+++ /dev/null
-/*
- * (C) Copyright IBM Corp. 1998-2014 - All Rights Reserved
- *
- */
-
-#ifndef __OPENTYPELAYOUTENGINE_H
-#define __OPENTYPELAYOUTENGINE_H
-
-#include "LETypes.h"
-#include "LEGlyphFilter.h"
-#include "LEFontInstance.h"
-#include "LayoutEngine.h"
-#include "LETableReference.h"
-
-#include "GlyphSubstitutionTables.h"
-#include "GlyphDefinitionTables.h"
-#include "GlyphPositioningTables.h"
-
-U_NAMESPACE_BEGIN
-
-/**
- * OpenTypeLayoutEngine implements complex text layout for OpenType fonts - that is
- * fonts which have GSUB and GPOS tables associated with them. In order to do this,
- * the glyph processsing step described for LayoutEngine is further broken into three
- * steps:
- *
- * 1) Character processing - this step analyses the characters and assigns a list of OpenType
- * feature tags to each one. It may also change, remove or add characters, and change
- * their order.
- *
- * 2) Glyph processing - This step performs character to glyph mapping,and uses the GSUB
- * table associated with the font to perform glyph substitutions, such as ligature substitution.
- *
- * 3) Glyph post processing - in cases where the font doesn't directly contain a GSUB table,
- * the previous two steps may have generated "fake" glyph indices to use with a "canned" GSUB
- * table. This step turns those glyph indices into actual font-specific glyph indices, and may
- * perform any other adjustments requried by the previous steps.
- *
- * OpenTypeLayoutEngine will also use the font's GPOS table to apply position adjustments
- * such as kerning and accent positioning.
- *
- * @see LayoutEngine
- *
- * @internal
- */
-class U_LAYOUT_API OpenTypeLayoutEngine : public LayoutEngine
-{
-public:
- /**
- * This is the main constructor. It constructs an instance of OpenTypeLayoutEngine for
- * a particular font, script and language. It takes the GSUB table as a parameter since
- * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has an
- * OpenType font.
- *
- * @param fontInstance - the font
- * @param scriptCode - the script
- * @param langaugeCode - the language
- * @param gsubTable - the GSUB table
- * @param success - set to an error code if the operation fails
- *
- * @see LayoutEngine::layoutEngineFactory
- * @see ScriptAndLangaugeTags.h for script and language codes
- *
- * @internal
- */
- OpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
- le_int32 typoFlags, const LEReferenceTo<GlyphSubstitutionTableHeader> &gsubTable, LEErrorCode &success);
-
- /**
- * This constructor is used when the font requires a "canned" GSUB table which can't be known
- * until after this constructor has been invoked.
- *
- * @param fontInstance - the font
- * @param scriptCode - the script
- * @param langaugeCode - the language
- * @param success - set to an error code if the operation fails
- *
- * @internal
- */
- OpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
- le_int32 typoFlags, LEErrorCode &success);
-
- /**
- * The destructor, virtual for correct polymorphic invocation.
- *
- * @internal
- */
- virtual ~OpenTypeLayoutEngine();
-
- /**
- * A convenience method used to convert the script code into
- * the four byte script tag required by OpenType.
- * For Indic languages where multiple script tags exist,
- * the version 1 (old style) tag is returned.
- *
- * @param scriptCode - the script code
- *
- * @return the four byte script tag
- *
- * @internal
- */
- static LETag getScriptTag(le_int32 scriptCode);
- /**
- * A convenience method used to convert the script code into
- * the four byte script tag required by OpenType.
- * For Indic languages where multiple script tags exist,
- * the version 2 tag is returned.
- *
- * @param scriptCode - the script code
- *
- * @return the four byte script tag
- *
- * @internal
- */
- static LETag getV2ScriptTag(le_int32 scriptCode);
-
- /**
- * A convenience method used to convert the langauge code into
- * the four byte langauge tag required by OpenType.
