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Unified Diff: skia/ext/image_operations_unittest.cc

Issue 1519243002: Remove many unused files from //skia/ext (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 5 years ago
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Index: skia/ext/image_operations_unittest.cc
diff --git a/skia/ext/image_operations_unittest.cc b/skia/ext/image_operations_unittest.cc
deleted file mode 100644
index 8f6d756f25f5ba4f35ba5051375b16db08e262c0..0000000000000000000000000000000000000000
--- a/skia/ext/image_operations_unittest.cc
+++ /dev/null
@@ -1,705 +0,0 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include <algorithm>
-#include <cmath>
-#include <iomanip>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "base/files/file_util.h"
-#include "base/strings/string_util.h"
-#include "skia/ext/image_operations.h"
-#include "testing/gtest/include/gtest/gtest.h"
-#include "third_party/skia/include/core/SkBitmap.h"
-#include "third_party/skia/include/core/SkRect.h"
-#include "ui/gfx/codec/png_codec.h"
-#include "ui/gfx/geometry/size.h"
-
-namespace {
-
-// Computes the average pixel value for the given range, inclusive.
-uint32_t AveragePixel(const SkBitmap& bmp,
- int x_min, int x_max,
- int y_min, int y_max) {
- float accum[4] = {0, 0, 0, 0};
- int count = 0;
- for (int y = y_min; y <= y_max; y++) {
- for (int x = x_min; x <= x_max; x++) {
- uint32_t cur = *bmp.getAddr32(x, y);
- accum[0] += SkColorGetB(cur);
- accum[1] += SkColorGetG(cur);
- accum[2] += SkColorGetR(cur);
- accum[3] += SkColorGetA(cur);
- count++;
- }
- }
-
- return SkColorSetARGB(static_cast<unsigned char>(accum[3] / count),
- static_cast<unsigned char>(accum[2] / count),
- static_cast<unsigned char>(accum[1] / count),
- static_cast<unsigned char>(accum[0] / count));
-}
-
-// Computes the average pixel (/color) value for the given colors.
-SkColor AveragePixel(const SkColor colors[], size_t color_count) {
- float accum[4] = { 0.0f, 0.0f, 0.0f, 0.0f };
- for (size_t i = 0; i < color_count; ++i) {
- const SkColor cur = colors[i];
- accum[0] += static_cast<float>(SkColorGetA(cur));
- accum[1] += static_cast<float>(SkColorGetR(cur));
- accum[2] += static_cast<float>(SkColorGetG(cur));
- accum[3] += static_cast<float>(SkColorGetB(cur));
- }
- const SkColor average_color =
- SkColorSetARGB(static_cast<uint8_t>(accum[0] / color_count),
- static_cast<uint8_t>(accum[1] / color_count),
- static_cast<uint8_t>(accum[2] / color_count),
- static_cast<uint8_t>(accum[3] / color_count));
- return average_color;
-}
-
-void PrintPixel(const SkBitmap& bmp,
- int x_min, int x_max,
- int y_min, int y_max) {
- char str[128];
-
- for (int y = y_min; y <= y_max; ++y) {
- for (int x = x_min; x <= x_max; ++x) {
- const uint32_t cur = *bmp.getAddr32(x, y);
- base::snprintf(str, sizeof(str), "bmp[%d,%d] = %08X", x, y, cur);
- ADD_FAILURE() << str;
- }
- }
-}
-
-// Returns the euclidian distance between two RGBA colors interpreted
-// as 4-components vectors.
-//
-// Notes:
-// - This is a really poor definition of color distance. Yet it
-// is "good enough" for our uses here.
-// - More realistic measures like the various Delta E formulas defined
-// by CIE are way more complex and themselves require the RGBA to
-// to transformed into CIELAB (typically via sRGB first).
-// - The static_cast<int> below are needed to avoid interpreting "negative"
-// differences as huge positive values.
