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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 "SkCoreBlitters.h"
      9 #include "SkColorPriv.h"
     10 #include "SkShader.h"
     11 #include "SkUtils.h"
     12 #include "SkXfermode.h"
     13 #include "SkBlitMask.h"
     14 
     15 ///////////////////////////////////////////////////////////////////////////////
     16 
     17 static void SkARGB32_Blit32(const SkPixmap& device, const SkMask& mask,
     18                             const SkIRect& clip, SkPMColor srcColor) {
     19     U8CPU alpha = SkGetPackedA32(srcColor);
     20     unsigned flags = SkBlitRow::kSrcPixelAlpha_Flag32;
     21     if (alpha != 255) {
     22         flags |= SkBlitRow::kGlobalAlpha_Flag32;
     23     }
     24     SkBlitRow::Proc32 proc = SkBlitRow::Factory32(flags);
     25 
     26     int x = clip.fLeft;
     27     int y = clip.fTop;
     28     int width = clip.width();
     29     int height = clip.height();
     30 
     31     SkPMColor* dstRow = device.writable_addr32(x, y);
     32     const SkPMColor* srcRow = reinterpret_cast<const SkPMColor*>(mask.getAddr8(x, y));
     33 
     34     do {
     35         proc(dstRow, srcRow, width, alpha);
     36         dstRow = (SkPMColor*)((char*)dstRow + device.rowBytes());
     37         srcRow = (const SkPMColor*)((const char*)srcRow + mask.fRowBytes);
     38     } while (--height != 0);
     39 }
     40 
     41 //////////////////////////////////////////////////////////////////////////////////////
     42 
     43 SkARGB32_Blitter::SkARGB32_Blitter(const SkPixmap& device, const SkPaint& paint)
     44         : INHERITED(device) {
     45     SkColor color = paint.getColor();
     46     fColor = color;
     47 
     48     fSrcA = SkColorGetA(color);
     49     unsigned scale = SkAlpha255To256(fSrcA);
     50     fSrcR = SkAlphaMul(SkColorGetR(color), scale);
     51     fSrcG = SkAlphaMul(SkColorGetG(color), scale);
     52     fSrcB = SkAlphaMul(SkColorGetB(color), scale);
     53 
     54     fPMColor = SkPackARGB32(fSrcA, fSrcR, fSrcG, fSrcB);
     55 }
     56 
     57 const SkPixmap* SkARGB32_Blitter::justAnOpaqueColor(uint32_t* value) {
     58     if (255 == fSrcA) {
     59         *value = fPMColor;
     60         return &fDevice;
     61     }
     62     return nullptr;
     63 }
     64 
     65 #if defined _WIN32 && _MSC_VER >= 1300  // disable warning : local variable used without having been initialized
     66 #pragma warning ( push )
     67 #pragma warning ( disable : 4701 )
     68 #endif
     69 
     70 void SkARGB32_Blitter::blitH(int x, int y, int width) {
     71     SkASSERT(x >= 0 && y >= 0 && x + width <= fDevice.width());
     72 
     73     uint32_t* device = fDevice.writable_addr32(x, y);
     74     SkBlitRow::Color32(device, device, width, fPMColor);
     75 }
     76 
     77 void SkARGB32_Blitter::blitAntiH(int x, int y, const SkAlpha antialias[],
     78                                  const int16_t runs[]) {
     79     if (fSrcA == 0) {
     80         return;
     81     }
     82 
     83     uint32_t    color = fPMColor;
     84     uint32_t*   device = fDevice.writable_addr32(x, y);
     85     unsigned    opaqueMask = fSrcA; // if fSrcA is 0xFF, then we will catch the fast opaque case
     86 
     87     for (;;) {
     88         int count = runs[0];
     89         SkASSERT(count >= 0);
     90         if (count <= 0) {
     91             return;
     92         }
     93         unsigned aa = antialias[0];
     94         if (aa) {
     95             if ((opaqueMask & aa) == 255) {
     96                 sk_memset32(device, color, count);
     97             } else {
     98                 uint32_t sc = SkAlphaMulQ(color, SkAlpha255To256(aa));
     99                 SkBlitRow::Color32(device, device, count, sc);
    100             }
    101         }
    102         runs += count;
    103         antialias += count;
    104         device += count;
    105     }
    106 }
    107 
    108 void SkARGB32_Blitter::blitAntiH2(int x, int y, U8CPU a0, U8CPU a1) {
    109     uint32_t* device = fDevice.writable_addr32(x, y);