- *
- * @param languageCode - the language code
- *
- * @return the four byte language tag
- *
- * @internal
- */
- static LETag getLangSysTag(le_int32 languageCode);
-
- /**
- * ICU "poor man's RTTI", returns a UClassID for the actual class.
- *
- * @deprecated ICU 54. See {@link icu::LayoutEngine}
- */
- virtual UClassID getDynamicClassID() const;
-
- /**
- * ICU "poor man's RTTI", returns a UClassID for this class.
- *
- * @deprecated ICU 54. See {@link icu::LayoutEngine}
- */
- static UClassID getStaticClassID();
-
- /**
- * The array of language tags, indexed by language code.
- *
- * @internal
- */
- static const LETag languageTags[];
-
-private:
-
- /**
- * This method is used by the constructors to convert the script
- * and language codes to four byte tags and save them.
- */
- void setScriptAndLanguageTags();
-
- /**
- * The array of script tags, indexed by script code.
- */
- static const LETag scriptTags[];
-
- /**
- * apply the typoflags. Only called by the c'tors.
- */
- void applyTypoFlags();
-
-protected:
- /**
- * A set of "default" features. The default characterProcessing method
- * will apply all of these features to every glyph.
- *
- * @internal
- */
- FeatureMask fFeatureMask;
-
- /**
- * A set of mappings from feature tags to feature masks. These may
- * be in the order in which the featues should be applied, but they
- * don't need to be.
- *
- * @internal
- */
- const FeatureMap *fFeatureMap;
-
- /**
- * The length of the feature map.
- *
- * @internal
- */
- le_int32 fFeatureMapCount;
-
- /**
- * <code>TRUE</code> if the features in the
- * feature map are in the order in which they
- * must be applied.
- *
- * @internal
- */
- le_bool fFeatureOrder;
-
- /**
- * The address of the GSUB table.
- *
- * @internal
- */
- LEReferenceTo<GlyphSubstitutionTableHeader> fGSUBTable;
-
- /**
- * The address of the GDEF table.
- *
- * @internal
- */
- LEReferenceTo<GlyphDefinitionTableHeader> fGDEFTable;
-
- /**
- * The address of the GPOS table.
- *
- * @internal
- */
- LEReferenceTo<GlyphPositioningTableHeader> fGPOSTable;
-
- /**
- * An optional filter used to inhibit substitutions
- * preformed by the GSUB table. This is used for some
- * "canned" GSUB tables to restrict substitutions to
- * glyphs that are in the font.
- *
- * @internal
- */
- LEGlyphFilter *fSubstitutionFilter;
-
- /**
- * The four byte script tag.
- *
- * @internal
- */
- LETag fScriptTag;
-
- /**
- * The four byte script tag for V2 fonts.
- *
- * @internal
- */
- LETag fScriptTagV2;
-
- /**
- * The four byte language tag
- *
- * @internal
- */
- LETag fLangSysTag;
-
- /**
- * This method does the OpenType character processing. It assigns the OpenType feature
- * tags to the characters, and may generate output characters that differ from the input
- * charcters due to insertions, deletions, or reorderings. In such cases, it will also
- * generate an output character index array reflecting these changes.
- *
- * Subclasses must override this method.
- *
- * Input parameters:
- * @param chars - the input character context
- * @param offset - the index of the first character to process
- * @param count - the number of characters to process
- * @param max - the number of characters in the input context
- * @param rightToLeft - TRUE if the characters are in a right to left directional run
- *
- * Output parameters:
- * @param outChars - the output character array, if different from the input
- * @param charIndices - the output character index array
- * @param featureTags - the output feature tag array
- * @param success - set to an error code if the operation fails
- *
- * @return the output character count (input character count if no change)
- *
- * @internal
- */
- virtual le_int32 characterProcessing(const LEUnicode /*chars*/[], le_int32 offset, le_int32 count, le_int32 max, le_bool /*rightToLeft*/,
- LEUnicode *&/*outChars*/, LEGlyphStorage &glyphStorage, LEErrorCode &success);
-
- /**
- * This method does character to glyph mapping, and applies the GSUB table. The
- * default implementation calls mapCharsToGlyphs and then applies the GSUB table,
- * if there is one.