-float ColorsEuclidianDistance(const SkColor a, const SkColor b) {
- int b_int_diff = static_cast<int>(SkColorGetB(a) - SkColorGetB(b));
- int g_int_diff = static_cast<int>(SkColorGetG(a) - SkColorGetG(b));
- int r_int_diff = static_cast<int>(SkColorGetR(a) - SkColorGetR(b));
- int a_int_diff = static_cast<int>(SkColorGetA(a) - SkColorGetA(b));
-
- float b_float_diff = static_cast<float>(b_int_diff);
- float g_float_diff = static_cast<float>(g_int_diff);
- float r_float_diff = static_cast<float>(r_int_diff);
- float a_float_diff = static_cast<float>(a_int_diff);
-
- return sqrtf((b_float_diff * b_float_diff) + (g_float_diff * g_float_diff) +
- (r_float_diff * r_float_diff) + (a_float_diff * a_float_diff));
-}
-
-// Returns true if each channel of the given two colors are "close." This is
-// used for comparing colors where rounding errors may cause off-by-one.
-bool ColorsClose(uint32_t a, uint32_t b) {
- return abs(static_cast<int>(SkColorGetB(a) - SkColorGetB(b))) < 2 &&
- abs(static_cast<int>(SkColorGetG(a) - SkColorGetG(b))) < 2 &&
- abs(static_cast<int>(SkColorGetR(a) - SkColorGetR(b))) < 2 &&
- abs(static_cast<int>(SkColorGetA(a) - SkColorGetA(b))) < 2;
-}
-
-void FillDataToBitmap(int w, int h, SkBitmap* bmp) {
- bmp->allocN32Pixels(w, h);
-
- for (int y = 0; y < h; ++y) {
- for (int x = 0; x < w; ++x) {
- const uint8_t component = static_cast<uint8_t>(y * w + x);
- const SkColor pixel = SkColorSetARGB(component, component,
- component, component);
- *bmp->getAddr32(x, y) = pixel;
- }
- }
-}
-
-// Draws a horizontal and vertical grid into the w x h bitmap passed in.
-// Each line in the grid is drawn with a width of "grid_width" pixels,
-// and those lines repeat every "grid_pitch" pixels. The top left pixel (0, 0)
-// is considered to be part of a grid line.
-// The pixels that fall on a line are colored with "grid_color", while those
-// outside of the lines are colored in "background_color".
-// Note that grid_with can be greather than or equal to grid_pitch, in which
-// case the resulting bitmap will be a solid color "grid_color".
-void DrawGridToBitmap(int w, int h,
- SkColor background_color, SkColor grid_color,
- int grid_pitch, int grid_width,
- SkBitmap* bmp) {
- ASSERT_GT(grid_pitch, 0);
- ASSERT_GT(grid_width, 0);
- ASSERT_NE(background_color, grid_color);
-
- bmp->allocN32Pixels(w, h);
-
- for (int y = 0; y < h; ++y) {
- bool y_on_grid = ((y % grid_pitch) < grid_width);
-
- for (int x = 0; x < w; ++x) {
- bool on_grid = (y_on_grid || ((x % grid_pitch) < grid_width));
-
- *bmp->getAddr32(x, y) = (on_grid ? grid_color : background_color);
- }
- }
-}
-
-// Draws a checkerboard pattern into the w x h bitmap passed in.
-// Each rectangle is rect_w in width, rect_h in height.
-// The colors alternate between color1 and color2, color1 being used
-// in the rectangle at the top left corner.
-void DrawCheckerToBitmap(int w, int h,
- SkColor color1, SkColor color2,
- int rect_w, int rect_h,
- SkBitmap* bmp) {
- ASSERT_GT(rect_w, 0);
- ASSERT_GT(rect_h, 0);
- ASSERT_NE(color1, color2);
-
- bmp->allocN32Pixels(w, h);
-
- for (int y = 0; y < h; ++y) {
- bool y_bit = (((y / rect_h) & 0x1) == 0);
-
- for (int x = 0; x < w; ++x) {
- bool x_bit = (((x / rect_w) & 0x1) == 0);
-
- bool use_color2 = (x_bit != y_bit); // xor
-
- *bmp->getAddr32(x, y) = (use_color2 ? color2 : color1);
- }
- }
-}
-
-// DEBUG_BITMAP_GENERATION (0 or 1) controls whether the routines
-// to save the test bitmaps are present. By default the test just fails
-// without reading/writing files but it is then convenient to have
-// a simple way to make the failing tests write out the input/output images
-// to check them visually.
