James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 1 | // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | #include <algorithm> |
| 6 | #include <cmath> |
| 7 | #include <iomanip> |
| 8 | #include <vector> |
| 9 | |
| 10 | #include "base/basictypes.h" |
| 11 | #include "base/compiler_specific.h" |
| 12 | #include "base/files/file_util.h" |
| 13 | #include "base/strings/string_util.h" |
| 14 | #include "skia/ext/image_operations.h" |
| 15 | #include "testing/gtest/include/gtest/gtest.h" |
| 16 | #include "third_party/skia/include/core/SkBitmap.h" |
| 17 | #include "third_party/skia/include/core/SkRect.h" |
| 18 | #include "ui/gfx/codec/png_codec.h" |
Nick Bray | 27a3f6e | 2015-01-08 16:39:35 -0800 | [diff] [blame] | 19 | #include "ui/gfx/geometry/size.h" |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 20 | |
| 21 | namespace { |
| 22 | |
| 23 | // Computes the average pixel value for the given range, inclusive. |
| 24 | uint32_t AveragePixel(const SkBitmap& bmp, |
| 25 | int x_min, int x_max, |
| 26 | int y_min, int y_max) { |
| 27 | float accum[4] = {0, 0, 0, 0}; |
| 28 | int count = 0; |
| 29 | for (int y = y_min; y <= y_max; y++) { |
| 30 | for (int x = x_min; x <= x_max; x++) { |
| 31 | uint32_t cur = *bmp.getAddr32(x, y); |
| 32 | accum[0] += SkColorGetB(cur); |
| 33 | accum[1] += SkColorGetG(cur); |
| 34 | accum[2] += SkColorGetR(cur); |
| 35 | accum[3] += SkColorGetA(cur); |
| 36 | count++; |
| 37 | } |
| 38 | } |
| 39 | |
| 40 | return SkColorSetARGB(static_cast<unsigned char>(accum[3] / count), |
| 41 | static_cast<unsigned char>(accum[2] / count), |
| 42 | static_cast<unsigned char>(accum[1] / count), |
| 43 | static_cast<unsigned char>(accum[0] / count)); |
| 44 | } |
| 45 | |
| 46 | // Computes the average pixel (/color) value for the given colors. |
| 47 | SkColor AveragePixel(const SkColor colors[], size_t color_count) { |
| 48 | float accum[4] = { 0.0f, 0.0f, 0.0f, 0.0f }; |
| 49 | for (size_t i = 0; i < color_count; ++i) { |
| 50 | const SkColor cur = colors[i]; |
| 51 | accum[0] += static_cast<float>(SkColorGetA(cur)); |
| 52 | accum[1] += static_cast<float>(SkColorGetR(cur)); |
| 53 | accum[2] += static_cast<float>(SkColorGetG(cur)); |
| 54 | accum[3] += static_cast<float>(SkColorGetB(cur)); |
| 55 | } |
| 56 | const SkColor average_color = |
| 57 | SkColorSetARGB(static_cast<uint8_t>(accum[0] / color_count), |
| 58 | static_cast<uint8_t>(accum[1] / color_count), |
| 59 | static_cast<uint8_t>(accum[2] / color_count), |
| 60 | static_cast<uint8_t>(accum[3] / color_count)); |
| 61 | return average_color; |
| 62 | } |
| 63 | |
| 64 | void PrintPixel(const SkBitmap& bmp, |
| 65 | int x_min, int x_max, |
| 66 | int y_min, int y_max) { |
| 67 | char str[128]; |
| 68 | |
| 69 | for (int y = y_min; y <= y_max; ++y) { |
| 70 | for (int x = x_min; x <= x_max; ++x) { |
| 71 | const uint32_t cur = *bmp.getAddr32(x, y); |
| 72 | base::snprintf(str, sizeof(str), "bmp[%d,%d] = %08X", x, y, cur); |
| 73 | ADD_FAILURE() << str; |
| 74 | } |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | // Returns the euclidian distance between two RGBA colors interpreted |
| 79 | // as 4-components vectors. |
| 80 | // |
| 81 | // Notes: |
| 82 | // - This is a really poor definition of color distance. Yet it |
| 83 | // is "good enough" for our uses here. |
| 84 | // - More realistic measures like the various Delta E formulas defined |
| 85 | // by CIE are way more complex and themselves require the RGBA to |
| 86 | // to transformed into CIELAB (typically via sRGB first). |
| 87 | // - The static_cast<int> below are needed to avoid interpreting "negative" |
| 88 | // differences as huge positive values. |
| 89 | float ColorsEuclidianDistance(const SkColor a, const SkColor b) { |
