SkShader.cpp revision c09abe66c1388c5da456c7686eab7a7928e9e9d6 
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 "SkReadBuffer.h"
10#include "SkMallocPixelRef.h"
11#include "SkPaint.h"
12#include "SkPicture.h"
13#include "SkPictureShader.h"
14#include "SkScalar.h"
15#include "SkShader.h"
16#include "SkWriteBuffer.h"
17
18SkShader::SkShader(const SkMatrix* localMatrix) {
19    if (localMatrix) {
20        fLocalMatrix = *localMatrix;
21    } else {
22        fLocalMatrix.reset();
23    }
24}
25
26SkShader::SkShader(SkReadBuffer& buffer)
27        : INHERITED(buffer) {
28    if (buffer.readBool()) {
29        buffer.readMatrix(&fLocalMatrix);
30    } else {
31        fLocalMatrix.reset();
32    }
33}
34
35SkShader::~SkShader() {
36}
37
38void SkShader::flatten(SkWriteBuffer& buffer) const {
39    this->INHERITED::flatten(buffer);
40    bool hasLocalM = this->hasLocalMatrix();
41    buffer.writeBool(hasLocalM);
42    if (hasLocalM) {
43        buffer.writeMatrix(fLocalMatrix);
44    }
45}
46
47bool SkShader::computeTotalInverse(const SkMatrix& matrix, SkMatrix* totalInverse) const {
48    const SkMatrix* m = &matrix;
49    SkMatrix        total;
50
51    if (this->hasLocalMatrix()) {
52        total.setConcat(matrix, this->getLocalMatrix());
53        m = &total;
54    }
55
56    return m->invert(totalInverse);
57}
58
59bool SkShader::validContext(const ContextRec& rec, SkMatrix* totalInverse) const {
60    return this->computeTotalInverse(*rec.fMatrix, totalInverse);
61}
62
63SkShader::Context* SkShader::createContext(const ContextRec&, void* storage) const {
64    return NULL;
65}
66
67size_t SkShader::contextSize() const {
68    return 0;
69}
70
71SkShader::Context::Context(const SkShader& shader, const ContextRec& rec)
72    : fShader(shader)
73{
74    SkASSERT(fShader.validContext(rec));
75
76    // Because the context parameters must be valid at this point, we know that the matrix is
77    // invertible.
78    SkAssertResult(fShader.computeTotalInverse(*rec.fMatrix, &fTotalInverse));
79    fTotalInverseClass = (uint8_t)ComputeMatrixClass(fTotalInverse);
80
81    fPaintAlpha = rec.fPaint->getAlpha();
82}
83
84SkShader::Context::~Context() {}
85
86SkShader::Context::ShadeProc SkShader::Context::asAShadeProc(void** ctx) {
87    return NULL;
88}
89
90#include "SkColorPriv.h"
91
92void SkShader::Context::shadeSpan16(int x, int y, uint16_t span16[], int count) {
93    SkASSERT(span16);
94    SkASSERT(count > 0);
95    SkASSERT(this->canCallShadeSpan16());
96
97    // basically, if we get here, the subclass screwed up
98    SkDEBUGFAIL("kHasSpan16 flag is set, but shadeSpan16() not implemented");
99}
100
101#define kTempColorQuadCount 6   // balance between speed (larger) and saving stack-space
102#define kTempColorCount     (kTempColorQuadCount << 2)
103
104#ifdef SK_CPU_BENDIAN
105    #define SkU32BitShiftToByteOffset(shift)    (3 - ((shift) >> 3))
106#else
107    #define SkU32BitShiftToByteOffset(shift)    ((shift) >> 3)
108#endif
109
110void SkShader::Context::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
111    SkASSERT(count > 0);
112
113    SkPMColor   colors[kTempColorCount];
114
115    while ((count -= kTempColorCount) >= 0) {
116        this->shadeSpan(x, y, colors, kTempColorCount);
117        x += kTempColorCount;
118
119        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
120        int quads = kTempColorQuadCount;
121        do {
122            U8CPU a0 = srcA[0];
123            U8CPU a1 = srcA[4];
124            U8CPU a2 = srcA[8];
125            U8CPU a3 = srcA[12];
126            srcA += 4*4;
127            *alpha++ = SkToU8(a0);
128            *alpha++ = SkToU8(a1);
129            *alpha++ = SkToU8(a2);
130            *alpha++ = SkToU8(a3);
131        } while (--quads != 0);
132    }
133    SkASSERT(count < 0);
134    SkASSERT(count + kTempColorCount >= 0);
135    if (count += kTempColorCount) {
136        this->shadeSpan(x, y, colors, count);
137
138        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
139        do {
140            *alpha++ = *srcA;
141            srcA += 4;
142        } while (--count != 0);
143    }
144#if 0
145    do {
146        int n = count;
147        if (n > kTempColorCount)
148            n = kTempColorCount;
149        SkASSERT(n > 0);
150
151        this->shadeSpan(x, y, colors, n);
152        x += n;
153        count -= n;
154
155        const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
156        do {
157            *alpha++ = *srcA;
158            srcA += 4;
159        } while (--n != 0);
160    } while (count > 0);
161#endif
162}
163
164SkShader::Context::MatrixClass SkShader::Context::ComputeMatrixClass(const SkMatrix& mat) {
165    MatrixClass mc = kLinear_MatrixClass;
166
167    if (mat.hasPerspective()) {
168        if (mat.fixedStepInX(0, NULL, NULL)) {
169            mc = kFixedStepInX_MatrixClass;
170        } else {
171            mc = kPerspective_MatrixClass;
172        }
173    }
174    return mc;
175}
176
177//////////////////////////////////////////////////////////////////////////////
178
179SkShader::BitmapType SkShader::asABitmap(SkBitmap*, SkMatrix*, TileMode*) const {
180    return kNone_BitmapType;
181}
182
183SkShader::GradientType SkShader::asAGradient(GradientInfo* info) const {
184    return kNone_GradientType;
185}
186
187GrEffectRef* SkShader::asNewEffect(GrContext*, const SkPaint&) const {
188    return NULL;
189}
190
191SkShader* SkShader::CreateBitmapShader(const SkBitmap& src, TileMode tmx, TileMode tmy,
192                                       const SkMatrix* localMatrix) {
193    return ::CreateBitmapShader(src, tmx, tmy, localMatrix, NULL);
194}
195
196SkShader* SkShader::CreatePictureShader(SkPicture* src, TileMode tmx, TileMode tmy) {
197    return SkPictureShader::Create(src, tmx, tmy);
198}
199
200#ifndef SK_IGNORE_TO_STRING
201void SkShader::toString(SkString* str) const {
202    if (this->hasLocalMatrix()) {
203        str->append(" ");
204        this->getLocalMatrix().toString(str);
205    }
206}
207#endif
208
209//////////////////////////////////////////////////////////////////////////////
210
211#include "SkColorShader.h"
212#include "SkUtils.h"
213
214SkColorShader::SkColorShader(SkColor c)
215    : fColor(c) {
216}
217
218bool SkColorShader::isOpaque() const {
219    return SkColorGetA(fColor) == 255;
220}
221
222SkColorShader::SkColorShader(SkReadBuffer& b) : INHERITED(b) {
223    // V25_COMPATIBILITY_CODE We had a boolean to make the color shader inherit the paint's
224    // color. We don't support that any more.