-#define DEBUG_BITMAP_GENERATION (0)
-
-#if DEBUG_BITMAP_GENERATION
-void SaveBitmapToPNG(const SkBitmap& bmp, const char* path) {
- SkAutoLockPixels lock(bmp);
- std::vector<unsigned char> png;
- gfx::PNGCodec::ColorFormat color_format = gfx::PNGCodec::FORMAT_RGBA;
- if (!gfx::PNGCodec::Encode(
- reinterpret_cast<const unsigned char*>(bmp.getPixels()),
- color_format, gfx::Size(bmp.width(), bmp.height()),
- static_cast<int>(bmp.rowBytes()),
- false, std::vector<gfx::PNGCodec::Comment>(), &png)) {
- FAIL() << "Failed to encode image";
- }
-
- const base::FilePath fpath(path);
- const int num_written =
- base::WriteFile(fpath, reinterpret_cast<const char*>(&png[0]),
- png.size());
- if (num_written != static_cast<int>(png.size())) {
- FAIL() << "Failed to write dest \"" << path << '"';
- }
-}
-#endif // #if DEBUG_BITMAP_GENERATION
-
-void CheckResampleToSame(skia::ImageOperations::ResizeMethod method) {
- // Make our source bitmap.
- const int src_w = 16, src_h = 34;
- SkBitmap src;
- FillDataToBitmap(src_w, src_h, &src);
-
- // Do a resize of the full bitmap to the same size. The lanczos filter is good
- // enough that we should get exactly the same image for output.
- SkBitmap results = skia::ImageOperations::Resize(src, method, src_w, src_h);
- ASSERT_EQ(src_w, results.width());
- ASSERT_EQ(src_h, results.height());
-
- SkAutoLockPixels src_lock(src);
- SkAutoLockPixels results_lock(results);
- for (int y = 0; y < src_h; y++) {
- for (int x = 0; x < src_w; x++) {
- EXPECT_EQ(*src.getAddr32(x, y), *results.getAddr32(x, y));
- }
- }
-}
-
-// Types defined outside of the ResizeShouldAverageColors test to allow
-// use of the arraysize() macro.
-//
-// 'max_color_distance_override' is used in a max() call together with
-// the value of 'max_color_distance' defined in a TestedPixel instance.
-// Hence a value of 0.0 in 'max_color_distance_override' means
-// "use the pixel-specific value" and larger values can be used to allow
-// worse computation errors than provided in a TestedPixel instance.
-struct TestedResizeMethod {
- skia::ImageOperations::ResizeMethod method;
- const char* name;
- float max_color_distance_override;
-};
-
-struct TestedPixel {
- int x;
- int y;
- float max_color_distance;
- const char* name;
-};
-
-// Helper function used by the test "ResizeShouldAverageColors" below.
-// Note that ASSERT_EQ does a "return;" on failure, hence we can't have
-// a "bool" return value to reflect success. Hence "all_pixels_pass"
-void CheckResizeMethodShouldAverageGrid(
- const SkBitmap& src,
- const TestedResizeMethod& tested_method,
- int dest_w, int dest_h, SkColor average_color,
- bool* method_passed) {
- *method_passed = false;
-
- const TestedPixel tested_pixels[] = {
- // Corners
- { 0, 0, 2.3f, "Top left corner" },
- { 0, dest_h - 1, 2.3f, "Bottom left corner" },
- { dest_w - 1, 0, 2.3f, "Top right corner" },
- { dest_w - 1, dest_h - 1, 2.3f, "Bottom right corner" },
- // Middle points of each side
- { dest_w / 2, 0, 1.0f, "Top middle" },
- { dest_w / 2, dest_h - 1, 1.0f, "Bottom middle" },
- { 0, dest_h / 2, 1.0f, "Left middle" },
- { dest_w - 1, dest_h / 2, 1.0f, "Right middle" },
- // Center
- { dest_w / 2, dest_h / 2, 1.0f, "Center" }
- };
-
- // Resize the src
- const skia::ImageOperations::ResizeMethod method = tested_method.method;
-
- SkBitmap dest = skia::ImageOperations::Resize(src, method, dest_w, dest_h);
- ASSERT_EQ(dest_w, dest.width());
- ASSERT_EQ(dest_h, dest.height());
-
- // Check that pixels match the expected average.
