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      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 "SkArenaAlloc.h"
      9 #include "SkAtomics.h"
     10 #include "SkBitmapProcShader.h"
     11 #include "SkColorShader.h"
     12 #include "SkEmptyShader.h"
     13 #include "SkMallocPixelRef.h"
     14 #include "SkPaint.h"
     15 #include "SkPicture.h"
     16 #include "SkPictureShader.h"
     17 #include "SkPM4fPriv.h"
     18 #include "SkRasterPipeline.h"
     19 #include "SkReadBuffer.h"
     20 #include "SkScalar.h"
     21 #include "SkShader.h"
     22 #include "SkTLazy.h"
     23 #include "SkWriteBuffer.h"
     24 
     25 #if SK_SUPPORT_GPU
     26 #include "GrFragmentProcessor.h"
     27 #endif
     28 
     29 //#define SK_TRACK_SHADER_LIFETIME
     30 
     31 #ifdef SK_TRACK_SHADER_LIFETIME
     32     static int32_t gShaderCounter;
     33 #endif
     34 
     35 static inline void inc_shader_counter() {
     36 #ifdef SK_TRACK_SHADER_LIFETIME
     37     int32_t prev = sk_atomic_inc(&gShaderCounter);
     38     SkDebugf("+++ shader counter %d\n", prev + 1);
     39 #endif
     40 }
     41 static inline void dec_shader_counter() {
     42 #ifdef SK_TRACK_SHADER_LIFETIME
     43     int32_t prev = sk_atomic_dec(&gShaderCounter);
     44     SkDebugf("--- shader counter %d\n", prev - 1);
     45 #endif
     46 }
     47 
     48 SkShader::SkShader(const SkMatrix* localMatrix) {
     49     inc_shader_counter();
     50     if (localMatrix) {
     51         fLocalMatrix = *localMatrix;
     52     } else {
     53         fLocalMatrix.reset();
     54     }
     55     // Pre-cache so future calls to fLocalMatrix.getType() are threadsafe.
     56     (void)fLocalMatrix.getType();
     57 }
     58 
     59 SkShader::~SkShader() {
     60     dec_shader_counter();
     61 }
     62 
     63 void SkShader::flatten(SkWriteBuffer& buffer) const {
     64     this->INHERITED::flatten(buffer);
     65     bool hasLocalM = !fLocalMatrix.isIdentity();
     66     buffer.writeBool(hasLocalM);
     67     if (hasLocalM) {
     68         buffer.writeMatrix(fLocalMatrix);
     69     }
     70 }
     71 
     72 bool SkShader::computeTotalInverse(const ContextRec& rec, SkMatrix* totalInverse) const {
     73     SkMatrix total = SkMatrix::Concat(*rec.fMatrix, fLocalMatrix);
     74     if (rec.fLocalMatrix) {
     75         total.preConcat(*rec.fLocalMatrix);
     76     }
     77 
     78     return total.invert(totalInverse);
     79 }
     80 
     81 bool SkShader::asLuminanceColor(SkColor* colorPtr) const {
     82     SkColor storage;
     83     if (nullptr == colorPtr) {
     84         colorPtr = &storage;
     85     }
     86     if (this->onAsLuminanceColor(colorPtr)) {
     87         *colorPtr = SkColorSetA(*colorPtr, 0xFF);   // we only return opaque
     88         return true;
     89     }
     90     return false;
     91 }
     92 
     93 SkShader::Context* SkShader::makeContext(const ContextRec& rec, SkArenaAlloc* alloc) const {
     94     if (!this->computeTotalInverse(rec, nullptr)) {
     95         return nullptr;
     96     }
     97     return this->onMakeContext(rec, alloc);
     98 }
     99 
    100 SkShader::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 
    111 SkShader::Context::~Context() {}
    112 
    113 SkShader::Context::ShadeProc SkShader::Context::asAShadeProc(void** ctx) {
    114     return nullptr;
    115 }
    116 
    117 void SkShader::Context::shadeSpan4f(int x, int y, SkPM4f dst[], int count) {
    118     const int N = 128;
    119     SkPMColor tmp[N];