    110     SkDEBUGCODE((void)fDevice.writable_addr32(x + 1, y);)
    111 
    112     device[0] = SkBlendARGB32(fPMColor, device[0], a0);
    113     device[1] = SkBlendARGB32(fPMColor, device[1], a1);
    114 }
    115 
    116 void SkARGB32_Blitter::blitAntiV2(int x, int y, U8CPU a0, U8CPU a1) {
    117     uint32_t* device = fDevice.writable_addr32(x, y);
    118     SkDEBUGCODE((void)fDevice.writable_addr32(x, y + 1);)
    119 
    120     device[0] = SkBlendARGB32(fPMColor, device[0], a0);
    121     device = (uint32_t*)((char*)device + fDevice.rowBytes());
    122     device[0] = SkBlendARGB32(fPMColor, device[0], a1);
    123 }
    124 
    125 //////////////////////////////////////////////////////////////////////////////////////
    126 
    127 #define solid_8_pixels(mask, dst, color)    \
    128     do {                                    \
    129         if (mask & 0x80) dst[0] = color;    \
    130         if (mask & 0x40) dst[1] = color;    \
    131         if (mask & 0x20) dst[2] = color;    \
    132         if (mask & 0x10) dst[3] = color;    \
    133         if (mask & 0x08) dst[4] = color;    \
    134         if (mask & 0x04) dst[5] = color;    \
    135         if (mask & 0x02) dst[6] = color;    \
    136         if (mask & 0x01) dst[7] = color;    \
    137     } while (0)
    138 
    139 #define SK_BLITBWMASK_NAME                  SkARGB32_BlitBW
    140 #define SK_BLITBWMASK_ARGS                  , SkPMColor color
    141 #define SK_BLITBWMASK_BLIT8(mask, dst)      solid_8_pixels(mask, dst, color)
    142 #define SK_BLITBWMASK_GETADDR               writable_addr32
    143 #define SK_BLITBWMASK_DEVTYPE               uint32_t
    144 #include "SkBlitBWMaskTemplate.h"
    145 
    146 #define blend_8_pixels(mask, dst, sc, dst_scale)                            \
    147     do {                                                                    \
    148         if (mask & 0x80) { dst[0] = sc + SkAlphaMulQ(dst[0], dst_scale); }  \
    149         if (mask & 0x40) { dst[1] = sc + SkAlphaMulQ(dst[1], dst_scale); }  \
    150         if (mask & 0x20) { dst[2] = sc + SkAlphaMulQ(dst[2], dst_scale); }  \
    151         if (mask & 0x10) { dst[3] = sc + SkAlphaMulQ(dst[3], dst_scale); }  \
    152         if (mask & 0x08) { dst[4] = sc + SkAlphaMulQ(dst[4], dst_scale); }  \
    153         if (mask & 0x04) { dst[5] = sc + SkAlphaMulQ(dst[5], dst_scale); }  \
    154         if (mask & 0x02) { dst[6] = sc + SkAlphaMulQ(dst[6], dst_scale); }  \
    155         if (mask & 0x01) { dst[7] = sc + SkAlphaMulQ(dst[7], dst_scale); }  \
    156     } while (0)
    157 
    158 #define SK_BLITBWMASK_NAME                  SkARGB32_BlendBW
    159 #define SK_BLITBWMASK_ARGS                  , uint32_t sc, unsigned dst_scale
    160 #define SK_BLITBWMASK_BLIT8(mask, dst)      blend_8_pixels(mask, dst, sc, dst_scale)
    161 #define SK_BLITBWMASK_GETADDR               writable_addr32
    162 #define SK_BLITBWMASK_DEVTYPE               uint32_t
    163 #include "SkBlitBWMaskTemplate.h"
    164 
    165 void SkARGB32_Blitter::blitMask(const SkMask& mask, const SkIRect& clip) {
    166     SkASSERT(mask.fBounds.contains(clip));
    167     SkASSERT(fSrcA != 0xFF);
    168 
    169     if (fSrcA == 0) {
    170         return;
    171     }
    172 
    173     if (SkBlitMask::BlitColor(fDevice, mask, clip, fColor)) {
    174         return;
    175     }
    176 
    177     if (mask.fFormat == SkMask::kBW_Format) {
    178         SkARGB32_BlendBW(fDevice, mask, clip, fPMColor, SkAlpha255To256(255 - fSrcA));
    179     } else if (SkMask::kARGB32_Format == mask.fFormat) {
    180         SkARGB32_Blit32(fDevice, mask, clip, fPMColor);
    181     }
    182 }
    183 
    184 void SkARGB32_Opaque_Blitter::blitMask(const SkMask& mask,
    185                                        const SkIRect& clip) {
    186     SkASSERT(mask.fBounds.contains(clip));
    187 
    188     if (SkBlitMask::BlitColor(fDevice, mask, clip, fColor)) {
    189         return;
    190     }
    191 
    192     if (mask.fFormat == SkMask::kBW_Format) {