- float max_observed_distance = 0.0f;
- bool all_pixels_ok = true;
-
- SkAutoLockPixels dest_lock(dest);
-
- for (size_t pixel_index = 0;
- pixel_index < arraysize(tested_pixels);
- ++pixel_index) {
- const TestedPixel& tested_pixel = tested_pixels[pixel_index];
-
- const int x = tested_pixel.x;
- const int y = tested_pixel.y;
- const float max_allowed_distance =
- std::max(tested_pixel.max_color_distance,
- tested_method.max_color_distance_override);
-
- const SkColor actual_color = *dest.getAddr32(x, y);
-
- // Check that the pixels away from the border region are very close
- // to the expected average color
- float distance = ColorsEuclidianDistance(average_color, actual_color);
-
- EXPECT_LE(distance, max_allowed_distance)
- << "Resizing method: " << tested_method.name
- << ", pixel tested: " << tested_pixel.name
- << "(" << x << ", " << y << ")"
- << std::hex << std::showbase
- << ", expected (avg) hex: " << average_color
- << ", actual hex: " << actual_color;
-
- if (distance > max_allowed_distance) {
- all_pixels_ok = false;
- }
- if (distance > max_observed_distance) {
- max_observed_distance = distance;
- }
- }
-
- if (!all_pixels_ok) {
- ADD_FAILURE() << "Maximum observed color distance for method "
- << tested_method.name << ": " << max_observed_distance;
-
-#if DEBUG_BITMAP_GENERATION
- char path[128];
- base::snprintf(path, sizeof(path),
- "/tmp/ResizeShouldAverageColors_%s_dest.png",
- tested_method.name);
- SaveBitmapToPNG(dest, path);
-#endif // #if DEBUG_BITMAP_GENERATION
- }
-
- *method_passed = all_pixels_ok;
-}
-
-
-} // namespace
-
-// Helper tests that saves bitmaps to PNGs in /tmp/ to visually check
-// that the bitmap generation functions work as expected.
-// Those tests are not enabled by default as verification is done
-// manually/visually, however it is convenient to leave the functions
-// in place.
-#if 0 && DEBUG_BITMAP_GENERATION
-TEST(ImageOperations, GenerateGradientBitmap) {
- // Make our source bitmap.
- const int src_w = 640, src_h = 480;
- SkBitmap src;
- FillDataToBitmap(src_w, src_h, &src);
-
- SaveBitmapToPNG(src, "/tmp/gradient_640x480.png");
-}
-
-TEST(ImageOperations, GenerateGridBitmap) {
- const int src_w = 640, src_h = 480, src_grid_pitch = 10, src_grid_width = 4;
- const SkColor grid_color = SK_ColorRED, background_color = SK_ColorBLUE;
- SkBitmap src;
- DrawGridToBitmap(src_w, src_h,
- background_color, grid_color,
- src_grid_pitch, src_grid_width,
- &src);
-
- SaveBitmapToPNG(src, "/tmp/grid_640x408_10_4_red_blue.png");
-}
-
-TEST(ImageOperations, GenerateCheckerBitmap) {
- const int src_w = 640, src_h = 480, rect_w = 10, rect_h = 4;
- const SkColor color1 = SK_ColorRED, color2 = SK_ColorBLUE;
- SkBitmap src;
- DrawCheckerToBitmap(src_w, src_h, color1, color2, rect_w, rect_h, &src);
-
- SaveBitmapToPNG(src, "/tmp/checker_640x408_10_4_red_blue.png");
-}
-#endif // #if ... && DEBUG_BITMAP_GENERATION
-
-// Makes the bitmap 50% the size as the original using a box filter. This is
-// an easy operation that we can check the results for manually.
-TEST(ImageOperations, Halve) {
- // Make our source bitmap.
- int src_w = 30, src_h = 38;
- SkBitmap src;
- FillDataToBitmap(src_w, src_h, &src);
-
- // Do a halving of the full bitmap.
- SkBitmap actual_results = skia::ImageOperations::Resize(
- src, skia::ImageOperations::RESIZE_BOX, src_w / 2, src_h / 2);
- ASSERT_EQ(src_w / 2, actual_results.width());
- ASSERT_EQ(src_h / 2, actual_results.height());
-
- // Compute the expected values & compare.
