355 lines
12 KiB
C++
355 lines
12 KiB
C++
/*
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* @(#)loengine.h 1.0 00/12/11
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*
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* (C) Copyright IBM Corp. 1998, 1999, 2000 - All Rights Reserved
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*
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*/
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#ifndef __LOENGINE_H
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#define __LOENGINE_H
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#include "unicode/utypes.h"
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#include "unicode/uobject.h"
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#include "unicode/uscript.h"
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#include "unicode/unistr.h"
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#include "layout/LETypes.h"
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#include "layout/LayoutEngine.h"
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U_NAMESPACE_BEGIN
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/**
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* This is a wrapper class designed to allow ICU clients to
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* use LayoutEngine in a way that is consistent with the rest
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* of ICU.
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*
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* (LayoutEngine was developed seperately from ICU and
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* the same source is used in non-ICU environments, so it cannot
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* be changed to match ICU coding conventions).
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*
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* This class is designed for clients who wish to use LayoutEngine
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* to layout complex text. If you need to subclass LayoutEngine,
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* you'll need to use the LayoutEngine interfaces directly.
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*
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* Basically, it creates an instance of LayoutEngine, stashes
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* it in fLayoutEngine, and uses it to implement the layout
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* functionality.
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*
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* Use the createInstance method to create an ICULayoutEngine. Use
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* delete to destroy it. The layoutChars method computes the glyphs
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* and positions, and saves them in the ICULayoutEngine object.
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* Use getGlyphs, getPositions and getCharIndices to retreive this
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* data.
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*
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* You'll also need an implementation of LEFontInstance for your platform.
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*
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* @see LayoutEngine.h
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* @see LEFontInstance.h
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*/
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class U_LAYOUT_API ICULayoutEngine : public UObject {
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private:
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/**
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* This holds the instance of LayoutEngine that does all
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* the work.
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*/
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LayoutEngine *fLayoutEngine;
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/**
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* This no argument constructor is private so that clients
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* can't envoke it. Clients should use createInstance.
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*
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* @see createInstance
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*/
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ICULayoutEngine();
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/**
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* The main constructor. It is defined as private to
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* stop clients from invoking it. Clients should use
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* createInstance.
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*
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* @param layoutEngine - the LayoutEngine that this instance wraps.
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*
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* @see createInstance
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*/
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ICULayoutEngine(LayoutEngine *layoutEngine);
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public:
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/**
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* The destructor. At least on Windows it needs to be
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* virtual to ensure that it deletes the object from the
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* same heap that createInstance will allocate it from. We
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* don't know why this is...
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*
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* @see createInstance
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*/
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virtual ~ICULayoutEngine();
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/**
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* This method computes the glyph, character index and position arrays
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* for the input characters.
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*
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* @param chars - the input character context
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* @param startOffset - the starting offset of the characters to process
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* @param endOffset - the ending offset of the characters to process
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* @param max - the number of characters in the input context
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* @param rightToLeft - true if the characers are in a right to left directional run
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* @param x - the initial X position
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* @param y - the initial Y position
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* @param success - output parameter set to an error code if the operation fails
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*
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* @return the number of glyphs in the glyph array
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*
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* Note; the glyph, character index and position array can be accessed
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* using the getter method below.
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*/
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int32_t layoutChars(const UChar chars[],
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int32_t startOffset,
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int32_t endOffset,
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int32_t maxOffset,
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UBool rightToLeft,
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float x, float y,
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UErrorCode &success);
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/**
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* This method computes the glyph, character index and position arrays
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* for the input characters.
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*
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* @param str - the input character context
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* @param startOffset - the starting offset of the characters to process
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* @param endOffset - the ending offset of the characters to process
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* @param rightToLeft - true if the characers are in a right to left directional run
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* @param x - the initial X position
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* @param y - the initial Y position
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* @param success - output parameter set to an error code if the operation fails
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*
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* @return the number of glyphs in the glyph array
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*
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* Note; the glyph, character index and position array can be accessed
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* using the getter method below.
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*/
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int32_t layoutString(const UnicodeString &str,
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int32_t startOffset,
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int32_t endOffset,
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UBool rightToLeft,
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float x, float y,
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UErrorCode &success);
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/**
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* This method returns the number of glyphs in the glyph array. Note
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* that the number of glyphs will be greater than or equal to the number
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* of characters used to create the LayoutEngine.
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*
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* @return the number of glyphs in the glyph array
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*/
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int32_t countGlyphs() const;
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/**
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* This method copies the glyph array into a caller supplied array.
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* The caller must ensure that the array is large enough to hold all
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* the glyphs.
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*
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* @param glyphs - the destiniation glyph array
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* @param success - output parameter set to an error code if the operation fails
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*/
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void getGlyphs(uint16_t glyphs[], UErrorCode &success);
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/**
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* This method copies the character index array into a caller supplied array.
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* The caller must ensure that the array is large enough to hold a character
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* index for each glyph.
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*
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* @param charIndices - the destiniation character index array
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* @param success - output parameter set to an error code if the operation fails
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*/
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void getCharIndices(int32_t charIndices[], UErrorCode &success);
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/**
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* This method copies the character index array into a caller supplied array.
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* The caller must ensure that the array is large enough to hold a character
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* index for each glyph.
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*
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* @param charIndices - the destiniation character index array
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* @param indexBase - an offset which will be added to each index
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* @param success - output parameter set to an error code if the operation fails
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*/
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void getCharIndices(int32_t charIndices[], int32_t indexBase, UErrorCode &success);
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/**
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* This method copies the position array into a caller supplied array.