    193         SkARGB32_BlitBW(fDevice, mask, clip, fPMColor);
    194     } else if (SkMask::kARGB32_Format == mask.fFormat) {
    195         SkARGB32_Blit32(fDevice, mask, clip, fPMColor);
    196     }
    197 }
    198 
    199 void SkARGB32_Opaque_Blitter::blitAntiH2(int x, int y, U8CPU a0, U8CPU a1) {
    200     uint32_t* device = fDevice.writable_addr32(x, y);
    201     SkDEBUGCODE((void)fDevice.writable_addr32(x + 1, y);)
    202 
    203     device[0] = SkFastFourByteInterp(fPMColor, device[0], a0);
    204     device[1] = SkFastFourByteInterp(fPMColor, device[1], a1);
    205 }
    206 
    207 void SkARGB32_Opaque_Blitter::blitAntiV2(int x, int y, U8CPU a0, U8CPU a1) {
    208     uint32_t* device = fDevice.writable_addr32(x, y);
    209     SkDEBUGCODE((void)fDevice.writable_addr32(x, y + 1);)
    210 
    211     device[0] = SkFastFourByteInterp(fPMColor, device[0], a0);
    212     device = (uint32_t*)((char*)device + fDevice.rowBytes());
    213     device[0] = SkFastFourByteInterp(fPMColor, device[0], a1);
    214 }
    215 
    216 ///////////////////////////////////////////////////////////////////////////////
    217 
    218 void SkARGB32_Blitter::blitV(int x, int y, int height, SkAlpha alpha) {
    219     if (alpha == 0 || fSrcA == 0) {
    220         return;
    221     }
    222 
    223     uint32_t* device = fDevice.writable_addr32(x, y);
    224     uint32_t  color = fPMColor;
    225 
    226     if (alpha != 255) {
    227         color = SkAlphaMulQ(color, SkAlpha255To256(alpha));
    228     }
    229 
    230     unsigned dst_scale = 255 - SkGetPackedA32(color);
    231     size_t rowBytes = fDevice.rowBytes();
    232     while (--height >= 0) {
    233         device[0] = color + SkAlphaMulQ(device[0], dst_scale);
    234         device = (uint32_t*)((char*)device + rowBytes);
    235     }
    236 }
    237 
    238 void SkARGB32_Blitter::blitRect(int x, int y, int width, int height) {
    239     SkASSERT(x >= 0 && y >= 0 && x + width <= fDevice.width() && y + height <= fDevice.height());
    240 
    241     if (fSrcA == 0) {
    242         return;
    243     }
    244 
    245     uint32_t*   device = fDevice.writable_addr32(x, y);
    246     uint32_t    color = fPMColor;
    247     size_t      rowBytes = fDevice.rowBytes();
    248 
    249     while (--height >= 0) {
    250         SkBlitRow::Color32(device, device, width, color);
    251         device = (uint32_t*)((char*)device + rowBytes);
    252     }
    253 }
    254 
    255 #if defined _WIN32 && _MSC_VER >= 1300
    256 #pragma warning ( pop )
    257 #endif
    258 
    259 ///////////////////////////////////////////////////////////////////////
    260 
    261 void SkARGB32_Black_Blitter::blitAntiH(int x, int y, const SkAlpha antialias[],
    262                                        const int16_t runs[]) {
    263     uint32_t*   device = fDevice.writable_addr32(x, y);
    264     SkPMColor   black = (SkPMColor)(SK_A32_MASK << SK_A32_SHIFT);
    265 
    266     for (;;) {
    267         int count = runs[0];
    268         SkASSERT(count >= 0);
    269         if (count <= 0) {
    270             return;
    271         }
    272         unsigned aa = antialias[0];
    273         if (aa) {
    274             if (aa == 255) {
    275                 sk_memset32(device, black, count);
    276             } else {
    277                 SkPMColor src = aa << SK_A32_SHIFT;
    278                 unsigned dst_scale = 256 - aa;
    279                 int n = count;
    280                 do {
    281                     --n;
    282                     device[n] = src + SkAlphaMulQ(device[n], dst_scale);
    283                 } while (n > 0);
    284             }
    285         }
    286         runs += count;
    287         antialias += count;
    288         device += count;
    289     }
    290 }
    291 
    292 void SkARGB32_Black_Blitter::blitAntiH2(int x, int y, U8CPU a0, U8CPU a1) {
    293     uint32_t* device = fDevice.writable_addr32(x, y);
    294     SkDEBUGCODE((void)fDevice.writable_addr32(x + 1, y);)
    295 
    296     device[0] = (a0 << SK_A32_SHIFT) + SkAlphaMulQ(device[0], 256 - a0);