- SkAutoLockPixels lock(actual_results);
- for (int y = 0; y < actual_results.height(); y++) {
- for (int x = 0; x < actual_results.width(); x++) {
- // Note that those expressions take into account the "half-pixel"
- // offset that comes into play due to considering the coordinates
- // of the center of the pixels. So x * 2 is a simplification
- // of ((x+0.5) * 2 - 1) and (x * 2 + 1) is really (x + 0.5) * 2.
- int first_x = x * 2;
- int last_x = std::min(src_w - 1, x * 2 + 1);
-
- int first_y = y * 2;
- int last_y = std::min(src_h - 1, y * 2 + 1);
-
- const uint32_t expected_color = AveragePixel(src,
- first_x, last_x,
- first_y, last_y);
- const uint32_t actual_color = *actual_results.getAddr32(x, y);
- const bool close = ColorsClose(expected_color, actual_color);
- EXPECT_TRUE(close);
- if (!close) {
- char str[128];
- base::snprintf(str, sizeof(str),
- "exp[%d,%d] = %08X, actual[%d,%d] = %08X",
- x, y, expected_color, x, y, actual_color);
- ADD_FAILURE() << str;
- PrintPixel(src, first_x, last_x, first_y, last_y);
- }
- }
- }
-}
-
-TEST(ImageOperations, HalveSubset) {
- // Make our source bitmap.
- int src_w = 16, src_h = 34;
- SkBitmap src;
- FillDataToBitmap(src_w, src_h, &src);
-
- // Do a halving of the full bitmap.
- SkBitmap full_results = skia::ImageOperations::Resize(
- src, skia::ImageOperations::RESIZE_BOX, src_w / 2, src_h / 2);
- ASSERT_EQ(src_w / 2, full_results.width());
- ASSERT_EQ(src_h / 2, full_results.height());
-
- // Now do a halving of a a subset, recall the destination subset is in the
- // destination coordinate system (max = half of the original image size).
- SkIRect subset_rect = { 2, 3, 3, 6 };
- SkBitmap subset_results = skia::ImageOperations::Resize(
- src, skia::ImageOperations::RESIZE_BOX,
- src_w / 2, src_h / 2, subset_rect);
- ASSERT_EQ(subset_rect.width(), subset_results.width());
- ASSERT_EQ(subset_rect.height(), subset_results.height());
-
- // The computed subset and the corresponding subset of the original image
- // should be the same.
- SkAutoLockPixels full_lock(full_results);
- SkAutoLockPixels subset_lock(subset_results);
- for (int y = 0; y < subset_rect.height(); y++) {
- for (int x = 0; x < subset_rect.width(); x++) {
- ASSERT_EQ(
- *full_results.getAddr32(x + subset_rect.fLeft, y + subset_rect.fTop),
- *subset_results.getAddr32(x, y));
- }
- }
-}
-
-TEST(ImageOperations, InvalidParams) {
- // Make our source bitmap.
- SkBitmap src;
- src.allocPixels(SkImageInfo::MakeA8(16, 34));
-
- // Scale it, don't die.
- SkBitmap full_results = skia::ImageOperations::Resize(
- src, skia::ImageOperations::RESIZE_BOX, 10, 20);
-}
-
-// Resamples an image to the same image, it should give the same result.
-TEST(ImageOperations, ResampleToSameHamming1) {
- CheckResampleToSame(skia::ImageOperations::RESIZE_HAMMING1);
-}
-
-TEST(ImageOperations, ResampleToSameLanczos2) {
- CheckResampleToSame(skia::ImageOperations::RESIZE_LANCZOS2);
-}
-
-TEST(ImageOperations, ResampleToSameLanczos3) {
- CheckResampleToSame(skia::ImageOperations::RESIZE_LANCZOS3);
-}
-
-// Check that all Good/Better/Best, Box, Lanczos2 and Lanczos3 generate purple
-// when resizing a 4x8 red/blue checker pattern by 1/16x1/16.
-TEST(ImageOperations, ResizeShouldAverageColors) {
- // Make our source bitmap.