    120     while (count > 0) {
    121         int n = SkTMin(count, N);
    122         this->shadeSpan(x, y, tmp, n);
    123         for (int i = 0; i < n; ++i) {
    124             dst[i] = SkPM4f::FromPMColor(tmp[i]);
    125         }
    126         dst += n;
    127         x += n;
    128         count -= n;
    129     }
    130 }
    131 
    132 #include "SkColorPriv.h"
    133 
    134 #define kTempColorQuadCount 6   // balance between speed (larger) and saving stack-space
    135 #define kTempColorCount     (kTempColorQuadCount << 2)
    136 
    137 #ifdef SK_CPU_BENDIAN
    138     #define SkU32BitShiftToByteOffset(shift)    (3 - ((shift) >> 3))
    139 #else
    140     #define SkU32BitShiftToByteOffset(shift)    ((shift) >> 3)
    141 #endif
    142 
    143 void SkShader::Context::shadeSpanAlpha(int x, int y, uint8_t alpha[], int count) {
    144     SkASSERT(count > 0);
    145 
    146     SkPMColor   colors[kTempColorCount];
    147 
    148     while ((count -= kTempColorCount) >= 0) {
    149         this->shadeSpan(x, y, colors, kTempColorCount);
    150         x += kTempColorCount;
    151 
    152         const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
    153         int quads = kTempColorQuadCount;
    154         do {
    155             U8CPU a0 = srcA[0];
    156             U8CPU a1 = srcA[4];
    157             U8CPU a2 = srcA[8];
    158             U8CPU a3 = srcA[12];
    159             srcA += 4*4;
    160             *alpha++ = SkToU8(a0);
    161             *alpha++ = SkToU8(a1);
    162             *alpha++ = SkToU8(a2);
    163             *alpha++ = SkToU8(a3);
    164         } while (--quads != 0);
    165     }
    166     SkASSERT(count < 0);
    167     SkASSERT(count + kTempColorCount >= 0);
    168     if (count += kTempColorCount) {
    169         this->shadeSpan(x, y, colors, count);
    170 
    171         const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
    172         do {
    173             *alpha++ = *srcA;
    174             srcA += 4;
    175         } while (--count != 0);
    176     }
    177 #if 0
    178     do {
    179         int n = count;
    180         if (n > kTempColorCount)
    181             n = kTempColorCount;
    182         SkASSERT(n > 0);
    183 
    184         this->shadeSpan(x, y, colors, n);
    185         x += n;
    186         count -= n;
    187 
    188         const uint8_t* srcA = (const uint8_t*)colors + SkU32BitShiftToByteOffset(SK_A32_SHIFT);
    189         do {
    190             *alpha++ = *srcA;
    191             srcA += 4;
    192         } while (--n != 0);
    193     } while (count > 0);
    194 #endif
    195 }
    196 
    197 SkShader::Context::MatrixClass SkShader::Context::ComputeMatrixClass(const SkMatrix& mat) {
    198     MatrixClass mc = kLinear_MatrixClass;
    199 
    200     if (mat.hasPerspective()) {
    201         if (mat.isFixedStepInX()) {
    202             mc = kFixedStepInX_MatrixClass;
    203         } else {
    204             mc = kPerspective_MatrixClass;
    205         }
    206     }
    207     return mc;
    208 }
    209 
    210 //////////////////////////////////////////////////////////////////////////////
    211 
    212 SkShader::GradientType SkShader::asAGradient(GradientInfo* info) const {
    213     return kNone_GradientType;
    214 }
    215 
    216 #if SK_SUPPORT_GPU
    217 sk_sp<GrFragmentProcessor> SkShader::asFragmentProcessor(const AsFPArgs&) const {
    218     return nullptr;
    219 }
    220 #endif
    221 
    222 sk_sp<SkShader> SkShader::makeAsALocalMatrixShader(SkMatrix*) const {