| 90 | int b_int_diff = static_cast<int>(SkColorGetB(a) - SkColorGetB(b)); |
| 91 | int g_int_diff = static_cast<int>(SkColorGetG(a) - SkColorGetG(b)); |
| 92 | int r_int_diff = static_cast<int>(SkColorGetR(a) - SkColorGetR(b)); |
| 93 | int a_int_diff = static_cast<int>(SkColorGetA(a) - SkColorGetA(b)); |
| 94 | |
| 95 | float b_float_diff = static_cast<float>(b_int_diff); |
| 96 | float g_float_diff = static_cast<float>(g_int_diff); |
| 97 | float r_float_diff = static_cast<float>(r_int_diff); |
| 98 | float a_float_diff = static_cast<float>(a_int_diff); |
| 99 | |
| 100 | return sqrtf((b_float_diff * b_float_diff) + (g_float_diff * g_float_diff) + |
| 101 | (r_float_diff * r_float_diff) + (a_float_diff * a_float_diff)); |
| 102 | } |
| 103 | |
| 104 | // Returns true if each channel of the given two colors are "close." This is |
| 105 | // used for comparing colors where rounding errors may cause off-by-one. |
| 106 | bool ColorsClose(uint32_t a, uint32_t b) { |
| 107 | return abs(static_cast<int>(SkColorGetB(a) - SkColorGetB(b))) < 2 && |
| 108 | abs(static_cast<int>(SkColorGetG(a) - SkColorGetG(b))) < 2 && |
| 109 | abs(static_cast<int>(SkColorGetR(a) - SkColorGetR(b))) < 2 && |
| 110 | abs(static_cast<int>(SkColorGetA(a) - SkColorGetA(b))) < 2; |
| 111 | } |
| 112 | |
| 113 | void FillDataToBitmap(int w, int h, SkBitmap* bmp) { |
| 114 | bmp->allocN32Pixels(w, h); |
| 115 | |
| 116 | for (int y = 0; y < h; ++y) { |
| 117 | for (int x = 0; x < w; ++x) { |
| 118 | const uint8_t component = static_cast<uint8_t>(y * w + x); |
| 119 | const SkColor pixel = SkColorSetARGB(component, component, |
| 120 | component, component); |
| 121 | *bmp->getAddr32(x, y) = pixel; |
| 122 | } |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | // Draws a horizontal and vertical grid into the w x h bitmap passed in. |
| 127 | // Each line in the grid is drawn with a width of "grid_width" pixels, |
| 128 | // and those lines repeat every "grid_pitch" pixels. The top left pixel (0, 0) |
| 129 | // is considered to be part of a grid line. |
| 130 | // The pixels that fall on a line are colored with "grid_color", while those |
| 131 | // outside of the lines are colored in "background_color". |
| 132 | // Note that grid_with can be greather than or equal to grid_pitch, in which |
| 133 | // case the resulting bitmap will be a solid color "grid_color". |
| 134 | void DrawGridToBitmap(int w, int h, |
| 135 | SkColor background_color, SkColor grid_color, |
| 136 | int grid_pitch, int grid_width, |
| 137 | SkBitmap* bmp) { |
| 138 | ASSERT_GT(grid_pitch, 0); |
| 139 | ASSERT_GT(grid_width, 0); |
| 140 | ASSERT_NE(background_color, grid_color); |
| 141 | |
| 142 | bmp->allocN32Pixels(w, h); |
| 143 | |
| 144 | for (int y = 0; y < h; ++y) { |
| 145 | bool y_on_grid = ((y % grid_pitch) < grid_width); |
| 146 | |
| 147 | for (int x = 0; x < w; ++x) { |
| 148 | bool on_grid = (y_on_grid || ((x % grid_pitch) < grid_width)); |
| 149 | |
| 150 | *bmp->getAddr32(x, y) = (on_grid ? grid_color : background_color); |
| 151 | } |
| 152 | } |
| 153 | } |
| 154 | |
| 155 | // Draws a checkerboard pattern into the w x h bitmap passed in. |
| 156 | // Each rectangle is rect_w in width, rect_h in height. |
| 157 | // The colors alternate between color1 and color2, color1 being used |
| 158 | // in the rectangle at the top left corner. |
| 159 | void DrawCheckerToBitmap(int w, int h, |
| 160 | SkColor color1, SkColor color2, |
| 161 | int rect_w, int rect_h, |
| 162 | SkBitmap* bmp) { |
| 163 | ASSERT_GT(rect_w, 0); |
| 164 | ASSERT_GT(rect_h, 0); |
| 165 | ASSERT_NE(color1, color2); |
| 166 | |
| 167 | bmp->allocN32Pixels(w, h); |
| 168 | |
| 169 | for (int y = 0; y < h; ++y) { |
