| /* libs/graphics/effects/SkGradientShader.cpp |
| ** |
| ** Copyright 2006, The Android Open Source Project |
| ** |
| ** Licensed under the Apache License, Version 2.0 (the "License"); |
| ** you may not use this file except in compliance with the License. |
| ** You may obtain a copy of the License at |
| ** |
| ** http://www.apache.org/licenses/LICENSE-2.0 |
| ** |
| ** Unless required by applicable law or agreed to in writing, software |
| ** distributed under the License is distributed on an "AS IS" BASIS, |
| ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| ** See the License for the specific language governing permissions and |
| ** limitations under the License. |
| */ |
| |
| #include "SkGradientShader.h" |
| #include "SkColorPriv.h" |
| #include "SkUnitMapper.h" |
| #include "SkUtils.h" |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| typedef SkFixed (*TileProc)(SkFixed); |
| |
| static SkFixed clamp_tileproc(SkFixed x) { |
| return SkClampMax(x, 0xFFFF); |
| } |
| |
| static SkFixed repeat_tileproc(SkFixed x) { |
| return x & 0xFFFF; |
| } |
| |
| static inline SkFixed mirror_tileproc(SkFixed x) { |
| int s = x << 15 >> 31; |
| return (x ^ s) & 0xFFFF; |
| } |
| |
| static const TileProc gTileProcs[] = { |
| clamp_tileproc, |
| repeat_tileproc, |
| mirror_tileproc |
| }; |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| static inline int repeat_6bits(int x) { |
| return x & 63; |
| } |
| |
| static inline int mirror_6bits(int x) { |
| #ifdef SK_CPU_HAS_CONDITIONAL_INSTR |
| if (x & 64) |
| x = ~x; |
| return x & 63; |
| #else |
| int s = x << 25 >> 31; |
| return (x ^ s) & 63; |
| #endif |
| } |
| |
| static inline int repeat_8bits(int x) { |
| return x & 0xFF; |
| } |
| |
| static inline int mirror_8bits(int x) { |
| #ifdef SK_CPU_HAS_CONDITIONAL_INSTR |
| if (x & 256) { |
| x = ~x; |
| } |
| return x & 255; |
| #else |
| int s = x << 23 >> 31; |
| return (x ^ s) & 0xFF; |
| #endif |
| } |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| class Gradient_Shader : public SkShader { |
| public: |
| Gradient_Shader(const SkColor colors[], const SkScalar pos[], |
| int colorCount, SkShader::TileMode mode, SkUnitMapper* mapper); |
| virtual ~Gradient_Shader(); |
| |
| // overrides |
| virtual bool setContext(const SkBitmap&, const SkPaint&, const SkMatrix&); |
| virtual uint32_t getFlags() { return fFlags; } |
| |
| protected: |
| Gradient_Shader(SkFlattenableReadBuffer& ); |
| SkUnitMapper* fMapper; |
| SkMatrix fPtsToUnit; // set by subclass |
| SkMatrix fDstToIndex; |
| SkMatrix::MapXYProc fDstToIndexProc; |
| TileMode fTileMode; |
| TileProc fTileProc; |
| int fColorCount; |
| uint8_t fDstToIndexClass; |
| uint8_t fFlags; |
| |
| struct Rec { |
| SkFixed fPos; // 0...1 |
| uint32_t fScale; // (1 << 24) / range |
| }; |
| Rec* fRecs; |
| |
| enum { |
| kCache16Bits = 6, // seems like enough for visual accuracy |
| kCache16Count = 1 << kCache16Bits, |
| kCache32Bits = 8, // pretty much should always be 8 |
| kCache32Count = 1 << kCache32Bits |
| }; |
| virtual void flatten(SkFlattenableWriteBuffer& ); |
| const uint16_t* getCache16(); |
| const SkPMColor* getCache32(); |
| |
| // called when we kill our cached colors (to be rebuilt later on demand) |
| virtual void onCacheReset() = 0; |
| |
| private: |
| enum { |
| kColorStorageCount = 4, // more than this many colors, and we'll use sk_malloc for the space |
| |
| kStorageSize = kColorStorageCount * (sizeof(SkColor) + sizeof(Rec)) |
| }; |
| SkColor fStorage[(kStorageSize + 3) >> 2]; |
| SkColor* fOrigColors; |
| |
| uint16_t* fCache16; // working ptr. If this is NULL, we need to recompute the cache values |
| SkPMColor* fCache32; // working ptr. If this is NULL, we need to recompute the cache values |
| |
| uint16_t* fCache16Storage; // storage for fCache16, allocated on demand |
| SkPMColor* fCache32Storage; // storage for fCache32, allocated on demand |
| unsigned fCacheAlpha; // the alpha value we used when we computed the cache. larger than 8bits so we can store uninitialized value |
| |
| typedef SkShader INHERITED; |
| }; |
| |
| static inline unsigned scalarToU16(SkScalar x) { |
| SkASSERT(x >= 0 && x <= SK_Scalar1); |
| |
| #ifdef SK_SCALAR_IS_FLOAT |
| return (unsigned)(x * 0xFFFF); |
| #else |
| return x - (x >> 16); // probably should be x - (x > 0x7FFF) but that is slower |
| #endif |
| } |
| |
| Gradient_Shader::Gradient_Shader(const SkColor colors[], const SkScalar pos[], |
| int colorCount, SkShader::TileMode mode, SkUnitMapper* mapper) { |
| SkASSERT(colorCount > 1); |
| |
| fCacheAlpha = 256; // init to a value that paint.getAlpha() can't return |
| |
| fMapper = mapper; |
| mapper->safeRef(); |
| |
| SkASSERT((unsigned)mode < SkShader::kTileModeCount); |
| SkASSERT(SkShader::kTileModeCount == SK_ARRAY_COUNT(gTileProcs)); |
| fTileMode = mode; |
| fTileProc = gTileProcs[mode]; |
| |
| fCache16 = fCache16Storage = NULL; |
| fCache32 = fCache32Storage = NULL; |
| |
| /* Note: we let the caller skip the first and/or last position. |
| i.e. pos[0] = 0.3, pos[1] = 0.7 |
| In these cases, we insert dummy entries to ensure that the final data |
| will be bracketed by [0, 1]. |
| i.e. our_pos[0] = 0, our_pos[1] = 0.3, our_pos[2] = 0.7, our_pos[3] = 1 |
| |
| Thus colorCount (the caller's value, and fColorCount (our value) may |
| differ by up to 2. In the above example: |
| colorCount = 2 |
| fColorCount = 4 |
| */ |
| fColorCount = colorCount; |
| // check if we need to add in dummy start and/or end position/colors |
| bool dummyFirst = false; |
| bool dummyLast = false; |
| if (pos) { |
| dummyFirst = pos[0] != 0; |
| dummyLast = pos[colorCount - 1] != SK_Scalar1; |
| fColorCount += dummyFirst + dummyLast; |
| } |
| |
| if (fColorCount > kColorStorageCount) { |
| size_t size = sizeof(SkColor) + sizeof(Rec); |
| fOrigColors = reinterpret_cast<SkColor*>( |
| sk_malloc_throw(size * fColorCount)); |
| } |
| else { |
| fOrigColors = fStorage; |
| } |
| |
| // Now copy over the colors, adding the dummies as needed |
| { |
| SkColor* origColors = fOrigColors; |
| if (dummyFirst) { |
| *origColors++ = colors[0]; |
| } |
| memcpy(origColors, colors, colorCount * sizeof(SkColor)); |
| if (dummyLast) { |
| origColors += colorCount; |
| *origColors = colors[colorCount - 1]; |
| } |
| } |
| |
| fRecs = (Rec*)(fOrigColors + fColorCount); |
| if (fColorCount > 2) { |
| Rec* recs = fRecs; |
| recs->fPos = 0; |
| // recs->fScale = 0; // unused; |
| recs += 1; |
| if (pos) { |
| /* We need to convert the user's array of relative positions into |
| fixed-point positions and scale factors. We need these results |
| to be strictly monotonic (no two values equal or out of order). |
| Hence this complex loop that just jams a zero for the scale |
| value if it sees a segment out of order, and it assures that |
| we start at 0 and end at 1.0 |
| */ |
