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