1
2/*
3 *
4 * (C) Copyright IBM Corp. 1998-2015 - All Rights Reserved
5 *
6 */
7
8#ifndef __LEFONTINSTANCE_H
9#define __LEFONTINSTANCE_H
10
11#include "LETypes.h"
12/**
13 * \file
14 * \brief C++ API: Layout Engine Font Instance object
15 */
16
17U_NAMESPACE_BEGIN
18
19/**
20 * Instances of this class are used by <code>LEFontInstance::mapCharsToGlyphs</code> and
21 * <code>LEFontInstance::mapCharToGlyph</code> to adjust character codes before the character
22 * to glyph mapping process. Examples of this are filtering out control characters
23 * and character mirroring - replacing a character which has both a left and a right
24 * hand form with the opposite form.
25 *
26 * @deprecated ICU 54. See {@link icu::LayoutEngine}
27 */
28class LECharMapper /* not : public UObject because this is an interface/mixin class */
29{
30public:
31    /**
32     * Destructor.
33     * @deprecated ICU 54. See {@link icu::LayoutEngine}
34     */
35    virtual ~LECharMapper();
36
37    /**
38     * This method does the adjustments.
39     *
40     * @param ch - the input character
41     *
42     * @return the adjusted character
43     *
44     * @deprecated ICU 54. See {@link icu::LayoutEngine}
45     */
46    virtual LEUnicode32 mapChar(LEUnicode32 ch) const = 0;
47};
48
49/**
50 * This is a forward reference to the class which holds the per-glyph
51 * storage.
52 *
53 * @deprecated ICU 54. See {@link icu::LayoutEngine}
54 */
55class LEGlyphStorage;
56
57/**
58 * This is a virtual base class that serves as the interface between a LayoutEngine
59 * and the platform font environment. It allows a LayoutEngine to access font tables, do
60 * character to glyph mapping, and obtain metrics information without knowing any platform
61 * specific details. There are also a few utility methods for converting between points,
62 * pixels and funits. (font design units)
63 *
64 * An instance of an <code>LEFontInstance</code> represents a font at a particular point
65 * size. Each instance can represent either a single physical font, or a composite font.
66 * A composite font is a collection of physical fonts, each of which contains a subset of
67 * the characters contained in the composite font.
68 *
69 * Note: with the exception of <code>getSubFont</code>, the methods in this class only
70 * make sense for a physical font. If you have an <code>LEFontInstance</code> which
71 * represents a composite font you should only call the methods below which have
72 * an <code>LEGlyphID</code>, an <code>LEUnicode</code> or an <code>LEUnicode32</code>
73 * as one of the arguments because these can be used to select a particular subfont.
74 *
75 * Subclasses which implement composite fonts should supply an implementation of these
76 * methods with some default behavior such as returning constant values, or using the
77 * values from the first subfont.
78 *
79 * @deprecated ICU 54. See {@link icu::LayoutEngine}
80 */
81class U_LAYOUT_API LEFontInstance : public UObject
82{
83public:
84
85    /**
86     * This virtual destructor is here so that the subclass
87     * destructors can be invoked through the base class.
88     *
89     * @deprecated ICU 54. See {@link icu::LayoutEngine}
90     */
91    virtual ~LEFontInstance();
92
93    /**
94     * Get a physical font which can render the given text. For composite fonts,
95     * if there is no single physical font which can render all of the text,
96     * return a physical font which can render an initial substring of the text,
97     * and set the <code>offset</code> parameter to the end of that substring.
98     *
99     * Internally, the LayoutEngine works with runs of text all in the same
100     * font and script, so it is best to call this method with text which is
101     * in a single script, passing the script code in as a hint. If you don't
102     * know the script of the text, you can use zero, which is the script code
103     * for characters used in more than one script.
104     *
105     * The default implementation of this method is intended for instances of
106     * <code>LEFontInstance</code> which represent a physical font. It returns
107     * <code>this</code> and indicates that the entire string can be rendered.
108     *
109     * This method will return a valid <code>LEFontInstance</code> unless you
110     * have passed illegal parameters, or an internal error has been encountered.
111     * For composite fonts, it may return the warning <code>LE_NO_SUBFONT_WARNING</code>
112     * to indicate that the returned font may not be able to render all of
113     * the text. Whenever a valid font is returned, the <code>offset</code> parameter
114     * will be advanced by at least one.
115     *
116     * Subclasses which implement composite fonts must override this method.
117     * Where it makes sense, they should use the script code as a hint to render
118     * characters from the COMMON script in the font which is used for the given
119     * script. For example, if the input text is a series of Arabic words separated
120     * by spaces, and the script code passed in is <code>arabScriptCode</code> you
121     * should return the font used for Arabic characters for all of the input text,
122     * including the spaces. If, on the other hand, the input text contains characters
123     * which cannot be rendered by the font used for Arabic characters, but which can
124     * be rendered by another font, you should return that font for those characters.
