SkShader.cpp revision 7ed173b1ebac84671fb0dc1b9bd323a5e6e63771 
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#include "SkBitmapProcShader.h"
9#include "SkEmptyShader.h"
10#include "SkReadBuffer.h"
11#include "SkMallocPixelRef.h"
12#include "SkPaint.h"
13#include "SkPicture.h"
14#include "SkPictureShader.h"
15#include "SkScalar.h"
16#include "SkShader.h"
17#include "SkThread.h"
18#include "SkWriteBuffer.h"
19
20//#define SK_TRACK_SHADER_LIFETIME
21
22#ifdef SK_TRACK_SHADER_LIFETIME
23    static int32_t gShaderCounter;
24#endif
25
26static inline void inc_shader_counter() {
27#ifdef SK_TRACK_SHADER_LIFETIME
28    int32_t prev = sk_atomic_inc(&gShaderCounter);
29    SkDebugf("+++ shader counter %d\n", prev + 1);
30#endif
31}
32static inline void dec_shader_counter() {
33#ifdef SK_TRACK_SHADER_LIFETIME
34    int32_t prev = sk_atomic_dec(&gShaderCounter);
35    SkDebugf("--- shader counter %d\n", prev - 1);
36#endif
37}
38
39SkShader::SkShader(const SkMatrix* localMatrix) {
40    inc_shader_counter();
41    if (localMatrix) {
42        fLocalMatrix = *localMatrix;
43    } else {
44        fLocalMatrix.reset();
45    }
46}
47
48SkShader::SkShader(SkReadBuffer& buffer) : INHERITED(buffer) {
49    inc_shader_counter();
50    if (buffer.readBool()) {
51        buffer.readMatrix(&fLocalMatrix);
52    } else {
53        fLocalMatrix.reset();
54    }
55}
56
57SkShader::~SkShader() {
58    dec_shader_counter();
59}
60
61void SkShader::flatten(SkWriteBuffer& buffer) const {
62    this->INHERITED::flatten(buffer);
63    bool hasLocalM = !fLocalMatrix.isIdentity();
64    buffer.writeBool(hasLocalM);
65    if (hasLocalM) {
66        buffer.writeMatrix(fLocalMatrix);
67    }
68}
69
70bool SkShader::computeTotalInverse(const ContextRec& rec, SkMatrix* totalInverse) const {
71    SkMatrix total;
72    total.setConcat(*rec.fMatrix, fLocalMatrix);
73
74    const SkMatrix* m = &total;
75    if (rec.fLocalMatrix) {
76        total.setConcat(*m, *rec.fLocalMatrix);
77        m = &total;
78    }
79    return m->invert(totalInverse);
80}
81
82SkShader::Context* SkShader::createContext(const ContextRec& rec, void* storage) const {
83    if (!this->computeTotalInverse(rec, NULL)) {
84        return NULL;
85    }
86    return this->onCreateContext(rec, storage);
87}
88
89SkShader::Context* SkShader::onCreateContext(const ContextRec& rec, void*) const {
90    return NULL;
91}
92
93size_t SkShader::contextSize() const {
94    return 0;
95}
96
97SkShader::Context::Context(const SkShader& shader, const ContextRec& rec)
98    : fShader(shader), fCTM(*rec.fMatrix)
99{
100    // Because the context parameters must be valid at this point, we know that the matrix is
101    // invertible.
