src/third_party/skia/tests/BitmapCopyTest.cpp

   1 /*
   2  * Copyright 2011 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 "SkBitmap.h"
   9 #include "SkRect.h"
  10 #include "Test.h"
  11
  12 static const char* boolStr(bool value) {
  13     return value ? "true" : "false";
  14 }
  15
  16 // these are in the same order as the SkColorType enum
  17 static const char* gColorTypeName[] = {
  18     "None", "A8", "565", "4444", "RGBA", "BGRA", "Index8"
  19 };
  20
  21 static void report_opaqueness(skiatest::Reporter* reporter, const SkBitmap& src,
  22                               const SkBitmap& dst) {
  23     ERRORF(reporter, "src %s opaque:%d, dst %s opaque:%d",
  24            gColorTypeName[src.colorType()], src.isOpaque(),
  25            gColorTypeName[dst.colorType()], dst.isOpaque());
  26 }
  27
  28 static bool canHaveAlpha(SkColorType ct) {
  29     return kRGB_565_SkColorType != ct;
  30 }
  31
  32 // copyTo() should preserve isOpaque when it makes sense
  33 static void test_isOpaque(skiatest::Reporter* reporter,
  34                           const SkBitmap& srcOpaque, const SkBitmap& srcPremul,
  35                           SkColorType dstColorType) {
  36     SkBitmap dst;
  37
  38     if (canHaveAlpha(srcPremul.colorType()) && canHaveAlpha(dstColorType)) {
  39         REPORTER_ASSERT(reporter, srcPremul.copyTo(&dst, dstColorType));
  40         REPORTER_ASSERT(reporter, dst.colorType() == dstColorType);
  41         if (srcPremul.isOpaque() != dst.isOpaque()) {
  42             report_opaqueness(reporter, srcPremul, dst);
  43         }
  44     }
  45
  46     REPORTER_ASSERT(reporter, srcOpaque.copyTo(&dst, dstColorType));
  47     REPORTER_ASSERT(reporter, dst.colorType() == dstColorType);
  48     if (srcOpaque.isOpaque() != dst.isOpaque()) {
  49         report_opaqueness(reporter, srcOpaque, dst);
  50     }
  51 }
  52
  53 static void init_src(const SkBitmap& bitmap) {
  54     SkAutoLockPixels lock(bitmap);
  55     if (bitmap.getPixels()) {
  56         if (bitmap.getColorTable()) {
  57             sk_bzero(bitmap.getPixels(), bitmap.getSize());
  58         } else {
  59             bitmap.eraseColor(SK_ColorWHITE);
  60         }
  61     }
  62 }
  63
  64 static SkColorTable* init_ctable(SkAlphaType alphaType) {
  65     static const SkColor colors[] = {
  66         SK_ColorBLACK, SK_ColorRED, SK_ColorGREEN, SK_ColorBLUE, SK_ColorWHITE
  67     };
  68     return new SkColorTable(colors, SK_ARRAY_COUNT(colors), alphaType);
  69 }
  70
  71 struct Pair {
  72     SkColorType fColorType;
  73     const char* fValid;
  74 };
  75
  76 // Utility functions for copyPixelsTo()/copyPixelsFrom() tests.
  77 // getPixel()
  78 // setPixel()
  79 // getSkConfigName()
  80 // struct Coordinates
  81 // reportCopyVerification()
  82 // writeCoordPixels()
  83
  84 // Utility function to read the value of a given pixel in bm. All
  85 // values converted to uint32_t for simplification of comparisons.
  86 static uint32_t getPixel(int x, int y, const SkBitmap& bm) {
  87     uint32_t val = 0;
  88     uint16_t val16;
  89     uint8_t val8;
  90     SkAutoLockPixels lock(bm);
  91     const void* rawAddr = bm.getAddr(x,y);
  92
  93     switch (bm.bytesPerPixel()) {
  94         case 4:
  95             memcpy(&val, rawAddr, sizeof(uint32_t));
  96             break;
  97         case 2:
  98             memcpy(&val16, rawAddr, sizeof(uint16_t));
  99             val = val16;
 100             break;
 101         case 1:
 102             memcpy(&val8, rawAddr, sizeof(uint8_t));
 103             val = val8;
 104             break;
 105         default:
 106             break;
 107     }
 108     return val;
 109 }
 110
 111 // Utility function to set value of any pixel in bm.
