1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
|
/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkScalerContext_DEFINED
#define SkScalerContext_DEFINED
#include <memory>
#include "include/core/SkFont.h"
#include "include/core/SkFontTypes.h"
#include "include/core/SkMaskFilter.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPaint.h"
#include "include/core/SkTypeface.h"
#include "include/private/base/SkMacros.h"
#include "src/core/SkGlyph.h"
#include "src/core/SkMask.h"
#include "src/core/SkMaskGamma.h"
#include "src/core/SkSurfacePriv.h"
#include "src/core/SkWriteBuffer.h"
class SkAutoDescriptor;
class SkDescriptor;
class SkMaskFilter;
class SkPathEffect;
class SkScalerContext;
class SkScalerContext_DW;
enum class SkScalerContextFlags : uint32_t {
kNone = 0,
kFakeGamma = 1 << 0,
kBoostContrast = 1 << 1,
kFakeGammaAndBoostContrast = kFakeGamma | kBoostContrast,
};
SK_MAKE_BITFIELD_OPS(SkScalerContextFlags)
/*
* To allow this to be forward-declared, it must be its own typename, rather
* than a nested struct inside SkScalerContext (where it started).
*
* SkScalerContextRec must be dense, and all bytes must be set to a know quantity because this
* structure is used to calculate a checksum.
*/
SK_BEGIN_REQUIRE_DENSE
struct SkScalerContextRec {
SkTypefaceID fTypefaceID;
SkScalar fTextSize, fPreScaleX, fPreSkewX;
SkScalar fPost2x2[2][2];
SkScalar fFrameWidth, fMiterLimit;
// This will be set if to the paint's foreground color if
// kNeedsForegroundColor is set, which will usually be the case for COLRv0 and
// COLRv1 fonts.
uint32_t fForegroundColor{SK_ColorBLACK};
private:
//These describe the parameters to create (uniquely identify) the pre-blend.
uint32_t fLumBits;
uint8_t fDeviceGamma; //2.6, (0.0, 4.0) gamma, 0.0 for sRGB
uint8_t fPaintGamma; //2.6, (0.0, 4.0) gamma, 0.0 for sRGB
uint8_t fContrast; //0.8+1, [0.0, 1.0] artificial contrast
const uint8_t fReservedAlign{0};
public:
SkScalar getDeviceGamma() const {
return SkIntToScalar(fDeviceGamma) / (1 << 6);
}
void setDeviceGamma(SkScalar dg) {
SkASSERT(0 <= dg && dg < SkIntToScalar(4));
fDeviceGamma = SkScalarFloorToInt(dg * (1 << 6));
}
SkScalar getPaintGamma() const {
return SkIntToScalar(fPaintGamma) / (1 << 6);
}
void setPaintGamma(SkScalar pg) {
SkASSERT(0 <= pg && pg < SkIntToScalar(4));
fPaintGamma = SkScalarFloorToInt(pg * (1 << 6));
}
SkScalar getContrast() const {
sk_ignore_unused_variable(fReservedAlign);
return SkIntToScalar(fContrast) / ((1 << 8) - 1);
}
void setContrast(SkScalar c) {
SkASSERT(0 <= c && c <= SK_Scalar1);
fContrast = SkScalarRoundToInt(c * ((1 << 8) - 1));
}
/**
* Causes the luminance color to be ignored, and the paint and device
* gamma to be effectively 1.0
*/
void ignoreGamma() {
setLuminanceColor(SK_ColorTRANSPARENT);
setPaintGamma(SK_Scalar1);
setDeviceGamma(SK_Scalar1);
}
/**
* Causes the luminance color and contrast to be ignored, and the
* paint and device gamma to be effectively 1.0.
*/
void ignorePreBlend() {
ignoreGamma();
setContrast(0);
}
SkMask::Format fMaskFormat;
private:
uint8_t fStrokeJoin : 4;
uint8_t fStrokeCap : 4;
public:
uint16_t fFlags;
// Warning: when adding members note that the size of this structure
// must be a multiple of 4. SkDescriptor requires that its arguments be
// multiples of four and this structure is put in an SkDescriptor in
// SkPaint::MakeRecAndEffects.