    223     return nullptr;
    224 }
    225 
    226 sk_sp<SkShader> SkShader::MakeEmptyShader() { return sk_make_sp<SkEmptyShader>(); }
    227 
    228 sk_sp<SkShader> SkShader::MakeColorShader(SkColor color) { return sk_make_sp<SkColorShader>(color); }
    229 
    230 sk_sp<SkShader> SkShader::MakeBitmapShader(const SkBitmap& src, TileMode tmx, TileMode tmy,
    231                                            const SkMatrix* localMatrix) {
    232     if (localMatrix && !localMatrix->invert(nullptr)) {
    233         return nullptr;
    234     }
    235     return SkMakeBitmapShader(src, tmx, tmy, localMatrix, kIfMutable_SkCopyPixelsMode);
    236 }
    237 
    238 sk_sp<SkShader> SkShader::MakePictureShader(sk_sp<SkPicture> src, TileMode tmx, TileMode tmy,
    239                                             const SkMatrix* localMatrix, const SkRect* tile) {
    240     if (localMatrix && !localMatrix->invert(nullptr)) {
    241         return nullptr;
    242     }
    243     return SkPictureShader::Make(std::move(src), tmx, tmy, localMatrix, tile);
    244 }
    245 
    246 #ifndef SK_IGNORE_TO_STRING
    247 void SkShader::toString(SkString* str) const {
    248     if (!fLocalMatrix.isIdentity()) {
    249         str->append(" ");
    250         fLocalMatrix.toString(str);
    251     }
    252 }
    253 #endif
    254 
    255 bool SkShader::appendStages(SkRasterPipeline* pipeline,
    256                             SkColorSpace* dst,
    257                             SkArenaAlloc* scratch,
    258                             const SkMatrix& ctm,
    259                             const SkPaint& paint) const {
    260     return this->onAppendStages(pipeline, dst, scratch, ctm, paint, nullptr);
    261 }
    262 
    263 bool SkShader::onAppendStages(SkRasterPipeline* p,
    264                               SkColorSpace* cs,
    265                               SkArenaAlloc* alloc,
    266                               const SkMatrix& ctm,
    267                               const SkPaint& paint,
    268                               const SkMatrix* localM) const {
    269     // Legacy shaders handle the paint opacity internally,
    270     // but RP applies it as a separate stage.
    271     SkTCopyOnFirstWrite<SkPaint> opaquePaint(paint);
    272     if (paint.getAlpha() != SK_AlphaOPAQUE) {
    273         opaquePaint.writable()->setAlpha(SK_AlphaOPAQUE);
    274     }
    275 
    276     ContextRec rec(*opaquePaint, ctm, localM, ContextRec::kPM4f_DstType, cs);
    277     if (auto* ctx = this->makeContext(rec, alloc)) {
    278         p->append(SkRasterPipeline::shader_adapter, ctx);
    279 
    280         // Legacy shaders aren't aware of color spaces. We can pretty
    281         // safely assume they're in sRGB gamut.
    282         return append_gamut_transform(p, alloc,
    283                                       SkColorSpace::MakeSRGB().get(), cs);
    284     }
    285     return false;
    286 }
    287 
    288 ///////////////////////////////////////////////////////////////////////////////////////////////////
    289 
    290 sk_sp<SkFlattenable> SkEmptyShader::CreateProc(SkReadBuffer&) {
    291     return SkShader::MakeEmptyShader();
    292 }
    293 
    294 #ifndef SK_IGNORE_TO_STRING
    295 #include "SkEmptyShader.h"
    296 
    297 void SkEmptyShader::toString(SkString* str) const {
    298     str->append("SkEmptyShader: (");
    299 
    300     this->INHERITED::toString(str);
    301 
    302     str->append(")");
    303 }
    304 #endif
    305