| SkFixed prev = 0; |
| int startIndex = dummyFirst ? 0 : 1; |
| int count = colorCount + dummyLast; |
| for (int i = startIndex; i < count; i++) { |
| // force the last value to be 1.0 |
| SkFixed curr; |
| if (i == colorCount) { // we're really at the dummyLast |
| curr = SK_Fixed1; |
| } else { |
| curr = SkScalarToFixed(pos[i]); |
| } |
| // pin curr withing range |
| if (curr < 0) { |
| curr = 0; |
| } else if (curr > SK_Fixed1) { |
| curr = SK_Fixed1; |
| } |
| recs->fPos = curr; |
| if (curr > prev) { |
| recs->fScale = (1 << 24) / (curr - prev); |
| } else { |
| recs->fScale = 0; // ignore this segment |
| } |
| // get ready for the next value |
| prev = curr; |
| recs += 1; |
| } |
| } else { // assume even distribution |
| SkFixed dp = SK_Fixed1 / (colorCount - 1); |
| SkFixed p = dp; |
| SkFixed scale = (colorCount - 1) << 8; // (1 << 24) / dp |
| for (int i = 1; i < colorCount; i++) { |
| recs->fPos = p; |
| recs->fScale = scale; |
| recs += 1; |
| p += dp; |
| } |
| } |
| } |
| fFlags = 0; |
| } |
| |
| Gradient_Shader::Gradient_Shader(SkFlattenableReadBuffer& buffer) : |
| INHERITED(buffer) { |
| fCacheAlpha = 256; |
| |
| fMapper = static_cast<SkUnitMapper*>(buffer.readFlattenable()); |
| |
| fCache16 = fCache16Storage = NULL; |
| fCache32 = fCache32Storage = NULL; |
| |
| int colorCount = fColorCount = buffer.readU32(); |
| if (colorCount > kColorStorageCount) { |
| size_t size = sizeof(SkColor) + sizeof(SkPMColor) + sizeof(Rec); |
| fOrigColors = (SkColor*)sk_malloc_throw(size * colorCount); |
| } else { |
| fOrigColors = fStorage; |
| } |
| buffer.read(fOrigColors, colorCount * sizeof(SkColor)); |
| |
| fTileMode = (TileMode)buffer.readU8(); |
| fTileProc = gTileProcs[fTileMode]; |
| fRecs = (Rec*)(fOrigColors + colorCount); |
| if (colorCount > 2) { |
| Rec* recs = fRecs; |
| recs[0].fPos = 0; |
| for (int i = 1; i < colorCount; i++) { |
| recs[i].fPos = buffer.readS32(); |
| recs[i].fScale = buffer.readU32(); |
| } |
| } |
| buffer.read(&fPtsToUnit, sizeof(SkMatrix)); |
| fFlags = 0; |
| } |
| |
| Gradient_Shader::~Gradient_Shader() { |
| if (fCache16Storage) { |
| sk_free(fCache16Storage); |
| } |
| if (fCache32Storage) { |
| sk_free(fCache32Storage); |
| } |
| if (fOrigColors != fStorage) { |
| sk_free(fOrigColors); |
| } |
| fMapper->safeUnref(); |
| } |
| |
| void Gradient_Shader::flatten(SkFlattenableWriteBuffer& buffer) { |
| this->INHERITED::flatten(buffer); |
| buffer.writeFlattenable(fMapper); |
| buffer.write32(fColorCount); |
| buffer.writeMul4(fOrigColors, fColorCount * sizeof(SkColor)); |
| buffer.write8(fTileMode); |
| if (fColorCount > 2) { |
| Rec* recs = fRecs; |
| for (int i = 1; i < fColorCount; i++) { |
| buffer.write32(recs[i].fPos); |
| buffer.write32(recs[i].fScale); |
| } |
| } |
| buffer.writeMul4(&fPtsToUnit, sizeof(SkMatrix)); |
| } |
| |
| bool Gradient_Shader::setContext(const SkBitmap& device, |
| const SkPaint& paint, |
| const SkMatrix& matrix) { |
| if (!this->INHERITED::setContext(device, paint, matrix)) { |
| return false; |
| } |
| |
| const SkMatrix& inverse = this->getTotalInverse(); |
| |
| if (!fDstToIndex.setConcat(fPtsToUnit, inverse)) { |
| return false; |
| } |
| |
| fDstToIndexProc = fDstToIndex.getMapXYProc(); |
| fDstToIndexClass = (uint8_t)SkShader::ComputeMatrixClass(fDstToIndex); |
| |
| // now convert our colors in to PMColors |
| unsigned paintAlpha = this->getPaintAlpha(); |
| unsigned colorAlpha = 0xFF; |
| |
| // FIXME: record colorAlpha in constructor, since this is not affected |
| // by setContext() |
| for (int i = 0; i < fColorCount; i++) { |
| SkColor src = fOrigColors[i]; |
| unsigned sa = SkColorGetA(src); |
| colorAlpha &= sa; |
| } |
| |
| fFlags = this->INHERITED::getFlags(); |
| if ((colorAlpha & paintAlpha) == 0xFF) { |
| fFlags |= kOpaqueAlpha_Flag; |
| } |
| // we can do span16 as long as our individual colors are opaque, |
| // regardless of the paint's alpha |
| if (0xFF == colorAlpha) { |
| fFlags |= kHasSpan16_Flag; |
| } |
| |
| // if the new alpha differs from the previous time we were called, inval our cache |
| // this will trigger the cache to be rebuilt. |
| // we don't care about the first time, since the cache ptrs will already be NULL |
| if (fCacheAlpha != paintAlpha) { |
| fCache16 = NULL; // inval the cache |
| fCache32 = NULL; // inval the cache |
| fCacheAlpha = paintAlpha; // record the new alpha |
| // inform our subclasses |
| this->onCacheReset(); |
| } |
| return true; |
| } |
| |
| static inline int blend8(int a, int b, int scale) { |
| SkASSERT(a == SkToU8(a)); |
| SkASSERT(b == SkToU8(b)); |
| SkASSERT(scale >= 0 && scale <= 256); |
| return a + ((b - a) * scale >> 8); |
| } |
| |
| static inline uint32_t dot8_blend_packed32(uint32_t s0, uint32_t s1, |
| int blend) { |
| #if 0 |
| int a = blend8(SkGetPackedA32(s0), SkGetPackedA32(s1), blend); |
| int r = blend8(SkGetPackedR32(s0), SkGetPackedR32(s1), blend); |
| int g = blend8(SkGetPackedG32(s0), SkGetPackedG32(s1), blend); |
| int b = blend8(SkGetPackedB32(s0), SkGetPackedB32(s1), blend); |
| |
| return SkPackARGB32(a, r, g, b); |
| #else |
| int otherBlend = 256 - blend; |
| |
| #if 0 |
| U32 t0 = (((s0 & 0xFF00FF) * blend + (s1 & 0xFF00FF) * otherBlend) >> 8) & 0xFF00FF; |
| U32 t1 = (((s0 >> 8) & 0xFF00FF) * blend + ((s1 >> 8) & 0xFF00FF) * otherBlend) & 0xFF00FF00; |
| SkASSERT((t0 & t1) == 0); |
| return t0 | t1; |
| #else |
| return ((((s0 & 0xFF00FF) * blend + (s1 & 0xFF00FF) * otherBlend) >> 8) & 0xFF00FF) | |
| ((((s0 >> 8) & 0xFF00FF) * blend + ((s1 >> 8) & 0xFF00FF) * otherBlend) & 0xFF00FF00); |
| #endif |
| |
| #endif |
| } |
| |
| #define Fixed_To_Dot8(x) (((x) + 0x80) >> 8) |
| |
| /** We take the original colors, not our premultiplied PMColors, since we can |
| build a 16bit table as long as the original colors are opaque, even if the |
| paint specifies a non-opaque alpha. |
| */ |
| static void build_16bit_cache(uint16_t cache[], SkColor c0, SkColor c1, |
| int count) { |
| SkASSERT(count > 1); |
| SkASSERT(SkColorGetA(c0) == 0xFF); |
| SkASSERT(SkColorGetA(c1) == 0xFF); |
| |
| SkFixed r = SkColorGetR(c0); |
| SkFixed g = SkColorGetG(c0); |
| SkFixed b = SkColorGetB(c0); |
| |
| SkFixed dr = SkIntToFixed(SkColorGetR(c1) - r) / (count - 1); |
| SkFixed dg = SkIntToFixed(SkColorGetG(c1) - g) / (count - 1); |
| SkFixed db = SkIntToFixed(SkColorGetB(c1) - b) / (count - 1); |
| |
| r = SkIntToFixed(r) + 0x8000; |
| g = SkIntToFixed(g) + 0x8000; |
| b = SkIntToFixed(b) + 0x8000; |
| |
| do { |
| unsigned rr = r >> 16; |
| unsigned gg = g >> 16; |
| unsigned bb = b >> 16; |
| cache[0] = SkPackRGB16(SkR32ToR16(rr), SkG32ToG16(gg), SkB32ToB16(bb)); |
| cache[64] = SkDitherPack888ToRGB16(rr, gg, bb); |
| cache += 1; |
| r += dr; |
| g += dg; |
| b += db; |
| } while (--count != 0); |
| } |
| |
| static void build_32bit_cache(SkPMColor cache[], SkColor c0, SkColor c1, |