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* The caller must ensure that the array is large enough to hold an
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* X and Y position for each glyph, plus an extra X and Y for the
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* advance of the last glyph.
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*
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* @param glyphs - the destiniation position array
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* @param success - output parameter set to an error code if the operation fails
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*/
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void getGlyphPositions(float positions[], UErrorCode &success);
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/**
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* This method returns the X and Y position of the glyph at the
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* given index.
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*
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* Input parameters:
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* @param glyphIndex - the index of the glyph
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*
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* Output parameters:
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* @param x - the glyph's X position
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* @param y - the glyph's Y position
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* @param success - output parameter set to an error code if the operation fails
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*
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*/
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void getGlyphPosition(int32_t glyphIndex, float &x, float &y, UErrorCode &success);
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/**
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* This method returns an ICULayoutEngine capable of laying out text
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* in the given font, script and langauge.
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*
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* @param fontInstance - the font of the text
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* @param scriptCode - the script of the text
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* @param locale - used to determine the language of the text
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* @param success - output parameter set to an error code if the operation fails
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*
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* @return an ICULayoutEngine which can layout text in the given font.
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*
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* NOTE: currently, locale is ignored...
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*
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* @see LEFontInstance
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*/
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static ICULayoutEngine *createInstance(const LEFontInstance *fontInstance,
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UScriptCode script, Locale &locale,
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UErrorCode &success);
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/**
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* ICU "poor man's RTTI", returns a UClassID for the actual class.
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*
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* @draft ICU 2.2
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*/
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virtual inline UClassID getDynamicClassID() const { return getStaticClassID(); }
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/**
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* ICU "poor man's RTTI", returns a UClassID for this class.
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*
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* @draft ICU 2.2
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*/
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static inline UClassID getStaticClassID() { return (UClassID)&fgClassID; }
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private:
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/**
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* The address of this static class variable serves as this class's ID
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* for ICU "poor man's RTTI".
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*/
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static const char fgClassID;
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};
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inline ICULayoutEngine::ICULayoutEngine()
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{
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// nothing at all...
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}
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inline ICULayoutEngine::ICULayoutEngine(LayoutEngine *layoutEngine)
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: fLayoutEngine(layoutEngine)
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{
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// nothing else to do
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}
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inline ICULayoutEngine::~ICULayoutEngine()
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{
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delete fLayoutEngine;
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fLayoutEngine = 0;
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}
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inline int32_t ICULayoutEngine::layoutChars(const UChar chars[],
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int32_t startOffset,
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int32_t endOffset,
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int32_t maxOffset,
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UBool rightToLeft,
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float x, float y,
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UErrorCode &success)
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{
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// NOTE: call reset() so that clients can safely reuse
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fLayoutEngine->reset();
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return fLayoutEngine->layoutChars(chars,
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startOffset,
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endOffset - startOffset,
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maxOffset,
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rightToLeft,
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x, y,
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(LEErrorCode &) success);
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}
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inline int32_t ICULayoutEngine::layoutString(const UnicodeString &str,
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int32_t startOffset,
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int32_t endOffset,
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UBool rightToLeft,
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float x, float y,
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UErrorCode &success)
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{
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int32_t glyphCount = 0;
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int32_t max = str.length();
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UChar *chars = new UChar[max];
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str.extract(0, max, chars);
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// NOTE: call reset() so that clients can safely reuse
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fLayoutEngine->reset();
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glyphCount = fLayoutEngine->layoutChars(chars,
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startOffset,
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endOffset - startOffset,
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max,
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rightToLeft,
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x, y,
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(LEErrorCode &) success);
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delete[] chars;
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return glyphCount;
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}
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inline int32_t ICULayoutEngine::countGlyphs() const
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{
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return fLayoutEngine->getGlyphCount();
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}
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inline void ICULayoutEngine::getGlyphs(uint16_t glyphs[], UErrorCode &success)
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{
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fLayoutEngine->getGlyphs(glyphs, (LEErrorCode &) success);
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}
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inline void ICULayoutEngine::getCharIndices(int32_t charIndices[], UErrorCode &success)
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{
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fLayoutEngine->getCharIndices(charIndices, (LEErrorCode &) success);
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}
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inline void ICULayoutEngine::getCharIndices(int32_t charIndices[], int32_t indexBase, UErrorCode &success)
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{
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fLayoutEngine->getCharIndices(charIndices, indexBase, (LEErrorCode &) success);
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}
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inline void ICULayoutEngine::getGlyphPositions(float positions[], UErrorCode &success)
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{
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fLayoutEngine->getGlyphPositions(positions, (LEErrorCode &) success);
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}
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inline void ICULayoutEngine::getGlyphPosition(int32_t glyphIndex, float &x, float &y, UErrorCode &success)
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{
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fLayoutEngine->getGlyphPosition(glyphIndex, x, y, (LEErrorCode &) success);
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}
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inline ICULayoutEngine *ICULayoutEngine::createInstance(const LEFontInstance *fontInstance,
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UScriptCode script,
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Locale &locale, UErrorCode &success)
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{
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LayoutEngine *engine = LayoutEngine::layoutEngineFactory(fontInstance,
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(le_int32) script,
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0,
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(LEErrorCode &) success);
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return new ICULayoutEngine(engine);
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}
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U_NAMESPACE_END
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#endif
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