| package sobel |
| |
| import ( |
| "bytes" |
| "fmt" |
| "image" |
| "image/draw" |
| "image/png" |
| "io/ioutil" |
| "testing" |
| |
| "github.com/stretchr/testify/assert" |
| "github.com/stretchr/testify/require" |
| "go.skia.org/infra/go/testutils/unittest" |
| "go.skia.org/infra/gold-client/go/imgmatching/fuzzy" |
| "go.skia.org/infra/gold-client/go/mocks" |
| "go.skia.org/infra/golden/go/image/text" |
| ) |
| |
| // matcherTestCase represents a test case for the sobel.Matcher's Match() method. |
| type matcherTestCase struct { |
| name string |
| inputImage1 image.Image |
| inputImage2 image.Image |
| |
| // Matcher parameters. |
| edgeThreshold int |
| maxDifferentPixels int |
| pixelDeltaThreshold int |
| |
| // Expected images passed to the embedded fuzzy.Matcher. |
| expectedFuzzyMatcherInputImage1 image.Image |
| expectedFuzzyMatcherInputImage2 image.Image |
| |
| expectImagesToMatch bool // Expected matcher output. |
| |
| // Debug information about the last matched pair of images. |
| expectedSobelOutput image.Image |
| expectedImage1WithEdgesRemoved image.Image |
| expectedImage2WithEdgesRemoved image.Image |
| expectedNumDifferentPixels int |
| expectedMaxPixelDelta int |
| } |
| |
| // makeMatcherTestCases returns a slice of test cases shared by the TestMatcher_Match_* tests |
| // below. |
| func makeMatcherTestCases() []matcherTestCase { |
| return []matcherTestCase{ |
| { |
| name: "edge threshold 0xFF", |
| inputImage1: text.MustToNRGBA(image1), |
| inputImage2: text.MustToNRGBA(image2), |
| edgeThreshold: 0xFF, |
| maxDifferentPixels: 3, |
| pixelDeltaThreshold: 10, |
| expectedFuzzyMatcherInputImage1: text.MustToNRGBA(image1), |
| expectedFuzzyMatcherInputImage2: text.MustToNRGBA(image2), |
| expectImagesToMatch: false, // 10 pixels off, max per-channel delta sum of 36. |
| expectedSobelOutput: text.MustToGray(image1Sobel), |
| expectedImage1WithEdgesRemoved: text.MustToNRGBA(image1), |
| expectedImage2WithEdgesRemoved: text.MustToNRGBA(image2), |
| expectedNumDifferentPixels: 10, |
| expectedMaxPixelDelta: 36, |
| }, |
| { |
| name: "edge threshold 0xAA", |
| inputImage1: text.MustToNRGBA(image1), |
| inputImage2: text.MustToNRGBA(image2), |
| edgeThreshold: 0xAA, |
| maxDifferentPixels: 3, |
| pixelDeltaThreshold: 10, |
| expectedFuzzyMatcherInputImage1: text.MustToNRGBA(image1NoEdgesAbove0xAA), |
| expectedFuzzyMatcherInputImage2: text.MustToNRGBA(image2NoEdgesAbove0xAA), |
| expectImagesToMatch: false, // 5 pixels off, max per-channel delta sum of 15. |
| expectedSobelOutput: text.MustToGray(image1Sobel), |
| expectedImage1WithEdgesRemoved: text.MustToNRGBA(image1NoEdgesAbove0xAA), |
| expectedImage2WithEdgesRemoved: text.MustToNRGBA(image2NoEdgesAbove0xAA), |
| expectedNumDifferentPixels: 5, |
| expectedMaxPixelDelta: 15, |
| }, |
| { |
| name: "edge threshold 0x66", |
| inputImage1: text.MustToNRGBA(image1), |
| inputImage2: text.MustToNRGBA(image2), |
| edgeThreshold: 0x66, |
| maxDifferentPixels: 3, |
| pixelDeltaThreshold: 10, |
| expectedFuzzyMatcherInputImage1: text.MustToNRGBA(image1NoEdgesAbove0x66), |
| expectedFuzzyMatcherInputImage2: text.MustToNRGBA(image2NoEdgesAbove0x66), |
| expectImagesToMatch: true, // 1 pixel off, max per-channel delta sum of 9. |
| expectedSobelOutput: text.MustToGray(image1Sobel), |
| expectedImage1WithEdgesRemoved: text.MustToNRGBA(image1NoEdgesAbove0x66), |