| int count, U8CPU paintAlpha) { |
| SkASSERT(count > 1); |
| |
| // need to apply paintAlpha to our two endpoints |
| SkFixed a = SkMulDiv255Round(SkColorGetA(c0), paintAlpha); |
| SkFixed da; |
| { |
| int tmp = SkMulDiv255Round(SkColorGetA(c1), paintAlpha); |
| da = SkIntToFixed(tmp - a) / (count - 1); |
| } |
| |
| SkFixed r = SkColorGetR(c0); |
| SkFixed g = SkColorGetG(c0); |
| SkFixed b = SkColorGetB(c0); |
| SkFixed dr = SkIntToFixed(SkColorGetR(c1) - r) / (count - 1); |
| SkFixed dg = SkIntToFixed(SkColorGetG(c1) - g) / (count - 1); |
| SkFixed db = SkIntToFixed(SkColorGetB(c1) - b) / (count - 1); |
| |
| a = SkIntToFixed(a) + 0x8000; |
| r = SkIntToFixed(r) + 0x8000; |
| g = SkIntToFixed(g) + 0x8000; |
| b = SkIntToFixed(b) + 0x8000; |
| |
| do { |
| *cache++ = SkPreMultiplyARGB(a >> 16, r >> 16, g >> 16, b >> 16); |
| a += da; |
| r += dr; |
| g += dg; |
| b += db; |
| } while (--count != 0); |
| } |
| |
| static inline int SkFixedToFFFF(SkFixed x) { |
| SkASSERT((unsigned)x <= SK_Fixed1); |
| return x - (x >> 16); |
| } |
| |
| static inline U16CPU dot6to16(unsigned x) { |
| SkASSERT(x < 64); |
| return (x << 10) | (x << 4) | (x >> 2); |
| } |
| |
| const uint16_t* Gradient_Shader::getCache16() { |
| if (fCache16 == NULL) { |
| if (fCache16Storage == NULL) { // set the storage and our working ptr |
| fCache16Storage = (uint16_t*)sk_malloc_throw(sizeof(uint16_t) * kCache16Count * 2); |
| } |
| fCache16 = fCache16Storage; |
| if (fColorCount == 2) { |
| build_16bit_cache(fCache16, fOrigColors[0], fOrigColors[1], kCache16Count); |
| } else { |
| Rec* rec = fRecs; |
| int prevIndex = 0; |
| for (int i = 1; i < fColorCount; i++) { |
| int nextIndex = SkFixedToFFFF(rec[i].fPos) >> (16 - kCache16Bits); |
| SkASSERT(nextIndex < kCache16Count); |
| |
| if (nextIndex > prevIndex) |
| build_16bit_cache(fCache16 + prevIndex, fOrigColors[i-1], fOrigColors[i], nextIndex - prevIndex + 1); |
| prevIndex = nextIndex; |
| } |
| SkASSERT(prevIndex == kCache16Count - 1); |
| } |
| |
| if (fMapper) { |
| fCache16Storage = (uint16_t*)sk_malloc_throw(sizeof(uint16_t) * kCache16Count * 2); |
| uint16_t* linear = fCache16; // just computed linear data |
| uint16_t* mapped = fCache16Storage; // storage for mapped data |
| SkUnitMapper* map = fMapper; |
| for (int i = 0; i < 64; i++) { |
| int index = map->mapUnit16(dot6to16(i)) >> 10; |
| mapped[i] = linear[index]; |
| mapped[i + 64] = linear[index + 64]; |
| } |
| sk_free(fCache16); |
| fCache16 = fCache16Storage; |
| } |
| } |
| return fCache16; |
| } |
| |
| const SkPMColor* Gradient_Shader::getCache32() { |
| if (fCache32 == NULL) { |
| if (fCache32Storage == NULL) // set the storage and our working ptr |
| fCache32Storage = (SkPMColor*)sk_malloc_throw(sizeof(SkPMColor) * kCache32Count); |
| |
| fCache32 = fCache32Storage; |
| if (fColorCount == 2) { |
| build_32bit_cache(fCache32, fOrigColors[0], fOrigColors[1], |
| kCache32Count, fCacheAlpha); |
| } else { |
| Rec* rec = fRecs; |
| int prevIndex = 0; |
| for (int i = 1; i < fColorCount; i++) { |
| int nextIndex = SkFixedToFFFF(rec[i].fPos) >> (16 - kCache32Bits); |
| SkASSERT(nextIndex < kCache32Count); |
| |
| if (nextIndex > prevIndex) |
| build_32bit_cache(fCache32 + prevIndex, fOrigColors[i-1], |
| fOrigColors[i], |
| nextIndex - prevIndex + 1, fCacheAlpha); |
| prevIndex = nextIndex; |
| } |
| SkASSERT(prevIndex == kCache32Count - 1); |
| } |
| |
| if (fMapper) { |
| fCache32Storage = (SkPMColor*)sk_malloc_throw(sizeof(SkPMColor) * kCache32Count); |
| SkPMColor* linear = fCache32; // just computed linear data |
| SkPMColor* mapped = fCache32Storage; // storage for mapped data |
| SkUnitMapper* map = fMapper; |
| for (int i = 0; i < 256; i++) { |
| mapped[i] = linear[map->mapUnit16((i << 8) | i) >> 8]; |
| } |
| sk_free(fCache32); |
| fCache32 = fCache32Storage; |
| } |
| } |
| return fCache32; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| |
| static void pts_to_unit_matrix(const SkPoint pts[2], SkMatrix* matrix) { |
| SkVector vec = pts[1] - pts[0]; |
| SkScalar mag = vec.length(); |
| SkScalar inv = mag ? SkScalarInvert(mag) : 0; |
| |
| vec.scale(inv); |
| matrix->setSinCos(-vec.fY, vec.fX, pts[0].fX, pts[0].fY); |
| matrix->postTranslate(-pts[0].fX, -pts[0].fY); |
| matrix->postScale(inv, inv); |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| class Linear_Gradient : public Gradient_Shader { |
| public: |
| Linear_Gradient(const SkPoint pts[2], |
| const SkColor colors[], const SkScalar pos[], int colorCount, |
| SkShader::TileMode mode, SkUnitMapper* mapper) |
| : Gradient_Shader(colors, pos, colorCount, mode, mapper) |
| { |
| fCachedBitmap = NULL; |
| pts_to_unit_matrix(pts, &fPtsToUnit); |
| } |
| virtual ~Linear_Gradient() { |
| if (fCachedBitmap) { |
| SkDELETE(fCachedBitmap); |
| } |
| } |
| |
| virtual bool setContext(const SkBitmap&, const SkPaint&, const SkMatrix&); |
| virtual void shadeSpan(int x, int y, SkPMColor dstC[], int count); |
| virtual void shadeSpan16(int x, int y, uint16_t dstC[], int count); |
| virtual bool asABitmap(SkBitmap*, SkMatrix*, TileMode*); |
| virtual void onCacheReset() { |
| if (fCachedBitmap) { |
| SkDELETE(fCachedBitmap); |
| fCachedBitmap = NULL; |
| } |
| } |
| |
| static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) { |
| return SkNEW_ARGS(Linear_Gradient, (buffer)); |
| } |
| |
| protected: |
| Linear_Gradient(SkFlattenableReadBuffer& buffer) : Gradient_Shader(buffer) { |
| fCachedBitmap = NULL; |
| } |
| virtual Factory getFactory() { return CreateProc; } |
| |
| private: |
| SkBitmap* fCachedBitmap; // allocated on demand |
| |
| typedef Gradient_Shader INHERITED; |
| }; |
| |
| bool Linear_Gradient::setContext(const SkBitmap& device, const SkPaint& paint, |
| const SkMatrix& matrix) { |
| if (!this->INHERITED::setContext(device, paint, matrix)) { |
| return false; |
| } |
| |
| unsigned mask = SkMatrix::kTranslate_Mask | SkMatrix::kScale_Mask; |
| if ((fDstToIndex.getType() & ~mask) == 0) { |
| fFlags |= SkShader::kConstInY32_Flag; |
| if ((fFlags & SkShader::kHasSpan16_Flag) && !paint.isDither()) { |
| // only claim this if we do have a 16bit mode (i.e. none of our |
| // colors have alpha), and if we are not dithering (which obviously |
| // is not const in Y). |
| fFlags |= SkShader::kConstInY16_Flag; |
| } |
| } |
| return true; |
| } |
| |
| // Return true if fx, fx+dx, fx+2*dx, ... is always in range |
| static inline bool no_need_for_clamp(int fx, int dx, int count) |
| { |
| SkASSERT(count > 0); |
| return (unsigned)((fx | (fx + (count - 1) * dx)) >> 8) <= 0xFF; |
| } |
| |
| void Linear_Gradient::shadeSpan(int x, int y, SkPMColor dstC[], int count) |
| { |
| SkASSERT(count > 0); |
| |
| SkPoint srcPt; |
| SkMatrix::MapXYProc dstProc = fDstToIndexProc; |
| TileProc proc = fTileProc; |
| const SkPMColor* cache = this->getCache32(); |
| |