125     *
126     * @param chars   - the array of Unicode characters.
127     * @param offset  - a pointer to the starting offset in the text. On exit this
128     *                  will be set the the limit offset of the text which can be
129     *                  rendered using the returned font.
130     * @param limit   - the limit offset for the input text.
131     * @param script  - the script hint.
132     * @param success - set to an error code if the arguments are illegal, or no font
133     *                  can be returned for some reason. May also be set to
134     *                  <code>LE_NO_SUBFONT_WARNING</code> if the subfont which
135     *                  was returned cannot render all of the text.
136     *
137     * @return an <code>LEFontInstance</code> for the sub font which can render the characters, or
138     *         <code>NULL</code> if there is an error.
139     *
140     * @see LEScripts.h
141     *
142     * @deprecated ICU 54. See {@link icu::LayoutEngine}
143     */
144    virtual const LEFontInstance *getSubFont(const LEUnicode chars[], le_int32 *offset, le_int32 limit, le_int32 script, LEErrorCode &success) const;
145
146    //
147    // Font file access
148    //
149
150    /**
151     * This method reads a table from the font. Note that in general,
152     * it only makes sense to call this method on an <code>LEFontInstance</code>
153     * which represents a physical font - i.e. one which has been returned by
154     * <code>getSubFont()</code>. This is because each subfont in a composite font
155     * will have different tables, and there's no way to know which subfont to access.
156     *
157     * Subclasses which represent composite fonts should always return <code>NULL</code>.
158     *
159     * @param tableTag - the four byte table tag. (e.g. 'cmap')
160     * @param length - ignored on entry, on exit will be the length of the table if known, or -1 if unknown.
161     * @return the address of the table in memory, or <code>NULL</code>
162     *         if the table doesn't exist.
163     * @deprecated ICU 54. See {@link LayoutEngine}
164     */
165    virtual const void* getFontTable(LETag tableTag, size_t &length) const = 0;
166
167    /**
168     * This method is used to determine if the font can
169     * render the given character. This can usually be done
170     * by looking the character up in the font's character
171     * to glyph mapping.
172     *
173     * The default implementation of this method will return
174     * <code>TRUE</code> if <code>mapCharToGlyph(ch)</code>
175     * returns a non-zero value.
176     *
177     * @param ch - the character to be tested
178     *
179     * @return <code>TRUE</code> if the font can render ch.
180     *
181     * @deprecated ICU 54. See {@link icu::LayoutEngine}
182     */
183    virtual le_bool canDisplay(LEUnicode32 ch) const;
184
185    /**
186     * This method returns the number of design units in
187     * the font's EM square.
188     *
189     * @return the number of design units pre EM.
190     *
191     * @deprecated ICU 54. See {@link icu::LayoutEngine}
192     */
193    virtual le_int32 getUnitsPerEM() const = 0;
194
195    /**
196     * This method maps an array of character codes to an array of glyph
197     * indices, using the font's character to glyph map.
198     *
199     * The default implementation iterates over all of the characters and calls
200     * <code>mapCharToGlyph(ch, mapper)</code> on each one. It also handles surrogate
201     * characters, storing the glyph ID for the high surrogate, and a deleted glyph (0xFFFF)
202     * for the low surrogate.
203     *
204     * Most sublcasses will not need to implement this method.
205     *
206     * @param chars - the character array
207     * @param offset - the index of the first character
208     * @param count - the number of characters
209     * @param reverse - if <code>TRUE</code>, store the glyph indices in reverse order.
210     * @param mapper - the character mapper.
211     * @param filterZeroWidth - <code>TRUE</code> if ZWJ / ZWNJ characters should map to a glyph w/ no contours.
212     * @param glyphStorage - the object which contains the output glyph array
213     *
214     * @see LECharMapper
215     *
216     * @deprecated ICU 54. See {@link icu::LayoutEngine}
217     */
218    virtual void mapCharsToGlyphs(const LEUnicode chars[], le_int32 offset, le_int32 count, le_bool reverse, const LECharMapper *mapper, le_bool filterZeroWidth, LEGlyphStorage &glyphStorage) const;
219
220    /**
221     * This method maps a single character to a glyph index, using the
222     * font's character to glyph map. The default implementation of this
223     * method calls the mapper, and then calls <code>mapCharToGlyph(mappedCh)</code>.
224     *
225     * @param ch - the character
226     * @param mapper - the character mapper
227     * @param filterZeroWidth - <code>TRUE</code> if ZWJ / ZWNJ characters should map to a glyph w/ no contours.
