src/core/SkRasterPipelineBlitter.cpp

   1 /*
   2  * Copyright 2016 Google Inc.
   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 "SkBlitter.h"
  10 #include "SkBlendModePriv.h"
  11 #include "SkColor.h"
  12 #include "SkColorFilter.h"
  13 #include "SkOpts.h"
  14 #include "SkPM4f.h"
  15 #include "SkPM4fPriv.h"
  16 #include "SkRasterPipeline.h"
  17 #include "SkShader.h"
  18 #include "SkUtils.h"
  19 #include "../jumper/SkJumper.h"
  20
  21 class SkRasterPipelineBlitter final : public SkBlitter {
  22 public:
  23     // Create using paint.getShader() or paint.getColor() if there is no shader.
  24     // If there's a shader, we will modulate the shader color by the paint alpha.
  25     static SkBlitter* Create(const SkPixmap&, const SkPaint&, SkArenaAlloc*, const SkMatrix& ctm);
  26
  27     // Create using pre-built shader pipeline.
  28     // This pre-built pipeline must already have handled modulating with the paint alpha.
  29     static SkBlitter* Create(const SkPixmap&, const SkPaint&, SkArenaAlloc*,
  30                              const SkRasterPipeline& shaderPipeline,
  31                              bool is_opaque, bool is_constant, bool wants_dither);
  32
  33     SkRasterPipelineBlitter(SkPixmap dst, SkBlendMode blend, SkArenaAlloc* alloc)
  34         : fDst(dst)
  35         , fBlend(blend)
  36         , fAlloc(alloc)
  37         , fColorPipeline(alloc)
  38     {}
  39
  40     void blitH    (int x, int y, int w)                            override;
  41     void blitAntiH(int x, int y, const SkAlpha[], const int16_t[]) override;
  42     void blitMask (const SkMask&, const SkIRect& clip)             override;
  43
  44     // TODO: The default implementations of the other blits look fine,
  45     // but some of them like blitV could probably benefit from custom
  46     // blits using something like a SkRasterPipeline::runFew() method.
  47
  48 private:
  49     void append_load_d(SkRasterPipeline*) const;
  50     void append_blend (SkRasterPipeline*) const;
  51     void maybe_clamp  (SkRasterPipeline*) const;
  52     void append_store (SkRasterPipeline*) const;
  53
  54     SkPixmap         fDst;
  55     SkBlendMode      fBlend;
  56     SkArenaAlloc*    fAlloc;
  57     SkRasterPipeline fColorPipeline;
  58
  59     // We may be able to specialize blitH() into a memset.
  60     bool     fCanMemsetInBlitH = false;
  61     uint64_t fMemsetColor      = 0;     // Big enough for largest dst format, F16.
  62
  63     // Built lazily on first use.
  64     std::function<void(size_t, size_t)> fBlitH,
  65                                         fBlitAntiH,
  66                                         fBlitMaskA8,
  67                                         fBlitMaskLCD16;
  68
  69     // These values are pointed to by the blit pipelines above,
  70     // which allows us to adjust them from call to call.
  71     void*              fDstPtr          = nullptr;
  72     const void*        fMaskPtr         = nullptr;
  73     float              fCurrentCoverage = 0.0f;
  74     int                fCurrentY        = 0;
  75     SkJumper_DitherCtx fDitherCtx = { &fCurrentY, 0.0f };
  76
  77     typedef SkBlitter INHERITED;
  78 };
  79
  80 SkBlitter* SkCreateRasterPipelineBlitter(const SkPixmap& dst,
  81                                          const SkPaint& paint,
  82                                          const SkMatrix& ctm,
  83                                          SkArenaAlloc* alloc) {
  84     return SkRasterPipelineBlitter::Create(dst, paint, alloc, ctm);
  85 }
  86
  87 SkBlitter* SkCreateRasterPipelineBlitter(const SkPixmap& dst,
  88                                          const SkPaint& paint,
  89                                          const SkRasterPipeline& shaderPipeline,
  90                                          bool is_opaque,
  91                                          bool wants_dither,
  92                                          SkArenaAlloc* alloc) {
  93     bool is_constant = false;  // If this were the case, it'd be better to just set a paint color.