| if (fDstToIndexClass != kPerspective_MatrixClass) { |
| dstProc(fDstToIndex, SkIntToScalar(x), SkIntToScalar(y), &srcPt); |
| SkFixed dx, fx = SkScalarToFixed(srcPt.fX); |
| // preround fx by half the amount we throw away |
| fx += 1 << 7; |
| |
| if (fDstToIndexClass == kFixedStepInX_MatrixClass) { |
| SkFixed dxStorage[1]; |
| (void)fDstToIndex.fixedStepInX(SkIntToScalar(y), dxStorage, NULL); |
| dx = dxStorage[0]; |
| } else { |
| SkASSERT(fDstToIndexClass == kLinear_MatrixClass); |
| dx = SkScalarToFixed(fDstToIndex.getScaleX()); |
| } |
| |
| if (SkFixedNearlyZero(dx)) { |
| // we're a vertical gradient, so no change in a span |
| unsigned fi = proc(fx); |
| SkASSERT(fi <= 0xFFFF); |
| sk_memset32(dstC, cache[fi >> (16 - kCache32Bits)], count); |
| } else if (proc == clamp_tileproc) { |
| #if 0 |
| if (no_need_for_clamp(fx, dx, count)) |
| { |
| unsigned fi; |
| while ((count -= 4) >= 0) |
| { |
| fi = fx >> 8; SkASSERT(fi <= 0xFF); fx += dx; *dstC++ = cache[fi]; |
| fi = fx >> 8; SkASSERT(fi <= 0xFF); fx += dx; *dstC++ = cache[fi]; |
| fi = fx >> 8; SkASSERT(fi <= 0xFF); fx += dx; *dstC++ = cache[fi]; |
| fi = fx >> 8; SkASSERT(fi <= 0xFF); fx += dx; *dstC++ = cache[fi]; |
| } |
| SkASSERT(count <= -1 && count >= -4); |
| count += 4; |
| while (--count >= 0) |
| { |
| fi = fx >> 8; |
| SkASSERT(fi <= 0xFF); |
| fx += dx; |
| *dstC++ = cache[fi]; |
| } |
| } |
| else |
| #endif |
| do { |
| unsigned fi = SkClampMax(fx >> 8, 0xFF); |
| SkASSERT(fi <= 0xFF); |
| fx += dx; |
| *dstC++ = cache[fi]; |
| } while (--count != 0); |
| } else if (proc == mirror_tileproc) { |
| do { |
| unsigned fi = mirror_8bits(fx >> 8); |
| SkASSERT(fi <= 0xFF); |
| fx += dx; |
| *dstC++ = cache[fi]; |
| } while (--count != 0); |
| } else { |
| SkASSERT(proc == repeat_tileproc); |
| do { |
| unsigned fi = repeat_8bits(fx >> 8); |
| SkASSERT(fi <= 0xFF); |
| fx += dx; |
| *dstC++ = cache[fi]; |
| } while (--count != 0); |
| } |
| } else { |
| SkScalar dstX = SkIntToScalar(x); |
| SkScalar dstY = SkIntToScalar(y); |
| do { |
| dstProc(fDstToIndex, dstX, dstY, &srcPt); |
| unsigned fi = proc(SkScalarToFixed(srcPt.fX)); |
| SkASSERT(fi <= 0xFFFF); |
| *dstC++ = cache[fi >> (16 - kCache32Bits)]; |
| dstX += SK_Scalar1; |
| } while (--count != 0); |
| } |
| } |
| |
| bool Linear_Gradient::asABitmap(SkBitmap* bitmap, SkMatrix* matrix, |
| TileMode xy[]) { |
| // we cache our "bitmap", so it's generationID will be const on subsequent |
| // calls to asABitmap |
| if (NULL == fCachedBitmap) { |
| fCachedBitmap = SkNEW(SkBitmap); |
| fCachedBitmap->setConfig(SkBitmap::kARGB_8888_Config, kCache32Count, 1); |
| fCachedBitmap->setPixels((void*)this->getCache32(), NULL); |
| } |
| |
| if (bitmap) { |
| *bitmap = *fCachedBitmap; |
| } |
| if (matrix) { |
| matrix->setScale(SkIntToScalar(kCache32Count), SK_Scalar1); |
| matrix->preConcat(fPtsToUnit); |
| } |
| if (xy) { |
| xy[0] = fTileMode; |
| xy[1] = kClamp_TileMode; |
| } |
| return true; |
| } |
| |
| static void dither_memset16(uint16_t dst[], uint16_t value, uint16_t other, |
| int count) { |
| if (reinterpret_cast<uintptr_t>(dst) & 2) { |
| *dst++ = value; |
| count -= 1; |
| SkTSwap(value, other); |
| } |
| |
| sk_memset32((uint32_t*)dst, (value << 16) | other, count >> 1); |
| |
| if (count & 1) { |
| dst[count - 1] = value; |
| } |
| } |
| |
| void Linear_Gradient::shadeSpan16(int x, int y, uint16_t dstC[], int count) |
| { |
| SkASSERT(count > 0); |
| |
| SkPoint srcPt; |
| SkMatrix::MapXYProc dstProc = fDstToIndexProc; |
| TileProc proc = fTileProc; |
| const uint16_t* cache = this->getCache16(); |
| int toggle = ((x ^ y) & 1) << kCache16Bits; |
| |
| if (fDstToIndexClass != kPerspective_MatrixClass) { |
| dstProc(fDstToIndex, SkIntToScalar(x), SkIntToScalar(y), &srcPt); |
| SkFixed dx, fx = SkScalarToFixed(srcPt.fX); |
| // preround fx by half the amount we throw away |
| fx += 1 << 7; |
| |
| if (fDstToIndexClass == kFixedStepInX_MatrixClass) { |
| SkFixed dxStorage[1]; |
| (void)fDstToIndex.fixedStepInX(SkIntToScalar(y), dxStorage, NULL); |
| dx = dxStorage[0]; |
| } else { |
| SkASSERT(fDstToIndexClass == kLinear_MatrixClass); |
| dx = SkScalarToFixed(fDstToIndex.getScaleX()); |
| } |
| |
| if (SkFixedNearlyZero(dx)) { |
| // we're a vertical gradient, so no change in a span |
| unsigned fi = proc(fx) >> 10; |
| SkASSERT(fi <= 63); |
| dither_memset16(dstC, cache[toggle + fi], cache[(toggle ^ (1 << kCache16Bits)) + fi], count); |
| } else if (proc == clamp_tileproc) { |
| do { |
| unsigned fi = SkClampMax(fx >> 10, 63); |
| SkASSERT(fi <= 63); |
| fx += dx; |
| *dstC++ = cache[toggle + fi]; |
| toggle ^= (1 << kCache16Bits); |
| } while (--count != 0); |
| } else if (proc == mirror_tileproc) { |
| do { |
| unsigned fi = mirror_6bits(fx >> 10); |
| SkASSERT(fi <= 0x3F); |
| fx += dx; |
| *dstC++ = cache[toggle + fi]; |
| toggle ^= (1 << kCache16Bits); |
| } while (--count != 0); |
| } else { |
| SkASSERT(proc == repeat_tileproc); |
| do { |
| unsigned fi = repeat_6bits(fx >> 10); |
| SkASSERT(fi <= 0x3F); |
| fx += dx; |
| *dstC++ = cache[toggle + fi]; |
| toggle ^= (1 << kCache16Bits); |
| } while (--count != 0); |
| } |
| } else { |
| SkScalar dstX = SkIntToScalar(x); |
| SkScalar dstY = SkIntToScalar(y); |
| do { |
| dstProc(fDstToIndex, dstX, dstY, &srcPt); |
| unsigned fi = proc(SkScalarToFixed(srcPt.fX)); |
| SkASSERT(fi <= 0xFFFF); |
| |
| int index = fi >> (16 - kCache16Bits); |
| *dstC++ = cache[toggle + index]; |
| toggle ^= (1 << kCache16Bits); |
| |
| dstX += SK_Scalar1; |
| } while (--count != 0); |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #define kSQRT_TABLE_BITS 11 |
| #define kSQRT_TABLE_SIZE (1 << kSQRT_TABLE_BITS) |
| |
| #include "SkRadialGradient_Table.h" |
| |
| #if defined(SK_BUILD_FOR_WIN32) && defined(SK_DEBUG) |
| |
| #include <stdio.h> |
| |
| void SkRadialGradient_BuildTable() |
| { |
| // build it 0..127 x 0..127, so we use 2^15 - 1 in the numerator for our "fixed" table |
| |
| FILE* file = ::fopen("SkRadialGradient_Table.h", "w"); |
| SkASSERT(file); |
| ::fprintf(file, "static const uint8_t gSqrt8Table[] = {\n"); |
| |
| for (int i = 0; i < kSQRT_TABLE_SIZE; i++) |
| { |
| if ((i & 15) == 0) |
| ::fprintf(file, "\t"); |
| |
| uint8_t value = SkToU8(SkFixedSqrt(i * SK_Fixed1 / kSQRT_TABLE_SIZE) >> 8); |
| |
| ::fprintf(file, "0x%02X", value); |
| if (i < kSQRT_TABLE_SIZE-1) |
| ::fprintf(file, ", "); |
| if ((i & 15) == 15) |
| ::fprintf(file, "\n"); |
| } |
| ::fprintf(file, "};\n"); |
| ::fclose(file); |
| } |
| |
| #endif |
| |
| |
| static void rad_to_unit_matrix(const SkPoint& center, SkScalar radius, SkMatrix* matrix) |
| { |
| SkScalar inv = SkScalarInvert(radius); |
| |
| matrix->setTranslate(-center.fX, -center.fY); |
| matrix->postScale(inv, inv); |
| } |
| |
| class Radial_Gradient : public Gradient_Shader { |
| public: |