| 170 | bool y_bit = (((y / rect_h) & 0x1) == 0); |
| 171 | |
| 172 | for (int x = 0; x < w; ++x) { |
| 173 | bool x_bit = (((x / rect_w) & 0x1) == 0); |
| 174 | |
| 175 | bool use_color2 = (x_bit != y_bit); // xor |
| 176 | |
| 177 | *bmp->getAddr32(x, y) = (use_color2 ? color2 : color1); |
| 178 | } |
| 179 | } |
| 180 | } |
| 181 | |
| 182 | // DEBUG_BITMAP_GENERATION (0 or 1) controls whether the routines |
| 183 | // to save the test bitmaps are present. By default the test just fails |
| 184 | // without reading/writing files but it is then convenient to have |
| 185 | // a simple way to make the failing tests write out the input/output images |
| 186 | // to check them visually. |
| 187 | #define DEBUG_BITMAP_GENERATION (0) |
| 188 | |
| 189 | #if DEBUG_BITMAP_GENERATION |
| 190 | void SaveBitmapToPNG(const SkBitmap& bmp, const char* path) { |
| 191 | SkAutoLockPixels lock(bmp); |
| 192 | std::vector<unsigned char> png; |
| 193 | gfx::PNGCodec::ColorFormat color_format = gfx::PNGCodec::FORMAT_RGBA; |
| 194 | if (!gfx::PNGCodec::Encode( |
| 195 | reinterpret_cast<const unsigned char*>(bmp.getPixels()), |
| 196 | color_format, gfx::Size(bmp.width(), bmp.height()), |
| 197 | static_cast<int>(bmp.rowBytes()), |
| 198 | false, std::vector<gfx::PNGCodec::Comment>(), &png)) { |
| 199 | FAIL() << "Failed to encode image"; |
| 200 | } |
| 201 | |
| 202 | const base::FilePath fpath(path); |
| 203 | const int num_written = |
| 204 | base::WriteFile(fpath, reinterpret_cast<const char*>(&png[0]), |
| 205 | png.size()); |
| 206 | if (num_written != static_cast<int>(png.size())) { |
| 207 | FAIL() << "Failed to write dest \"" << path << '"'; |
| 208 | } |
| 209 | } |
| 210 | #endif // #if DEBUG_BITMAP_GENERATION |
| 211 | |
| 212 | void CheckResampleToSame(skia::ImageOperations::ResizeMethod method) { |
| 213 | // Make our source bitmap. |
| 214 | const int src_w = 16, src_h = 34; |
| 215 | SkBitmap src; |
| 216 | FillDataToBitmap(src_w, src_h, &src); |
| 217 | |
| 218 | // Do a resize of the full bitmap to the same size. The lanczos filter is good |
| 219 | // enough that we should get exactly the same image for output. |
| 220 | SkBitmap results = skia::ImageOperations::Resize(src, method, src_w, src_h); |
| 221 | ASSERT_EQ(src_w, results.width()); |
| 222 | ASSERT_EQ(src_h, results.height()); |
| 223 | |
| 224 | SkAutoLockPixels src_lock(src); |
| 225 | SkAutoLockPixels results_lock(results); |
| 226 | for (int y = 0; y < src_h; y++) { |
| 227 | for (int x = 0; x < src_w; x++) { |
| 228 | EXPECT_EQ(*src.getAddr32(x, y), *results.getAddr32(x, y)); |
| 229 | } |
| 230 | } |
| 231 | } |
| 232 | |
| 233 | // Types defined outside of the ResizeShouldAverageColors test to allow |
| 234 | // use of the arraysize() macro. |
| 235 | // |
| 236 | // 'max_color_distance_override' is used in a max() call together with |
| 237 | // the value of 'max_color_distance' defined in a TestedPixel instance. |
| 238 | // Hence a value of 0.0 in 'max_color_distance_override' means |
| 239 | // "use the pixel-specific value" and larger values can be used to allow |
| 240 | // worse computation errors than provided in a TestedPixel instance. |
| 241 | struct TestedResizeMethod { |
| 242 | skia::ImageOperations::ResizeMethod method; |
| 243 | const char* name; |
| 244 | float max_color_distance_override; |
| 245 | }; |
| 246 | |
| 247 | struct TestedPixel { |
| 248 | int x; |
| 249 | int y; |
| 250 | float max_color_distance; |
| 251 | const char* name; |
| 252 | }; |
| 253 | |
| 254 | // Helper function used by the test "ResizeShouldAverageColors" below. |
| 255 | // Note that ASSERT_EQ does a "return;" on failure, hence we can't have |
| 256 | // a "bool" return value to reflect success. Hence "all_pixels_pass" |