228     *
229     * @return the glyph index
230     *
231     * @see LECharMapper
232     *
233     * @deprecated ICU 54. See {@link icu::LayoutEngine}
234     */
235    virtual LEGlyphID mapCharToGlyph(LEUnicode32 ch, const LECharMapper *mapper, le_bool filterZeroWidth) const;
236
237    /**
238     * This method maps a single character to a glyph index, using the
239     * font's character to glyph map. The default implementation of this
240     * method calls the mapper, and then calls <code>mapCharToGlyph(mappedCh)</code>.
241     *
242     * @param ch - the character
243     * @param mapper - the character mapper
244     *
245     * @return the glyph index
246     *
247     * @see LECharMapper
248     *
249     * @deprecated ICU 54. See {@link icu::LayoutEngine}
250     */
251    virtual LEGlyphID mapCharToGlyph(LEUnicode32 ch, const LECharMapper *mapper) const;
252
253    /**
254     * This method maps a single character to a glyph index, using the
255     * font's character to glyph map. There is no default implementation
256     * of this method because it requires information about the platform
257     * font implementation.
258     *
259     * @param ch - the character
260     *
261     * @return the glyph index
262     *
263     * @deprecated ICU 54. See {@link icu::LayoutEngine}
264     */
265    virtual LEGlyphID mapCharToGlyph(LEUnicode32 ch) const = 0;
266
267    //
268    // Metrics
269    //
270
271    /**
272     * This method gets the X and Y advance of a particular glyph, in pixels.
273     *
274     * @param glyph - the glyph index
275     * @param advance - the X and Y pixel values will be stored here
276     *
277     * @deprecated ICU 54. See {@link icu::LayoutEngine}
278     */
279    virtual void getGlyphAdvance(LEGlyphID glyph, LEPoint &advance) const = 0;
280
281    /**
282     * This method gets the hinted X and Y pixel coordinates of a particular
283     * point in the outline of the given glyph.
284     *
285     * @param glyph - the glyph index
286     * @param pointNumber - the number of the point
287     * @param point - the point's X and Y pixel values will be stored here
288     *
289     * @return <code>TRUE</code> if the point coordinates could be stored.
290     *
291     * @deprecated ICU 54. See {@link icu::LayoutEngine}
292     */
293    virtual le_bool getGlyphPoint(LEGlyphID glyph, le_int32 pointNumber, LEPoint &point) const = 0;
294
295    /**
296     * This method returns the width of the font's EM square
297     * in pixels.
298     *
299     * @return the pixel width of the EM square
300     *
301     * @deprecated ICU 54. See {@link icu::LayoutEngine}
302     */
303    virtual float getXPixelsPerEm() const = 0;
304
305    /**
306     * This method returns the height of the font's EM square
307     * in pixels.
308     *
309     * @return the pixel height of the EM square
310     *
311     * @deprecated ICU 54. See {@link icu::LayoutEngine}
312     */
313    virtual float getYPixelsPerEm() const = 0;
314
315    /**
316     * This method converts font design units in the
317     * X direction to points.
318     *
319     * @param xUnits - design units in the X direction
320     *
321     * @return points in the X direction
322     *
323     * @deprecated ICU 54. See {@link icu::LayoutEngine}
324     */
325    virtual float xUnitsToPoints(float xUnits) const;
326
327    /**
328     * This method converts font design units in the
329     * Y direction to points.
330     *
331     * @param yUnits - design units in the Y direction
332     *
333     * @return points in the Y direction
334     *
335     * @deprecated ICU 54. See {@link icu::LayoutEngine}
336     */
337    virtual float yUnitsToPoints(float yUnits) const;
338
339    /**
340     * This method converts font design units to points.
341     *
342     * @param units - X and Y design units
343     * @param points - set to X and Y points
344     *
345     * @deprecated ICU 54. See {@link icu::LayoutEngine}
346     */
347    virtual void unitsToPoints(LEPoint &units, LEPoint &points) const;
348
349    /**
350     * This method converts pixels in the
351     * X direction to font design units.
352     *
353     * @param xPixels - pixels in the X direction
354     *
355     * @return font design units in the X direction
356     *
357     * @deprecated ICU 54. See {@link icu::LayoutEngine}
358     */
359    virtual float xPixelsToUnits(float xPixels) const;
360
361    /**
362     * This method converts pixels in the
363     * Y direction to font design units.
364     *
365     * @param yPixels - pixels in the Y direction
366     *
367     * @return font design units in the Y direction
368     *
369     * @deprecated ICU 54. See {@link icu::LayoutEngine}
370     */
371    virtual float yPixelsToUnits(float yPixels) const;
372
373    /**
374     * This method converts pixels to font design units.