102    SkAssertResult(fShader.computeTotalInverse(rec, &fTotalInverse));
103    fTotalInverseClass = (uint8_t)ComputeMatrixClass(fTotalInverse);
104
105    fPaintAlpha = rec.fPaint->getAlpha();
106}
107
108SkShader::Context::~Context() {}
109
110SkShader::Context::ShadeProc SkShader::Context::asAShadeProc(void** ctx) {
111    return NULL;
112}
113
114#include "SkColorPriv.h"
115
116void SkShader::Context::shadeSpan16(int x, int y, uint16_t span16[], int count) {
117    SkASSERT(span16);
118    SkASSERT(count > 0);
119    SkASSERT(this->canCallShadeSpan16());
120
121    // basically, if we get here, the subclass screwed up
122    SkDEBUGFAIL("kHasSpan16 flag is set, but shadeSpan16() not implemented");
123}
124
125#define kTempColorQuadCount 6   // balance between speed (larger) and saving stack-space
126#define kTempColorCount     (kTempColorQuadCount << 2)
127
128#ifdef SK_CPU_BENDIAN
129    #define SkU32BitShiftToByteOffset(shift)    (3 - ((shift) >> 3))
130#else
131    #define SkU32BitShiftToByteOffset(shift)    ((shift) >> 3)
132#endif
133
134void SkShader::Context::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
135    SkASSERT(count > 0);
136
137    SkPMColor   colors[kTempColorCount];
138
139    while ((count -= kTempColorCount) >= 0) {
140        this->shadeSpan(x, y, colors, kTempColorCount);
141        x += kTempColorCount;
142
143        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
144        int quads = kTempColorQuadCount;
145        do {
146            U8CPU a0 = srcA[0];
147            U8CPU a1 = srcA[4];
148            U8CPU a2 = srcA[8];
149            U8CPU a3 = srcA[12];
150            srcA += 4*4;
151            *alpha++ = SkToU8(a0);
152            *alpha++ = SkToU8(a1);
153            *alpha++ = SkToU8(a2);
154            *alpha++ = SkToU8(a3);
155        } while (--quads != 0);
156    }
157    SkASSERT(count < 0);
158    SkASSERT(count + kTempColorCount >= 0);
159    if (count += kTempColorCount) {
160        this->shadeSpan(x, y, colors, count);
161
162        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
163        do {
164            *alpha++ = *srcA;
165            srcA += 4;
166        } while (--count != 0);
167    }
168#if 0
169    do {
170        int n = count;
171        if (n > kTempColorCount)
172            n = kTempColorCount;
173        SkASSERT(n > 0);
174
175        this->shadeSpan(x, y, colors, n);
176        x += n;
177        count -= n;
178
179        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
180        do {
181            *alpha++ = *srcA;
182            srcA += 4;
183        } while (--n != 0);
184    } while (count > 0);
185#endif
186}
187
188SkShader::Context::MatrixClass SkShader::Context::ComputeMatrixClass(const SkMatrix& mat) {
189    MatrixClass mc = kLinear_MatrixClass;
190
191    if (mat.hasPerspective()) {
192        if (mat.fixedStepInX(0, NULL, NULL)) {
193            mc = kFixedStepInX_MatrixClass;
194        } else {
195            mc = kPerspective_MatrixClass;
196        }
197    }
198    return mc;
199}
200
201//////////////////////////////////////////////////////////////////////////////
202
203SkShader::BitmapType SkShader::asABitmap(SkBitmap*, SkMatrix*, TileMode*) const {
204    return kNone_BitmapType;
205}
206
207SkShader::GradientType SkShader::asAGradient(GradientInfo* info) const {
208    return kNone_GradientType;
209}
210
211GrEffectRef* SkShader::asNewEffect(GrContext*, const SkPaint&, const SkMatrix*) const {
212    return NULL;
213}
214
215SkShader* SkShader::refAsALocalMatrixShader(SkMatrix*) const {
216    return NULL;
217}
218
219SkShader* SkShader::CreateEmptyShader() {
220    return SkNEW(SkEmptyShader);
221}
222
223SkShader* SkShader::CreateBitmapShader(const SkBitmap& src, TileMode tmx, TileMode tmy,
224                                       const SkMatrix* localMatrix) {
225    return ::CreateBitmapShader(src, tmx, tmy, localMatrix, NULL);
226}
227
228SkShader* SkShader::CreatePictureShader(SkPicture* src, TileMode tmx, TileMode tmy,
229                                       const SkMatrix* localMatrix) {
230    return SkPictureShader::Create(src, tmx, tmy, localMatrix);
231}
232
233#ifndef SK_IGNORE_TO_STRING
234void SkShader::toString(SkString* str) const {
235    if (!fLocalMatrix.isIdentity()) {
236        str->append(" ");
237        fLocalMatrix.toString(str);
238    }
239}
240#endif
241
242//////////////////////////////////////////////////////////////////////////////
243
244#include "SkColorShader.h"
245#include "SkUtils.h"
246
247SkColorShader::SkColorShader(SkColor c)
248    : fColor(c) {
249}
250
251bool SkColorShader::isOpaque() const {
252    return SkColorGetA(fColor) == 255;
253}
254
255SkColorShader::SkColorShader(SkReadBuffer& b) : INHERITED(b) {
256    // V25_COMPATIBILITY_CODE We had a boolean to make the color shader inherit the paint's
257    // color. We don't support that any more.