| expectedImage2WithEdgesRemoved: text.MustToNRGBA(image2NoEdgesAbove0x66), |
| expectedNumDifferentPixels: 1, |
| expectedMaxPixelDelta: 9, |
| }, |
| { |
| name: "edge threshold 0x00", |
| inputImage1: text.MustToNRGBA(image1), |
| inputImage2: text.MustToNRGBA(image2), |
| edgeThreshold: 0x00, |
| maxDifferentPixels: 3, |
| pixelDeltaThreshold: 10, |
| expectedFuzzyMatcherInputImage1: text.MustToNRGBA(image1NoEdgesAbove0x00), |
| expectedFuzzyMatcherInputImage2: text.MustToNRGBA(image2NoEdgesAbove0x00), |
| expectImagesToMatch: true, // The above images are identical. |
| expectedSobelOutput: text.MustToGray(image1Sobel), |
| expectedImage1WithEdgesRemoved: text.MustToNRGBA(image1NoEdgesAbove0x00), |
| expectedImage2WithEdgesRemoved: text.MustToNRGBA(image2NoEdgesAbove0x00), |
| expectedNumDifferentPixels: 0, |
| expectedMaxPixelDelta: 0, |
| }, |
| } |
| } |
| |
| // TestMatcher_Match_MockFuzzyMatcher_CallsFuzzyMatcherWithExpectedInputImages tests |
| // sobel.Matcher's Match() method in isolation with respect to the embedded fuzzy.Matcher. |
| func TestMatcher_Match_MockFuzzyMatcher_CallsFuzzyMatcherWithExpectedInputImages(t *testing.T) { |
| unittest.SmallTest(t) |
| |
| for _, tc := range makeMatcherTestCases() { |
| t.Run(tc.name, func(t *testing.T) { |
| fuzzyMatcher := &mocks.Matcher{} |
| |
| // Return value does not matter, we're only testing that the right inputs are passed. |
| fuzzyMatcher.On("Match", tc.expectedFuzzyMatcherInputImage1, tc.expectedFuzzyMatcherInputImage2).Return(true) |
| |
| sobelMatcher := Matcher{ |
| EdgeThreshold: tc.edgeThreshold, |
| fuzzyMatcherForTesting: fuzzyMatcher, |
| } |
| |
| assert.True(t, sobelMatcher.Match(tc.inputImage1, tc.inputImage2)) |
| fuzzyMatcher.AssertExpectations(t) |
| }) |
| } |
| } |
| |
| // TestMatcher_Match_Success tests sobel.Matcher's Match() method using a real fuzzy.Matcher. |
| func TestMatcher_Match_Success(t *testing.T) { |
| unittest.SmallTest(t) |
| |
| for _, tc := range makeMatcherTestCases() { |
| t.Run(tc.name, func(t *testing.T) { |
| matcher := Matcher{ |
| Matcher: fuzzy.Matcher{ |
| MaxDifferentPixels: tc.maxDifferentPixels, |
| PixelDeltaThreshold: tc.pixelDeltaThreshold, |
| }, |
| EdgeThreshold: tc.edgeThreshold, |
| } |
| |
| assert.Equal(t, tc.expectImagesToMatch, matcher.Match(tc.inputImage1, tc.inputImage2)) |
| assertImagesEqualWithMessage(t, tc.expectedSobelOutput, matcher.SobelOutput(), "sobel output") |
| assertImagesEqualWithMessage(t, tc.expectedImage1WithEdgesRemoved, matcher.ExpectedImageWithEdgesRemoved(), "image1 with edges removed") |
| assertImagesEqualWithMessage(t, tc.expectedImage2WithEdgesRemoved, matcher.ActualImageWithEdgesRemoved(), "image2 with edges removed") |
| assert.Equal(t, tc.expectedNumDifferentPixels, matcher.Matcher.NumDifferentPixels()) |
| assert.Equal(t, tc.expectedMaxPixelDelta, matcher.Matcher.MaxPixelDelta()) |
| }) |
| } |
| } |
| |
| func TestMatcher_Match_DifferentSizeImages_ReturnsFalse(t *testing.T) { |
| unittest.SmallTest(t) |
| |
| smallImage := text.MustToNRGBA(`! SKTEXTSIMPLE |
| 7 7 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00`) |
| |
| largeImage := text.MustToNRGBA(`! SKTEXTSIMPLE |
| 8 8 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00`) |
| |
| matcher := Matcher{ |
| Matcher: fuzzy.Matcher{ |
| MaxDifferentPixels: 1000, |
| PixelDeltaThreshold: 10, |
| }, |
