SkShader.cpp revision 8fae213590981b8ca37839a4e3cae1dae4e611fd 
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 = this->hasLocalMatrix();
64    buffer.writeBool(hasLocalM);
65    if (hasLocalM) {
66        buffer.writeMatrix(fLocalMatrix);
67    }
68}
69
70bool SkShader::computeTotalInverse(const ContextRec& rec, SkMatrix* totalInverse) const {
71    const SkMatrix* m = rec.fMatrix;
72    SkMatrix        total;
73
74    if (this->hasLocalMatrix()) {
75        total.setConcat(*m, this->getLocalMatrix());
76        m = &total;
77    }
78    if (rec.fLocalMatrix) {
79        total.setConcat(*m, *rec.fLocalMatrix);
80        m = &total;
81    }
82    return m->invert(totalInverse);
83}
84
85SkShader::Context* SkShader::createContext(const ContextRec& rec, void* storage) const {
86    if (!this->computeTotalInverse(rec, NULL)) {
87        return NULL;
88    }
89    return this->onCreateContext(rec, storage);
90}
91
92SkShader::Context* SkShader::onCreateContext(const ContextRec& rec, void*) const {
93    return NULL;
94}
95
96size_t SkShader::contextSize() const {
97    return 0;
98}
99
100SkShader::Context::Context(const SkShader& shader, const ContextRec& rec)
101    : fShader(shader), fCTM(*rec.fMatrix)
102{
103    // Because the context parameters must be valid at this point, we know that the matrix is
104    // invertible.
105    SkAssertResult(fShader.computeTotalInverse(rec, &fTotalInverse));
106    fTotalInverseClass = (uint8_t)ComputeMatrixClass(fTotalInverse);
107
108    fPaintAlpha = rec.fPaint->getAlpha();
109}
110
111SkShader::Context::~Context() {}
112
113SkShader::Context::ShadeProc SkShader::Context::asAShadeProc(void** ctx) {
114    return NULL;
115}
116
117#include "SkColorPriv.h"
118
119void SkShader::Context::shadeSpan16(int x, int y, uint16_t span16[], int count) {
120    SkASSERT(span16);
121    SkASSERT(count > 0);
122    SkASSERT(this->canCallShadeSpan16());
123
124    // basically, if we get here, the subclass screwed up
125    SkDEBUGFAIL("kHasSpan16 flag is set, but shadeSpan16() not implemented");
126}
127
128#define kTempColorQuadCount 6   // balance between speed (larger) and saving stack-space
129#define kTempColorCount     (kTempColorQuadCount << 2)
130
131#ifdef SK_CPU_BENDIAN
132    #define SkU32BitShiftToByteOffset(shift)    (3 - ((shift) >> 3))
133#else
134    #define SkU32BitShiftToByteOffset(shift)    ((shift) >> 3)
135#endif
136
137void SkShader::Context::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
138    SkASSERT(count > 0);
139
140    SkPMColor   colors[kTempColorCount];
141
142    while ((count -= kTempColorCount) >= 0) {
143        this->shadeSpan(x, y, colors, kTempColorCount);
144        x += kTempColorCount;
145
146        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
147        int quads = kTempColorQuadCount;
148        do {
149            U8CPU a0 = srcA[0];
150            U8CPU a1 = srcA[4];
151            U8CPU a2 = srcA[8];
152            U8CPU a3 = srcA[12];
153            srcA += 4*4;
154            *alpha++ = SkToU8(a0);
155            *alpha++ = SkToU8(a1);
156            *alpha++ = SkToU8(a2);
157            *alpha++ = SkToU8(a3);
158        } while (--quads != 0);
159    }
160    SkASSERT(count < 0);
161    SkASSERT(count + kTempColorCount >= 0);
162    if (count += kTempColorCount) {
163        this->shadeSpan(x, y, colors, count);
164
165        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
166        do {
167            *alpha++ = *srcA;
168            srcA += 4;
169        } while (--count != 0);
170    }
171#if 0
172    do {
173        int n = count;
174        if (n > kTempColorCount)
175            n = kTempColorCount;
176        SkASSERT(n > 0);
177
178        this->shadeSpan(x, y, colors, n);
179        x += n;
180        count -= n;
181
182        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
183        do {
184            *alpha++ = *srcA;
185            srcA += 4;
186        } while (--n != 0);
187    } while (count > 0);
188#endif
189}
190
191SkShader::Context::MatrixClass SkShader::Context::ComputeMatrixClass(const SkMatrix& mat) {
192    MatrixClass mc = kLinear_MatrixClass;
193
194    if (mat.hasPerspective()) {
195        if (mat.fixedStepInX(0, NULL, NULL)) {
196            mc = kFixedStepInX_MatrixClass;
197        } else {
198            mc = kPerspective_MatrixClass;
199        }
200    }
201    return mc;
202}
203
204//////////////////////////////////////////////////////////////////////////////
205
206SkShader::BitmapType SkShader::asABitmap(SkBitmap*, SkMatrix*, TileMode*) const {
207    return kNone_BitmapType;
208}
209
210SkShader::GradientType SkShader::asAGradient(GradientInfo* info) const {
211    return kNone_GradientType;
212}
213
214GrEffectRef* SkShader::asNewEffect(GrContext*, const SkPaint&) const {
215    return NULL;
216}
217
218SkShader* SkShader::refAsALocalMatrixShader(SkMatrix*) const {
219    return NULL;
220}
221
222SkShader* SkShader::CreateEmptyShader() {
223    return SkNEW(SkEmptyShader);
224}
225
226SkShader* SkShader::CreateBitmapShader(const SkBitmap& src, TileMode tmx, TileMode tmy,
227                                       const SkMatrix* localMatrix) {
228    return ::CreateBitmapShader(src, tmx, tmy, localMatrix, NULL);
229}
230
231SkShader* SkShader::CreatePictureShader(SkPicture* src, TileMode tmx, TileMode tmy,
232                                       const SkMatrix* localMatrix) {
233    return SkPictureShader::Create(src, tmx, tmy, localMatrix);
234}
235
236#ifndef SK_IGNORE_TO_STRING
237void SkShader::toString(SkString* str) const {
238    if (this->hasLocalMatrix()) {
239        str->append(" ");
240        this->getLocalMatrix().toString(str);
241    }
242}
243#endif
244
245//////////////////////////////////////////////////////////////////////////////
246
247#include "SkColorShader.h"
248#include "SkUtils.h"
249
250SkColorShader::SkColorShader(SkColor c)
251    : fColor(c) {
252}
253
254bool SkColorShader::isOpaque() const {
255    return SkColorGetA(fColor) == 255;
256}
257
258SkColorShader::SkColorShader(SkReadBuffer& b) : INHERITED(b) {
259    // V25_COMPATIBILITY_CODE We had a boolean to make the color shader inherit the paint's
260    // color. We don't support that any more.