    297     device[1] = (a1 << SK_A32_SHIFT) + SkAlphaMulQ(device[1], 256 - a1);
    298 }
    299 
    300 void SkARGB32_Black_Blitter::blitAntiV2(int x, int y, U8CPU a0, U8CPU a1) {
    301     uint32_t* device = fDevice.writable_addr32(x, y);
    302     SkDEBUGCODE((void)fDevice.writable_addr32(x, y + 1);)
    303 
    304     device[0] = (a0 << SK_A32_SHIFT) + SkAlphaMulQ(device[0], 256 - a0);
    305     device = (uint32_t*)((char*)device + fDevice.rowBytes());
    306     device[0] = (a1 << SK_A32_SHIFT) + SkAlphaMulQ(device[0], 256 - a1);
    307 }
    308 
    309 ///////////////////////////////////////////////////////////////////////////////
    310 
    311 // Special version of SkBlitRow::Factory32 that knows we're in kSrc_Mode,
    312 // instead of kSrcOver_Mode
    313 static void blend_srcmode(SkPMColor* SK_RESTRICT device,
    314                           const SkPMColor* SK_RESTRICT span,
    315                           int count, U8CPU aa) {
    316     int aa256 = SkAlpha255To256(aa);
    317     for (int i = 0; i < count; ++i) {
    318         device[i] = SkFourByteInterp256(span[i], device[i], aa256);
    319     }
    320 }
    321 
    322 SkARGB32_Shader_Blitter::SkARGB32_Shader_Blitter(const SkPixmap& device,
    323         const SkPaint& paint, SkShader::Context* shaderContext)
    324     : INHERITED(device, paint, shaderContext)
    325 {
    326     fBuffer = (SkPMColor*)sk_malloc_throw(device.width() * (sizeof(SkPMColor)));
    327 
    328     fXfermode = paint.getXfermode();
    329     SkSafeRef(fXfermode);
    330 
    331     int flags = 0;
    332     if (!(shaderContext->getFlags() & SkShader::kOpaqueAlpha_Flag)) {
    333         flags |= SkBlitRow::kSrcPixelAlpha_Flag32;
    334     }
    335     // we call this on the output from the shader
    336     fProc32 = SkBlitRow::Factory32(flags);
    337     // we call this on the output from the shader + alpha from the aa buffer
    338     fProc32Blend = SkBlitRow::Factory32(flags | SkBlitRow::kGlobalAlpha_Flag32);
    339 
    340     fShadeDirectlyIntoDevice = false;
    341     if (fXfermode == nullptr) {
    342         if (shaderContext->getFlags() & SkShader::kOpaqueAlpha_Flag) {
    343             fShadeDirectlyIntoDevice = true;
    344         }
    345     } else {
    346         SkXfermode::Mode mode;
    347         if (fXfermode->asMode(&mode)) {
    348             if (SkXfermode::kSrc_Mode == mode) {
    349                 fShadeDirectlyIntoDevice = true;
    350                 fProc32Blend = blend_srcmode;
    351             }
    352         }
    353     }
    354 
    355     fConstInY = SkToBool(shaderContext->getFlags() & SkShader::kConstInY32_Flag);
    356 }
    357 
    358 SkARGB32_Shader_Blitter::~SkARGB32_Shader_Blitter() {
    359     SkSafeUnref(fXfermode);
    360     sk_free(fBuffer);
    361 }
    362 
    363 void SkARGB32_Shader_Blitter::blitH(int x, int y, int width) {
    364     SkASSERT(x >= 0 && y >= 0 && x + width <= fDevice.width());
    365 
    366     uint32_t* device = fDevice.writable_addr32(x, y);
    367 
    368     if (fShadeDirectlyIntoDevice) {
    369         fShaderContext->shadeSpan(x, y, device, width);
    370     } else {
    371         SkPMColor*  span = fBuffer;
    372         fShaderContext->shadeSpan(x, y, span, width);
    373         if (fXfermode) {
    374             fXfermode->xfer32(device, span, width, nullptr);
    375         } else {
    376             fProc32(device, span, width, 255);
    377         }
    378     }
    379 }
    380 
    381 void SkARGB32_Shader_Blitter::blitRect(int x, int y, int width, int height) {
    382     SkASSERT(x >= 0 && y >= 0 &&
    383              x + width <= fDevice.width() && y + height <= fDevice.height());
    384 
    385     uint32_t*          device = fDevice.writable_addr32(x, y);
    386     size_t             deviceRB = fDevice.rowBytes();
    387     SkShader::Context* shaderContext = fShaderContext;
    388     SkPMColor*         span = fBuffer;
    389 
    390     if (fConstInY) {
    391         if (fShadeDirectlyIntoDevice) {