 112 // bm.getConfig() specifies what format 'val' must be
 113 // converted to, but at present uint32_t can handle all formats.
 114 static void setPixel(int x, int y, uint32_t val, SkBitmap& bm) {
 115     uint16_t val16;
 116     uint8_t val8;
 117     SkAutoLockPixels lock(bm);
 118     void* rawAddr = bm.getAddr(x,y);
 119
 120     switch (bm.bytesPerPixel()) {
 121         case 4:
 122             memcpy(rawAddr, &val, sizeof(uint32_t));
 123             break;
 124         case 2:
 125             val16 = val & 0xFFFF;
 126             memcpy(rawAddr, &val16, sizeof(uint16_t));
 127             break;
 128         case 1:
 129             val8 = val & 0xFF;
 130             memcpy(rawAddr, &val8, sizeof(uint8_t));
 131             break;
 132         default:
 133             // Ignore.
 134             break;
 135     }
 136 }
 137
 138 // Helper struct to contain pixel locations, while avoiding need for STL.
 139 struct Coordinates {
 140
 141     const int length;
 142     SkIPoint* const data;
 143
 144     explicit Coordinates(int _length): length(_length)
 145                                      , data(new SkIPoint[length]) { }
 146
 147     ~Coordinates(){
 148         delete [] data;
 149     }
 150
 151     SkIPoint* operator[](int i) const {
 152         // Use with care, no bounds checking.
 153         return data + i;
 154     }
 155 };
 156
 157 // A function to verify that two bitmaps contain the same pixel values
 158 // at all coordinates indicated by coords. Simplifies verification of
 159 // copied bitmaps.
 160 static void reportCopyVerification(const SkBitmap& bm1, const SkBitmap& bm2,
 161                             Coordinates& coords,
 162                             const char* msg,
 163                             skiatest::Reporter* reporter){
 164     bool success = true;
 165
 166     // Confirm all pixels in the list match.
 167     for (int i = 0; i < coords.length; ++i) {
 168         success = success &&
 169                   (getPixel(coords[i]->fX, coords[i]->fY, bm1) ==
 170                    getPixel(coords[i]->fX, coords[i]->fY, bm2));
 171     }
 172
 173     if (!success) {
 174         ERRORF(reporter, "%s [colortype = %s]", msg,
 175                gColorTypeName[bm1.colorType()]);
 176     }
 177 }
 178
 179 // Writes unique pixel values at locations specified by coords.
 180 static void writeCoordPixels(SkBitmap& bm, const Coordinates& coords) {
 181     for (int i = 0; i < coords.length; ++i)
 182         setPixel(coords[i]->fX, coords[i]->fY, i, bm);
 183 }
 184
 185 static const Pair gPairs[] = {
 186     { kUnknown_SkColorType,     "000000"  },
 187     { kAlpha_8_SkColorType,     "010101"  },
 188     { kIndex_8_SkColorType,     "011111"  },
 189     { kRGB_565_SkColorType,     "010101"  },
 190     { kARGB_4444_SkColorType,   "010111"  },
 191     { kN32_SkColorType,         "010111"  },
 192 };
 193
 194 static const int W = 20;
 195 static const int H = 33;
 196
 197 static void setup_src_bitmaps(SkBitmap* srcOpaque, SkBitmap* srcPremul,
 198                               SkColorType ct) {
 199     SkColorTable* ctOpaque = NULL;
 200     SkColorTable* ctPremul = NULL;
 201     if (kIndex_8_SkColorType == ct) {
 202         ctOpaque = init_ctable(kOpaque_SkAlphaType);
 203         ctPremul = init_ctable(kPremul_SkAlphaType);
 204     }
 205
 206     srcOpaque->allocPixels(SkImageInfo::Make(W, H, ct, kOpaque_SkAlphaType),
 207                            NULL, ctOpaque);
 208     srcPremul->allocPixels(SkImageInfo::Make(W, H, ct, kPremul_SkAlphaType),
 209                            NULL, ctPremul);
 210     SkSafeUnref(ctOpaque);
 211     SkSafeUnref(ctPremul);
 212     init_src(*srcOpaque);
 213     init_src(*srcPremul);
 214 }
 215
 216 DEF_TEST(BitmapCopy_extractSubset, reporter) {
 217     for (size_t i = 0; i < SK_ARRAY_COUNT(gPairs); i++) {
 218         SkBitmap srcOpaque, srcPremul;
 219         setup_src_bitmaps(&srcOpaque, &srcPremul, gPairs[i].fColorType);
 220
 221         SkBitmap bitmap(srcOpaque);
 222         SkBitmap subset;
 223         SkIRect r;
 224         // Extract a subset which has the same width as the original. This
 225         // catches a bug where we cloned the genID incorrectly.