261    if (b.pictureVersion() < 26 && 0 != b.pictureVersion()) {
262        if (b.readBool()) {
263            SkDEBUGFAIL("We shouldn't have pictures that recorded the inherited case.");
264            fColor = SK_ColorWHITE;
265            return;
266        }
267    }
268    fColor = b.readColor();
269}
270
271void SkColorShader::flatten(SkWriteBuffer& buffer) const {
272    this->INHERITED::flatten(buffer);
273    buffer.writeColor(fColor);
274}
275
276uint32_t SkColorShader::ColorShaderContext::getFlags() const {
277    return fFlags;
278}
279
280uint8_t SkColorShader::ColorShaderContext::getSpan16Alpha() const {
281    return SkGetPackedA32(fPMColor);
282}
283
284SkShader::Context* SkColorShader::onCreateContext(const ContextRec& rec, void* storage) const {
285    return SkNEW_PLACEMENT_ARGS(storage, ColorShaderContext, (*this, rec));
286}
287
288SkColorShader::ColorShaderContext::ColorShaderContext(const SkColorShader& shader,
289                                                      const ContextRec& rec)
290    : INHERITED(shader, rec)
291{
292    SkColor color = shader.fColor;
293    unsigned a = SkAlphaMul(SkColorGetA(color), SkAlpha255To256(rec.fPaint->getAlpha()));
294
295    unsigned r = SkColorGetR(color);
296    unsigned g = SkColorGetG(color);
297    unsigned b = SkColorGetB(color);
298
299    // we want this before we apply any alpha
300    fColor16 = SkPack888ToRGB16(r, g, b);
301
302    if (a != 255) {
303        r = SkMulDiv255Round(r, a);
304        g = SkMulDiv255Round(g, a);
305        b = SkMulDiv255Round(b, a);
306    }
307    fPMColor = SkPackARGB32(a, r, g, b);
308
309    fFlags = kConstInY32_Flag;
310    if (255 == a) {
311        fFlags |= kOpaqueAlpha_Flag;
312        if (rec.fPaint->isDither() == false) {
313            fFlags |= kHasSpan16_Flag;
314        }
315    }
316}
317
318void SkColorShader::ColorShaderContext::shadeSpan(int x, int y, SkPMColor span[], int count) {
319    sk_memset32(span, fPMColor, count);
320}
321
322void SkColorShader::ColorShaderContext::shadeSpan16(int x, int y, uint16_t span[], int count) {
323    sk_memset16(span, fColor16, count);
324}
325
326void SkColorShader::ColorShaderContext::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
327    memset(alpha, SkGetPackedA32(fPMColor), count);
328}
329
330// if we had a asAColor method, that would be more efficient...
331SkShader::BitmapType SkColorShader::asABitmap(SkBitmap* bitmap, SkMatrix* matrix,
332                                              TileMode modes[]) const {
333    return kNone_BitmapType;
334}
335
336SkShader::GradientType SkColorShader::asAGradient(GradientInfo* info) const {
337    if (info) {
338        if (info->fColors && info->fColorCount >= 1) {
339            info->fColors[0] = fColor;
340        }
341        info->fColorCount = 1;
342        info->fTileMode = SkShader::kRepeat_TileMode;
343    }
344    return kColor_GradientType;
345}
346
347#ifndef SK_IGNORE_TO_STRING
348void SkColorShader::toString(SkString* str) const {
349    str->append("SkColorShader: (");
350
351    str->append("Color: ");
352    str->appendHex(fColor);
353
354    this->INHERITED::toString(str);
355
356    str->append(")");
357}
358#endif
359
360///////////////////////////////////////////////////////////////////////////////
361
362#ifndef SK_IGNORE_TO_STRING
363#include "SkEmptyShader.h"
364
365void SkEmptyShader::toString(SkString* str) const {
366    str->append("SkEmptyShader: (");
367
368    this->INHERITED::toString(str);
369
370    str->append(")");
371}
372#endif
373