| Radial_Gradient(const SkPoint& center, SkScalar radius, |
| const SkColor colors[], const SkScalar pos[], int colorCount, |
| SkShader::TileMode mode, SkUnitMapper* mapper) |
| : Gradient_Shader(colors, pos, colorCount, mode, mapper) |
| { |
| // make sure our table is insync with our current #define for kSQRT_TABLE_SIZE |
| SkASSERT(sizeof(gSqrt8Table) == kSQRT_TABLE_SIZE); |
| |
| rad_to_unit_matrix(center, radius, &fPtsToUnit); |
| } |
| virtual void shadeSpan(int x, int y, SkPMColor dstC[], int count) |
| { |
| SkASSERT(count > 0); |
| |
| SkPoint srcPt; |
| SkMatrix::MapXYProc dstProc = fDstToIndexProc; |
| TileProc proc = fTileProc; |
| const SkPMColor* cache = this->getCache32(); |
| |
| if (fDstToIndexClass != kPerspective_MatrixClass) |
| { |
| dstProc(fDstToIndex, SkIntToScalar(x), SkIntToScalar(y), &srcPt); |
| SkFixed dx, fx = SkScalarToFixed(srcPt.fX); |
| SkFixed dy, fy = SkScalarToFixed(srcPt.fY); |
| |
| if (fDstToIndexClass == kFixedStepInX_MatrixClass) |
| { |
| SkFixed storage[2]; |
| (void)fDstToIndex.fixedStepInX(SkIntToScalar(y), &storage[0], &storage[1]); |
| dx = storage[0]; |
| dy = storage[1]; |
| } |
| else |
| { |
| SkASSERT(fDstToIndexClass == kLinear_MatrixClass); |
| dx = SkScalarToFixed(fDstToIndex.getScaleX()); |
| dy = SkScalarToFixed(fDstToIndex.getSkewY()); |
| } |
| |
| if (proc == clamp_tileproc) |
| { |
| const uint8_t* sqrt_table = gSqrt8Table; |
| fx >>= 1; |
| dx >>= 1; |
| fy >>= 1; |
| dy >>= 1; |
| do { |
| unsigned xx = SkPin32(fx, -0xFFFF >> 1, 0xFFFF >> 1); |
| unsigned fi = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1); |
| fi = (xx * xx + fi * fi) >> (14 + 16 - kSQRT_TABLE_BITS); |
| fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS)); |
| *dstC++ = cache[sqrt_table[fi] >> (8 - kCache32Bits)]; |
| fx += dx; |
| fy += dy; |
| } while (--count != 0); |
| } |
| else if (proc == mirror_tileproc) |
| { |
| do { |
| SkFixed dist = SkFixedSqrt(SkFixedSquare(fx) + SkFixedSquare(fy)); |
| unsigned fi = mirror_tileproc(dist); |
| SkASSERT(fi <= 0xFFFF); |
| *dstC++ = cache[fi >> (16 - kCache32Bits)]; |
| fx += dx; |
| fy += dy; |
| } while (--count != 0); |
| } |
| else |
| { |
| SkASSERT(proc == repeat_tileproc); |
| do { |
| SkFixed dist = SkFixedSqrt(SkFixedSquare(fx) + SkFixedSquare(fy)); |
| unsigned fi = repeat_tileproc(dist); |
| SkASSERT(fi <= 0xFFFF); |
| *dstC++ = cache[fi >> (16 - kCache32Bits)]; |
| fx += dx; |
| fy += dy; |
| } while (--count != 0); |
| } |
| } |
| else // perspective case |
| { |
| SkScalar dstX = SkIntToScalar(x); |
| SkScalar dstY = SkIntToScalar(y); |
| do { |
| dstProc(fDstToIndex, dstX, dstY, &srcPt); |
| unsigned fi = proc(SkScalarToFixed(srcPt.length())); |
| SkASSERT(fi <= 0xFFFF); |
| *dstC++ = cache[fi >> (16 - kCache32Bits)]; |
| dstX += SK_Scalar1; |
| } while (--count != 0); |
| } |
| } |
| |
| virtual void shadeSpan16(int x, int y, uint16_t dstC[], int count) { |
| SkASSERT(count > 0); |
| |
| SkPoint srcPt; |
| SkMatrix::MapXYProc dstProc = fDstToIndexProc; |
| TileProc proc = fTileProc; |
| const uint16_t* cache = this->getCache16(); |
| int toggle = ((x ^ y) & 1) << kCache16Bits; |
| |
| if (fDstToIndexClass != kPerspective_MatrixClass) { |
| dstProc(fDstToIndex, SkIntToScalar(x), SkIntToScalar(y), &srcPt); |
| SkFixed dx, fx = SkScalarToFixed(srcPt.fX); |
| SkFixed dy, fy = SkScalarToFixed(srcPt.fY); |
| |
| if (fDstToIndexClass == kFixedStepInX_MatrixClass) { |
| SkFixed storage[2]; |
| (void)fDstToIndex.fixedStepInX(SkIntToScalar(y), &storage[0], &storage[1]); |
| dx = storage[0]; |
| dy = storage[1]; |
| } else { |
| SkASSERT(fDstToIndexClass == kLinear_MatrixClass); |
| dx = SkScalarToFixed(fDstToIndex.getScaleX()); |
| dy = SkScalarToFixed(fDstToIndex.getSkewY()); |
| } |
| |
| if (proc == clamp_tileproc) { |
| const uint8_t* sqrt_table = gSqrt8Table; |
| |
| /* knock these down so we can pin against +- 0x7FFF, which is an immediate load, |
| rather than 0xFFFF which is slower. This is a compromise, since it reduces our |
| precision, but that appears to be visually OK. If we decide this is OK for |
| all of our cases, we could (it seems) put this scale-down into fDstToIndex, |
| to avoid having to do these extra shifts each time. |
| */ |
| fx >>= 1; |
| dx >>= 1; |
| fy >>= 1; |
| dy >>= 1; |
| if (dy == 0) { // might perform this check for the other modes, but the win will be a smaller % of the total |
| fy = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1); |
| fy *= fy; |
| do { |
| unsigned xx = SkPin32(fx, -0xFFFF >> 1, 0xFFFF >> 1); |
| unsigned fi = (xx * xx + fy) >> (14 + 16 - kSQRT_TABLE_BITS); |
| fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS)); |
| fx += dx; |
| *dstC++ = cache[toggle + (sqrt_table[fi] >> (8 - kCache16Bits))]; |
| toggle ^= (1 << kCache16Bits); |
| } while (--count != 0); |
| } else { |
| do { |
| unsigned xx = SkPin32(fx, -0xFFFF >> 1, 0xFFFF >> 1); |
| unsigned fi = SkPin32(fy, -0xFFFF >> 1, 0xFFFF >> 1); |
| fi = (xx * xx + fi * fi) >> (14 + 16 - kSQRT_TABLE_BITS); |
| fi = SkFastMin32(fi, 0xFFFF >> (16 - kSQRT_TABLE_BITS)); |
| fx += dx; |
| fy += dy; |
| *dstC++ = cache[toggle + (sqrt_table[fi] >> (8 - kCache16Bits))]; |
| toggle ^= (1 << kCache16Bits); |
| } while (--count != 0); |
| } |
| } else if (proc == mirror_tileproc) { |
| do { |
| SkFixed dist = SkFixedSqrt(SkFixedSquare(fx) + SkFixedSquare(fy)); |
| unsigned fi = mirror_tileproc(dist); |
| SkASSERT(fi <= 0xFFFF); |
| fx += dx; |
| fy += dy; |
| *dstC++ = cache[toggle + (fi >> (16 - kCache16Bits))]; |
| toggle ^= (1 << kCache16Bits); |
| } while (--count != 0); |
| } else { |
| SkASSERT(proc == repeat_tileproc); |
| do { |
| SkFixed dist = SkFixedSqrt(SkFixedSquare(fx) + SkFixedSquare(fy)); |
| unsigned fi = repeat_tileproc(dist); |
| SkASSERT(fi <= 0xFFFF); |
| fx += dx; |
| fy += dy; |
| *dstC++ = cache[toggle + (fi >> (16 - kCache16Bits))]; |
| toggle ^= (1 << kCache16Bits); |
| } while (--count != 0); |
| } |
| } else { // perspective case |
| SkScalar dstX = SkIntToScalar(x); |
| SkScalar dstY = SkIntToScalar(y); |
| do { |
| dstProc(fDstToIndex, dstX, dstY, &srcPt); |
| unsigned fi = proc(SkScalarToFixed(srcPt.length())); |
| SkASSERT(fi <= 0xFFFF); |
| |
| int index = fi >> (16 - kCache16Bits); |
| *dstC++ = cache[toggle + index]; |
| toggle ^= (1 << kCache16Bits); |
| |
| dstX += SK_Scalar1; |
| } while (--count != 0); |
| } |
| } |
| |
| static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) { |
| return SkNEW_ARGS(Radial_Gradient, (buffer)); |
| } |
| |
| protected: |
| Radial_Gradient(SkFlattenableReadBuffer& buffer) : Gradient_Shader(buffer) {}; |
| virtual Factory getFactory() { return CreateProc; } |
| virtual void onCacheReset() {} |
| |
| private: |
| typedef Gradient_Shader INHERITED; |
| }; |
| |
| /* Two-point radial gradients are specified by two circles, each with a center |
