gecko-dev/layout/generic/nsILineIterator.h
kipp%netscape.com 11644c02d0 new
1999-05-13 00:54:03 +00:00

90 lines
3.8 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (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/NPL/
*
* 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 Netscape are Copyright (C) 1998
* Netscape Communications Corporation. All Rights Reserved.
*/
#ifndef nsILineIterator_h___
#define nsILineIterator_h___
#include "nsISupports.h"
/* a6cf90ff-15b3-11d2-932e-00805f8add32 */
#define NS_ILINE_ITERATOR_IID \
{ 0xa6cf90ff, 0x15b3, 0x11d2,{0x93, 0x2e, 0x00, 0x80, 0x5f, 0x8a, 0xdd, 0x32}}
// Line iterator API.
//
// Lines are numbered from 0 to N, where 0 is the top line and N is
// the bottom line.
//
// NOTE: while you can get this interface by doing a slezy hacky
// QueryInterface on block frames, it isn't like a normal com
// interface: its not reflexive (you can't query back to the block
// frame) and unlike other frames, it *IS* reference counted so don't
// forget to NS_RELEASE it when you are done with it!
class nsILineIterator : public nsISupports {
public:
NS_DEFINE_STATIC_IID_ACCESSOR(NS_ILINE_ITERATOR_IID)
// Return the number of lines in the block.
NS_IMETHOD GetNumLines(PRInt32* aResult) = 0;
// Return the prevailing direction for the line. aIsRightToLeft will
// be set to PR_TRUE if the CSS direction property for the block is
// "rtl", otherwise aIsRightToLeft will be set to PR_FALSE.
NS_IMETHOD GetDirection(PRBool* aIsRightToLeft) = 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).
NS_IMETHOD GetLine(PRInt32 aLineNumber,
nsIFrame** aFirstFrameOnLine,
PRInt32* aNumFramesOnLine,
nsRect& aLineBounds) = 0;
// Given a frame thats a child of the block, find which line its on
// and return that line index into aIndexResult. aIndexResult will
// be set to -1 if the frame cannot be found.
NS_IMETHOD FindLineContaining(nsIFrame* aFrame,
PRInt32* aLineNumberResult) = 0;
// Given a Y coordinate relative to the block that provided this
// line iterator, find the line that contains the Y
// coordinate. Returns -1 in aLineNumberResult if the Y coordinate
// is above the first line. Returns N (where N is the number of
// lines) if the Y coordinate is below the last line.
NS_IMETHOD FindLineAt(nscoord aY,
PRInt32* aLineNumberResult) = 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,
PRBool* aXIsBeforeFirstFrame,
PRBool* aXIsAfterLastFrame) = 0;
};
#endif /* nsILineIterator_h___ */