    392             // shade the first row directly into the device
    393             shaderContext->shadeSpan(x, y, device, width);
    394             span = device;
    395             while (--height > 0) {
    396                 device = (uint32_t*)((char*)device + deviceRB);
    397                 memcpy(device, span, width << 2);
    398             }
    399         } else {
    400             shaderContext->shadeSpan(x, y, span, width);
    401             SkXfermode* xfer = fXfermode;
    402             if (xfer) {
    403                 do {
    404                     xfer->xfer32(device, span, width, nullptr);
    405                     y += 1;
    406                     device = (uint32_t*)((char*)device + deviceRB);
    407                 } while (--height > 0);
    408             } else {
    409                 SkBlitRow::Proc32 proc = fProc32;
    410                 do {
    411                     proc(device, span, width, 255);
    412                     y += 1;
    413                     device = (uint32_t*)((char*)device + deviceRB);
    414                 } while (--height > 0);
    415             }
    416         }
    417         return;
    418     }
    419 
    420     if (fShadeDirectlyIntoDevice) {
    421         void* ctx;
    422         SkShader::Context::ShadeProc shadeProc = shaderContext->asAShadeProc(&ctx);
    423         if (shadeProc) {
    424             do {
    425                 shadeProc(ctx, x, y, device, width);
    426                 y += 1;
    427                 device = (uint32_t*)((char*)device + deviceRB);
    428             } while (--height > 0);
    429         } else {
    430             do {
    431                 shaderContext->shadeSpan(x, y, device, width);
    432                 y += 1;
    433                 device = (uint32_t*)((char*)device + deviceRB);
    434             } while (--height > 0);
    435         }
    436     } else {
    437         SkXfermode* xfer = fXfermode;
    438         if (xfer) {
    439             do {
    440                 shaderContext->shadeSpan(x, y, span, width);
    441                 xfer->xfer32(device, span, width, nullptr);
    442                 y += 1;
    443                 device = (uint32_t*)((char*)device + deviceRB);
    444             } while (--height > 0);
    445         } else {
    446             SkBlitRow::Proc32 proc = fProc32;
    447             do {
    448                 shaderContext->shadeSpan(x, y, span, width);
    449                 proc(device, span, width, 255);
    450                 y += 1;
    451                 device = (uint32_t*)((char*)device + deviceRB);
    452             } while (--height > 0);
    453         }
    454     }
    455 }
    456 
    457 void SkARGB32_Shader_Blitter::blitAntiH(int x, int y, const SkAlpha antialias[],
    458                                         const int16_t runs[]) {
    459     SkPMColor*         span = fBuffer;
    460     uint32_t*          device = fDevice.writable_addr32(x, y);
    461     SkShader::Context* shaderContext = fShaderContext;
    462 
    463     if (fXfermode && !fShadeDirectlyIntoDevice) {
    464         for (;;) {
    465             SkXfermode* xfer = fXfermode;
    466 
    467             int count = *runs;
    468             if (count <= 0)
    469                 break;
    470             int aa = *antialias;
    471             if (aa) {
    472                 shaderContext->shadeSpan(x, y, span, count);
    473                 if (aa == 255) {
    474                     xfer->xfer32(device, span, count, nullptr);
    475                 } else {
    476                     // count is almost always 1
    477                     for (int i = count - 1; i >= 0; --i) {
    478                         xfer->xfer32(&device[i], &span[i], 1, antialias);
    479                     }
    480                 }
    481             }
    482             device += count;
    483             runs += count;
    484             antialias += count;
    485             x += count;
    486         }
    487     } else if (fShadeDirectlyIntoDevice ||
