SkShader.cpp revision f51de259ada8dacd44eca41945b49a8dba1606ae 
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#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
47    fGenerationID = 0;
48#endif
49}
50
51SkShader::SkShader(SkReadBuffer& buffer) : INHERITED(buffer) {
52    inc_shader_counter();
53    if (buffer.readBool()) {
54        buffer.readMatrix(&fLocalMatrix);
55    } else {
56        fLocalMatrix.reset();
57    }
58#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
59    fGenerationID = 0;
60#endif
61}
62
63SkShader::~SkShader() {
64    dec_shader_counter();
65}
66
67void SkShader::flatten(SkWriteBuffer& buffer) const {
68    this->INHERITED::flatten(buffer);
69    bool hasLocalM = !fLocalMatrix.isIdentity();
70    buffer.writeBool(hasLocalM);
71    if (hasLocalM) {
72        buffer.writeMatrix(fLocalMatrix);
73    }
74}
75
76bool SkShader::computeTotalInverse(const ContextRec& rec, SkMatrix* totalInverse) const {
77    SkMatrix total;
78    total.setConcat(*rec.fMatrix, fLocalMatrix);
79
80    const SkMatrix* m = &total;
81    if (rec.fLocalMatrix) {
82        total.setConcat(*m, *rec.fLocalMatrix);
83        m = &total;
84    }
85    return m->invert(totalInverse);
86}
87
88SkShader::Context* SkShader::createContext(const ContextRec& rec, void* storage) const {
89    if (!this->computeTotalInverse(rec, NULL)) {
90        return NULL;
91    }
92    return this->onCreateContext(rec, storage);
93}
94
95SkShader::Context* SkShader::onCreateContext(const ContextRec& rec, void*) const {
96    return NULL;
97}
98
99size_t SkShader::contextSize() const {
100    return 0;
101}
102
103SkShader::Context::Context(const SkShader& shader, const ContextRec& rec)
104    : fShader(shader), fCTM(*rec.fMatrix)
105{
106    // Because the context parameters must be valid at this point, we know that the matrix is
107    // invertible.
108    SkAssertResult(fShader.computeTotalInverse(rec, &fTotalInverse));
109    fTotalInverseClass = (uint8_t)ComputeMatrixClass(fTotalInverse);
110
111    fPaintAlpha = rec.fPaint->getAlpha();
112}
113
114SkShader::Context::~Context() {}
115
116SkShader::Context::ShadeProc SkShader::Context::asAShadeProc(void** ctx) {
117    return NULL;
118}
119
120#include "SkColorPriv.h"
121
122void SkShader::Context::shadeSpan16(int x, int y, uint16_t span16[], int count) {
123    SkASSERT(span16);
124    SkASSERT(count > 0);
125    SkASSERT(this->canCallShadeSpan16());
126
127    // basically, if we get here, the subclass screwed up
128    SkDEBUGFAIL("kHasSpan16 flag is set, but shadeSpan16() not implemented");
129}
130
131#define kTempColorQuadCount 6   // balance between speed (larger) and saving stack-space
132#define kTempColorCount     (kTempColorQuadCount << 2)
133
134#ifdef SK_CPU_BENDIAN
135    #define SkU32BitShiftToByteOffset(shift)    (3 - ((shift) >> 3))
136#else
137    #define SkU32BitShiftToByteOffset(shift)    ((shift) >> 3)
138#endif
139
140void SkShader::Context::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
141    SkASSERT(count > 0);
142
143    SkPMColor   colors[kTempColorCount];
144
145    while ((count -= kTempColorCount) >= 0) {
146        this->shadeSpan(x, y, colors, kTempColorCount);
147        x += kTempColorCount;
148
149        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
150        int quads = kTempColorQuadCount;
151        do {
152            U8CPU a0 = srcA[0];
153            U8CPU a1 = srcA[4];
154            U8CPU a2 = srcA[8];
