aXIsBeforeFirstFrame,
michael@0:                          bool* aXIsAfterLastFrame) = 0;
michael@0: 
michael@0:   // Give the line iterator implementor a chance todo something more complicated than
michael@0:   // nsIFrame::GetNextSibling()
michael@0:   NS_IMETHOD GetNextSiblingOnLine(nsIFrame*& aFrame, int32_t aLineNumber) = 0;
michael@0: 
michael@0:   // Check whether visual and logical order of frames within a line are identical.
michael@0:   //  If not, return the first and last visual frames
michael@0:   NS_IMETHOD CheckLineOrder(int32_t                  aLine,
michael@0:                             bool                     *aIsReordered,
michael@0:                             nsIFrame                 **aFirstVisual,
michael@0:                             nsIFrame                 **aLastVisual) = 0;
michael@0: };
michael@0: 
michael@0: class nsAutoLineIterator
michael@0: {
michael@0: public:
michael@0:   nsAutoLineIterator() : mRawPtr(nullptr) { }
michael@0:   nsAutoLineIterator(nsILineIterator *i) : mRawPtr(i) { }
michael@0: 
michael@0:   ~nsAutoLineIterator() {
michael@0:     if (mRawPtr)
michael@0:       mRawPtr->DisposeLineIterator();
michael@0:   }
michael@0: 
michael@0:   operator nsILineIterator*() { return mRawPtr; }
michael@0:   nsILineIterator* operator->() { return mRawPtr; }
michael@0: 
michael@0:   nsILineIterator* operator=(nsILineIterator* i) {
michael@0:     if (i == mRawPtr)
michael@0:       return i;
michael@0: 
michael@0:     if (mRawPtr)
michael@0:       mRawPtr->DisposeLineIterator();
michael@0: 
michael@0:     mRawPtr = i;
michael@0:     return i;
michael@0:   }
michael@0: 
michael@0: private:
michael@0:   nsILineIterator* mRawPtr;
michael@0: };
michael@0: 
michael@0: #endif /* nsILineIterator_h___ */