| EdgeThreshold: 0xFF, |
| } |
| |
| assert.False(t, matcher.Match(smallImage, largeImage)) |
| assert.False(t, matcher.Match(largeImage, smallImage)) |
| } |
| |
| // TestSobel_Success tests the sobel() function using the canonical image1 and image1Sobel images |
| // used throughout this file. |
| func TestSobel_Success(t *testing.T) { |
| unittest.SmallTest(t) |
| assertImagesEqual(t, text.MustToGray(image1Sobel), sobel(text.MustToGray(image1))) |
| } |
| |
| // TestSobel_SmallImages_Success tests various edge cases involving small images. |
| // |
| // Notes: |
| // - In practice the sobel() function will usually be invoked with much larger images. |
| // - While these edge cases are unlikely to occur in practice, they exposed a number of bugs during |
| // development (e.g. indexing and off-by-one errors). Those same bugs could be exposed with |
| // larger, more realistic images, but using small images makes it easier to debug failing tests. |
| func TestSobel_SmallImages_Success(t *testing.T) { |
| unittest.SmallTest(t) |
| |
| tests := []struct { |
| name string |
| input *image.Gray |
| expectedOutput *image.Gray |
| }{ |
| { |
| name: "empty image, returns empty image", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 0 0`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 0 0`), |
| }, |
| { |
| name: "1x1 black image, returns 1x1 black image", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 1 1 |
| 0x00`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 1 1 |
| 0x00`), |
| }, |
| { |
| name: "1x1 white image, returns 1x1 black image", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 1 1 |
| 0xFF`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 1 1 |
| 0x00`), |
| }, |
| { |
| name: "2x2 black image, returns 2x2 black image", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 2 2 |
| 0x00 0x00 |
| 0x00 0x00`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 2 2 |
| 0x00 0x00 |
| 0x00 0x00`), |
| }, |
| { |
| name: "2x2 white image, returns 2x2 black image", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 2 2 |
| 0xFF 0xFF |
| 0xFF 0xFF`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 2 2 |
| 0x00 0x00 |
| 0x00 0x00`), |
| }, |
| { |
| name: "2x2 image with an edge, returns 2x2 black image", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 2 2 |
| 0x00 0xFF |
| 0x00 0xFF`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 2 2 |
| 0x00 0x00 |
| 0x00 0x00`), |
| }, |
| { |
| name: "3x3 black image, returns 3x3 black image", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 3 3 |
| 0x00 0x00 0x00 |
| 0x00 0x00 0x00 |
| 0x00 0x00 0x00`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 3 3 |
| 0x00 0x00 0x00 |
| 0x00 0x00 0x00 |
| 0x00 0x00 0x00`), |
| }, |
| { |
| name: "3x3 white image, returns 3x3 black image", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 3 3 |
| 0xFF 0xFF 0xFF |
| 0xFF 0xFF 0xFF |
| 0xFF 0xFF 0xFF`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 3 3 |
| 0x00 0x00 0x00 |
| 0x00 0x00 0x00 |
| 0x00 0x00 0x00`), |
| }, |
| { |
| name: "3x3 image with an edge, returns 3x3 image with one high intensity pixel", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 3 3 |
| 0x00 0xFF 0xFF |
| 0x00 0xFF 0xFF |
| 0x00 0xFF 0xFF`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 3 3 |
| 0x00 0x00 0x00 |
| 0x00 0xFF 0x00 |
| 0x00 0x00 0x00`), |