  94     return SkRasterPipelineBlitter::Create(dst, paint, alloc,
  95                                            shaderPipeline, is_opaque, is_constant, wants_dither);
  96 }
  97
  98 SkBlitter* SkRasterPipelineBlitter::Create(const SkPixmap& dst,
  99                                            const SkPaint& paint,
 100                                            SkArenaAlloc* alloc,
 101                                            const SkMatrix& ctm) {
 102     auto paintColor = alloc->make<SkPM4f>(SkPM4f_from_SkColor(paint.getColor(),
 103                                                               dst.colorSpace()));
 104     SkRasterPipeline_<256> shaderPipeline;
 105     if (auto shader = paint.getShader()) {
 106         if (!shader->appendStages(&shaderPipeline, dst.colorSpace(), alloc, ctm, paint)) {
 107             // When a shader fails to append stages, it means it has vetoed drawing entirely.
 108             return alloc->make<SkNullBlitter>();
 109         }
 110
 111         bool is_opaque = shader->isOpaque();
 112         if (paintColor->a() != 1.0f) {
 113             shaderPipeline.append(SkRasterPipeline::scale_1_float, &paintColor->fVec[SkPM4f::A]);
 114             is_opaque = false;
 115         }
 116
 117         bool is_constant  = shader->isConstant();
 118         bool wants_dither = shader->asAGradient(nullptr) >= SkShader::kLinear_GradientType;
 119         return Create(dst, paint, alloc, shaderPipeline, is_opaque, is_constant, wants_dither);
 120     }
 121
 122     shaderPipeline.append(SkRasterPipeline::constant_color, paintColor);
 123     bool is_opaque    = paintColor->a() == 1.0f,
 124          is_constant  = true,
 125          wants_dither = false;
 126     return Create(dst, paint, alloc, shaderPipeline, is_opaque, is_constant, wants_dither);
 127 }
 128
 129 SkBlitter* SkRasterPipelineBlitter::Create(const SkPixmap& dst,
 130                                            const SkPaint& paint,
 131                                            SkArenaAlloc* alloc,
 132                                            const SkRasterPipeline& shaderPipeline,
 133                                            bool is_opaque,
 134                                            bool is_constant,
 135                                            bool wants_dither) {
 136     auto blitter = alloc->make<SkRasterPipelineBlitter>(dst, paint.getBlendMode(), alloc);
 137
 138     // Our job in this factory is to fill out the blitter's color pipeline.
 139     // This is the common front of the full blit pipelines, each constructed lazily on first use.
 140     // The full blit pipelines handle reading and writing the dst, blending, coverage, dithering.
 141     auto colorPipeline = &blitter->fColorPipeline;
 142
 143     // Let's get the shader in first.  If the shader's not constant, it'll need seeding with x,y.
 144     if (!is_constant) {
 145         colorPipeline->append(SkRasterPipeline::seed_shader, &blitter->fCurrentY);
 146     }
 147     colorPipeline->extend(shaderPipeline);
 148
 149     // If there's a color filter it comes next.
 150     if (auto colorFilter = paint.getColorFilter()) {
 151         colorFilter->appendStages(colorPipeline, dst.colorSpace(), alloc, is_opaque);
 152         is_opaque = is_opaque && (colorFilter->getFlags() & SkColorFilter::kAlphaUnchanged_Flag);
 153     }
 154
 155     // We'll dither if the shader wants to, or if we're drawing 565 and the paint wants to.
 156     // Not all formats make sense to dither (think, F16).  We set their dither rate to zero.
 157     // We need to decide if we're going to dither now to keep is_constant accurate.
 158     if (wants_dither ||
 159             (paint.isDither() && dst.info().colorType() == kRGB_565_SkColorType)) {
 160         switch (dst.info().colorType()) {
 161             default:                     blitter->fDitherCtx.rate =     0.0f; break;
 162             case   kRGB_565_SkColorType: blitter->fDitherCtx.rate =  1/63.0f; break;
 163             case kRGBA_8888_SkColorType:
 164             case kBGRA_8888_SkColorType: blitter->fDitherCtx.rate = 1/255.0f; break;
 165         }
 166     }
 167     is_constant = is_constant && (blitter->fDitherCtx.rate == 0.0f);
 168
 169     // We're logically done here.  The code between here and return blitter is all optimization.
 170
 171     // A pipeline that's still constant here can collapse back into a constant color.
 172     if (is_constant) {
 173         auto constantColor = alloc->make<SkPM4f>();
 174         colorPipeline->append(SkRasterPipeline::store_f32, &constantColor);
 175         colorPipeline->run(0,1);
 176         colorPipeline->reset();
 177         colorPipeline->append(SkRasterPipeline::constant_color, constantColor);
 178
 179         is_opaque = constantColor->a() == 1.0f;
 180     }
 181
 182     // We can strength-reduce SrcOver into Src when opaque.
