1/* 2 * %W% %E% 3 * 4 * (C) Copyright IBM Corp. 1998-2011 - All Rights Reserved 5 * 6 */ 7 8#ifndef __SCRIPTCOMPOSITEFONTINSTANCE_H 9#define __SCRIPTCOMPOSITEFONTINSTANCE_H 10 11#include "layout/LETypes.h" 12#include "layout/LEFontInstance.h" 13 14#include "FontMap.h" 15 16// U_NAMESPACE_BEGIN 17 18class ScriptCompositeFontInstance : public LEFontInstance 19{ 20public: 21 22 ScriptCompositeFontInstance(FontMap *fontMap); 23 24 virtual ~ScriptCompositeFontInstance(); 25 26 /** 27 * Get a physical font which can render the given text. For composite fonts, 28 * if there is no single physical font which can render all of the text, 29 * return a physical font which can render an initial substring of the text, 30 * and set the <code>offset</code> parameter to the end of that substring. 31 * 32 * Internally, the LayoutEngine works with runs of text all in the same 33 * font and script, so it is best to call this method with text which is 34 * in a single script, passing the script code in as a hint. If you don't 35 * know the script of the text, you can use zero, which is the script code 36 * for characters used in more than one script. 37 * 38 * The default implementation of this method is intended for instances of 39 * <code>LEFontInstance</code> which represent a physical font. It returns 40 * <code>this</code> and indicates that the entire string can be rendered. 41 * 42 * This method will return a valid <code>LEFontInstance</code> unless you 43 * have passed illegal parameters, or an internal error has been encountered. 44 * For composite fonts, it may return the warning <code>LE_NO_SUBFONT_WARNING</code> 45 * to indicate that the returned font may not be able to render all of 46 * the text. Whenever a valid font is returned, the <code>offset</code> parameter 47 * will be advanced by at least one. 48 * 49 * Subclasses which implement composite fonts must override this method. 50 * Where it makes sense, they should use the script code as a hint to render 51 * characters from the COMMON script in the font which is used for the given 52 * script. For example, if the input text is a series of Arabic words separated 53 * by spaces, and the script code passed in is <code>arabScriptCode</code> you 54 * should return the font used for Arabic characters for all of the input text, 55 * including the spaces. If, on the other hand, the input text contains characters 56 * which cannot be rendered by the font used for Arabic characters, but which can 57 * be rendered by another font, you should return that font for those characters. 58 * 59 * @param chars - the array of Unicode characters. 60 * @param offset - a pointer to the starting offset in the text. On exit this 61 * will be set the the limit offset of the text which can be 62 * rendered using the returned font. 63 * @param limit - the limit offset for the input text. 64 * @param script - the script hint. 65 * @param success - set to an error code if the arguments are illegal, or no font 66 * can be returned for some reason. May also be set to 67 * <code>LE_NO_SUBFONT_WARNING</code> if the subfont which 68 * was returned cannot render all of the text. 69 * 70 * @return an <code>LEFontInstance</code> for the sub font which can render the characters, or 71 * <code>NULL</code> if there is an error. 72 * 73 * @see LEScripts.h 74 */ 75 virtual const LEFontInstance *getSubFont(const LEUnicode chars[], le_int32 *offset, le_int32 limit, le_int32 script, LEErrorCode &success) const; 76 77 /** 78 * This method maps a single character to a glyph index, using the 79 * font's charcter to glyph map. 80 * 81 * @param ch - the character 82 * 83 * @return the glyph index 84 */ 85 virtual LEGlyphID mapCharToGlyph(LEUnicode32 ch) const; 86 87 virtual const void *getFontTable(LETag tableTag) const; 88 89 virtual le_int32 getUnitsPerEM() const; 90 91 virtual le_int32 getAscent() const; 92 93 virtual le_int32 getDescent() const; 94 95 virtual le_int32 getLeading() const; 96 97 virtual void getGlyphAdvance(LEGlyphID glyph, LEPoint &advance) const; 98 99 virtual le_bool getGlyphPoint(LEGlyphID glyph, le_int32 pointNumber, LEPoint &point) const; 100 101 float getXPixelsPerEm() const; 102 103 float getYPixelsPerEm() const; 104 105 float getScaleFactorX() const; 106 107 float getScaleFactorY() const; 108 109 /** 110 * ICU "poor man's RTTI", returns a UClassID for the actual class. 111 */ 112 virtual inline UClassID getDynamicClassID() const { return getStaticClassID(); } 113 114 /** 115 * ICU "poor man's RTTI", returns a UClassID for this class. 116 */ 117 static inline UClassID getStaticClassID() { return (UClassID)&fgClassID; } 118 119protected: 120 FontMap *fFontMap; 121 122private: 123 124 /** 125 * The address of this static class variable serves as this class's ID 126 * for ICU "poor man's RTTI". 127 */ 128 static const char fgClassID; 129}; 130 131inline const void *ScriptCompositeFontInstance::getFontTable(LETag /*tableTag*/) const 132{ 133 return NULL; 134} 135 136// Can't get units per EM without knowing which sub-font, so 137// return a value that will make units == points 138inline le_int32 ScriptCompositeFontInstance::getUnitsPerEM() const 139{ 140 return 1; 141} 142 143inline le_int32 ScriptCompositeFontInstance::getAscent() const 144{ 145 return fFontMap->getAscent(); 146} 147 148inline le_int32 ScriptCompositeFontInstance::getDescent() const 149{ 150 return fFontMap->getDescent(); 151} 152 153inline le_int32 ScriptCompositeFontInstance::getLeading() const 154{ 155 return fFontMap->getLeading(); 156} 157 158inline float ScriptCompositeFontInstance::getXPixelsPerEm() const 159{ 160 return fFontMap->getPointSize(); 161} 162 163inline float ScriptCompositeFontInstance::getYPixelsPerEm() const 164{ 165 return fFontMap->getPointSize(); 166} 167 168// Can't get a scale factor without knowing the sub-font, so 169// return 1.0. 170inline float ScriptCompositeFontInstance::getScaleFactorX() const 171{ 172 return 1.0; 173} 174 175// Can't get a scale factor without knowing the sub-font, so 176// return 1.0 177inline float ScriptCompositeFontInstance::getScaleFactorY() const 178{ 179 return 1.0; 180} 181 182// U_NAMESPACE_END 183#endif 184