    488                (shaderContext->getFlags() & SkShader::kOpaqueAlpha_Flag)) {
    489         for (;;) {
    490             int count = *runs;
    491             if (count <= 0) {
    492                 break;
    493             }
    494             int aa = *antialias;
    495             if (aa) {
    496                 if (aa == 255) {
    497                     // cool, have the shader draw right into the device
    498                     shaderContext->shadeSpan(x, y, device, count);
    499                 } else {
    500                     shaderContext->shadeSpan(x, y, span, count);
    501                     fProc32Blend(device, span, count, aa);
    502                 }
    503             }
    504             device += count;
    505             runs += count;
    506             antialias += count;
    507             x += count;
    508         }
    509     } else {
    510         for (;;) {
    511             int count = *runs;
    512             if (count <= 0) {
    513                 break;
    514             }
    515             int aa = *antialias;
    516             if (aa) {
    517                 shaderContext->shadeSpan(x, y, span, count);
    518                 if (aa == 255) {
    519                     fProc32(device, span, count, 255);
    520                 } else {
    521                     fProc32Blend(device, span, count, aa);
    522                 }
    523             }
    524             device += count;
    525             runs += count;
    526             antialias += count;
    527             x += count;
    528         }
    529     }
    530 }
    531 
    532 void SkARGB32_Shader_Blitter::blitMask(const SkMask& mask, const SkIRect& clip) {
    533     // we only handle kA8 with an xfermode
    534     if (fXfermode && (SkMask::kA8_Format != mask.fFormat)) {
    535         this->INHERITED::blitMask(mask, clip);
    536         return;
    537     }
    538 
    539     SkASSERT(mask.fBounds.contains(clip));
    540 
    541     SkShader::Context*  shaderContext = fShaderContext;
    542     SkBlitMask::RowProc proc = nullptr;
    543     if (!fXfermode) {
    544         unsigned flags = 0;
    545         if (shaderContext->getFlags() & SkShader::kOpaqueAlpha_Flag) {
    546             flags |= SkBlitMask::kSrcIsOpaque_RowFlag;
    547         }
    548         proc = SkBlitMask::RowFactory(kN32_SkColorType, mask.fFormat,
    549                                       (SkBlitMask::RowFlags)flags);
    550         if (nullptr == proc) {
    551             this->INHERITED::blitMask(mask, clip);
    552             return;
    553         }
    554     }
    555 
    556     const int x = clip.fLeft;
    557     const int width = clip.width();
    558     int y = clip.fTop;
    559     int height = clip.height();
    560 
    561     char* dstRow = (char*)fDevice.writable_addr32(x, y);
    562     const size_t dstRB = fDevice.rowBytes();
    563     const uint8_t* maskRow = (const uint8_t*)mask.getAddr(x, y);
    564     const size_t maskRB = mask.fRowBytes;
    565 
    566     SkPMColor* span = fBuffer;
    567 
    568     if (fXfermode) {
    569         SkASSERT(SkMask::kA8_Format == mask.fFormat);
    570         SkXfermode* xfer = fXfermode;
    571         do {
    572             shaderContext->shadeSpan(x, y, span, width);
    573             xfer->xfer32(reinterpret_cast<SkPMColor*>(dstRow), span, width, maskRow);
    574             dstRow += dstRB;
    575             maskRow += maskRB;
    576             y += 1;
    577         } while (--height > 0);
    578     } else {
    579         do {
    580             shaderContext->shadeSpan(x, y, span, width);
    581             proc(reinterpret_cast<SkPMColor*>(dstRow), maskRow, span, width);
    582             dstRow += dstRB;
    583             maskRow += maskRB;
    584             y += 1;
    585         } while (--height > 0);
    586     }
    587 }
    588 
    589 void SkARGB32_Shader_Blitter::blitV(int x, int y, int height, SkAlpha alpha) {
    590     SkASSERT(x >= 0 && y >= 0 && y + height <= fDevice.height());
    591 