 183     if (is_opaque && blitter->fBlend == SkBlendMode::kSrcOver) {
 184         blitter->fBlend = SkBlendMode::kSrc;
 185     }
 186
 187     // When we're drawing a constant color in Src mode, we can sometimes just memset.
 188     // (The previous two optimizations help find more opportunities for this one.)
 189     if (is_constant && blitter->fBlend == SkBlendMode::kSrc) {
 190         // Run our color pipeline all the way through to produce what we'd memset when we can.
 191         // Not all blits can memset, so we need to keep colorPipeline too.
 192         SkRasterPipeline_<256> p;
 193         p.extend(*colorPipeline);
 194         blitter->fDstPtr = &blitter->fMemsetColor;
 195         blitter->append_store(&p);
 196         p.run(0,1);
 197
 198         blitter->fCanMemsetInBlitH = true;
 199     }
 200
 201     return blitter;
 202 }
 203
 204 void SkRasterPipelineBlitter::append_load_d(SkRasterPipeline* p) const {
 205     p->append(SkRasterPipeline::move_src_dst);
 206     switch (fDst.info().colorType()) {
 207         case kAlpha_8_SkColorType:   p->append(SkRasterPipeline::load_a8,   &fDstPtr); break;
 208         case kRGB_565_SkColorType:   p->append(SkRasterPipeline::load_565,  &fDstPtr); break;
 209         case kBGRA_8888_SkColorType:
 210         case kRGBA_8888_SkColorType: p->append(SkRasterPipeline::load_8888, &fDstPtr); break;
 211         case kRGBA_F16_SkColorType:  p->append(SkRasterPipeline::load_f16,  &fDstPtr); break;
 212         default: break;
 213     }
 214     if (fDst.info().colorType() == kBGRA_8888_SkColorType) {
 215         p->append(SkRasterPipeline::swap_rb);
 216     }
 217     if (fDst.info().gammaCloseToSRGB()) {
 218         p->append_from_srgb(fDst.info().alphaType());
 219     }
 220     p->append(SkRasterPipeline::swap);
 221 }
 222
 223 void SkRasterPipelineBlitter::append_store(SkRasterPipeline* p) const {
 224     if (fDst.info().gammaCloseToSRGB()) {
 225         p->append(SkRasterPipeline::to_srgb);
 226     }
 227     if (fDitherCtx.rate > 0.0f) {
 228         // We dither after any sRGB transfer function to make sure our 1/255.0f is sensible
 229         // over the whole range.  If we did it before, 1/255.0f is too big a rate near zero.
 230         p->append(SkRasterPipeline::dither, &fDitherCtx);
 231     }
 232
 233     if (fDst.info().colorType() == kBGRA_8888_SkColorType) {
 234         p->append(SkRasterPipeline::swap_rb);
 235     }
 236     switch (fDst.info().colorType()) {
 237         case kAlpha_8_SkColorType:   p->append(SkRasterPipeline::store_a8,   &fDstPtr); break;
 238         case kRGB_565_SkColorType:   p->append(SkRasterPipeline::store_565,  &fDstPtr); break;
 239         case kBGRA_8888_SkColorType:
 240         case kRGBA_8888_SkColorType: p->append(SkRasterPipeline::store_8888, &fDstPtr); break;
 241         case kRGBA_F16_SkColorType:  p->append(SkRasterPipeline::store_f16,  &fDstPtr); break;
 242         default: break;
 243     }
 244 }
 245
 246 void SkRasterPipelineBlitter::append_blend(SkRasterPipeline* p) const {
 247     SkBlendMode_AppendStages(fBlend, p);
 248 }
 249
 250 void SkRasterPipelineBlitter::maybe_clamp(SkRasterPipeline* p) const {
 251     if (SkBlendMode_CanOverflow(fBlend)) {
 252         p->append(SkRasterPipeline::clamp_a);
 253     }
 254 }
 255
 256 void SkRasterPipelineBlitter::blitH(int x, int y, int w) {
 257     fDstPtr = fDst.writable_addr(0,y);
 258     fCurrentY = y;
 259
 260     if (fCanMemsetInBlitH) {
 261         switch (fDst.shiftPerPixel()) {
 262             case 0:    memset  ((uint8_t *)fDstPtr + x, fMemsetColor, w); return;
 263             case 1: sk_memset16((uint16_t*)fDstPtr + x, fMemsetColor, w); return;
 264             case 2: sk_memset32((uint32_t*)fDstPtr + x, fMemsetColor, w); return;