- const int src_w = 640, src_h = 480, checker_rect_w = 4, checker_rect_h = 8;
- const SkColor checker_color1 = SK_ColorRED, checker_color2 = SK_ColorBLUE;
-
- const int dest_w = src_w / (4 * checker_rect_w);
- const int dest_h = src_h / (2 * checker_rect_h);
-
- // Compute the expected (average) color
- const SkColor colors[] = { checker_color1, checker_color2 };
- const SkColor average_color = AveragePixel(colors, arraysize(colors));
-
- static const TestedResizeMethod tested_methods[] = {
- { skia::ImageOperations::RESIZE_GOOD, "GOOD", 0.0f },
- { skia::ImageOperations::RESIZE_BETTER, "BETTER", 0.0f },
- { skia::ImageOperations::RESIZE_BEST, "BEST", 0.0f },
- { skia::ImageOperations::RESIZE_BOX, "BOX", 0.0f },
- { skia::ImageOperations::RESIZE_HAMMING1, "HAMMING1", 0.0f },
- { skia::ImageOperations::RESIZE_LANCZOS2, "LANCZOS2", 0.0f },
- { skia::ImageOperations::RESIZE_LANCZOS3, "LANCZOS3", 0.0f },
- };
-
- // Create our source bitmap.
- SkBitmap src;
- DrawCheckerToBitmap(src_w, src_h,
- checker_color1, checker_color2,
- checker_rect_w, checker_rect_h,
- &src);
-
- // For each method, downscale by 16 in each dimension,
- // and check each tested pixel against the expected average color.
- bool all_methods_ok = true;
-
- for (size_t method_index = 0;
- method_index < arraysize(tested_methods);
- ++method_index) {
- bool pass = true;
- CheckResizeMethodShouldAverageGrid(src,
- tested_methods[method_index],
- dest_w, dest_h, average_color,
- &pass);
- if (!pass) {
- all_methods_ok = false;
- }
- }
-
- if (!all_methods_ok) {
-#if DEBUG_BITMAP_GENERATION
- SaveBitmapToPNG(src, "/tmp/ResizeShouldAverageColors_src.png");
-#endif // #if DEBUG_BITMAP_GENERATION
- }
-}
-
-
-// Check that Lanczos2 and Lanczos3 thumbnails produce similar results
-TEST(ImageOperations, CompareLanczosMethods) {
- const int src_w = 640, src_h = 480, src_grid_pitch = 8, src_grid_width = 4;
-
- const int dest_w = src_w / 4;
- const int dest_h = src_h / 4;
-
- // 5.0f is the maximum distance we see in this test given the current
- // parameters. The value is very ad-hoc and the parameters of the scaling
- // were picked to produce a small value. So this test is very much about
- // revealing egregious regression rather than doing a good job at checking
- // the math behind the filters.
- // TODO(evannier): because of the half pixel error mentioned inside
- // image_operations.cc, this distance is much larger than it should be.
- // This should read:
- // const float max_color_distance = 5.0f;
- const float max_color_distance = 12.1f;
-
- // Make our source bitmap.
- SkColor grid_color = SK_ColorRED, background_color = SK_ColorBLUE;
- SkBitmap src;
- DrawGridToBitmap(src_w, src_h,
- background_color, grid_color,
- src_grid_pitch, src_grid_width,
- &src);
-
- // Resize the src using both methods.
- SkBitmap dest_l2 = skia::ImageOperations::Resize(
- src,
- skia::ImageOperations::RESIZE_LANCZOS2,
- dest_w, dest_h);
- ASSERT_EQ(dest_w, dest_l2.width());
- ASSERT_EQ(dest_h, dest_l2.height());
-
- SkBitmap dest_l3 = skia::ImageOperations::Resize(
- src,
- skia::ImageOperations::RESIZE_LANCZOS3,
- dest_w, dest_h);
- ASSERT_EQ(dest_w, dest_l3.width());
- ASSERT_EQ(dest_h, dest_l3.height());
-
- // Compare the pixels produced by both methods.
