/*--------------------------------------------------------------------*//*:Ignore this sentence.
Copyright (C) 1999, 2001 SIL International. All rights reserved.

Distributable under the terms of either the Common Public License or the
GNU Lesser General Public License, as specified in the LICENSING.txt file.

File: ITextSource.h
Responsibility: Sharon Correll
Last reviewed: Not yet.

Description:
	An interface for a text source that is used by the Graphite engine.
-------------------------------------------------------------------------------*//*:End Ignore*/
#ifdef _MSC_VER
#pragma once
#endif
#ifndef IGRTXTSRC_INCLUDED
#define IGRTXTSRC_INCLUDED


#include "GrAppData.h"
#include "GrStructs.h"
#include "GrResult.h"

namespace gr
{

/*----------------------------------------------------------------------------------------------
	Class: ITextSource
	This class provides an interface for a text source for the Graphite engine.
----------------------------------------------------------------------------------------------*/
class ITextSource
{
public:
	virtual ~ITextSource() {};
	virtual UtfType utfEncodingForm() = 0;
	virtual size_t getLength() = 0;
	virtual size_t fetch(toffset ichMin, size_t cch, utf32 * prgchBuffer) = 0;
	virtual size_t fetch(toffset ichMin, size_t cch, utf16 * prgchwBuffer) = 0;
	virtual size_t fetch(toffset ichMin, size_t cch, utf8  * prgchsBuffer) = 0;
	virtual bool getRightToLeft(toffset ich) = 0;
	virtual unsigned int getDirectionDepth(toffset ich) = 0;
	virtual float getVerticalOffset(toffset ich) = 0;
	virtual isocode getLanguage(toffset ich) = 0;

	virtual std::pair<toffset, toffset> propertyRange(toffset ich) = 0;
	virtual size_t getFontFeatures(toffset ich, FeatureSetting * prgfset) = 0;
	virtual bool sameSegment(toffset ich1, toffset ich2) = 0;
};


/*----------------------------------------------------------------------------------------------
	Class: IColorTextSource
	Defines a method to get the color informtion from the text source. 
	It is needed for SegmentPainters that want to handle color.
----------------------------------------------------------------------------------------------*/
class IColorTextSource : public ITextSource
{
public:
	virtual void getColors(toffset ich, int * pclrFore, int * pclrBack) = 0;
};

} // namespace gr

#if defined(GR_NO_NAMESPACE)
using namespace gr;
#endif

#endif // !IGRTXTSRC_INCLUDED