| }, |
| { |
| name: "4x4 black image, returns 4x4 black image", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 4 4 |
| 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 4 4 |
| 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00`), |
| }, |
| { |
| name: "4x4 white image, returns 4x4 black image", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 4 4 |
| 0xFF 0xFF 0xFF 0xFF |
| 0xFF 0xFF 0xFF 0xFF |
| 0xFF 0xFF 0xFF 0xFF |
| 0xFF 0xFF 0xFF 0xFF`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 4 4 |
| 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00`), |
| }, |
| { |
| name: "4x4 image with an edge, returns 4x4 image with 4 high intensity pixels", |
| input: text.MustToGray(`! SKTEXTSIMPLE |
| 4 4 |
| 0x00 0x00 0xFF 0xFF |
| 0x00 0x00 0xFF 0xFF |
| 0x00 0x00 0xFF 0xFF |
| 0x00 0x00 0xFF 0xFF`), |
| expectedOutput: text.MustToGray(`! SKTEXTSIMPLE |
| 4 4 |
| 0x00 0x00 0x00 0x00 |
| 0x00 0xFF 0xFF 0x00 |
| 0x00 0xFF 0xFF 0x00 |
| 0x00 0x00 0x00 0x00`), |
| }, |
| } |
| |
| for _, tc := range tests { |
| t.Run(tc.name, func(t *testing.T) { |
| assertImagesEqual(t, tc.expectedOutput, sobel(tc.input)) |
| }) |
| } |
| } |
| |
| func TestSobel_EdgesAtVariousAngles_Success(t *testing.T) { |
| unittest.SmallTest(t) |
| |
| input0Degrees := text.MustToGray(`! SKTEXTSIMPLE |
| 10 10 |
| 0x00 0x00 0x00 0x00 0x00 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x44 0x44 0x44 0x44 0x44`) |
| |
| expectedOutput0Degrees := text.MustToGray(`! SKTEXTSIMPLE |
| 10 10 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0xFF 0xFF 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0xFF 0xFF 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0xFF 0xFF 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0xFF 0xFF 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0xFF 0xFF 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0xFF 0xFF 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0xFF 0xFF 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0xFF 0xFF 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00`) |
| |
| input30Degrees := text.MustToGray(`! SKTEXTSIMPLE |
| 10 10 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x0E 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x36 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x0E 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x36 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x0E 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x36 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x0E 0x44 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x36 0x44 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x0E 0x44 0x44 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x36 0x44 0x44 0x44 0x44 0x44 0x44 0x44`) |
| |
| expectedOutput30Degrees := text.MustToGray(`! SKTEXTSIMPLE |
| 10 10 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x13 0xCE 0xFF 0x62 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x62 0xFF 0xCE 0x13 0x00 0x00 |
| 0x00 0x00 0x00 0x13 0xCE 0xFF 0x62 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x62 0xFF 0xCE 0x13 0x00 0x00 0x00 |
| 0x00 0x00 0x13 0xCE 0xFF 0x62 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x62 0xFF 0xCE 0x13 0x00 0x00 0x00 0x00 |
| 0x00 0x13 0xCE 0xFF 0x62 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x62 0xFF 0xCE 0x13 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00`) |