| point and radius. The gradient can be considered to be a series of |
| concentric circles, with the color interpolated from the start circle |
| (at t=0) to the end circle (at t=1). |
| |
| For each point (x, y) in the span, we want to find the |
| interpolated circle that intersects that point. The center |
| of the desired circle (Cx, Cy) falls at some distance t |
| along the line segment between the start point (Sx, Sy) and |
| end point (Ex, Ey): |
| |
| Cx = (1 - t) * Sx + t * Ex (0 <= t <= 1) |
| Cy = (1 - t) * Sy + t * Ey |
| |
| The radius of the desired circle (r) is also a linear interpolation t |
| between the start and end radii (Sr and Er): |
| |
| r = (1 - t) * Sr + t * Er |
| |
| But |
| |
| (x - Cx)^2 + (y - Cy)^2 = r^2 |
| |
| so |
| |
| (x - ((1 - t) * Sx + t * Ex))^2 |
| + (y - ((1 - t) * Sy + t * Ey))^2 |
| = ((1 - t) * Sr + t * Er)^2 |
| |
| Solving for t yields |
| |
| [(Sx - Ex)^2 + (Sy - Ey)^2 - (Er - Sr)^2)] * t^2 |
| + [2 * (Sx - Ex)(x - Sx) + 2 * (Sy - Ey)(y - Sy) - 2 * (Er - Sr) * Sr] * t |
| + [(x - Sx)^2 + (y - Sy)^2 - Sr^2] = 0 |
| |
| To simplify, let Dx = Sx - Ex, Dy = Sy - Ey, Dr = Er - Sr, dx = x - Sx, dy = y - Sy |
| |
| [Dx^2 + Dy^2 - Dr^2)] * t^2 |
| + 2 * [Dx * dx + Dy * dy - Dr * Sr] * t |
| + [dx^2 + dy^2 - Sr^2] = 0 |
| |
| A quadratic in t. The two roots of the quadratic reflect the two |
| possible circles on which the point may fall. Solving for t yields |
| the gradient value to use. |
| |
| If a<0, the start circle is entirely contained in the |
| end circle, and one of the roots will be <0 or >1 (off the line |
| segment). If a>0, the start circle falls at least partially |
| outside the end circle (or vice versa), and the gradient |
| defines a "tube" where a point may be on one circle (on the |
| inside of the tube) or the other (outside of the tube). We choose |
| one arbitrarily. |
| |
| In order to keep the math to within the limits of fixed point, |
| we divide the entire quadratic by Dr^2, and replace |
| (x - Sx)/Dr with x' and (y - Sy)/Dr with y', giving |
| |
| [Dx^2 / Dr^2 + Dy^2 / Dr^2 - 1)] * t^2 |
| + 2 * [x' * Dx / Dr + y' * Dy / Dr - Sr / Dr] * t |
| + [x'^2 + y'^2 - Sr^2/Dr^2] = 0 |
| |
| (x' and y' are computed by appending the subtract and scale to the |
| fDstToIndex matrix in the constructor). |
| |
| Since the 'A' component of the quadratic is independent of x' and y', it |
| is precomputed in the constructor. Since the 'B' component is linear in |
| x' and y', if x and y are linear in the span, 'B' can be computed |
| incrementally with a simple delta (db below). If it is not (e.g., |
| a perspective projection), it must be computed in the loop. |
| |
| */ |
| |
| static inline SkFixed two_point_radial(SkFixed b, SkFixed fx, SkFixed fy, SkFixed sr2d2, SkFixed foura, SkFixed oneOverTwoA, bool posRoot) { |
| SkFixed c = SkFixedSquare(fx) + SkFixedSquare(fy) - sr2d2; |
| SkFixed discrim = SkFixedSquare(b) - SkFixedMul(foura, c); |
| if (discrim < 0) { |
| discrim = -discrim; |
| } |
| SkFixed rootDiscrim = SkFixedSqrt(discrim); |
| if (posRoot) { |
| return SkFixedMul(-b + rootDiscrim, oneOverTwoA); |
| } else { |
| return SkFixedMul(-b - rootDiscrim, oneOverTwoA); |
| } |
| } |
| |
| class Two_Point_Radial_Gradient : public Gradient_Shader { |
| public: |
| Two_Point_Radial_Gradient(const SkPoint& start, SkScalar startRadius, |
| const SkPoint& end, SkScalar endRadius, |
| const SkColor colors[], const SkScalar pos[], |
| int colorCount, SkShader::TileMode mode, |
| SkUnitMapper* mapper) |
| : Gradient_Shader(colors, pos, colorCount, mode, mapper) |
| { |
| fDiff = start - end; |
| fDiffRadius = endRadius - startRadius; |
| SkScalar inv = SkScalarInvert(fDiffRadius); |
| fDiff.fX = SkScalarMul(fDiff.fX, inv); |
| fDiff.fY = SkScalarMul(fDiff.fY, inv); |
| fStartRadius = SkScalarMul(startRadius, inv); |
| fSr2D2 = SkScalarSquare(fStartRadius); |
| fA = SkScalarSquare(fDiff.fX) + SkScalarSquare(fDiff.fY) - SK_Scalar1; |
| fOneOverTwoA = SkScalarInvert(fA * 2); |
| |
| fPtsToUnit.setTranslate(-start.fX, -start.fY); |
| fPtsToUnit.postScale(inv, inv); |
| } |
| virtual void shadeSpan(int x, int y, SkPMColor dstC[], int count) |
| { |
| SkASSERT(count > 0); |
| |
| // Zero difference between radii: fill with transparent black. |
| if (fDiffRadius == 0) { |
| sk_bzero(dstC, count * sizeof(*dstC)); |
| return; |
| } |
| SkMatrix::MapXYProc dstProc = fDstToIndexProc; |
| TileProc proc = fTileProc; |
| const SkPMColor* cache = this->getCache32(); |
| SkFixed diffx = SkScalarToFixed(fDiff.fX); |
| SkFixed diffy = SkScalarToFixed(fDiff.fY); |
| SkFixed foura = SkScalarToFixed(SkScalarMul(fA, 4)); |
| SkFixed startRadius = SkScalarToFixed(fStartRadius); |
| SkFixed sr2D2 = SkScalarToFixed(fSr2D2); |
| SkFixed oneOverTwoA = SkScalarToFixed(fOneOverTwoA); |
| bool posRoot = fDiffRadius < 0; |
| if (fDstToIndexClass != kPerspective_MatrixClass) |
| { |
| SkPoint srcPt; |
| dstProc(fDstToIndex, SkIntToScalar(x), SkIntToScalar(y), &srcPt); |
| SkFixed dx, fx = SkScalarToFixed(srcPt.fX); |
| SkFixed dy, fy = SkScalarToFixed(srcPt.fY); |
| |
| if (fDstToIndexClass == kFixedStepInX_MatrixClass) |
| { |
| (void)fDstToIndex.fixedStepInX(SkIntToScalar(y), &dx, &dy); |
| } |
| else |
| { |
| SkASSERT(fDstToIndexClass == kLinear_MatrixClass); |
| dx = SkScalarToFixed(fDstToIndex.getScaleX()); |
| dy = SkScalarToFixed(fDstToIndex.getSkewY()); |
| } |
| SkFixed b = (SkFixedMul(diffx, fx) + |
| SkFixedMul(diffy, fy) - startRadius) << 1; |
| SkFixed db = (SkFixedMul(diffx, dx) + |
| SkFixedMul(diffy, dy)) << 1; |
| if (proc == clamp_tileproc) |
| { |
| for (; count > 0; --count) { |
| SkFixed t = two_point_radial(b, fx, fy, sr2D2, foura, oneOverTwoA, posRoot); |
| SkFixed index = SkClampMax(t, 0xFFFF); |
| SkASSERT(index <= 0xFFFF); |
| *dstC++ = cache[index >> (16 - kCache32Bits)]; |
| fx += dx; |
| fy += dy; |
| b += db; |
| } |
| } |
| else if (proc == mirror_tileproc) |
| { |
| for (; count > 0; --count) { |
| SkFixed t = two_point_radial(b, fx, fy, sr2D2, foura, oneOverTwoA, posRoot); |
| SkFixed index = mirror_tileproc(t); |
| SkASSERT(index <= 0xFFFF); |
| *dstC++ = cache[index >> (16 - kCache32Bits)]; |
| fx += dx; |
| fy += dy; |
| b += db; |
| } |
| } |
| else |
| { |
| SkASSERT(proc == repeat_tileproc); |
| for (; count > 0; --count) { |
| SkFixed t = two_point_radial(b, fx, fy, sr2D2, foura, oneOverTwoA, posRoot); |
| SkFixed index = repeat_tileproc(t); |
| SkASSERT(index <= 0xFFFF); |
| *dstC++ = cache[index >> (16 - kCache32Bits)]; |
| fx += dx; |
| fy += dy; |
| b += db; |
| } |
| } |
| } |
| else // perspective case |
| { |
| SkScalar dstX = SkIntToScalar(x); |
| SkScalar dstY = SkIntToScalar(y); |
| for (; count > 0; --count) { |
| SkPoint srcPt; |
| dstProc(fDstToIndex, dstX, dstY, &srcPt); |
| SkFixed fx = SkScalarToFixed(srcPt.fX); |
| SkFixed fy = SkScalarToFixed(srcPt.fY); |