- *
- * Note that in the case of "canned" GSUB tables, the output glyph indices may be
- * "fake" glyph indices that need to be converted to "real" glyph indices by the
- * glyphPostProcessing method.
- *
- * Input parameters:
- * @param chars - the input character context
- * @param offset - the index of the first character to process
- * @param count - the number of characters to process
- * @param max - the number of characters in the input context
- * @param rightToLeft - TRUE if the characters are in a right to left directional run
- * @param featureTags - the feature tag array
- *
- * Output parameters:
- * @param glyphs - the output glyph index array
- * @param charIndices - the output character index array
- * @param success - set to an error code if the operation fails
- *
- * @return the number of glyphs in the output glyph index array
- *
- * Note: if the character index array was already set by the characterProcessing
- * method, this method won't change it.
- *
- * @internal
- */
- virtual le_int32 glyphProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
- LEGlyphStorage &glyphStorage, LEErrorCode &success);
-
- virtual le_int32 glyphSubstitution(le_int32 count, le_int32 max, le_bool rightToLeft, LEGlyphStorage &glyphStorage, LEErrorCode &success);
-
- /**
- * This method does any processing necessary to convert "fake"
- * glyph indices used by the glyphProcessing method into "real" glyph
- * indices which can be used to render the text. Note that in some
- * cases, such as CDAC Indic fonts, several "real" glyphs may be needed
- * to render one "fake" glyph.
- *
- * The default implementation of this method just returns the input glyph
- * index and character index arrays, assuming that no "fake" glyph indices
- * were needed to do GSUB processing.
- *
- * Input paramters:
- * @param tempGlyphs - the input "fake" glyph index array
- * @param tempCharIndices - the input "fake" character index array
- * @param tempGlyphCount - the number of "fake" glyph indices
- *
- * Output parameters:
- * @param glyphs - the output glyph index array
- * @param charIndices - the output character index array
- * @param success - set to an error code if the operation fails
- *
- * @return the number of glyph indices in the output glyph index array
- *
- * @internal
- */
- virtual le_int32 glyphPostProcessing(LEGlyphStorage &tempGlyphStorage, LEGlyphStorage &glyphStorage, LEErrorCode &success);
-
- /**
- * This method applies the characterProcessing, glyphProcessing and glyphPostProcessing
- * methods. Most subclasses will not need to override this method.
- *
- * Input parameters:
- * @param chars - the input character context
- * @param offset - the index of the first character to process
- * @param count - the number of characters to process
- * @param max - the number of characters in the input context
- * @param rightToLeft - TRUE if the text is in a right to left directional run
- *
- * Output parameters:
- * @param glyphs - the glyph index array
- * @param charIndices - the character index array
- * @param success - set to an error code if the operation fails
- *
- * @return the number of glyphs in the glyph index array
- *
- * @see LayoutEngine::computeGlyphs
- *
- * @internal
- */
- virtual le_int32 computeGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft, LEGlyphStorage &glyphStorage, LEErrorCode &success);
-
- /**
- * This method uses the GPOS table, if there is one, to adjust the glyph positions.
- *
- * Input parameters:
- * @param glyphs - the input glyph array
- * @param glyphCount - the number of glyphs in the glyph array
- * @param x - the starting X position
- * @param y - the starting Y position
- *
- * Output parameters:
- * @param positions - the output X and Y positions (two entries per glyph)
- * @param success - set to an error code if the operation fails
- *
- * @internal
- */
- virtual void adjustGlyphPositions(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, LEGlyphStorage &glyphStorage, LEErrorCode &success);
-
- /**
- * This method frees the feature tag array so that the
- * OpenTypeLayoutEngine can be reused for different text.
- * It is also called from our destructor.
- *
- * @internal
- */
- virtual void reset();
-};
-
-U_NAMESPACE_END
-#endif
-
projects / apple / icu.git / blobdiff