- float max_observed_distance = 0.0f;
- bool all_pixels_ok = true;
-
- SkAutoLockPixels l2_lock(dest_l2);
- SkAutoLockPixels l3_lock(dest_l3);
- for (int y = 0; y < dest_h; ++y) {
- for (int x = 0; x < dest_w; ++x) {
- const SkColor color_lanczos2 = *dest_l2.getAddr32(x, y);
- const SkColor color_lanczos3 = *dest_l3.getAddr32(x, y);
-
- float distance = ColorsEuclidianDistance(color_lanczos2, color_lanczos3);
-
- EXPECT_LE(distance, max_color_distance)
- << "pixel tested: (" << x << ", " << y
- << std::hex << std::showbase
- << "), lanczos2 hex: " << color_lanczos2
- << ", lanczos3 hex: " << color_lanczos3
- << std::setprecision(2)
- << ", distance: " << distance;
-
- if (distance > max_color_distance) {
- all_pixels_ok = false;
- }
- if (distance > max_observed_distance) {
- max_observed_distance = distance;
- }
- }
- }
-
- if (!all_pixels_ok) {
- ADD_FAILURE() << "Maximum observed color distance: "
- << max_observed_distance;
-
-#if DEBUG_BITMAP_GENERATION
- SaveBitmapToPNG(src, "/tmp/CompareLanczosMethods_source.png");
- SaveBitmapToPNG(dest_l2, "/tmp/CompareLanczosMethods_lanczos2.png");
- SaveBitmapToPNG(dest_l3, "/tmp/CompareLanczosMethods_lanczos3.png");
-#endif // #if DEBUG_BITMAP_GENERATION
- }
-}
-
-#ifndef M_PI
-// No M_PI in math.h on windows? No problem.
-#define M_PI 3.14159265358979323846
-#endif
-
-static double sinc(double x) {
- if (x == 0.0) return 1.0;
- x *= M_PI;
- return sin(x) / x;
-}
-
-static double lanczos3(double offset) {
- if (fabs(offset) >= 3) return 0.0;
- return sinc(offset) * sinc(offset / 3.0);
-}
-
-TEST(ImageOperations, ScaleUp) {
- const int src_w = 3;
- const int src_h = 3;
- const int dst_w = 9;
- const int dst_h = 9;
- SkBitmap src;
- src.allocN32Pixels(src_w, src_h);
-
- for (int src_y = 0; src_y < src_h; ++src_y) {
- for (int src_x = 0; src_x < src_w; ++src_x) {
- *src.getAddr32(src_x, src_y) = SkColorSetARGBInline(255,
- 10 + src_x * 100,
- 10 + src_y * 100,
- 0);
- }
- }
-
- SkBitmap dst = skia::ImageOperations::Resize(
- src,
- skia::ImageOperations::RESIZE_LANCZOS3,
- dst_w, dst_h);
- SkAutoLockPixels dst_lock(dst);
- for (int dst_y = 0; dst_y < dst_h; ++dst_y) {
- for (int dst_x = 0; dst_x < dst_w; ++dst_x) {
- float dst_x_in_src = (dst_x + 0.5) * src_w / dst_w;
- float dst_y_in_src = (dst_y + 0.5) * src_h / dst_h;
- float a = 0.0f;
- float r = 0.0f;
- float g = 0.0f;
- float b = 0.0f;
- float sum = 0.0f;
- for (int src_y = 0; src_y < src_h; ++src_y) {
- for (int src_x = 0; src_x < src_w; ++src_x) {
- double coeff =
- lanczos3(src_x + 0.5 - dst_x_in_src) *
- lanczos3(src_y + 0.5 - dst_y_in_src);
- sum += coeff;
- SkColor tmp = *src.getAddr32(src_x, src_y);
- a += coeff * SkColorGetA(tmp);
- r += coeff * SkColorGetR(tmp);
- g += coeff * SkColorGetG(tmp);
- b += coeff * SkColorGetB(tmp);
- }
- }
- a /= sum;
- r /= sum;
- g /= sum;
- b /= sum;
- if (a < 0.0f) a = 0.0f;
- if (r < 0.0f) r = 0.0f;
- if (g < 0.0f) g = 0.0f;
- if (b < 0.0f) b = 0.0f;
- if (a > 255.0f) a = 255.0f;
- if (r > 255.0f) r = 255.0f;
- if (g > 255.0f) g = 255.0f;
- if (b > 255.0f) b = 255.0f;
- SkColor dst_color = *dst.getAddr32(dst_x, dst_y);
- EXPECT_LE(fabs(SkColorGetA(dst_color) - a), 1.5f);
- EXPECT_LE(fabs(SkColorGetR(dst_color) - r), 1.5f);
- EXPECT_LE(fabs(SkColorGetG(dst_color) - g), 1.5f);
- EXPECT_LE(fabs(SkColorGetB(dst_color) - b), 1.5f);
- if (HasFailure()) {
- return;
- }
- }
- }
-}
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