SkShader.cpp revision 6fcbfcead5dc1b61fa5b4c139a1a3714e8c58091 
1/*
2 * Copyright 2006 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8
9#include "SkScalar.h"
10#include "SkShader.h"
11#include "SkFlattenableBuffers.h"
12#include "SkPaint.h"
13#include "SkMallocPixelRef.h"
14
15SK_DEFINE_INST_COUNT(SkShader)
16
17SkShader::SkShader() {
18    fLocalMatrix.reset();
19    SkDEBUGCODE(fInSetContext = false;)
20}
21
22SkShader::SkShader(SkFlattenableReadBuffer& buffer)
23        : INHERITED(buffer) {
24    if (buffer.readBool()) {
25        buffer.readMatrix(&fLocalMatrix);
26    } else {
27        fLocalMatrix.reset();
28    }
29
30    SkDEBUGCODE(fInSetContext = false;)
31}
32
33SkShader::~SkShader() {
34    SkASSERT(!fInSetContext);
35}
36
37void SkShader::flatten(SkFlattenableWriteBuffer& buffer) const {
38    this->INHERITED::flatten(buffer);
39    bool hasLocalM = this->hasLocalMatrix();
40    buffer.writeBool(hasLocalM);
41    if (hasLocalM) {
42        buffer.writeMatrix(fLocalMatrix);
43    }
44}
45
46bool SkShader::setContext(const SkBitmap& device,
47                          const SkPaint& paint,
48                          const SkMatrix& matrix) {
49    SkASSERT(!this->setContextHasBeenCalled());
50
51    const SkMatrix* m = &matrix;
52    SkMatrix        total;
53
54    fDeviceConfig = SkToU8(device.getConfig());
55    fPaintAlpha = paint.getAlpha();
56    if (this->hasLocalMatrix()) {
57        total.setConcat(matrix, this->getLocalMatrix());
58        m = &total;
59    }
60    if (m->invert(&fTotalInverse)) {
61        fTotalInverseClass = (uint8_t)ComputeMatrixClass(fTotalInverse);
62        SkDEBUGCODE(fInSetContext = true;)
63        return true;
64    }
65    return false;
66}
67
68void SkShader::endContext() {
69    SkASSERT(fInSetContext);
70    SkDEBUGCODE(fInSetContext = false;)
71}
72
73SkShader::ShadeProc SkShader::asAShadeProc(void** ctx) {
74    return NULL;
75}
76
77#include "SkColorPriv.h"
78
79void SkShader::shadeSpan16(int x, int y, uint16_t span16[], int count) {
80    SkASSERT(span16);
81    SkASSERT(count > 0);
82    SkASSERT(this->canCallShadeSpan16());
83
84    // basically, if we get here, the subclass screwed up
85    SkDEBUGFAIL("kHasSpan16 flag is set, but shadeSpan16() not implemented");
86}
87
88#define kTempColorQuadCount 6   // balance between speed (larger) and saving stack-space
89#define kTempColorCount     (kTempColorQuadCount << 2)
90
91#ifdef SK_CPU_BENDIAN
92    #define SkU32BitShiftToByteOffset(shift)    (3 - ((shift) >> 3))
93#else
94    #define SkU32BitShiftToByteOffset(shift)    ((shift) >> 3)
95#endif
96
97void SkShader::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
98    SkASSERT(count > 0);
99
100    SkPMColor   colors[kTempColorCount];
101
102    while ((count -= kTempColorCount) >= 0) {
103        this->shadeSpan(x, y, colors, kTempColorCount);
104        x += kTempColorCount;
105
106        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
107        int quads = kTempColorQuadCount;
108        do {
109            U8CPU a0 = srcA[0];
110            U8CPU a1 = srcA[4];
111            U8CPU a2 = srcA[8];
112            U8CPU a3 = srcA[12];
113            srcA += 4*4;
114            *alpha++ = SkToU8(a0);
115            *alpha++ = SkToU8(a1);
116            *alpha++ = SkToU8(a2);
117            *alpha++ = SkToU8(a3);
118        } while (--quads != 0);
119    }
120    SkASSERT(count < 0);
121    SkASSERT(count + kTempColorCount >= 0);