    592     uint32_t*          device = fDevice.writable_addr32(x, y);
    593     size_t             deviceRB = fDevice.rowBytes();
    594     SkShader::Context* shaderContext = fShaderContext;
    595 
    596     if (fConstInY) {
    597         SkPMColor c;
    598         shaderContext->shadeSpan(x, y, &c, 1);
    599 
    600         if (fShadeDirectlyIntoDevice) {
    601             if (255 == alpha) {
    602                 do {
    603                     *device = c;
    604                     device = (uint32_t*)((char*)device + deviceRB);
    605                 } while (--height > 0);
    606             } else {
    607                 do {
    608                     *device = SkFourByteInterp(c, *device, alpha);
    609                     device = (uint32_t*)((char*)device + deviceRB);
    610                 } while (--height > 0);
    611             }
    612         } else {
    613             SkXfermode* xfer = fXfermode;
    614             if (xfer) {
    615                 do {
    616                     xfer->xfer32(device, &c, 1, &alpha);
    617                     device = (uint32_t*)((char*)device + deviceRB);
    618                 } while (--height > 0);
    619             } else {
    620                 SkBlitRow::Proc32 proc = (255 == alpha) ? fProc32 : fProc32Blend;
    621                 do {
    622                     proc(device, &c, 1, alpha);
    623                     device = (uint32_t*)((char*)device + deviceRB);
    624                 } while (--height > 0);
    625             }
    626         }
    627         return;
    628     }
    629 
    630     if (fShadeDirectlyIntoDevice) {
    631         void* ctx;
    632         SkShader::Context::ShadeProc shadeProc = shaderContext->asAShadeProc(&ctx);
    633         if (255 == alpha) {
    634             if (shadeProc) {
    635                 do {
    636                     shadeProc(ctx, x, y, device, 1);
    637                     y += 1;
    638                     device = (uint32_t*)((char*)device + deviceRB);
    639                 } while (--height > 0);
    640             } else {
    641                 do {
    642                     shaderContext->shadeSpan(x, y, device, 1);
    643                     y += 1;
    644                     device = (uint32_t*)((char*)device + deviceRB);
    645                 } while (--height > 0);
    646             }
    647         } else {    // alpha < 255
    648             SkPMColor c;
    649             if (shadeProc) {
    650                 do {
    651                     shadeProc(ctx, x, y, &c, 1);
    652                     *device = SkFourByteInterp(c, *device, alpha);
    653                     y += 1;
    654                     device = (uint32_t*)((char*)device + deviceRB);
    655                 } while (--height > 0);
    656             } else {
    657                 do {
    658                     shaderContext->shadeSpan(x, y, &c, 1);
    659                     *device = SkFourByteInterp(c, *device, alpha);
    660                     y += 1;
    661                     device = (uint32_t*)((char*)device + deviceRB);
    662                 } while (--height > 0);
    663             }
    664         }
    665     } else {
    666         SkPMColor* span = fBuffer;
    667         SkXfermode* xfer = fXfermode;
    668         if (xfer) {
    669             do {
    670                 shaderContext->shadeSpan(x, y, span, 1);
    671                 xfer->xfer32(device, span, 1, &alpha);
    672                 y += 1;
    673                 device = (uint32_t*)((char*)device + deviceRB);
    674             } while (--height > 0);
    675         } else {
    676             SkBlitRow::Proc32 proc = (255 == alpha) ? fProc32 : fProc32Blend;
    677             do {
    678                 shaderContext->shadeSpan(x, y, span, 1);
    679                 proc(device, span, 1, alpha);
    680                 y += 1;
    681                 device = (uint32_t*)((char*)device + deviceRB);
    682             } while (--height > 0);
    683         }
    684     }
    685 }
    686