258    if (b.isVersionLT(SkReadBuffer::kColorShaderNoBool_Version)) {
259        if (b.readBool()) {
260            SkDEBUGFAIL("We shouldn't have pictures that recorded the inherited case.");
261            fColor = SK_ColorWHITE;
262            return;
263        }
264    }
265    fColor = b.readColor();
266}
267
268void SkColorShader::flatten(SkWriteBuffer& buffer) const {
269    this->INHERITED::flatten(buffer);
270    buffer.writeColor(fColor);
271}
272
273uint32_t SkColorShader::ColorShaderContext::getFlags() const {
274    return fFlags;
275}
276
277uint8_t SkColorShader::ColorShaderContext::getSpan16Alpha() const {
278    return SkGetPackedA32(fPMColor);
279}
280
281SkShader::Context* SkColorShader::onCreateContext(const ContextRec& rec, void* storage) const {
282    return SkNEW_PLACEMENT_ARGS(storage, ColorShaderContext, (*this, rec));
283}
284
285SkColorShader::ColorShaderContext::ColorShaderContext(const SkColorShader& shader,
286                                                      const ContextRec& rec)
287    : INHERITED(shader, rec)
288{
289    SkColor color = shader.fColor;
290    unsigned a = SkAlphaMul(SkColorGetA(color), SkAlpha255To256(rec.fPaint->getAlpha()));
291
292    unsigned r = SkColorGetR(color);
293    unsigned g = SkColorGetG(color);
294    unsigned b = SkColorGetB(color);
295
296    // we want this before we apply any alpha
297    fColor16 = SkPack888ToRGB16(r, g, b);
298
299    if (a != 255) {
300        r = SkMulDiv255Round(r, a);
301        g = SkMulDiv255Round(g, a);
302        b = SkMulDiv255Round(b, a);
303    }
304    fPMColor = SkPackARGB32(a, r, g, b);
305
306    fFlags = kConstInY32_Flag;
307    if (255 == a) {
308        fFlags |= kOpaqueAlpha_Flag;
309        if (rec.fPaint->isDither() == false) {
310            fFlags |= kHasSpan16_Flag;
311        }
312    }
313}
314
315void SkColorShader::ColorShaderContext::shadeSpan(int x, int y, SkPMColor span[], int count) {
316    sk_memset32(span, fPMColor, count);
317}
318
319void SkColorShader::ColorShaderContext::shadeSpan16(int x, int y, uint16_t span[], int count) {
320    sk_memset16(span, fColor16, count);
321}
322
323void SkColorShader::ColorShaderContext::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
324    memset(alpha, SkGetPackedA32(fPMColor), count);
325}
326
327// if we had a asAColor method, that would be more efficient...
328SkShader::BitmapType SkColorShader::asABitmap(SkBitmap* bitmap, SkMatrix* matrix,
329                                              TileMode modes[]) const {
330    return kNone_BitmapType;
331}
332
333SkShader::GradientType SkColorShader::asAGradient(GradientInfo* info) const {
334    if (info) {
335        if (info->fColors && info->fColorCount >= 1) {
336            info->fColors[0] = fColor;
337        }
338        info->fColorCount = 1;
339        info->fTileMode = SkShader::kRepeat_TileMode;
340    }
341    return kColor_GradientType;
342}
343
344#ifndef SK_IGNORE_TO_STRING
345void SkColorShader::toString(SkString* str) const {
346    str->append("SkColorShader: (");
347
348    str->append("Color: ");
349    str->appendHex(fColor);
350
351    this->INHERITED::toString(str);
352
353    str->append(")");
354}
355#endif
356
357///////////////////////////////////////////////////////////////////////////////
358
359#ifndef SK_IGNORE_TO_STRING
360#include "SkEmptyShader.h"
361
362void SkEmptyShader::toString(SkString* str) const {
363    str->append("SkEmptyShader: (");
364
365    this->INHERITED::toString(str);
366
367    str->append(")");
368}
369#endif
370