 226         r.set(0, 1, W, 3);
 227         bitmap.setIsVolatile(true);
 228         // Relies on old behavior of extractSubset failing if colortype is unknown
 229         if (kUnknown_SkColorType != bitmap.colorType() && bitmap.extractSubset(&subset, r)) {
 230             REPORTER_ASSERT(reporter, subset.width() == W);
 231             REPORTER_ASSERT(reporter, subset.height() == 2);
 232             REPORTER_ASSERT(reporter, subset.alphaType() == bitmap.alphaType());
 233             REPORTER_ASSERT(reporter, subset.isVolatile() == true);
 234
 235             // Test copying an extracted subset.
 236             for (size_t j = 0; j < SK_ARRAY_COUNT(gPairs); j++) {
 237                 SkBitmap copy;
 238                 bool success = subset.copyTo(&copy, gPairs[j].fColorType);
 239                 if (!success) {
 240                     // Skip checking that success matches fValid, which is redundant
 241                     // with the code below.
 242                     REPORTER_ASSERT(reporter, gPairs[i].fColorType != gPairs[j].fColorType);
 243                     continue;
 244                 }
 245
 246                 // When performing a copy of an extracted subset, the gen id should
 247                 // change.
 248                 REPORTER_ASSERT(reporter, copy.getGenerationID() != subset.getGenerationID());
 249
 250                 REPORTER_ASSERT(reporter, copy.width() == W);
 251                 REPORTER_ASSERT(reporter, copy.height() == 2);
 252
 253                 if (gPairs[i].fColorType == gPairs[j].fColorType) {
 254                     SkAutoLockPixels alp0(subset);
 255                     SkAutoLockPixels alp1(copy);
 256                     // they should both have, or both not-have, a colortable
 257                     bool hasCT = subset.getColorTable() != NULL;
 258                     REPORTER_ASSERT(reporter, (copy.getColorTable() != NULL) == hasCT);
 259                 }
 260             }
 261         }
 262
 263         bitmap = srcPremul;
 264         bitmap.setIsVolatile(false);
 265         if (bitmap.extractSubset(&subset, r)) {
 266             REPORTER_ASSERT(reporter, subset.alphaType() == bitmap.alphaType());
 267             REPORTER_ASSERT(reporter, subset.isVolatile() == false);
 268         }
 269     }
 270 }
 271
 272 DEF_TEST(BitmapCopy, reporter) {
 273     static const bool isExtracted[] = {
 274         false, true
 275     };
 276
 277     for (size_t i = 0; i < SK_ARRAY_COUNT(gPairs); i++) {
 278         SkBitmap srcOpaque, srcPremul;
 279         setup_src_bitmaps(&srcOpaque, &srcPremul, gPairs[i].fColorType);
 280
 281         for (size_t j = 0; j < SK_ARRAY_COUNT(gPairs); j++) {
 282             SkBitmap dst;
 283
 284             bool success = srcPremul.copyTo(&dst, gPairs[j].fColorType);
 285             bool expected = gPairs[i].fValid[j] != '0';
 286             if (success != expected) {
 287                 ERRORF(reporter, "SkBitmap::copyTo from %s to %s. expected %s "
 288                        "returned %s", gColorTypeName[i], gColorTypeName[j],
 289                        boolStr(expected), boolStr(success));
 290             }
 291
 292             bool canSucceed = srcPremul.canCopyTo(gPairs[j].fColorType);
 293             if (success != canSucceed) {
 294                 ERRORF(reporter, "SkBitmap::copyTo from %s to %s. returned %s "
 295                        "canCopyTo %s", gColorTypeName[i], gColorTypeName[j],
 296                        boolStr(success), boolStr(canSucceed));
 297             }
 298
 299             if (success) {
 300                 REPORTER_ASSERT(reporter, srcPremul.width() == dst.width());
 301                 REPORTER_ASSERT(reporter, srcPremul.height() == dst.height());
 302                 REPORTER_ASSERT(reporter, dst.colorType() == gPairs[j].fColorType);