 265             case 3: sk_memset64((uint64_t*)fDstPtr + x, fMemsetColor, w); return;
 266             default: break;
 267         }
 268     }
 269
 270     if (!fBlitH) {
 271         SkRasterPipeline p(fAlloc);
 272         p.extend(fColorPipeline);
 273         if (fBlend != SkBlendMode::kSrc) {
 274             this->append_load_d(&p);
 275             this->append_blend(&p);
 276             this->maybe_clamp(&p);
 277         }
 278         this->append_store(&p);
 279         fBlitH = p.compile();
 280     }
 281     fBlitH(x,w);
 282 }
 283
 284 void SkRasterPipelineBlitter::blitAntiH(int x, int y, const SkAlpha aa[], const int16_t runs[]) {
 285     if (!fBlitAntiH) {
 286         SkRasterPipeline p(fAlloc);
 287         p.extend(fColorPipeline);
 288         if (fBlend == SkBlendMode::kSrcOver) {
 289             p.append(SkRasterPipeline::scale_1_float, &fCurrentCoverage);
 290             this->append_load_d(&p);
 291             this->append_blend(&p);
 292         } else {
 293             this->append_load_d(&p);
 294             this->append_blend(&p);
 295             p.append(SkRasterPipeline::lerp_1_float, &fCurrentCoverage);
 296         }
 297         this->maybe_clamp(&p);
 298         this->append_store(&p);
 299         fBlitAntiH = p.compile();
 300     }
 301
 302     fDstPtr = fDst.writable_addr(0,y);
 303     fCurrentY = y;
 304     for (int16_t run = *runs; run > 0; run = *runs) {
 305         switch (*aa) {
 306             case 0x00:                       break;
 307             case 0xff: this->blitH(x,y,run); break;
 308             default:
 309                 fCurrentCoverage = *aa * (1/255.0f);
 310                 fBlitAntiH(x,run);
 311         }
 312         x    += run;
 313         runs += run;
 314         aa   += run;
 315     }
 316 }
 317
 318 void SkRasterPipelineBlitter::blitMask(const SkMask& mask, const SkIRect& clip) {
 319     if (mask.fFormat == SkMask::kBW_Format) {
 320         // TODO: native BW masks?
 321         return INHERITED::blitMask(mask, clip);
 322     }
 323
 324     if (mask.fFormat == SkMask::kA8_Format && !fBlitMaskA8) {
 325         SkRasterPipeline p(fAlloc);
 326         p.extend(fColorPipeline);
 327         if (fBlend == SkBlendMode::kSrcOver) {
 328             p.append(SkRasterPipeline::scale_u8, &fMaskPtr);
 329             this->append_load_d(&p);
 330             this->append_blend(&p);
 331         } else {
 332             this->append_load_d(&p);
 333             this->append_blend(&p);
 334             p.append(SkRasterPipeline::lerp_u8, &fMaskPtr);
 335         }
 336         this->maybe_clamp(&p);
 337         this->append_store(&p);
 338         fBlitMaskA8 = p.compile();
 339     }
 340
 341     if (mask.fFormat == SkMask::kLCD16_Format && !fBlitMaskLCD16) {
 342         SkRasterPipeline p(fAlloc);
 343         p.extend(fColorPipeline);
 344         this->append_load_d(&p);
 345         this->append_blend(&p);
 346         p.append(SkRasterPipeline::lerp_565, &fMaskPtr);
 347         this->maybe_clamp(&p);
 348         this->append_store(&p);
 349         fBlitMaskLCD16 = p.compile();
 350     }
 351
 352     int x = clip.left();
 353     for (int y = clip.top(); y < clip.bottom(); y++) {
 354         fDstPtr = fDst.writable_addr(0,y);
 355         fCurrentY = y;
 356
 357         switch (mask.fFormat) {
 358             case SkMask::kA8_Format:
 359                 fMaskPtr = mask.getAddr8(x,y)-x;
 360                 fBlitMaskA8(x,clip.width());
 361                 break;
 362             case SkMask::kLCD16_Format:
 363                 fMaskPtr = mask.getAddrLCD16(x,y)-x;
 364                 fBlitMaskLCD16(x,clip.width());
 365                 break;
 366             default:
 367                 // TODO
 368                 break;
 369         }
 370     }
 371 }