| |
| input45Degrees := text.MustToGray(`! SKTEXTSIMPLE |
| 10 10 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x05 0x3F |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x05 0x3F 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x05 0x3F 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x00 0x05 0x3F 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x05 0x3F 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x00 0x05 0x3F 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x05 0x3F 0x44 0x44 0x44 0x44 0x44 0x44 |
| 0x00 0x05 0x3F 0x44 0x44 0x44 0x44 0x44 0x44 0x44 |
| 0x05 0x3F 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 |
| 0x3F 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44`) |
| |
| expectedOutput45Degrees := text.MustToGray(`! SKTEXTSIMPLE |
| 10 10 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x07 0x67 0xFF 0xFF 0x00 |
| 0x00 0x00 0x00 0x00 0x07 0x67 0xFF 0xFF 0x67 0x00 |
| 0x00 0x00 0x00 0x07 0x67 0xFF 0xFF 0x67 0x07 0x00 |
| 0x00 0x00 0x07 0x67 0xFF 0xFF 0x67 0x07 0x00 0x00 |
| 0x00 0x07 0x67 0xFF 0xFF 0x67 0x07 0x00 0x00 0x00 |
| 0x00 0x67 0xFF 0xFF 0x67 0x07 0x00 0x00 0x00 0x00 |
| 0x00 0xFF 0xFF 0x67 0x07 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0xFF 0x67 0x07 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00`) |
| |
| input60Degrees := text.MustToGray(`! SKTEXTSIMPLE |
| 10 10 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x0E 0x36 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x0E 0x36 0x44 0x44 |
| 0x00 0x00 0x00 0x00 0x0E 0x36 0x44 0x44 0x44 0x44 |
| 0x00 0x00 0x0E 0x36 0x44 0x44 0x44 0x44 0x44 0x44 |
| 0x0E 0x36 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44 0x44`) |
| |
| expectedOutput60Degrees := text.MustToGray(`! SKTEXTSIMPLE |
| 10 10 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x13 0x62 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x13 0x62 0xCE 0xFF 0x00 |
| 0x00 0x00 0x00 0x13 0x62 0xCE 0xFF 0xFF 0xCE 0x00 |
| 0x00 0x13 0x62 0xCE 0xFF 0xFF 0xCE 0x62 0x13 0x00 |
| 0x00 0xCE 0xFF 0xFF 0xCE 0x62 0x13 0x00 0x00 0x00 |
| 0x00 0xFF 0xCE 0x62 0x13 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x62 0x13 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00`) |
| |
| test := func(name string, input, expectedOutput *image.Gray) { |
| t.Run(name, func(t *testing.T) { |
| assertImagesEqual(t, expectedOutput, sobel(input)) |
| }) |
| } |
| |
| test("0 degrees", input0Degrees, expectedOutput0Degrees) |
| test("30 degrees", input30Degrees, expectedOutput30Degrees) |
| test("45 degrees", input45Degrees, expectedOutput45Degrees) |
| test("60 degrees", input60Degrees, expectedOutput60Degrees) |
| } |
| |
| func TestSobel_GoldenImage_Success(t *testing.T) { |
| unittest.MediumTest(t) |
| |
| // Attribution for the test/input.png image used below: |
| // |
| // Author: Simpsons contributor. |
| // License: CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0). |
| // Source: https://en.wikipedia.org/wiki/File:Valve_original_%281%29.PNG. |
| // Modifications: PNG image was recoded using Golang's png.Decode() and png.Encode(). |
| |
| input := readPngAsGray(t, "test/input.png") |
| expectedOutput := readPngAsGray(t, "test/sobel-expected-output.png") |
| assert.Equal(t, expectedOutput, sobel(input)) |
| } |
| |
| // TestZeroOutEdges_Success tests function zeroOutEdges() against image1 and image2 using the edges |