SkString dump() const {
SkString msg;
msg.appendf(" Rec\n");
msg.appendf(" textsize %a prescale %a preskew %a post [%a %a %a %a]\n",
fTextSize, fPreScaleX, fPreSkewX, fPost2x2[0][0],
fPost2x2[0][1], fPost2x2[1][0], fPost2x2[1][1]);
msg.appendf(" frame %g miter %g format %d join %d cap %d flags %#hx\n",
fFrameWidth, fMiterLimit, fMaskFormat, fStrokeJoin, fStrokeCap, fFlags);
msg.appendf(" lum bits %x, device gamma %d, paint gamma %d contrast %d\n", fLumBits,
fDeviceGamma, fPaintGamma, fContrast);
msg.appendf(" foreground color %x\n", fForegroundColor);
return msg;
}
void getMatrixFrom2x2(SkMatrix*) const;
void getLocalMatrix(SkMatrix*) const;
void getSingleMatrix(SkMatrix*) const;
/** The kind of scale which will be applied by the underlying port (pre-matrix). */
enum class PreMatrixScale {
kFull, // The underlying port can apply both x and y scale.
kVertical, // The underlying port can only apply a y scale.
kVerticalInteger // The underlying port can only apply an integer y scale.
};
/**
* Compute useful matrices for use with sizing in underlying libraries.
*
* There are two kinds of text size, a 'requested/logical size' which is like asking for size
* '12' and a 'real' size which is the size after the matrix is applied. The matrices produced
* by this method are based on the 'real' size. This method effectively finds the total device
* matrix and decomposes it in various ways.
*
* The most useful decomposition is into 'scale' and 'remaining'. The 'scale' is applied first
* and then the 'remaining' to fully apply the total matrix. This decomposition is useful when
* the text size ('scale') may have meaning apart from the total matrix. This is true when
* hinting, and sometimes true for other properties as well.
*
* The second (optional) decomposition is of 'remaining' into a non-rotational part
* 'remainingWithoutRotation' and a rotational part 'remainingRotation'. The 'scale' is applied
* first, then 'remainingWithoutRotation', then 'remainingRotation' to fully apply the total
* matrix. This decomposition is helpful when only horizontal metrics can be trusted, so the
* 'scale' and 'remainingWithoutRotation' will be handled by the underlying library, but
* the final rotation 'remainingRotation' will be handled manually.
*
* The 'total' matrix is also (optionally) available. This is useful in cases where the
* underlying library will not be used, often when working directly with font data.
*
* The parameters 'scale' and 'remaining' are required, the other pointers may be nullptr.
*
* @param preMatrixScale the kind of scale to extract from the total matrix.
* @param scale the scale extracted from the total matrix (both values positive).
* @param remaining apply after scale to apply the total matrix.
* @param remainingWithoutRotation apply after scale to apply the total matrix sans rotation.
* @param remainingRotation apply after remainingWithoutRotation to apply the total matrix.
* @param total the total matrix.
* @return false if the matrix was singular. The output will be valid but not invertible.
*/
bool computeMatrices(PreMatrixScale preMatrixScale,
SkVector* scale, SkMatrix* remaining,
SkMatrix* remainingWithoutRotation = nullptr,
SkMatrix* remainingRotation = nullptr,
SkMatrix* total = nullptr);
SkAxisAlignment computeAxisAlignmentForHText() const;
inline SkFontHinting getHinting() const;
inline void setHinting(SkFontHinting);
SkMask::Format getFormat() const {
return fMaskFormat;
}
SkColor getLuminanceColor() const {
return fLumBits;
}
// setLuminanceColor forces the alpha to be 0xFF because the blitter that draws the glyph
// will apply the alpha from the paint. Don't apply the alpha twice.
void setLuminanceColor(SkColor c);
private:
// TODO: remove
friend class SkScalerContext;
};
SK_END_REQUIRE_DENSE
// TODO: rename SkScalerContextEffects -> SkStrikeEffects
struct SkScalerContextEffects {
SkScalerContextEffects() : fPathEffect(nullptr), fMaskFilter(nullptr) {}
SkScalerContextEffects(SkPathEffect* pe, SkMaskFilter* mf)
: fPathEffect(pe), fMaskFilter(mf) {}
explicit SkScalerContextEffects(const SkPaint& paint)
: fPathEffect(paint.getPathEffect())
, fMaskFilter(paint.getMaskFilter()) {}
SkPathEffect* fPathEffect;
SkMaskFilter* fMaskFilter;
};
//The following typedef hides from the rest of the implementation the number of
//most significant bits to consider when creating mask gamma tables. Two bits
//per channel was chosen as a balance between fidelity (more bits) and cache
//sizes (fewer bits). Three bits per channel was chosen when #303942; (used by
//the Chrome UI) turned out too green.
typedef SkTMaskGamma<3, 3, 3> SkMaskGamma;
class SkScalerContext {
public:
enum Flags {
kFrameAndFill_Flag = 0x0001,
kUnused = 0x0002,
kEmbeddedBitmapText_Flag = 0x0004,
kEmbolden_Flag = 0x0008,
kSubpixelPositioning_Flag = 0x0010,
kForceAutohinting_Flag = 0x0020, // Use auto instead of bytcode hinting if hinting.