375     *
376     * @param pixels - X and Y pixel
377     * @param units - set to X and Y font design units
378     *
379     * @deprecated ICU 54. See {@link icu::LayoutEngine}
380     */
381    virtual void pixelsToUnits(LEPoint &pixels, LEPoint &units) const;
382
383    /**
384     * Get the X scale factor from the font's transform. The default
385     * implementation of <code>transformFunits()</code> will call this method.
386     *
387     * @return the X scale factor.
388     *
389     *
390     * @see transformFunits
391     *
392     * @deprecated ICU 54. See {@link icu::LayoutEngine}
393     */
394    virtual float getScaleFactorX() const = 0;
395
396    /**
397     * Get the Y scale factor from the font's transform. The default
398     * implementation of <code>transformFunits()</code> will call this method.
399     *
400     * @return the Yscale factor.
401     *
402     * @see transformFunits
403     *
404     * @deprecated ICU 54. See {@link icu::LayoutEngine}
405     */
406    virtual float getScaleFactorY() const = 0;
407
408    /**
409     * This method transforms an X, Y point in font design units to a
410     * pixel coordinate, applying the font's transform. The default
411     * implementation of this method calls <code>getScaleFactorX()</code>
412     * and <code>getScaleFactorY()</code>.
413     *
414     * @param xFunits - the X coordinate in font design units
415     * @param yFunits - the Y coordinate in font design units
416     * @param pixels - the tranformed co-ordinate in pixels
417     *
418     * @see getScaleFactorX
419     * @see getScaleFactorY
420     *
421     * @deprecated ICU 54. See {@link icu::LayoutEngine}
422     */
423    virtual void transformFunits(float xFunits, float yFunits, LEPoint &pixels) const;
424
425    /**
426     * This is a convenience method used to convert
427     * values in a 16.16 fixed point format to floating point.
428     *
429     * @param fixed - the fixed point value
430     *
431     * @return the floating point value
432     *
433     * @deprecated ICU 54. See {@link icu::LayoutEngine}
434     */
435    static inline float fixedToFloat(le_int32 fixed);
436
437    /**
438     * This is a convenience method used to convert
439     * floating point values to 16.16 fixed point format.
440     *
441     * @param theFloat - the floating point value
442     *
443     * @return the fixed point value
444     *
445     * @deprecated ICU 54. See {@link icu::LayoutEngine}
446     */
447    static inline le_int32 floatToFixed(float theFloat);
448
449    //
450    // These methods won't ever be called by the LayoutEngine,
451    // but are useful for clients of <code>LEFontInstance</code> who
452    // need to render text.
453    //
454
455    /**
456     * Get the font's ascent.
457     *
458     * @return the font's ascent, in points. This value
459     * will always be positive.
460     *
461     * @deprecated ICU 54. See {@link icu::LayoutEngine}
462     */
463    virtual le_int32 getAscent() const = 0;
464
465    /**
466     * Get the font's descent.
467     *
468     * @return the font's descent, in points. This value
469     * will always be positive.
470     *
471     * @deprecated ICU 54. See {@link icu::LayoutEngine}
472     */
473    virtual le_int32 getDescent() const = 0;
474
475    /**
476     * Get the font's leading.
477     *
478     * @return the font's leading, in points. This value
479     * will always be positive.
480     *
481     * @deprecated ICU 54. See {@link icu::LayoutEngine}
482     */
483    virtual le_int32 getLeading() const = 0;
484
485    /**
486     * Get the line height required to display text in
487     * this font. The default implementation of this method
488     * returns the sum of the ascent, descent, and leading.
489     *
490     * @return the line height, in points. This vaule will
491     * always be positive.
492     *
493     * @deprecated ICU 54. See {@link icu::LayoutEngine}
494     */
495    virtual le_int32 getLineHeight() const;
496
497    /**
498     * ICU "poor man's RTTI", returns a UClassID for the actual class.
499     *
500     * @deprecated ICU 54. See {@link icu::LayoutEngine}
501     */
502    virtual UClassID getDynamicClassID() const;
503
504    /**
505     * ICU "poor man's RTTI", returns a UClassID for this class.
506     *
507     * @deprecated ICU 54. See {@link icu::LayoutEngine}
508     */
509    static UClassID getStaticClassID();
510
511};
512
513inline float LEFontInstance::fixedToFloat(le_int32 fixed)
514{
515    return (float) (fixed / 65536.0);
516}
517
518inline le_int32 LEFontInstance::floatToFixed(float theFloat)
519{
520    return (le_int32) (theFloat * 65536.0);
521}
522
523U_NAMESPACE_END
524#endif
525