| // from image1 (i.e. image1Sobel) in both cases, and a variety of edge thresholds. |
| func TestZeroOutEdges_Success(t *testing.T) { |
| unittest.SmallTest(t) |
| |
| test := func(name, expectedOutput, input string, edgeThreshold uint8) { |
| t.Run(name, func(t *testing.T) { |
| // All tests use the edges from image1 (i.e. image1Sobel). |
| actualOutput := zeroOutEdges(text.MustToNRGBA(input), text.MustToGray(image1Sobel), edgeThreshold) |
| assertImagesEqual(t, text.MustToNRGBA(expectedOutput), actualOutput) |
| }) |
| } |
| |
| // Test against image1. |
| test("image1 with edge threshold 0xFF, no pixels zeroed out", image1, image1, 0xFF) |
| test("image1 with edge threshold 0xAA, some pixels zeroed out", image1NoEdgesAbove0xAA, image1, 0xAA) |
| test("image1 with edge threshold 0x66, some pixels zeroed out", image1NoEdgesAbove0x66, image1, 0x66) |
| test("image1 with edge threshold 0x00, some pixels zeroed out", image1NoEdgesAbove0x00, image1, 0x00) |
| |
| // Test against image2. |
| test("image2 with edge threshold 0xFF, no pixels zeroed out", image2, image2, 0xFF) |
| test("image2 with edge threshold 0xAA, some pixels zeroed out", image2NoEdgesAbove0xAA, image2, 0xAA) |
| test("image2 with edge threshold 0x66, some pixels zeroed out", image2NoEdgesAbove0x66, image2, 0x66) |
| test("image2 with edge threshold 0x00, some pixels zeroed out", image2NoEdgesAbove0x00, image2, 0x00) |
| } |
| |
| // TestZeroOutEdges_SmallImages_Success tests various edge cases involving small images. |
| func TestZeroOutEdges_SmallImages_Success(t *testing.T) { |
| unittest.SmallTest(t) |
| |
| tests := []struct { |
| name string |
| input image.Image |
| edges *image.Gray |
| edgeThreshold uint8 |
| expectedOutput image.Image |
| }{ |
| { |
| name: "empty image, returns empty image", |
| input: text.MustToNRGBA(`! SKTEXTSIMPLE |
| 0 0`), |
| edges: text.MustToGray(`! SKTEXTSIMPLE |
| 0 0`), |
| edgeThreshold: 0, |
| expectedOutput: text.MustToNRGBA(`! SKTEXTSIMPLE |
| 0 0`), |
| }, |
| { |
| name: "1x1 image with pixel below threshold, returns original image", |
| input: text.MustToNRGBA(`! SKTEXTSIMPLE |
| 1 1 |
| 0xAABBCCFF`), |
| edges: text.MustToGray(`! SKTEXTSIMPLE |
| 1 1 |
| 0x55`), |
| edgeThreshold: 0xBB, |
| expectedOutput: text.MustToNRGBA(`! SKTEXTSIMPLE |
| 1 1 |
| 0xAABBCCFF`), |
| }, |
| { |
| name: "1x1 image with pixel above threshold, returns black image", |
| input: text.MustToNRGBA(`! SKTEXTSIMPLE |
| 1 1 |
| 0xAABBCCFF`), |
| edges: text.MustToGray(`! SKTEXTSIMPLE |
| 1 1 |
| 0xCC`), |
| edgeThreshold: 0xBB, |
| expectedOutput: text.MustToNRGBA(`! SKTEXTSIMPLE |
| 1 1 |
| 0x000000FF`), |
| }, |
| } |
| |
| for _, tc := range tests { |
| t.Run(tc.name, func(t *testing.T) { |
| assertImagesEqual(t, tc.expectedOutput, zeroOutEdges(tc.input, tc.edges, tc.edgeThreshold)) |
| }) |
| } |
| } |
| |
| func TestZeroOutEdges_GoldenImage_Success(t *testing.T) { |
| unittest.MediumTest(t) |
| |
| input := readPng(t, "test/input.png") |
| edges := readPngAsGray(t, "test/sobel-expected-output.png") |
| expectedOutput := readPng(t, "test/zero-out-edges-expected-output.png") |
| assert.Equal(t, expectedOutput, zeroOutEdges(input, edges, 0x55)) |
| } |
| |
| func TestZeroOutEdges_InputAndEdgesImagesHaveDifferentBounds_Panics(t *testing.T) { |
| unittest.SmallTest(t) |
| |
| assert.Panics(t, func() { |