// together, these two flags resulting in a two bit value which matches
// up with the SkPaint::Hinting enum.
kHinting_Shift = 7, // to shift into the other flags above
kHintingBit1_Flag = 0x0080,
kHintingBit2_Flag = 0x0100,
// Pixel geometry information.
// only meaningful if fMaskFormat is kLCD16
kLCD_Vertical_Flag = 0x0200, // else Horizontal
kLCD_BGROrder_Flag = 0x0400, // else RGB order
// Generate A8 from LCD source (for GDI and CoreGraphics).
// only meaningful if fMaskFormat is kA8
kGenA8FromLCD_Flag = 0x0800, // could be 0x200 (bit meaning dependent on fMaskFormat)
kLinearMetrics_Flag = 0x1000,
kBaselineSnap_Flag = 0x2000,
kNeedsForegroundColor_Flag = 0x4000,
kLightOnDark_Flag = 0x8000, // Moz + Mac only, used to distinguish different mask dilations
};
// computed values
enum {
kHinting_Mask = kHintingBit1_Flag | kHintingBit2_Flag,
};
SkScalerContext(sk_sp<SkTypeface>, const SkScalerContextEffects&, const SkDescriptor*);
virtual ~SkScalerContext();
SkTypeface* getTypeface() const { return fTypeface.get(); }
SkMask::Format getMaskFormat() const {
return fRec.fMaskFormat;
}
bool isSubpixel() const {
return SkToBool(fRec.fFlags & kSubpixelPositioning_Flag);
}
bool isLinearMetrics() const {
return SkToBool(fRec.fFlags & kLinearMetrics_Flag);
}
// DEPRECATED
bool isVertical() const { return false; }
SkGlyph makeGlyph(SkPackedGlyphID, SkArenaAlloc*);
void getImage(const SkGlyph&);
void getPath(SkGlyph&, SkArenaAlloc*);
sk_sp<SkDrawable> getDrawable(SkGlyph&);
void getFontMetrics(SkFontMetrics*);
/** Return the size in bytes of the associated gamma lookup table
*/
static size_t GetGammaLUTSize(SkScalar contrast, SkScalar paintGamma, SkScalar deviceGamma,
int* width, int* height);
/** Get the associated gamma lookup table. The 'data' pointer must point to pre-allocated
* memory, with size in bytes greater than or equal to the return value of getGammaLUTSize().
*
* If the lookup table hasn't been initialized (e.g., it's linear), this will return false.
*/
static bool GetGammaLUTData(SkScalar contrast, SkScalar paintGamma, SkScalar deviceGamma,
uint8_t* data);
static void MakeRecAndEffects(const SkFont& font, const SkPaint& paint,
const SkSurfaceProps& surfaceProps,
SkScalerContextFlags scalerContextFlags,
const SkMatrix& deviceMatrix,
SkScalerContextRec* rec,
SkScalerContextEffects* effects);
// If we are creating rec and effects from a font only, then there is no device around either.
static void MakeRecAndEffectsFromFont(const SkFont& font,
SkScalerContextRec* rec,
SkScalerContextEffects* effects) {
SkPaint paint;
return MakeRecAndEffects(
font, paint, SkSurfaceProps(),
SkScalerContextFlags::kNone, SkMatrix::I(), rec, effects);
}
static std::unique_ptr<SkScalerContext> MakeEmpty(
sk_sp<SkTypeface> typeface, const SkScalerContextEffects& effects,
const SkDescriptor* desc);
static SkDescriptor* AutoDescriptorGivenRecAndEffects(
const SkScalerContextRec& rec,
const SkScalerContextEffects& effects,
SkAutoDescriptor* ad);
static std::unique_ptr<SkDescriptor> DescriptorGivenRecAndEffects(
const SkScalerContextRec& rec,
const SkScalerContextEffects& effects);
static void DescriptorBufferGiveRec(const SkScalerContextRec& rec, void* buffer);
static bool CheckBufferSizeForRec(const SkScalerContextRec& rec,
const SkScalerContextEffects& effects,
size_t size);
static SkMaskGamma::PreBlend GetMaskPreBlend(const SkScalerContextRec& rec);
const SkScalerContextRec& getRec() const { return fRec; }
SkScalerContextEffects getEffects() const {
return { fPathEffect.get(), fMaskFilter.get() };
}
/**
* Return the axis (if any) that the baseline for horizontal text should land on.