 303                 test_isOpaque(reporter, srcOpaque, srcPremul, dst.colorType());
 304                 if (srcPremul.colorType() == dst.colorType()) {
 305                     SkAutoLockPixels srcLock(srcPremul);
 306                     SkAutoLockPixels dstLock(dst);
 307                     REPORTER_ASSERT(reporter, srcPremul.readyToDraw());
 308                     REPORTER_ASSERT(reporter, dst.readyToDraw());
 309                     const char* srcP = (const char*)srcPremul.getAddr(0, 0);
 310                     const char* dstP = (const char*)dst.getAddr(0, 0);
 311                     REPORTER_ASSERT(reporter, srcP != dstP);
 312                     REPORTER_ASSERT(reporter, !memcmp(srcP, dstP,
 313                                                       srcPremul.getSize()));
 314                     REPORTER_ASSERT(reporter, srcPremul.getGenerationID() == dst.getGenerationID());
 315                 } else {
 316                     REPORTER_ASSERT(reporter, srcPremul.getGenerationID() != dst.getGenerationID());
 317                 }
 318             } else {
 319                 // dst should be unchanged from its initial state
 320                 REPORTER_ASSERT(reporter, dst.colorType() == kUnknown_SkColorType);
 321                 REPORTER_ASSERT(reporter, dst.width() == 0);
 322                 REPORTER_ASSERT(reporter, dst.height() == 0);
 323             }
 324         } // for (size_t j = ...
 325
 326         // Tests for getSafeSize(), getSafeSize64(), copyPixelsTo(),
 327         // copyPixelsFrom().
 328         //
 329         for (size_t copyCase = 0; copyCase < SK_ARRAY_COUNT(isExtracted);
 330              ++copyCase) {
 331             // Test copying to/from external buffer.
 332             // Note: the tests below have hard-coded values ---
 333             //       Please take care if modifying.
 334
 335             // Tests for getSafeSize64().
 336             // Test with a very large configuration without pixel buffer
 337             // attached.
 338             SkBitmap tstSafeSize;
 339             tstSafeSize.setInfo(SkImageInfo::Make(100000000U, 100000000U,
 340                                                   gPairs[i].fColorType, kPremul_SkAlphaType));
 341             int64_t safeSize = tstSafeSize.computeSafeSize64();
 342             if (safeSize < 0) {
 343                 ERRORF(reporter, "getSafeSize64() negative: %s",
 344                        gColorTypeName[tstSafeSize.colorType()]);
 345             }
 346             bool sizeFail = false;
 347             // Compare against hand-computed values.
 348             switch (gPairs[i].fColorType) {
 349                 case kUnknown_SkColorType:
 350                     break;
 351
 352                 case kAlpha_8_SkColorType:
 353                 case kIndex_8_SkColorType:
 354                     if (safeSize != 0x2386F26FC10000LL) {
 355                         sizeFail = true;
 356                     }
 357                     break;
 358
 359                 case kRGB_565_SkColorType:
 360                 case kARGB_4444_SkColorType:
 361                     if (safeSize != 0x470DE4DF820000LL) {
 362                         sizeFail = true;
 363                     }
 364                     break;
 365
 366                 case kN32_SkColorType:
 367                     if (safeSize != 0x8E1BC9BF040000LL) {
 368                         sizeFail = true;
 369                     }
 370                     break;
 371
 372                 default:
 373                     break;
 374             }
 375             if (sizeFail) {
 376                 ERRORF(reporter, "computeSafeSize64() wrong size: %s",
 377                        gColorTypeName[tstSafeSize.colorType()]);
 378             }
 379
 380             int subW = 2;
 381             int subH = 2;
 382
 383             // Create bitmap to act as source for copies and subsets.