122    if (count += kTempColorCount) {
123        this->shadeSpan(x, y, colors, count);
124
125        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
126        do {
127            *alpha++ = *srcA;
128            srcA += 4;
129        } while (--count != 0);
130    }
131#if 0
132    do {
133        int n = count;
134        if (n > kTempColorCount)
135            n = kTempColorCount;
136        SkASSERT(n > 0);
137
138        this->shadeSpan(x, y, colors, n);
139        x += n;
140        count -= n;
141
142        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
143        do {
144            *alpha++ = *srcA;
145            srcA += 4;
146        } while (--n != 0);
147    } while (count > 0);
148#endif
149}
150
151SkShader::MatrixClass SkShader::ComputeMatrixClass(const SkMatrix& mat) {
152    MatrixClass mc = kLinear_MatrixClass;
153
154    if (mat.hasPerspective()) {
155        if (mat.fixedStepInX(0, NULL, NULL)) {
156            mc = kFixedStepInX_MatrixClass;
157        } else {
158            mc = kPerspective_MatrixClass;
159        }
160    }
161    return mc;
162}
163
164//////////////////////////////////////////////////////////////////////////////
165
166SkShader::BitmapType SkShader::asABitmap(SkBitmap*, SkMatrix*,
167                                         TileMode*) const {
168    return kNone_BitmapType;
169}
170
171SkShader::GradientType SkShader::asAGradient(GradientInfo* info) const {
172    return kNone_GradientType;
173}
174
175GrEffectRef* SkShader::asNewEffect(GrContext*, const SkPaint&) const {
176    return NULL;
177}
178
179SkShader* SkShader::CreateBitmapShader(const SkBitmap& src,
180                                       TileMode tmx, TileMode tmy) {
181    return SkShader::CreateBitmapShader(src, tmx, tmy, NULL, 0);
182}
183
184#ifdef SK_DEVELOPER
185void SkShader::toString(SkString* str) const {
186    if (this->hasLocalMatrix()) {
187        str->append(" ");
188        this->getLocalMatrix().toString(str);
189    }
190}
191#endif
192
193//////////////////////////////////////////////////////////////////////////////
194
195#include "SkColorShader.h"
196#include "SkUtils.h"
197
198SkColorShader::SkColorShader() {
199    fFlags = 0;
200    fInheritColor = true;
201}
202
203SkColorShader::SkColorShader(SkColor c) {
204    fFlags = 0;
205    fColor = c;
206    fInheritColor = false;
207}
208
209SkColorShader::~SkColorShader() {}
210
211bool SkColorShader::isOpaque() const {
212    if (fInheritColor) {
213        return true; // using paint's alpha
214    }
215    return SkColorGetA(fColor) == 255;
216}
217
218SkColorShader::SkColorShader(SkFlattenableReadBuffer& b) : INHERITED(b) {
219    fFlags = 0; // computed in setContext
220
221    fInheritColor = b.readBool();
222    if (fInheritColor) {
223        return;
224    }
225    fColor = b.readColor();
226}
227
228void SkColorShader::flatten(SkFlattenableWriteBuffer& buffer) const {
229    this->INHERITED::flatten(buffer);
230    buffer.writeBool(fInheritColor);
231    if (fInheritColor) {
232        return;
233    }
234    buffer.writeColor(fColor);
235}
236
237uint32_t SkColorShader::getFlags() {
238    return fFlags;
239}
240
241uint8_t SkColorShader::getSpan16Alpha() const {
242    return SkGetPackedA32(fPMColor);
243}
244
245bool SkColorShader::setContext(const SkBitmap& device, const SkPaint& paint,
246                               const SkMatrix& matrix) {
247    if (!this->INHERITED::setContext(device, paint, matrix)) {