| SkFixed b = (SkFixedMul(diffx, fx) + |
| SkFixedMul(diffy, fy) - startRadius) << 1; |
| SkFixed t = two_point_radial(b, fx, fy, sr2D2, foura, oneOverTwoA, posRoot); |
| SkFixed index = proc(t); |
| SkASSERT(index <= 0xFFFF); |
| *dstC++ = cache[index >> (16 - kCache32Bits)]; |
| dstX += SK_Scalar1; |
| } |
| } |
| } |
| |
| virtual bool setContext(const SkBitmap& device, |
| const SkPaint& paint, |
| const SkMatrix& matrix) { |
| if (!this->INHERITED::setContext(device, paint, matrix)) { |
| return false; |
| } |
| |
| // we don't have a span16 proc |
| fFlags &= ~kHasSpan16_Flag; |
| return true; |
| } |
| |
| static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) { |
| return SkNEW_ARGS(Two_Point_Radial_Gradient, (buffer)); |
| } |
| |
| virtual void flatten(SkFlattenableWriteBuffer& buffer) { |
| this->INHERITED::flatten(buffer); |
| buffer.writeScalar(fDiff.fX); |
| buffer.writeScalar(fDiff.fY); |
| buffer.writeScalar(fStartRadius); |
| buffer.writeScalar(fDiffRadius); |
| buffer.writeScalar(fSr2D2); |
| buffer.writeScalar(fA); |
| buffer.writeScalar(fOneOverTwoA); |
| } |
| |
| protected: |
| Two_Point_Radial_Gradient(SkFlattenableReadBuffer& buffer) |
| : Gradient_Shader(buffer) { |
| fDiff.fX = buffer.readScalar(); |
| fDiff.fY = buffer.readScalar(); |
| fStartRadius = buffer.readScalar(); |
| fDiffRadius = buffer.readScalar(); |
| fSr2D2 = buffer.readScalar(); |
| fA = buffer.readScalar(); |
| fOneOverTwoA = buffer.readScalar(); |
| }; |
| virtual Factory getFactory() { return CreateProc; } |
| virtual void onCacheReset() {} |
| |
| private: |
| typedef Gradient_Shader INHERITED; |
| SkPoint fDiff; |
| SkScalar fStartRadius, fDiffRadius, fSr2D2, fA, fOneOverTwoA; |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| class Sweep_Gradient : public Gradient_Shader { |
| public: |
| Sweep_Gradient(SkScalar cx, SkScalar cy, const SkColor colors[], |
| const SkScalar pos[], int count, SkUnitMapper* mapper) |
| : Gradient_Shader(colors, pos, count, SkShader::kClamp_TileMode, mapper) |
| { |
| fPtsToUnit.setTranslate(-cx, -cy); |
| } |
| virtual void shadeSpan(int x, int y, SkPMColor dstC[], int count); |
| virtual void shadeSpan16(int x, int y, uint16_t dstC[], int count); |
| |
| static SkFlattenable* CreateProc(SkFlattenableReadBuffer& buffer) { |
| return SkNEW_ARGS(Sweep_Gradient, (buffer)); |
| } |
| |
| protected: |
| Sweep_Gradient(SkFlattenableReadBuffer& buffer) : Gradient_Shader(buffer) {} |
| virtual Factory getFactory() { return CreateProc; } |
| virtual void onCacheReset() {} |
| |
| private: |
| typedef Gradient_Shader INHERITED; |
| }; |
| |
| #ifdef COMPUTE_SWEEP_TABLE |
| #define PI 3.14159265 |
| static bool gSweepTableReady; |
| static uint8_t gSweepTable[65]; |
| |
| /* Our table stores precomputed values for atan: [0...1] -> [0..PI/4] |
| We scale the results to [0..32] |
| */ |
| static const uint8_t* build_sweep_table() |
| { |
| if (!gSweepTableReady) |
| { |
| const int N = 65; |
| const double DENOM = N - 1; |
| |
| for (int i = 0; i < N; i++) |
| { |
| double arg = i / DENOM; |
| double v = atan(arg); |
| int iv = (int)round(v * DENOM * 2 / PI); |
| // printf("[%d] atan(%g) = %g %d\n", i, arg, v, iv); |
| printf("%d, ", iv); |
| gSweepTable[i] = iv; |
| } |
| gSweepTableReady = true; |
| } |
| return gSweepTable; |
| } |
| #else |
| static const uint8_t gSweepTable[] = { |
| 0, 1, 1, 2, 3, 3, 4, 4, 5, 6, 6, 7, 8, 8, 9, 9, |
| 10, 11, 11, 12, 12, 13, 13, 14, 15, 15, 16, 16, 17, 17, 18, 18, |
| 19, 19, 20, 20, 21, 21, 22, 22, 23, 23, 24, 24, 25, 25, 25, 26, |
| 26, 27, 27, 27, 28, 28, 29, 29, 29, 30, 30, 30, 31, 31, 31, 32, |
| 32 |
| }; |
| static const uint8_t* build_sweep_table() { return gSweepTable; } |
| #endif |
| |
| // divide numer/denom, with a bias of 6bits. Assumes numer <= denom |
| // and denom != 0. Since our table is 6bits big (+1), this is a nice fit. |
| // Same as (but faster than) SkFixedDiv(numer, denom) >> 10 |
| |
| //unsigned div_64(int numer, int denom); |
| static unsigned div_64(int numer, int denom) |
| { |
| SkASSERT(numer <= denom); |
| SkASSERT(numer > 0); |
| SkASSERT(denom > 0); |
| |
| int nbits = SkCLZ(numer); |
| int dbits = SkCLZ(denom); |
| int bits = 6 - nbits + dbits; |
| SkASSERT(bits <= 6); |
| |
| if (bits < 0) // detect underflow |
| return 0; |
| |
| denom <<= dbits - 1; |
| numer <<= nbits - 1; |
| |
| unsigned result = 0; |
| |
| // do the first one |
| if ((numer -= denom) >= 0) |
| result = 1; |
| else |
| numer += denom; |
| |
| // Now fall into our switch statement if there are more bits to compute |
| if (bits > 0) |
| { |
| // make room for the rest of the answer bits |
| result <<= bits; |
| switch (bits) { |
| case 6: |
| if ((numer = (numer << 1) - denom) >= 0) |
| result |= 32; |
| else |
| numer += denom; |
| case 5: |
| if ((numer = (numer << 1) - denom) >= 0) |
| result |= 16; |
| else |
| numer += denom; |
| case 4: |
| if ((numer = (numer << 1) - denom) >= 0) |
| result |= 8; |
| else |
| numer += denom; |
| case 3: |
| if ((numer = (numer << 1) - denom) >= 0) |
| result |= 4; |
| else |
| numer += denom; |
| case 2: |
| if ((numer = (numer << 1) - denom) >= 0) |
| result |= 2; |
| else |
| numer += denom; |
| case 1: |
| default: // not strictly need, but makes GCC make better ARM code |
| if ((numer = (numer << 1) - denom) >= 0) |
| result |= 1; |
| else |
| numer += denom; |
| } |
| } |
| return result; |
| } |
| |
| // Given x,y in the first quadrant, return 0..63 for the angle [0..90] |
| static unsigned atan_0_90(SkFixed y, SkFixed x) |
| { |
| #ifdef SK_DEBUG |
| { |
| static bool gOnce; |
| if (!gOnce) |
| { |
| gOnce = true; |
| SkASSERT(div_64(55, 55) == 64); |
| SkASSERT(div_64(128, 256) == 32); |
| SkASSERT(div_64(2326528, 4685824) == 31); |
| SkASSERT(div_64(753664, 5210112) == 9); |
| SkASSERT(div_64(229376, 4882432) == 3); |
| SkASSERT(div_64(2, 64) == 2); |
| SkASSERT(div_64(1, 64) == 1); |
| // test that we handle underflow correctly |
| SkASSERT(div_64(12345, 0x54321234) == 0); |
| } |
| } |
| #endif |
| |
| SkASSERT(y > 0 && x > 0); |
| const uint8_t* table = build_sweep_table(); |
| |
| unsigned result; |
| bool swap = (x < y); |
| if (swap) |
| { |
| // first part of the atan(v) = PI/2 - atan(1/v) identity |
| // since our div_64 and table want v <= 1, where v = y/x |
| SkTSwap<SkFixed>(x, y); |
| } |
| |
| result = div_64(y, x); |
| |
| #ifdef SK_DEBUG |
| { |
| unsigned result2 = SkDivBits(y, x, 6); |
| SkASSERT(result2 == result || |
| (result == 1 && result2 == 0)); |
| } |
| #endif |
| |
| SkASSERT(result < SK_ARRAY_COUNT(gSweepTable)); |
| result = table[result]; |
| |
| if (swap) |
| { |
| // complete the atan(v) = PI/2 - atan(1/v) identity |
| result = 64 - result; |
| // pin to 63 |
| result -= result >> 6; |
| } |
| |
| SkASSERT(result <= 63); |
| return result; |
| } |
| |
| // returns angle in a circle [0..2PI) -> [0..255] |