155            U8CPU a3 = srcA[12];
156            srcA += 4*4;
157            *alpha++ = SkToU8(a0);
158            *alpha++ = SkToU8(a1);
159            *alpha++ = SkToU8(a2);
160            *alpha++ = SkToU8(a3);
161        } while (--quads != 0);
162    }
163    SkASSERT(count < 0);
164    SkASSERT(count + kTempColorCount >= 0);
165    if (count += kTempColorCount) {
166        this->shadeSpan(x, y, colors, count);
167
168        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
169        do {
170            *alpha++ = *srcA;
171            srcA += 4;
172        } while (--count != 0);
173    }
174#if 0
175    do {
176        int n = count;
177        if (n > kTempColorCount)
178            n = kTempColorCount;
179        SkASSERT(n > 0);
180
181        this->shadeSpan(x, y, colors, n);
182        x += n;
183        count -= n;
184
185        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
186        do {
187            *alpha++ = *srcA;
188            srcA += 4;
189        } while (--n != 0);
190    } while (count > 0);
191#endif
192}
193
194SkShader::Context::MatrixClass SkShader::Context::ComputeMatrixClass(const SkMatrix& mat) {
195    MatrixClass mc = kLinear_MatrixClass;
196
197    if (mat.hasPerspective()) {
198        if (mat.fixedStepInX(0, NULL, NULL)) {
199            mc = kFixedStepInX_MatrixClass;
200        } else {
201            mc = kPerspective_MatrixClass;
202        }
203    }
204    return mc;
205}
206
207//////////////////////////////////////////////////////////////////////////////
208
209SkShader::BitmapType SkShader::asABitmap(SkBitmap*, SkMatrix*, TileMode*) const {
210    return kNone_BitmapType;
211}
212
213SkShader::GradientType SkShader::asAGradient(GradientInfo* info) const {
214    return kNone_GradientType;
215}
216
217bool SkShader::asNewEffect(GrContext* context, const SkPaint& paint,
218                           const SkMatrix* localMatrixOrNull, GrColor* grColor,
219                           GrEffectRef** grEffect)  const {
220    return false;
221}
222
223SkShader* SkShader::refAsALocalMatrixShader(SkMatrix*) const {
224    return NULL;
225}
226
227SkShader* SkShader::CreateEmptyShader() {
228    return SkNEW(SkEmptyShader);
229}
230
231SkShader* SkShader::CreateBitmapShader(const SkBitmap& src, TileMode tmx, TileMode tmy,
232                                       const SkMatrix* localMatrix) {
233    return ::CreateBitmapShader(src, tmx, tmy, localMatrix, NULL);
234}
235
236SkShader* SkShader::CreatePictureShader(SkPicture* src, TileMode tmx, TileMode tmy,
237                                       const SkMatrix* localMatrix) {
238    return SkPictureShader::Create(src, tmx, tmy, localMatrix);
239}
240
241#ifndef SK_IGNORE_TO_STRING
242void SkShader::toString(SkString* str) const {
243    if (!fLocalMatrix.isIdentity()) {
244        str->append(" ");
245        fLocalMatrix.toString(str);
246    }
247}
248#endif
249
250//////////////////////////////////////////////////////////////////////////////
251
252#include "SkColorShader.h"
253#include "SkUtils.h"
254
255SkColorShader::SkColorShader(SkColor c)
256    : fColor(c) {
257}
258
259bool SkColorShader::isOpaque() const {
260    return SkColorGetA(fColor) == 255;
261}
262
263SkColorShader::SkColorShader(SkReadBuffer& b) : INHERITED(b) {
264    // V25_COMPATIBILITY_CODE We had a boolean to make the color shader inherit the paint's
265    // color. We don't support that any more.