| 257 | void CheckResizeMethodShouldAverageGrid( |
| 258 | const SkBitmap& src, |
| 259 | const TestedResizeMethod& tested_method, |
| 260 | int dest_w, int dest_h, SkColor average_color, |
| 261 | bool* method_passed) { |
| 262 | *method_passed = false; |
| 263 | |
| 264 | const TestedPixel tested_pixels[] = { |
| 265 | // Corners |
| 266 | { 0, 0, 2.3f, "Top left corner" }, |
| 267 | { 0, dest_h - 1, 2.3f, "Bottom left corner" }, |
| 268 | { dest_w - 1, 0, 2.3f, "Top right corner" }, |
| 269 | { dest_w - 1, dest_h - 1, 2.3f, "Bottom right corner" }, |
| 270 | // Middle points of each side |
| 271 | { dest_w / 2, 0, 1.0f, "Top middle" }, |
| 272 | { dest_w / 2, dest_h - 1, 1.0f, "Bottom middle" }, |
| 273 | { 0, dest_h / 2, 1.0f, "Left middle" }, |
| 274 | { dest_w - 1, dest_h / 2, 1.0f, "Right middle" }, |
| 275 | // Center |
| 276 | { dest_w / 2, dest_h / 2, 1.0f, "Center" } |
| 277 | }; |
| 278 | |
| 279 | // Resize the src |
| 280 | const skia::ImageOperations::ResizeMethod method = tested_method.method; |
| 281 | |
| 282 | SkBitmap dest = skia::ImageOperations::Resize(src, method, dest_w, dest_h); |
| 283 | ASSERT_EQ(dest_w, dest.width()); |
| 284 | ASSERT_EQ(dest_h, dest.height()); |
| 285 | |
| 286 | // Check that pixels match the expected average. |
| 287 | float max_observed_distance = 0.0f; |
| 288 | bool all_pixels_ok = true; |
| 289 | |
| 290 | SkAutoLockPixels dest_lock(dest); |
| 291 | |
| 292 | for (size_t pixel_index = 0; |
| 293 | pixel_index < arraysize(tested_pixels); |
| 294 | ++pixel_index) { |
| 295 | const TestedPixel& tested_pixel = tested_pixels[pixel_index]; |
| 296 | |
| 297 | const int x = tested_pixel.x; |
| 298 | const int y = tested_pixel.y; |
| 299 | const float max_allowed_distance = |
| 300 | std::max(tested_pixel.max_color_distance, |
| 301 | tested_method.max_color_distance_override); |
| 302 | |
| 303 | const SkColor actual_color = *dest.getAddr32(x, y); |
| 304 | |
| 305 | // Check that the pixels away from the border region are very close |
| 306 | // to the expected average color |
| 307 | float distance = ColorsEuclidianDistance(average_color, actual_color); |
| 308 | |
| 309 | EXPECT_LE(distance, max_allowed_distance) |
| 310 | << "Resizing method: " << tested_method.name |
| 311 | << ", pixel tested: " << tested_pixel.name |
| 312 | << "(" << x << ", " << y << ")" |
| 313 | << std::hex << std::showbase |
| 314 | << ", expected (avg) hex: " << average_color |
| 315 | << ", actual hex: " << actual_color; |
| 316 | |
| 317 | if (distance > max_allowed_distance) { |
| 318 | all_pixels_ok = false; |
| 319 | } |
| 320 | if (distance > max_observed_distance) { |
| 321 | max_observed_distance = distance; |
| 322 | } |
| 323 | } |
| 324 | |
| 325 | if (!all_pixels_ok) { |
| 326 | ADD_FAILURE() << "Maximum observed color distance for method " |
| 327 | << tested_method.name << ": " << max_observed_distance; |
| 328 | |
| 329 | #if DEBUG_BITMAP_GENERATION |
| 330 | char path[128]; |
| 331 | base::snprintf(path, sizeof(path), |
| 332 | "/tmp/ResizeShouldAverageColors_%s_dest.png", |
| 333 | tested_method.name); |
| 334 | SaveBitmapToPNG(dest, path); |
| 335 | #endif // #if DEBUG_BITMAP_GENERATION |
| 336 | } |
| 337 | |
| 338 | *method_passed = all_pixels_ok; |
| 339 | } |
| 340 | |
| 341 | |
| 342 | } // namespace |
| 343 | |
| 344 | // Helper tests that saves bitmaps to PNGs in /tmp/ to visually check |
| 345 | // that the bitmap generation functions work as expected. |
| 346 | // Those tests are not enabled by default as verification is done |
| 347 | // manually/visually, however it is convenient to leave the functions |
| 348 | // in place. |
| 349 | #if 0 && DEBUG_BITMAP_GENERATION |
| 350 | TEST(ImageOperations, GenerateGradientBitmap) { |