* As an example, the identity matrix will return SkAxisAlignment::kX.
*/
SkAxisAlignment computeAxisAlignmentForHText() const;
static SkDescriptor* CreateDescriptorAndEffectsUsingPaint(
const SkFont&, const SkPaint&, const SkSurfaceProps&,
SkScalerContextFlags scalerContextFlags,
const SkMatrix& deviceMatrix, SkAutoDescriptor* ad,
SkScalerContextEffects* effects);
protected:
SkScalerContextRec fRec;
/** Generates the contents of glyph.fAdvanceX and glyph.fAdvanceY if it can do so quickly.
* Returns true if it could, false otherwise.
*/
virtual bool generateAdvance(SkGlyph* glyph) = 0;
/** Generates the contents of glyph.fWidth, fHeight, fTop, fLeft,
* as well as fAdvanceX and fAdvanceY if not already set.
* The fMaskFormat will already be set to a requested format but may be changed.
*/
virtual void generateMetrics(SkGlyph* glyph, SkArenaAlloc*) = 0;
static bool GenerateMetricsFromPath(
SkGlyph* glyph, const SkPath& path, SkMask::Format format,
bool verticalLCD, bool a8FromLCD, bool hairline);
/** Generates the contents of glyph.fImage.
* When called, glyph.fImage will be pointing to a pre-allocated,
* uninitialized region of memory of size glyph.imageSize().
* This method may not change glyph.fMaskFormat.
*
* Because glyph.imageSize() will determine the size of fImage,
* generateMetrics will be called before generateImage.
*/
virtual void generateImage(const SkGlyph& glyph) = 0;
static void GenerateImageFromPath(
const SkMask& mask, const SkPath& path, const SkMaskGamma::PreBlend& maskPreBlend,
bool doBGR, bool verticalLCD, bool a8FromLCD, bool hairline);
/** Sets the passed path to the glyph outline.
* If this cannot be done the path is set to empty;
* Does not apply subpixel positioning to the path.
* @return false if this glyph does not have any path.
*/
virtual bool SK_WARN_UNUSED_RESULT generatePath(const SkGlyph&, SkPath*) = 0;
/** Returns the drawable for the glyph (if any).
*
* The generated drawable will be lifetime scoped to the lifetime of this scaler context.
* This means the drawable may refer to the scaler context and associated font data.
*
* The drawable does not need to be flattenable (e.g. implement getFactory and getTypeName).
* Any necessary serialization will be done with newPictureSnapshot.
*/
virtual sk_sp<SkDrawable> generateDrawable(const SkGlyph&); // TODO: = 0
/** Retrieves font metrics. */
virtual void generateFontMetrics(SkFontMetrics*) = 0;
void forceGenerateImageFromPath() { fGenerateImageFromPath = true; }
void forceOffGenerateImageFromPath() { fGenerateImageFromPath = false; }
private:
friend class PathText; // For debug purposes
friend class PathTextBench; // For debug purposes
friend class RandomScalerContext; // For debug purposes
static SkScalerContextRec PreprocessRec(const SkTypeface&,
const SkScalerContextEffects&,
const SkDescriptor&);
// never null
sk_sp<SkTypeface> fTypeface;
// optional objects, which may be null
sk_sp<SkPathEffect> fPathEffect;
sk_sp<SkMaskFilter> fMaskFilter;
// if this is set, we draw the image from a path, rather than
// calling generateImage.
bool fGenerateImageFromPath;
void internalGetPath(SkGlyph&, SkArenaAlloc*);
SkGlyph internalMakeGlyph(SkPackedGlyphID, SkMask::Format, SkArenaAlloc*);
protected:
// SkMaskGamma::PreBlend converts linear masks to gamma correcting masks.
// Visible to subclasses so that generateImage can apply the pre-blend directly.
const SkMaskGamma::PreBlend fPreBlend;
};
#define kRec_SkDescriptorTag SkSetFourByteTag('s', 'r', 'e', 'c')
#define kEffects_SkDescriptorTag SkSetFourByteTag('e', 'f', 'c', 't')
///////////////////////////////////////////////////////////////////////////////
SkFontHinting SkScalerContextRec::getHinting() const {
unsigned hint = (fFlags & SkScalerContext::kHinting_Mask) >>
SkScalerContext::kHinting_Shift;
return static_cast<SkFontHinting>(hint);
}
void SkScalerContextRec::setHinting(SkFontHinting hinting) {
fFlags = (fFlags & ~SkScalerContext::kHinting_Mask) |
(static_cast<unsigned>(hinting) << SkScalerContext::kHinting_Shift);
}
#endif
|