 384             SkBitmap src, subset;
 385             SkColorTable* ct = NULL;
 386             if (kIndex_8_SkColorType == src.colorType()) {
 387                 ct = init_ctable(kPremul_SkAlphaType);
 388             }
 389
 390             int localSubW;
 391             if (isExtracted[copyCase]) { // A larger image to extract from.
 392                 localSubW = 2 * subW + 1;
 393             } else { // Tests expect a 2x2 bitmap, so make smaller.
 394                 localSubW = subW;
 395             }
 396             // could fail if we pass kIndex_8 for the colortype
 397             if (src.tryAllocPixels(SkImageInfo::Make(localSubW, subH, gPairs[i].fColorType,
 398                                                      kPremul_SkAlphaType))) {
 399                 // failure is fine, as we will notice later on
 400             }
 401             SkSafeUnref(ct);
 402
 403             // Either copy src or extract into 'subset', which is used
 404             // for subsequent calls to copyPixelsTo/From.
 405             bool srcReady = false;
 406             // Test relies on older behavior that extractSubset will fail on
 407             // kUnknown_SkColorType
 408             if (kUnknown_SkColorType != src.colorType() &&
 409                 isExtracted[copyCase]) {
 410                 // The extractedSubset() test case allows us to test copy-
 411                 // ing when src and dst mave possibly different strides.
 412                 SkIRect r;
 413                 r.set(1, 0, 1 + subW, subH); // 2x2 extracted bitmap
 414
 415                 srcReady = src.extractSubset(&subset, r);
 416             } else {
 417                 srcReady = src.copyTo(&subset);
 418             }
 419
 420             // Not all configurations will generate a valid 'subset'.
 421             if (srcReady) {
 422
 423                 // Allocate our target buffer 'buf' for all copies.
 424                 // To simplify verifying correctness of copies attach
 425                 // buf to a SkBitmap, but copies are done using the
 426                 // raw buffer pointer.
 427                 const size_t bufSize = subH *
 428                     SkColorTypeMinRowBytes(src.colorType(), subW) * 2;
 429                 SkAutoMalloc autoBuf (bufSize);
 430                 uint8_t* buf = static_cast<uint8_t*>(autoBuf.get());
 431
 432                 SkBitmap bufBm; // Attach buf to this bitmap.
 433                 bool successExpected;
 434
 435                 // Set up values for each pixel being copied.
 436                 Coordinates coords(subW * subH);
 437                 for (int x = 0; x < subW; ++x)
 438                     for (int y = 0; y < subH; ++y)
 439                     {
 440                         int index = y * subW + x;
 441                         SkASSERT(index < coords.length);
 442                         coords[index]->fX = x;
 443                         coords[index]->fY = y;
 444                     }
 445
 446                 writeCoordPixels(subset, coords);
 447
 448                 // Test #1 ////////////////////////////////////////////
 449
 450                 const SkImageInfo info = SkImageInfo::Make(subW, subH,
 451                                                            gPairs[i].fColorType,
 452                                                            kPremul_SkAlphaType);
 453                 // Before/after comparisons easier if we attach buf
 454                 // to an appropriately configured SkBitmap.
 455                 memset(buf, 0xFF, bufSize);
 456                 // Config with stride greater than src but that fits in buf.
 457                 bufBm.installPixels(info, buf, info.minRowBytes() * 2);
 458                 successExpected = false;
 459                 // Then attempt to copy with a stride that is too large
 460                 // to fit in the buffer.
 461                 REPORTER_ASSERT(reporter,
 462                     subset.copyPixelsTo(buf, bufSize, bufBm.rowBytes() * 3)
 463                     == successExpected);
 464
 465                 if (successExpected)
 466                     reportCopyVerification(subset, bufBm, coords,
 467                         "copyPixelsTo(buf, bufSize, 1.5*maxRowBytes)",
 468                         reporter);
 469
 470                 // Test #2 ////////////////////////////////////////////
 471                 // This test should always succeed, but in the case
 472                 // of extracted bitmaps only because we handle the
 473                 // issue of getSafeSize(). Without getSafeSize()
 474                 // buffer overrun/read would occur.