| 351 | // Make our source bitmap. |
| 352 | const int src_w = 640, src_h = 480; |
| 353 | SkBitmap src; |
| 354 | FillDataToBitmap(src_w, src_h, &src); |
| 355 | |
| 356 | SaveBitmapToPNG(src, "/tmp/gradient_640x480.png"); |
| 357 | } |
| 358 | |
| 359 | TEST(ImageOperations, GenerateGridBitmap) { |
| 360 | const int src_w = 640, src_h = 480, src_grid_pitch = 10, src_grid_width = 4; |
| 361 | const SkColor grid_color = SK_ColorRED, background_color = SK_ColorBLUE; |
| 362 | SkBitmap src; |
| 363 | DrawGridToBitmap(src_w, src_h, |
| 364 | background_color, grid_color, |
| 365 | src_grid_pitch, src_grid_width, |
| 366 | &src); |
| 367 | |
| 368 | SaveBitmapToPNG(src, "/tmp/grid_640x408_10_4_red_blue.png"); |
| 369 | } |
| 370 | |
| 371 | TEST(ImageOperations, GenerateCheckerBitmap) { |
| 372 | const int src_w = 640, src_h = 480, rect_w = 10, rect_h = 4; |
| 373 | const SkColor color1 = SK_ColorRED, color2 = SK_ColorBLUE; |
| 374 | SkBitmap src; |
| 375 | DrawCheckerToBitmap(src_w, src_h, color1, color2, rect_w, rect_h, &src); |
| 376 | |
| 377 | SaveBitmapToPNG(src, "/tmp/checker_640x408_10_4_red_blue.png"); |
| 378 | } |
| 379 | #endif // #if ... && DEBUG_BITMAP_GENERATION |
| 380 | |
| 381 | // Makes the bitmap 50% the size as the original using a box filter. This is |
| 382 | // an easy operation that we can check the results for manually. |
| 383 | TEST(ImageOperations, Halve) { |
| 384 | // Make our source bitmap. |
| 385 | int src_w = 30, src_h = 38; |
| 386 | SkBitmap src; |
| 387 | FillDataToBitmap(src_w, src_h, &src); |
| 388 | |
| 389 | // Do a halving of the full bitmap. |
| 390 | SkBitmap actual_results = skia::ImageOperations::Resize( |
| 391 | src, skia::ImageOperations::RESIZE_BOX, src_w / 2, src_h / 2); |
| 392 | ASSERT_EQ(src_w / 2, actual_results.width()); |
| 393 | ASSERT_EQ(src_h / 2, actual_results.height()); |
| 394 | |
| 395 | // Compute the expected values & compare. |
| 396 | SkAutoLockPixels lock(actual_results); |
| 397 | for (int y = 0; y < actual_results.height(); y++) { |
| 398 | for (int x = 0; x < actual_results.width(); x++) { |
| 399 | // Note that those expressions take into account the "half-pixel" |
| 400 | // offset that comes into play due to considering the coordinates |
| 401 | // of the center of the pixels. So x * 2 is a simplification |
| 402 | // of ((x+0.5) * 2 - 1) and (x * 2 + 1) is really (x + 0.5) * 2. |
| 403 | int first_x = x * 2; |
| 404 | int last_x = std::min(src_w - 1, x * 2 + 1); |
| 405 | |
| 406 | int first_y = y * 2; |
| 407 | int last_y = std::min(src_h - 1, y * 2 + 1); |
| 408 | |
| 409 | const uint32_t expected_color = AveragePixel(src, |
| 410 | first_x, last_x, |
| 411 | first_y, last_y); |
| 412 | const uint32_t actual_color = *actual_results.getAddr32(x, y); |
| 413 | const bool close = ColorsClose(expected_color, actual_color); |
| 414 | EXPECT_TRUE(close); |
| 415 | if (!close) { |
| 416 | char str[128]; |
| 417 | base::snprintf(str, sizeof(str), |
| 418 | "exp[%d,%d] = %08X, actual[%d,%d] = %08X", |
| 419 | x, y, expected_color, x, y, actual_color); |
| 420 | ADD_FAILURE() << str; |
| 421 | PrintPixel(src, first_x, last_x, first_y, last_y); |
| 422 | } |
| 423 | } |
| 424 | } |
| 425 | } |
| 426 | |
| 427 | TEST(ImageOperations, HalveSubset) { |
| 428 | // Make our source bitmap. |
| 429 | int src_w = 16, src_h = 34; |
| 430 | SkBitmap src; |
| 431 | FillDataToBitmap(src_w, src_h, &src); |
| 432 | |
| 433 | // Do a halving of the full bitmap. |
| 434 | SkBitmap full_results = skia::ImageOperations::Resize( |
| 435 | src, skia::ImageOperations::RESIZE_BOX, src_w / 2, src_h / 2); |
| 436 | ASSERT_EQ(src_w / 2, full_results.width()); |
| 437 | ASSERT_EQ(src_h / 2, full_results.height()); |
