1
2/*
3 * HanLayoutEngine.h: OpenType processing for Han fonts.
4 *
5 * (C) Copyright IBM Corp. 1998-2014 - All Rights Reserved.
6 */
7
8#ifndef __HANLAYOUTENGINE_H
9#define __HANLAYOUTENGINE_H
10
11#include "LETypes.h"
12#include "LEFontInstance.h"
13#include "LayoutEngine.h"
14#include "OpenTypeLayoutEngine.h"
15
16#include "GlyphSubstitutionTables.h"
17
18U_NAMESPACE_BEGIN
19
20class LEGlyphStorage;
21
22/**
23 * This class implements OpenType layout for Han fonts. It overrides
24 * the characerProcessing method to assign the correct OpenType feature
25 * tags for the CJK language-specific forms.
26 *
27 * @internal
28 */
29class HanOpenTypeLayoutEngine : public OpenTypeLayoutEngine
30{
31public:
32    /**
33     * This is the main constructor. It constructs an instance of HanOpenTypeLayoutEngine for
34     * a particular font, script and language. It takes the GSUB table as a parameter since
35     * LayoutEngine::layoutEngineFactory has to read the GSUB table to know that it has a
36     * Han OpenType font.
37     *
38     * @param fontInstance - the font
39     * @param scriptCode - the script
40     * @param langaugeCode - the language
41     * @param gsubTable - the GSUB table
42     * @param success - set to an error code if the operation fails
43     *
44     * @see LayoutEngine::layoutEngineFactory
45     * @see OpenTypeLayoutEngine
46     * @see ScriptAndLangaugeTags.h for script and language codes
47     *
48     * @internal
49     */
50    HanOpenTypeLayoutEngine(const LEFontInstance *fontInstance, le_int32 scriptCode, le_int32 languageCode,
51                            le_int32 typoFlags, const LEReferenceTo<GlyphSubstitutionTableHeader> &gsubTablem, LEErrorCode &success);
52
53
54    /**
55     * The destructor, virtual for correct polymorphic invocation.
56     *
57     * @internal
58     */
59    virtual ~HanOpenTypeLayoutEngine();
60
61    /**
62     * ICU "poor man's RTTI", returns a UClassID for the actual class.
63     *
64     * @deprecated ICU 54. See {@link icu::LayoutEngine}
65     */
66    virtual UClassID getDynamicClassID() const;
67
68    /**
69     * ICU "poor man's RTTI", returns a UClassID for this class.
70     *
71     * @deprecated ICU 54. See {@link icu::LayoutEngine}
72     */
73    static UClassID getStaticClassID();
74
75protected:
76
77    /**
78     * This method does Han OpenType character processing. It assigns the OpenType feature
79     * tags to the characters to generate the correct language-specific variants.
80     *
81     * Input parameters:
82     * @param chars - the input character context
83     * @param offset - the index of the first character to process
84     * @param count - the number of characters to process
85     * @param max - the number of characters in the input context
86     * @param rightToLeft - <code>TRUE</code> if the characters are in a right to left directional run
87     * @param glyphStorage - the object holding the glyph storage. The char index and auxillary data arrays will be set.
88     *
89     * Output parameters:
90     * @param outChars - the output character arrayt
91     * @param charIndices - the output character index array
92     * @param featureTags - the output feature tag array
93     * @param success - set to an error code if the operation fails
94     *
95     * @return the output character count
96     *
97     * @internal
98     */
99    virtual le_int32 characterProcessing(const LEUnicode chars[], le_int32 offset, le_int32 count, le_int32 max, le_bool rightToLeft,
100            LEUnicode *&outChars, LEGlyphStorage &glyphStorage, LEErrorCode &success);
101
102};
103
104U_NAMESPACE_END
105#endif
106