 475                 memset(buf, 0xFF, bufSize);
 476                 bufBm.installPixels(info, buf, subset.rowBytes());
 477                 successExpected = subset.getSafeSize() <= bufSize;
 478                 REPORTER_ASSERT(reporter,
 479                     subset.copyPixelsTo(buf, bufSize) ==
 480                         successExpected);
 481                 if (successExpected)
 482                     reportCopyVerification(subset, bufBm, coords,
 483                     "copyPixelsTo(buf, bufSize)", reporter);
 484
 485                 // Test #3 ////////////////////////////////////////////
 486                 // Copy with different stride between src and dst.
 487                 memset(buf, 0xFF, bufSize);
 488                 bufBm.installPixels(info, buf, subset.rowBytes()+1);
 489                 successExpected = true; // Should always work.
 490                 REPORTER_ASSERT(reporter,
 491                         subset.copyPixelsTo(buf, bufSize,
 492                             subset.rowBytes()+1) == successExpected);
 493                 if (successExpected)
 494                     reportCopyVerification(subset, bufBm, coords,
 495                     "copyPixelsTo(buf, bufSize, rowBytes+1)", reporter);
 496
 497                 // Test #4 ////////////////////////////////////////////
 498                 // Test copy with stride too small.
 499                 memset(buf, 0xFF, bufSize);
 500                 bufBm.installPixels(info, buf, info.minRowBytes());
 501                 successExpected = false;
 502                 // Request copy with stride too small.
 503                 REPORTER_ASSERT(reporter,
 504                     subset.copyPixelsTo(buf, bufSize, bufBm.rowBytes()-1)
 505                         == successExpected);
 506                 if (successExpected)
 507                     reportCopyVerification(subset, bufBm, coords,
 508                     "copyPixelsTo(buf, bufSize, rowBytes()-1)", reporter);
 509
 510 #if 0   // copyPixelsFrom is gone
 511                 // Test #5 ////////////////////////////////////////////
 512                 // Tests the case where the source stride is too small
 513                 // for the source configuration.
 514                 memset(buf, 0xFF, bufSize);
 515                 bufBm.installPixels(info, buf, info.minRowBytes());
 516                 writeCoordPixels(bufBm, coords);
 517                 REPORTER_ASSERT(reporter,
 518                     subset.copyPixelsFrom(buf, bufSize, 1) == false);
 519
 520                 // Test #6 ///////////////////////////////////////////
 521                 // Tests basic copy from an external buffer to the bitmap.
 522                 // If the bitmap is "extracted", this also tests the case
 523                 // where the source stride is different from the dest.
 524                 // stride.
 525                 // We've made the buffer large enough to always succeed.
 526                 bufBm.installPixels(info, buf, info.minRowBytes());
 527                 writeCoordPixels(bufBm, coords);
 528                 REPORTER_ASSERT(reporter,
 529                     subset.copyPixelsFrom(buf, bufSize, bufBm.rowBytes()) ==
 530                         true);
 531                 reportCopyVerification(bufBm, subset, coords,
 532                     "copyPixelsFrom(buf, bufSize)",
 533                     reporter);
 534
 535                 // Test #7 ////////////////////////////////////////////
 536                 // Tests the case where the source buffer is too small
 537                 // for the transfer.
 538                 REPORTER_ASSERT(reporter,
 539                     subset.copyPixelsFrom(buf, 1, subset.rowBytes()) ==
 540                         false);
 541
 542 #endif
 543             }
 544         } // for (size_t copyCase ...
 545     }
 546 }
 547
 548 #include "SkColorPriv.h"
 549 #include "SkUtils.h"
 550
 551 /**
 552  *  Construct 4x4 pixels where we can look at a color and determine where it should be in the grid.
