gecko-dev/layout/generic/nsILineIterator.h

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/* -*- 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 1.1 (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.
*
* Contributor(s):
*/
#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!
// Line Flags (see GetLine below)
// This bit is set when the line is wrapping up a block frame. When
// clear, it means that the line contains inline elements.
#define NS_LINE_FLAG_IS_BLOCK 0x1
// This bit, when set, indicates that the line has had a trailing
// white-space compressed. The bit is only set on lines that contain
// inline elements, and is only set when actual white-space is
// compressed.
#define NS_LINE_FLAG_IS_TRIMMED 0x2
// This bit is set when the line ends in some sort of break.
#define NS_LINE_FLAG_ENDS_IN_BREAK 0x4
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).
//
// In addition, aLineFlags will contain flag information about the
// line.
NS_IMETHOD GetLine(PRInt32 aLineNumber,
nsIFrame** aFirstFrameOnLine,
PRInt32* aNumFramesOnLine,
nsRect& aLineBounds,
PRUint32* aLineFlags) = 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___ */