| 438 | |
| 439 | // Now do a halving of a a subset, recall the destination subset is in the |
| 440 | // destination coordinate system (max = half of the original image size). |
| 441 | SkIRect subset_rect = { 2, 3, 3, 6 }; |
| 442 | SkBitmap subset_results = skia::ImageOperations::Resize( |
| 443 | src, skia::ImageOperations::RESIZE_BOX, |
| 444 | src_w / 2, src_h / 2, subset_rect); |
| 445 | ASSERT_EQ(subset_rect.width(), subset_results.width()); |
| 446 | ASSERT_EQ(subset_rect.height(), subset_results.height()); |
| 447 | |
| 448 | // The computed subset and the corresponding subset of the original image |
| 449 | // should be the same. |
| 450 | SkAutoLockPixels full_lock(full_results); |
| 451 | SkAutoLockPixels subset_lock(subset_results); |
| 452 | for (int y = 0; y < subset_rect.height(); y++) { |
| 453 | for (int x = 0; x < subset_rect.width(); x++) { |
| 454 | ASSERT_EQ( |
| 455 | *full_results.getAddr32(x + subset_rect.fLeft, y + subset_rect.fTop), |
| 456 | *subset_results.getAddr32(x, y)); |
| 457 | } |
| 458 | } |
| 459 | } |
| 460 | |
| 461 | TEST(ImageOperations, InvalidParams) { |
| 462 | // Make our source bitmap. |
| 463 | SkBitmap src; |
| 464 | src.allocPixels(SkImageInfo::MakeA8(16, 34)); |
| 465 | |
| 466 | // Scale it, don't die. |
| 467 | SkBitmap full_results = skia::ImageOperations::Resize( |
| 468 | src, skia::ImageOperations::RESIZE_BOX, 10, 20); |
| 469 | } |
| 470 | |
| 471 | // Resamples an image to the same image, it should give the same result. |
| 472 | TEST(ImageOperations, ResampleToSameHamming1) { |
| 473 | CheckResampleToSame(skia::ImageOperations::RESIZE_HAMMING1); |
| 474 | } |
| 475 | |
| 476 | TEST(ImageOperations, ResampleToSameLanczos2) { |
| 477 | CheckResampleToSame(skia::ImageOperations::RESIZE_LANCZOS2); |
| 478 | } |
| 479 | |
| 480 | TEST(ImageOperations, ResampleToSameLanczos3) { |
| 481 | CheckResampleToSame(skia::ImageOperations::RESIZE_LANCZOS3); |
| 482 | } |
| 483 | |
| 484 | // Check that all Good/Better/Best, Box, Lanczos2 and Lanczos3 generate purple |
| 485 | // when resizing a 4x8 red/blue checker pattern by 1/16x1/16. |
| 486 | TEST(ImageOperations, ResizeShouldAverageColors) { |
| 487 | // Make our source bitmap. |
| 488 | const int src_w = 640, src_h = 480, checker_rect_w = 4, checker_rect_h = 8; |
| 489 | const SkColor checker_color1 = SK_ColorRED, checker_color2 = SK_ColorBLUE; |
| 490 | |
| 491 | const int dest_w = src_w / (4 * checker_rect_w); |
| 492 | const int dest_h = src_h / (2 * checker_rect_h); |
| 493 | |
| 494 | // Compute the expected (average) color |
| 495 | const SkColor colors[] = { checker_color1, checker_color2 }; |
| 496 | const SkColor average_color = AveragePixel(colors, arraysize(colors)); |
| 497 | |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 498 | static const TestedResizeMethod tested_methods[] = { |
| 499 | { skia::ImageOperations::RESIZE_GOOD, "GOOD", 0.0f }, |
| 500 | { skia::ImageOperations::RESIZE_BETTER, "BETTER", 0.0f }, |
| 501 | { skia::ImageOperations::RESIZE_BEST, "BEST", 0.0f }, |
| 502 | { skia::ImageOperations::RESIZE_BOX, "BOX", 0.0f }, |
| 503 | { skia::ImageOperations::RESIZE_HAMMING1, "HAMMING1", 0.0f }, |
| 504 | { skia::ImageOperations::RESIZE_LANCZOS2, "LANCZOS2", 0.0f }, |
| 505 | { skia::ImageOperations::RESIZE_LANCZOS3, "LANCZOS3", 0.0f }, |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 506 | }; |
| 507 | |
| 508 | // Create our source bitmap. |
| 509 | SkBitmap src; |
| 510 | DrawCheckerToBitmap(src_w, src_h, |
| 511 | checker_color1, checker_color2, |
| 512 | checker_rect_w, checker_rect_h, |
| 513 | &src); |
| 514 | |
| 515 | // For each method, downscale by 16 in each dimension, |
| 516 | // and check each tested pixel against the expected average color. |