 553  *  alpha = 0xFF, blue = 0x80, red = x, green = y
 554  */
 555 static void fill_4x4_pixels(SkPMColor colors[16]) {
 556     for (int y = 0; y < 4; ++y) {
 557         for (int x = 0; x < 4; ++x) {
 558             colors[y*4+x] = SkPackARGB32(0xFF, x, y, 0x80);
 559         }
 560     }
 561 }
 562
 563 static bool check_4x4_pixel(SkPMColor color, unsigned x, unsigned y) {
 564     SkASSERT(x < 4 && y < 4);
 565     return  0xFF == SkGetPackedA32(color) &&
 566             x    == SkGetPackedR32(color) &&
 567             y    == SkGetPackedG32(color) &&
 568             0x80 == SkGetPackedB32(color);
 569 }
 570
 571 /**
 572  *  Fill with all zeros, which will never match any value from fill_4x4_pixels
 573  */
 574 static void clear_4x4_pixels(SkPMColor colors[16]) {
 575     sk_memset32(colors, 0, 16);
 576 }
 577
 578 // Much of readPixels is exercised by copyTo testing, since readPixels is the backend for that
 579 // method. Here we explicitly test subset copies.
 580 //
 581 DEF_TEST(BitmapReadPixels, reporter) {
 582     const int W = 4;
 583     const int H = 4;
 584     const size_t rowBytes = W * sizeof(SkPMColor);
 585     const SkImageInfo srcInfo = SkImageInfo::MakeN32Premul(W, H);
 586     SkPMColor srcPixels[16];
 587     fill_4x4_pixels(srcPixels);
 588     SkBitmap srcBM;
 589     srcBM.installPixels(srcInfo, srcPixels, rowBytes);
 590
 591     SkImageInfo dstInfo = SkImageInfo::MakeN32Premul(W, H);
 592     SkPMColor dstPixels[16];
 593
 594     const struct {
 595         bool     fExpectedSuccess;
 596         SkIPoint fRequestedSrcLoc;
 597         SkISize  fRequestedDstSize;
 598         // If fExpectedSuccess, check these, otherwise ignore
 599         SkIPoint fExpectedDstLoc;
 600         SkIRect  fExpectedSrcR;
 601     } gRec[] = {
 602         { true,  { 0, 0 }, { 4, 4 }, { 0, 0 }, { 0, 0, 4, 4 } },
 603         { true,  { 1, 1 }, { 2, 2 }, { 0, 0 }, { 1, 1, 3, 3 } },
 604         { true,  { 2, 2 }, { 4, 4 }, { 0, 0 }, { 2, 2, 4, 4 } },
 605         { true,  {-1,-1 }, { 2, 2 }, { 1, 1 }, { 0, 0, 1, 1 } },
 606         { false, {-1,-1 }, { 1, 1 }, { 0, 0 }, { 0, 0, 0, 0 } },
 607     };
 608
 609     for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) {
 610         clear_4x4_pixels(dstPixels);
 611
 612         dstInfo = dstInfo.makeWH(gRec[i].fRequestedDstSize.width(),
 613                                  gRec[i].fRequestedDstSize.height());
 614         bool success = srcBM.readPixels(dstInfo, dstPixels, rowBytes,
 615                                         gRec[i].fRequestedSrcLoc.x(), gRec[i].fRequestedSrcLoc.y());
 616
 617         REPORTER_ASSERT(reporter, gRec[i].fExpectedSuccess == success);
 618         if (success) {
 619             const SkIRect srcR = gRec[i].fExpectedSrcR;
 620             const int dstX = gRec[i].fExpectedDstLoc.x();
 621             const int dstY = gRec[i].fExpectedDstLoc.y();
 622             // Walk the dst pixels, and check if we got what we expected
 623             for (int y = 0; y < H; ++y) {
 624                 for (int x = 0; x < W; ++x) {
 625                     SkPMColor dstC = dstPixels[y*4+x];
 626                     // get into src coordinates
 627                     int sx = x - dstX + srcR.x();
 628                     int sy = y - dstY + srcR.y();
 629                     if (srcR.contains(sx, sy)) {
 630                         REPORTER_ASSERT(reporter, check_4x4_pixel(dstC, sx, sy));
 631                     } else {
 632                         REPORTER_ASSERT(reporter, 0 == dstC);
 633                     }
 634                 }
 635             }
 636         }
 637     }
 638 }
 639