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187 lines
6.1 KiB
187 lines
6.1 KiB
/*
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* %W% %E%
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*
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* © 2016 and later: Unicode, Inc. and others.
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* License & terms of use: http://www.unicode.org/copyright.html
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*
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* (C) Copyright IBM Corp. 1998-2011 - All Rights Reserved
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*
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*/
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#ifndef __SCRIPTCOMPOSITEFONTINSTANCE_H
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#define __SCRIPTCOMPOSITEFONTINSTANCE_H
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#include "layout/LETypes.h"
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#include "layout/LEFontInstance.h"
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#include "FontMap.h"
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// U_NAMESPACE_BEGIN
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class ScriptCompositeFontInstance : public LEFontInstance
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{
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public:
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ScriptCompositeFontInstance(FontMap *fontMap);
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virtual ~ScriptCompositeFontInstance();
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/**
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* Get a physical font which can render the given text. For composite fonts,
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* if there is no single physical font which can render all of the text,
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* return a physical font which can render an initial substring of the text,
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* and set the <code>offset</code> parameter to the end of that substring.
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*
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* Internally, the LayoutEngine works with runs of text all in the same
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* font and script, so it is best to call this method with text which is
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* in a single script, passing the script code in as a hint. If you don't
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* know the script of the text, you can use zero, which is the script code
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* for characters used in more than one script.
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*
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* The default implementation of this method is intended for instances of
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* <code>LEFontInstance</code> which represent a physical font. It returns
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* <code>this</code> and indicates that the entire string can be rendered.
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*
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* This method will return a valid <code>LEFontInstance</code> unless you
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* have passed illegal parameters, or an internal error has been encountered.
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* For composite fonts, it may return the warning <code>LE_NO_SUBFONT_WARNING</code>
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* to indicate that the returned font may not be able to render all of
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* the text. Whenever a valid font is returned, the <code>offset</code> parameter
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* will be advanced by at least one.
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*
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* Subclasses which implement composite fonts must override this method.
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* Where it makes sense, they should use the script code as a hint to render
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* characters from the COMMON script in the font which is used for the given
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* script. For example, if the input text is a series of Arabic words separated
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* by spaces, and the script code passed in is <code>arabScriptCode</code> you
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* should return the font used for Arabic characters for all of the input text,
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* including the spaces. If, on the other hand, the input text contains characters
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* which cannot be rendered by the font used for Arabic characters, but which can
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* be rendered by another font, you should return that font for those characters.
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*
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* @param chars - the array of Unicode characters.
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* @param offset - a pointer to the starting offset in the text. On exit this
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* will be set the the limit offset of the text which can be
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* rendered using the returned font.
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* @param limit - the limit offset for the input text.
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* @param script - the script hint.
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* @param success - set to an error code if the arguments are illegal, or no font
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* can be returned for some reason. May also be set to
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* <code>LE_NO_SUBFONT_WARNING</code> if the subfont which
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* was returned cannot render all of the text.
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*
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* @return an <code>LEFontInstance</code> for the sub font which can render the characters, or
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* <code>NULL</code> if there is an error.
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*
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* @see LEScripts.h
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*/
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virtual const LEFontInstance *getSubFont(const LEUnicode chars[], le_int32 *offset, le_int32 limit, le_int32 script, LEErrorCode &success) const;
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/**
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* This method maps a single character to a glyph index, using the
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* font's charcter to glyph map.
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*
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* @param ch - the character
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*
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* @return the glyph index
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*/
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virtual LEGlyphID mapCharToGlyph(LEUnicode32 ch) const;
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virtual const void *getFontTable(LETag tableTag) const;
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virtual le_int32 getUnitsPerEM() const;
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virtual le_int32 getAscent() const;
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virtual le_int32 getDescent() const;
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virtual le_int32 getLeading() const;
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virtual void getGlyphAdvance(LEGlyphID glyph, LEPoint &advance) const;
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virtual le_bool getGlyphPoint(LEGlyphID glyph, le_int32 pointNumber, LEPoint &point) const;
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float getXPixelsPerEm() const;
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float getYPixelsPerEm() const;
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float getScaleFactorX() const;
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float getScaleFactorY() const;
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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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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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static inline UClassID getStaticClassID() { return (UClassID)&fgClassID; }
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protected:
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FontMap *fFontMap;
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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 const void *ScriptCompositeFontInstance::getFontTable(LETag /*tableTag*/) const
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{
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return NULL;
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}
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// Can't get units per EM without knowing which sub-font, so
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// return a value that will make units == points
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inline le_int32 ScriptCompositeFontInstance::getUnitsPerEM() const
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{
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return 1;
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}
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inline le_int32 ScriptCompositeFontInstance::getAscent() const
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{
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return fFontMap->getAscent();
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}
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inline le_int32 ScriptCompositeFontInstance::getDescent() const
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{
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return fFontMap->getDescent();
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}
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inline le_int32 ScriptCompositeFontInstance::getLeading() const
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{
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return fFontMap->getLeading();
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}
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inline float ScriptCompositeFontInstance::getXPixelsPerEm() const
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{
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return fFontMap->getPointSize();
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}
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inline float ScriptCompositeFontInstance::getYPixelsPerEm() const
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{
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return fFontMap->getPointSize();
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}
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// Can't get a scale factor without knowing the sub-font, so
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// return 1.0.
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inline float ScriptCompositeFontInstance::getScaleFactorX() const
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{
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return 1.0;
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}
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// Can't get a scale factor without knowing the sub-font, so
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// return 1.0
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inline float ScriptCompositeFontInstance::getScaleFactorY() const
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{
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return 1.0;
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}
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// U_NAMESPACE_END
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#endif
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