James Robinson | e2ac7e8 | 2014-10-15 13:21:59 -0700 | [diff] [blame] | 517 | bool all_methods_ok = true; |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 518 | |
| 519 | for (size_t method_index = 0; |
| 520 | method_index < arraysize(tested_methods); |
| 521 | ++method_index) { |
| 522 | bool pass = true; |
| 523 | CheckResizeMethodShouldAverageGrid(src, |
| 524 | tested_methods[method_index], |
| 525 | dest_w, dest_h, average_color, |
| 526 | &pass); |
| 527 | if (!pass) { |
| 528 | all_methods_ok = false; |
| 529 | } |
| 530 | } |
| 531 | |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 532 | if (!all_methods_ok) { |
James Robinson | e2ac7e8 | 2014-10-15 13:21:59 -0700 | [diff] [blame] | 533 | #if DEBUG_BITMAP_GENERATION |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 534 | SaveBitmapToPNG(src, "/tmp/ResizeShouldAverageColors_src.png"); |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 535 | #endif // #if DEBUG_BITMAP_GENERATION |
James Robinson | e2ac7e8 | 2014-10-15 13:21:59 -0700 | [diff] [blame] | 536 | } |
James Robinson | 646469d | 2014-10-03 15:33:28 -0700 | [diff] [blame] | 537 | } |
| 538 | |
| 539 | |
| 540 | // Check that Lanczos2 and Lanczos3 thumbnails produce similar results |
| 541 | TEST(ImageOperations, CompareLanczosMethods) { |
| 542 | const int src_w = 640, src_h = 480, src_grid_pitch = 8, src_grid_width = 4; |
| 543 | |
| 544 | const int dest_w = src_w / 4; |
| 545 | const int dest_h = src_h / 4; |
| 546 | |
| 547 | // 5.0f is the maximum distance we see in this test given the current |
| 548 | // parameters. The value is very ad-hoc and the parameters of the scaling |
| 549 | // were picked to produce a small value. So this test is very much about |
| 550 | // revealing egregious regression rather than doing a good job at checking |
| 551 | // the math behind the filters. |
| 552 | // TODO(evannier): because of the half pixel error mentioned inside |
| 553 | // image_operations.cc, this distance is much larger than it should be. |
| 554 | // This should read: |
| 555 | // const float max_color_distance = 5.0f; |
| 556 | const float max_color_distance = 12.1f; |
| 557 | |
| 558 | // Make our source bitmap. |
| 559 | SkColor grid_color = SK_ColorRED, background_color = SK_ColorBLUE; |
| 560 | SkBitmap src; |
| 561 | DrawGridToBitmap(src_w, src_h, |
| 562 | background_color, grid_color, |
| 563 | src_grid_pitch, src_grid_width, |
| 564 | &src); |
| 565 | |
| 566 | // Resize the src using both methods. |
| 567 | SkBitmap dest_l2 = skia::ImageOperations::Resize( |
| 568 | src, |
| 569 | skia::ImageOperations::RESIZE_LANCZOS2, |
| 570 | dest_w, dest_h); |
| 571 | ASSERT_EQ(dest_w, dest_l2.width()); |
| 572 | ASSERT_EQ(dest_h, dest_l2.height()); |
| 573 | |
| 574 | SkBitmap dest_l3 = skia::ImageOperations::Resize( |
| 575 | src, |
| 576 | skia::ImageOperations::RESIZE_LANCZOS3, |
| 577 | dest_w, dest_h); |
| 578 | ASSERT_EQ(dest_w, dest_l3.width()); |
| 579 | ASSERT_EQ(dest_h, dest_l3.height()); |
| 580 | |
| 581 | // Compare the pixels produced by both methods. |
| 582 | float max_observed_distance = 0.0f; |
| 583 | bool all_pixels_ok = true; |
| 584 | |
| 585 | SkAutoLockPixels l2_lock(dest_l2); |
| 586 | SkAutoLockPixels l3_lock(dest_l3); |
| 587 | for (int y = 0; y < dest_h; ++y) { |
| 588 | for (int x = 0; x < dest_w; ++x) { |
| 589 | const SkColor color_lanczos2 = *dest_l2.getAddr32(x, y); |
| 590 | const SkColor color_lanczos3 = *dest_l3.getAddr32(x, y); |
| 591 | |
| 592 | float distance = ColorsEuclidianDistance(color_lanczos2, color_lanczos3); |
| 593 | |
| 594 | EXPECT_LE(distance, max_color_distance) |
| 595 | << "pixel tested: (" << x << ", " << y |
| 596 | << std::hex << std::showbase |
