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
17 U_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 */
28 class LECharMapper /* not : public UObject because this is an interface/mixin class */
29 {
30 public:
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 */
55 class 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 */
81 class U_LAYOUT_API LEFontInstance : public UObject
82 {
83 public:
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
fixedToFloat(le_int32 fixed)513 inline float LEFontInstance::fixedToFloat(le_int32 fixed)
514 {
515 return (float) (fixed / 65536.0);
516 }
517
floatToFixed(float theFloat)518 inline le_int32 LEFontInstance::floatToFixed(float theFloat)
519 {
520 return (le_int32) (theFloat * 65536.0);
521 }
522
523 U_NAMESPACE_END
524 #endif
525