266    if (b.isVersionLT(SkReadBuffer::kColorShaderNoBool_Version)) {
267        if (b.readBool()) {
268            SkDEBUGFAIL("We shouldn't have pictures that recorded the inherited case.");
269            fColor = SK_ColorWHITE;
270            return;
271        }
272    }
273    fColor = b.readColor();
274}
275
276void SkColorShader::flatten(SkWriteBuffer& buffer) const {
277    this->INHERITED::flatten(buffer);
278    buffer.writeColor(fColor);
279}
280
281uint32_t SkColorShader::ColorShaderContext::getFlags() const {
282    return fFlags;
283}
284
285uint8_t SkColorShader::ColorShaderContext::getSpan16Alpha() const {
286    return SkGetPackedA32(fPMColor);
287}
288
289SkShader::Context* SkColorShader::onCreateContext(const ContextRec& rec, void* storage) const {
290    return SkNEW_PLACEMENT_ARGS(storage, ColorShaderContext, (*this, rec));
291}
292
293SkColorShader::ColorShaderContext::ColorShaderContext(const SkColorShader& shader,
294                                                      const ContextRec& rec)
295    : INHERITED(shader, rec)
296{
297    SkColor color = shader.fColor;
298    unsigned a = SkAlphaMul(SkColorGetA(color), SkAlpha255To256(rec.fPaint->getAlpha()));
299
300    unsigned r = SkColorGetR(color);
301    unsigned g = SkColorGetG(color);
302    unsigned b = SkColorGetB(color);
303
304    // we want this before we apply any alpha
305    fColor16 = SkPack888ToRGB16(r, g, b);
306
307    if (a != 255) {
308        r = SkMulDiv255Round(r, a);
309        g = SkMulDiv255Round(g, a);
310        b = SkMulDiv255Round(b, a);
311    }
312    fPMColor = SkPackARGB32(a, r, g, b);
313
314    fFlags = kConstInY32_Flag;
315    if (255 == a) {
316        fFlags |= kOpaqueAlpha_Flag;
317        if (rec.fPaint->isDither() == false) {
318            fFlags |= kHasSpan16_Flag;
319        }
320    }
321}
322
323void SkColorShader::ColorShaderContext::shadeSpan(int x, int y, SkPMColor span[], int count) {
324    sk_memset32(span, fPMColor, count);
325}
326
327void SkColorShader::ColorShaderContext::shadeSpan16(int x, int y, uint16_t span[], int count) {
328    sk_memset16(span, fColor16, count);
329}
330
331void SkColorShader::ColorShaderContext::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
332    memset(alpha, SkGetPackedA32(fPMColor), count);
333}
334
335// if we had a asAColor method, that would be more efficient...
336SkShader::BitmapType SkColorShader::asABitmap(SkBitmap* bitmap, SkMatrix* matrix,
337                                              TileMode modes[]) const {
338    return kNone_BitmapType;
339}
340
341SkShader::GradientType SkColorShader::asAGradient(GradientInfo* info) const {
342    if (info) {
343        if (info->fColors && info->fColorCount >= 1) {
344            info->fColors[0] = fColor;
345        }
346        info->fColorCount = 1;
347        info->fTileMode = SkShader::kRepeat_TileMode;
348    }
349    return kColor_GradientType;
350}
351
352#if SK_SUPPORT_GPU
353
354#include "SkGr.h"
355
356bool SkColorShader::asNewEffect(GrContext* context, const SkPaint& paint,
357                                const SkMatrix* localMatrix, GrColor* grColor,
358                                GrEffectRef** grEffect) const {
359    *grEffect = NULL;
360    SkColor skColor = fColor;
361    U8CPU newA = SkMulDiv255Round(SkColorGetA(fColor), paint.getAlpha());
362    *grColor = SkColor2GrColor(SkColorSetA(skColor, newA));
363    return true;
364}
365
366#else
367
368bool SkColorShader::asNewEffect(GrContext* context, const SkPaint& paint,
369                                     const SkMatrix* localMatrix, GrColor* grColor,
370                                     GrEffectRef** grEffect) const {
371    SkDEBUGFAIL("Should not call in GPU-less build");
372    return false;
373}
374
375#endif
376
377#ifndef SK_IGNORE_TO_STRING
378void SkColorShader::toString(SkString* str) const {
379    str->append("SkColorShader: (");
380
381    str->append("Color: ");
382    str->appendHex(fColor);
383
384    this->INHERITED::toString(str);
385
386    str->append(")");
387}
388#endif
389
390///////////////////////////////////////////////////////////////////////////////
391
392#ifndef SK_IGNORE_TO_STRING
393#include "SkEmptyShader.h"
394
395void SkEmptyShader::toString(SkString* str) const {
396    str->append("SkEmptyShader: (");
397
398    this->INHERITED::toString(str);
399
400    str->append(")");
401}
402#endif
403