| 597 | << "), lanczos2 hex: " << color_lanczos2 |
| 598 | << ", lanczos3 hex: " << color_lanczos3 |
| 599 | << std::setprecision(2) |
| 600 | << ", distance: " << distance; |
| 601 | |
| 602 | if (distance > max_color_distance) { |
| 603 | all_pixels_ok = false; |
| 604 | } |
| 605 | if (distance > max_observed_distance) { |
| 606 | max_observed_distance = distance; |
| 607 | } |
| 608 | } |
| 609 | } |
| 610 | |
| 611 | if (!all_pixels_ok) { |
| 612 | ADD_FAILURE() << "Maximum observed color distance: " |
| 613 | << max_observed_distance; |
| 614 | |
| 615 | #if DEBUG_BITMAP_GENERATION |
| 616 | SaveBitmapToPNG(src, "/tmp/CompareLanczosMethods_source.png"); |
| 617 | SaveBitmapToPNG(dest_l2, "/tmp/CompareLanczosMethods_lanczos2.png"); |
| 618 | SaveBitmapToPNG(dest_l3, "/tmp/CompareLanczosMethods_lanczos3.png"); |
| 619 | #endif // #if DEBUG_BITMAP_GENERATION |
| 620 | } |
| 621 | } |
| 622 | |
| 623 | #ifndef M_PI |
| 624 | // No M_PI in math.h on windows? No problem. |
| 625 | #define M_PI 3.14159265358979323846 |
| 626 | #endif |
| 627 | |
| 628 | static double sinc(double x) { |
| 629 | if (x == 0.0) return 1.0; |
| 630 | x *= M_PI; |
| 631 | return sin(x) / x; |
| 632 | } |
| 633 | |
| 634 | static double lanczos3(double offset) { |
| 635 | if (fabs(offset) >= 3) return 0.0; |
| 636 | return sinc(offset) * sinc(offset / 3.0); |
| 637 | } |
| 638 | |
| 639 | TEST(ImageOperations, ScaleUp) { |
| 640 | const int src_w = 3; |
| 641 | const int src_h = 3; |
| 642 | const int dst_w = 9; |
| 643 | const int dst_h = 9; |
| 644 | SkBitmap src; |
| 645 | src.allocN32Pixels(src_w, src_h); |
| 646 | |
| 647 | for (int src_y = 0; src_y < src_h; ++src_y) { |
| 648 | for (int src_x = 0; src_x < src_w; ++src_x) { |
| 649 | *src.getAddr32(src_x, src_y) = SkColorSetARGBInline(255, |
| 650 | 10 + src_x * 100, |
| 651 | 10 + src_y * 100, |
| 652 | 0); |
| 653 | } |
| 654 | } |
| 655 | |
| 656 | SkBitmap dst = skia::ImageOperations::Resize( |
| 657 | src, |
| 658 | skia::ImageOperations::RESIZE_LANCZOS3, |
| 659 | dst_w, dst_h); |
| 660 | SkAutoLockPixels dst_lock(dst); |
| 661 | for (int dst_y = 0; dst_y < dst_h; ++dst_y) { |
| 662 | for (int dst_x = 0; dst_x < dst_w; ++dst_x) { |
| 663 | float dst_x_in_src = (dst_x + 0.5) * src_w / dst_w; |
| 664 | float dst_y_in_src = (dst_y + 0.5) * src_h / dst_h; |
| 665 | float a = 0.0f; |
| 666 | float r = 0.0f; |
| 667 | float g = 0.0f; |
| 668 | float b = 0.0f; |
| 669 | float sum = 0.0f; |
| 670 | for (int src_y = 0; src_y < src_h; ++src_y) { |
| 671 | for (int src_x = 0; src_x < src_w; ++src_x) { |
| 672 | double coeff = |
| 673 | lanczos3(src_x + 0.5 - dst_x_in_src) * |
| 674 | lanczos3(src_y + 0.5 - dst_y_in_src); |
| 675 | sum += coeff; |
| 676 | SkColor tmp = *src.getAddr32(src_x, src_y); |
| 677 | a += coeff * SkColorGetA(tmp); |
| 678 | r += coeff * SkColorGetR(tmp); |
| 679 | g += coeff * SkColorGetG(tmp); |
| 680 | b += coeff * SkColorGetB(tmp); |
| 681 | } |
| 682 | } |
| 683 | a /= sum; |
| 684 | r /= sum; |
| 685 | g /= sum; |
| 686 | b /= sum; |
| 687 | if (a < 0.0f) a = 0.0f; |
| 688 | if (r < 0.0f) r = 0.0f; |
| 689 | if (g < 0.0f) g = 0.0f; |
| 690 | if (b < 0.0f) b = 0.0f; |
| 691 | if (a > 255.0f) a = 255.0f; |
| 692 | if (r > 255.0f) r = 255.0f; |
| 693 | if (g > 255.0f) g = 255.0f; |
| 694 | if (b > 255.0f) b = 255.0f; |
| 695 | SkColor dst_color = *dst.getAddr32(dst_x, dst_y); |
| 696 | EXPECT_LE(fabs(SkColorGetA(dst_color) - a), 1.5f); |
| 697 | EXPECT_LE(fabs(SkColorGetR(dst_color) - r), 1.5f); |
| 698 | EXPECT_LE(fabs(SkColorGetG(dst_color) - g), 1.5f); |
| 699 | EXPECT_LE(fabs(SkColorGetB(dst_color) - b), 1.5f); |
| 700 | if (HasFailure()) { |
| 701 | return; |
| 702 | } |
| 703 | } |
| 704 | } |
| 705 | } |