225    if (b.pictureVersion() < 26 && 0 != b.pictureVersion()) {
226        if (b.readBool()) {
227            SkDEBUGFAIL("We shouldn't have pictures that recorded the inherited case.");
228            fColor = SK_ColorWHITE;
229            return;
230        }
231    }
232    fColor = b.readColor();
233}
234
235void SkColorShader::flatten(SkWriteBuffer& buffer) const {
236    this->INHERITED::flatten(buffer);
237    buffer.writeColor(fColor);
238}
239
240uint32_t SkColorShader::ColorShaderContext::getFlags() const {
241    return fFlags;
242}
243
244uint8_t SkColorShader::ColorShaderContext::getSpan16Alpha() const {
245    return SkGetPackedA32(fPMColor);
246}
247
248SkShader::Context* SkColorShader::createContext(const ContextRec& rec, void* storage) const {
249    if (!this->validContext(rec)) {
250        return NULL;
251    }
252
253    return SkNEW_PLACEMENT_ARGS(storage, ColorShaderContext, (*this, rec));
254}
255
256SkColorShader::ColorShaderContext::ColorShaderContext(const SkColorShader& shader,
257                                                      const ContextRec& rec)
258    : INHERITED(shader, rec)
259{
260    SkColor color = shader.fColor;
261    unsigned a = SkAlphaMul(SkColorGetA(color), SkAlpha255To256(rec.fPaint->getAlpha()));
262
263    unsigned r = SkColorGetR(color);
264    unsigned g = SkColorGetG(color);
265    unsigned b = SkColorGetB(color);
266
267    // we want this before we apply any alpha
268    fColor16 = SkPack888ToRGB16(r, g, b);
269
270    if (a != 255) {
271        r = SkMulDiv255Round(r, a);
272        g = SkMulDiv255Round(g, a);
273        b = SkMulDiv255Round(b, a);
274    }
275    fPMColor = SkPackARGB32(a, r, g, b);
276
277    fFlags = kConstInY32_Flag;
278    if (255 == a) {
279        fFlags |= kOpaqueAlpha_Flag;
280        if (rec.fPaint->isDither() == false) {
281            fFlags |= kHasSpan16_Flag;
282        }
283    }
284}
285
286void SkColorShader::ColorShaderContext::shadeSpan(int x, int y, SkPMColor span[], int count) {
287    sk_memset32(span, fPMColor, count);
288}
289
290void SkColorShader::ColorShaderContext::shadeSpan16(int x, int y, uint16_t span[], int count) {
291    sk_memset16(span, fColor16, count);
292}
293
294void SkColorShader::ColorShaderContext::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
295    memset(alpha, SkGetPackedA32(fPMColor), count);
296}
297
298// if we had a asAColor method, that would be more efficient...
299SkShader::BitmapType SkColorShader::asABitmap(SkBitmap* bitmap, SkMatrix* matrix,
300                                              TileMode modes[]) const {
301    return kNone_BitmapType;
302}
303
304SkShader::GradientType SkColorShader::asAGradient(GradientInfo* info) const {
305    if (info) {
306        if (info->fColors && info->fColorCount >= 1) {
307            info->fColors[0] = fColor;
308        }
309        info->fColorCount = 1;
310        info->fTileMode = SkShader::kRepeat_TileMode;
311    }
312    return kColor_GradientType;
313}
314
315#ifndef SK_IGNORE_TO_STRING
316void SkColorShader::toString(SkString* str) const {
317    str->append("SkColorShader: (");
318
319    str->append("Color: ");
320    str->appendHex(fColor);
321
322    this->INHERITED::toString(str);
323
324    str->append(")");
325}
326#endif
327
328///////////////////////////////////////////////////////////////////////////////
329
330#ifndef SK_IGNORE_TO_STRING
331#include "SkEmptyShader.h"
332
333void SkEmptyShader::toString(SkString* str) const {
334    str->append("SkEmptyShader: (");
335
336    this->INHERITED::toString(str);
337
338    str->append(")");
339}
340#endif
341