248        return false;
249    }
250
251    unsigned a;
252
253    if (fInheritColor) {
254        fColor = paint.getColor();
255        a = SkColorGetA(fColor);
256    } else {
257        a = SkAlphaMul(SkColorGetA(fColor), SkAlpha255To256(paint.getAlpha()));
258    }
259
260    unsigned r = SkColorGetR(fColor);
261    unsigned g = SkColorGetG(fColor);
262    unsigned b = SkColorGetB(fColor);
263
264    // we want this before we apply any alpha
265    fColor16 = SkPack888ToRGB16(r, g, b);
266
267    if (a != 255) {
268        r = SkMulDiv255Round(r, a);
269        g = SkMulDiv255Round(g, a);
270        b = SkMulDiv255Round(b, a);
271    }
272    fPMColor = SkPackARGB32(a, r, g, b);
273
274    fFlags = kConstInY32_Flag;
275    if (255 == a) {
276        fFlags |= kOpaqueAlpha_Flag;
277        if (paint.isDither() == false) {
278            fFlags |= kHasSpan16_Flag;
279        }
280    }
281
282    return true;
283}
284
285void SkColorShader::shadeSpan(int x, int y, SkPMColor span[], int count) {
286    sk_memset32(span, fPMColor, count);
287}
288
289void SkColorShader::shadeSpan16(int x, int y, uint16_t span[], int count) {
290    sk_memset16(span, fColor16, count);
291}
292
293void SkColorShader::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
294    memset(alpha, SkGetPackedA32(fPMColor), count);
295}
296
297// if we had a asAColor method, that would be more efficient...
298SkShader::BitmapType SkColorShader::asABitmap(SkBitmap* bitmap, SkMatrix* matrix,
299                                              TileMode modes[]) const {
300    return kNone_BitmapType;
301}
302
303SkShader::GradientType SkColorShader::asAGradient(GradientInfo* info) const {
304    if (info) {
305        if (info->fColors && info->fColorCount >= 1) {
306            info->fColors[0] = fColor;
307        }
308        info->fColorCount = 1;
309        info->fTileMode = SkShader::kRepeat_TileMode;
310    }
311    return kColor_GradientType;
312}
313
314#ifdef SK_DEVELOPER
315void SkColorShader::toString(SkString* str) const {
316    str->append("SkColorShader: (");
317
318    if (fInheritColor) {
319        str->append("Color: inherited from paint");
320    } else {
321        str->append("Color: ");
322        str->appendHex(fColor);
323    }
324
325    this->INHERITED::toString(str);
326
327    str->append(")");
328}
329#endif
330
331///////////////////////////////////////////////////////////////////////////////
332
333#include "SkEmptyShader.h"
334
335uint32_t SkEmptyShader::getFlags() { return 0; }
336uint8_t SkEmptyShader::getSpan16Alpha() const { return 0; }
337
338bool SkEmptyShader::setContext(const SkBitmap&, const SkPaint&,
339                               const SkMatrix&) { return false; }
340
341void SkEmptyShader::shadeSpan(int x, int y, SkPMColor span[], int count) {
342    SkDEBUGFAIL("should never get called, since setContext() returned false");
343}
344
345void SkEmptyShader::shadeSpan16(int x, int y, uint16_t span[], int count) {
346    SkDEBUGFAIL("should never get called, since setContext() returned false");
347}
348
349void SkEmptyShader::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
350    SkDEBUGFAIL("should never get called, since setContext() returned false");
351}
352
353#ifdef SK_DEVELOPER
354void SkEmptyShader::toString(SkString* str) const {
355    str->append("SkEmptyShader: (");
356
357    this->INHERITED::toString(str);
358
359    str->append(")");
360}
361#endif
362