| static unsigned SkATan2_255(SkFixed y, SkFixed x) |
| { |
| if (x == 0) |
| { |
| if (y == 0) |
| return 0; |
| return y < 0 ? 192 : 64; |
| } |
| if (y == 0) |
| return x < 0 ? 128 : 0; |
| |
| /* Find the right quadrant for x,y |
| Since atan_0_90 only handles the first quadrant, we rotate x,y |
| appropriately before calling it, and then add the right amount |
| to account for the real quadrant. |
| quadrant 0 : add 0 | x > 0 && y > 0 |
| quadrant 1 : add 64 (90 degrees) | x < 0 && y > 0 |
| quadrant 2 : add 128 (180 degrees) | x < 0 && y < 0 |
| quadrant 3 : add 192 (270 degrees) | x > 0 && y < 0 |
| |
| map x<0 to (1 << 6) |
| map y<0 to (3 << 6) |
| add = map_x ^ map_y |
| */ |
| int xsign = x >> 31; |
| int ysign = y >> 31; |
| int add = ((-xsign) ^ (ysign & 3)) << 6; |
| |
| #ifdef SK_DEBUG |
| if (0 == add) |
| SkASSERT(x > 0 && y > 0); |
| else if (64 == add) |
| SkASSERT(x < 0 && y > 0); |
| else if (128 == add) |
| SkASSERT(x < 0 && y < 0); |
| else if (192 == add) |
| SkASSERT(x > 0 && y < 0); |
| else |
| SkASSERT(!"bad value for add"); |
| #endif |
| |
| /* This ^ trick makes x, y positive, and the swap<> handles quadrants |
| where we need to rotate x,y by 90 or -90 |
| */ |
| x = (x ^ xsign) - xsign; |
| y = (y ^ ysign) - ysign; |
| if (add & 64) // quads 1 or 3 need to swap x,y |
| SkTSwap<SkFixed>(x, y); |
| |
| unsigned result = add + atan_0_90(y, x); |
| SkASSERT(result < 256); |
| return result; |
| } |
| |
| void Sweep_Gradient::shadeSpan(int x, int y, SkPMColor dstC[], int count) |
| { |
| SkMatrix::MapXYProc proc = fDstToIndexProc; |
| const SkMatrix& matrix = fDstToIndex; |
| const SkPMColor* cache = this->getCache32(); |
| SkPoint srcPt; |
| |
| if (fDstToIndexClass != kPerspective_MatrixClass) |
| { |
| proc(matrix, SkIntToScalar(x) + SK_ScalarHalf, |
| SkIntToScalar(y) + SK_ScalarHalf, &srcPt); |
| SkFixed dx, fx = SkScalarToFixed(srcPt.fX); |
| SkFixed dy, fy = SkScalarToFixed(srcPt.fY); |
| |
| if (fDstToIndexClass == kFixedStepInX_MatrixClass) |
| { |
| SkFixed storage[2]; |
| (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf, |
| &storage[0], &storage[1]); |
| dx = storage[0]; |
| dy = storage[1]; |
| } |
| else |
| { |
| SkASSERT(fDstToIndexClass == kLinear_MatrixClass); |
| dx = SkScalarToFixed(matrix.getScaleX()); |
| dy = SkScalarToFixed(matrix.getSkewY()); |
| } |
| |
| for (; count > 0; --count) |
| { |
| *dstC++ = cache[SkATan2_255(fy, fx)]; |
| fx += dx; |
| fy += dy; |
| } |
| } |
| else // perspective case |
| { |
| for (int stop = x + count; x < stop; x++) |
| { |
| proc(matrix, SkIntToScalar(x) + SK_ScalarHalf, |
| SkIntToScalar(y) + SK_ScalarHalf, &srcPt); |
| |
| int index = SkATan2_255(SkScalarToFixed(srcPt.fY), |
| SkScalarToFixed(srcPt.fX)); |
| *dstC++ = cache[index]; |
| } |
| } |
| } |
| |
| void Sweep_Gradient::shadeSpan16(int x, int y, uint16_t dstC[], int count) |
| { |
| SkMatrix::MapXYProc proc = fDstToIndexProc; |
| const SkMatrix& matrix = fDstToIndex; |
| const uint16_t* cache = this->getCache16(); |
| int toggle = ((x ^ y) & 1) << kCache16Bits; |
| SkPoint srcPt; |
| |
| if (fDstToIndexClass != kPerspective_MatrixClass) |
| { |
| proc(matrix, SkIntToScalar(x) + SK_ScalarHalf, |
| SkIntToScalar(y) + SK_ScalarHalf, &srcPt); |
| SkFixed dx, fx = SkScalarToFixed(srcPt.fX); |
| SkFixed dy, fy = SkScalarToFixed(srcPt.fY); |
| |
| if (fDstToIndexClass == kFixedStepInX_MatrixClass) |
| { |
| SkFixed storage[2]; |
| (void)matrix.fixedStepInX(SkIntToScalar(y) + SK_ScalarHalf, |
| &storage[0], &storage[1]); |
| dx = storage[0]; |
| dy = storage[1]; |
| } |
| else |
| { |
| SkASSERT(fDstToIndexClass == kLinear_MatrixClass); |
| dx = SkScalarToFixed(matrix.getScaleX()); |
| dy = SkScalarToFixed(matrix.getSkewY()); |
| } |
| |
| for (; count > 0; --count) |
| { |
| int index = SkATan2_255(fy, fx) >> (8 - kCache16Bits); |
| *dstC++ = cache[toggle + index]; |
| toggle ^= (1 << kCache16Bits); |
| fx += dx; |
| fy += dy; |
| } |
| } |
| else // perspective case |
| { |
| for (int stop = x + count; x < stop; x++) |
| { |
| proc(matrix, SkIntToScalar(x) + SK_ScalarHalf, |
| SkIntToScalar(y) + SK_ScalarHalf, &srcPt); |
| |
| int index = SkATan2_255(SkScalarToFixed(srcPt.fY), |
| SkScalarToFixed(srcPt.fX)); |
| index >>= (8 - kCache16Bits); |
| *dstC++ = cache[toggle + index]; |
| toggle ^= (1 << kCache16Bits); |
| } |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////// |
| /////////////////////////////////////////////////////////////////////////// |
| |
| // assumes colors is SkColor* and pos is SkScalar* |
| #define EXPAND_1_COLOR(count) \ |
| SkColor tmp[2]; \ |
| do { \ |
| if (1 == count) { \ |
| tmp[0] = tmp[1] = colors[0]; \ |
| colors = tmp; \ |
| pos = NULL; \ |
| count = 2; \ |
| } \ |
| } while (0) |
| |
| SkShader* SkGradientShader::CreateLinear( const SkPoint pts[2], |
| const SkColor colors[], const SkScalar pos[], int colorCount, |
| SkShader::TileMode mode, SkUnitMapper* mapper) |
| { |
| if (NULL == pts || NULL == colors || colorCount < 1) { |
| return NULL; |
| } |
| EXPAND_1_COLOR(colorCount); |
| |
| return SkNEW_ARGS(Linear_Gradient, |
| (pts, colors, pos, colorCount, mode, mapper)); |
| } |
| |
| SkShader* SkGradientShader::CreateRadial( const SkPoint& center, SkScalar radius, |
| const SkColor colors[], const SkScalar pos[], int colorCount, |
| SkShader::TileMode mode, SkUnitMapper* mapper) |
| { |
| if (radius <= 0 || NULL == colors || colorCount < 1) { |
| return NULL; |
| } |
| EXPAND_1_COLOR(colorCount); |
| |
| return SkNEW_ARGS(Radial_Gradient, |
| (center, radius, colors, pos, colorCount, mode, mapper)); |
| } |
| |
| SkShader* SkGradientShader::CreateTwoPointRadial(const SkPoint& start, |
| SkScalar startRadius, |
| const SkPoint& end, |
| SkScalar endRadius, |
| const SkColor colors[], |
| const SkScalar pos[], |
| int colorCount, |
| SkShader::TileMode mode, |
| SkUnitMapper* mapper) |
| { |
| if (startRadius < 0 || endRadius < 0 || NULL == colors || colorCount < 1) { |
| return NULL; |
| } |
| EXPAND_1_COLOR(colorCount); |
| |
| return SkNEW_ARGS(Two_Point_Radial_Gradient, |
| (start, startRadius, end, endRadius, colors, pos, colorCount, mode, mapper)); |
| } |
| |
| SkShader* SkGradientShader::CreateSweep(SkScalar cx, SkScalar cy, |
| const SkColor colors[], |
| const SkScalar pos[], |
| int count, SkUnitMapper* mapper) |
| { |
| if (NULL == colors || count < 1) { |
| return NULL; |
| } |
| EXPAND_1_COLOR(count); |
| |
| return SkNEW_ARGS(Sweep_Gradient, (cx, cy, colors, pos, count, mapper)); |
| } |
| |
| static SkFlattenable::Registrar gLinearGradientReg("Linear_Gradient", |
| Linear_Gradient::CreateProc); |
| |
| static SkFlattenable::Registrar gRadialGradientReg("Radial_Gradient", |
| Radial_Gradient::CreateProc); |
| |
| static SkFlattenable::Registrar gSweepGradientReg("Sweep_Gradient", |
| Sweep_Gradient::CreateProc); |
| |