| img := text.MustToNRGBA(`! SKTEXTSIMPLE |
| 2 1 |
| 0x00 0x00`) |
| edges := text.MustToGray(`! SKTEXTSIMPLE |
| 1 1 |
| 0x00`) |
| zeroOutEdges(img, edges, 0) |
| }) |
| } |
| |
| // image1 is a grayscale image with a diagonal, antialiased edge from 0x44 to 0x88. |
| const image1 = `! SKTEXTSIMPLE |
| 8 8 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x49 0x83 |
| 0x44 0x44 0x44 0x44 0x44 0x49 0x83 0x88 |
| 0x44 0x44 0x44 0x44 0x49 0x83 0x88 0x88 |
| 0x44 0x44 0x44 0x49 0x83 0x88 0x88 0x88 |
| 0x44 0x44 0x49 0x83 0x88 0x88 0x88 0x88 |
| 0x44 0x49 0x83 0x88 0x88 0x88 0x88 0x88 |
| 0x49 0x83 0x88 0x88 0x88 0x88 0x88 0x88 |
| 0x83 0x88 0x88 0x88 0x88 0x88 0x88 0x88` |
| |
| // image1Sobel is a grayscale image with the result of applying the Sobel operator to each |
| // non-border pixel in image1. Border pixels are set to 0. |
| const image1Sobel = `! SKTEXTSIMPLE |
| 8 8 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x07 0x67 0xFF 0xFF 0x00 |
| 0x00 0x00 0x07 0x67 0xFF 0xFF 0x67 0x00 |
| 0x00 0x07 0x67 0xFF 0xFF 0x67 0x07 0x00 |
| 0x00 0x67 0xFF 0xFF 0x67 0x07 0x00 0x00 |
| 0x00 0xFF 0xFF 0x67 0x07 0x00 0x00 0x00 |
| 0x00 0xFF 0x67 0x07 0x00 0x00 0x00 0x00 |
| 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00` |
| |
| // image1NoEdgesAbove0xAA is the result of zeroing out all pixels in image1 with a Sobel operator |
| // value above 0xAA. |
| const image1NoEdgesAbove0xAA = `! SKTEXTSIMPLE |
| 8 8 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x49 0x83 |
| 0x44 0x44 0x44 0x44 0x44 0x00 0x00 0x88 |
| 0x44 0x44 0x44 0x44 0x00 0x00 0x88 0x88 |
| 0x44 0x44 0x44 0x00 0x00 0x88 0x88 0x88 |
| 0x44 0x44 0x00 0x00 0x88 0x88 0x88 0x88 |
| 0x44 0x00 0x00 0x88 0x88 0x88 0x88 0x88 |
| 0x49 0x00 0x88 0x88 0x88 0x88 0x88 0x88 |
| 0x83 0x88 0x88 0x88 0x88 0x88 0x88 0x88` |
| |
| // image1NoEdgesAbove0x66 is the result of zeroing out all pixels in image1 with a Sobel operator |
| // value above 0x66. |
| const image1NoEdgesAbove0x66 = `! SKTEXTSIMPLE |
| 8 8 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x49 0x83 |
| 0x44 0x44 0x44 0x44 0x00 0x00 0x00 0x88 |
| 0x44 0x44 0x44 0x00 0x00 0x00 0x00 0x88 |
| 0x44 0x44 0x00 0x00 0x00 0x00 0x88 0x88 |
| 0x44 0x00 0x00 0x00 0x00 0x88 0x88 0x88 |
| 0x44 0x00 0x00 0x00 0x88 0x88 0x88 0x88 |
| 0x49 0x00 0x00 0x88 0x88 0x88 0x88 0x88 |
| 0x83 0x88 0x88 0x88 0x88 0x88 0x88 0x88` |
| |
| // image1NoEdgesAbove0x00 is the result of zeroing out all pixels in image1 with a Sobel operator |
| // value above 0. |
| const image1NoEdgesAbove0x00 = `! SKTEXTSIMPLE |
| 8 8 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x49 0x83 |
| 0x44 0x44 0x44 0x00 0x00 0x00 0x00 0x88 |
| 0x44 0x44 0x00 0x00 0x00 0x00 0x00 0x88 |
| 0x44 0x00 0x00 0x00 0x00 0x00 0x00 0x88 |
| 0x44 0x00 0x00 0x00 0x00 0x00 0x88 0x88 |
| 0x44 0x00 0x00 0x00 0x00 0x88 0x88 0x88 |
| 0x49 0x00 0x00 0x00 0x88 0x88 0x88 0x88 |
| 0x83 0x88 0x88 0x88 0x88 0x88 0x88 0x88` |
| |
| // image2 is identical to image1 except for some antialiasing differences. |
| // |
| // It differs from image1 by 10 pixels, with a maximum per-channel delta sum of 36. |
| const image2 = `! SKTEXTSIMPLE |
| 8 8 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x49 0x83 |
| 0x44 0x44 0x44 0x44 0x44 0x49 0x83 0x88 |
| 0x44 0x44 0x47 0x49 0x55 0x83 0x88 0x88 |
| 0x44 0x44 0x49 0x4D 0x7F 0x87 0x88 0x88 |
| 0x44 0x44 0x55 0x7F 0x88 0x88 0x88 0x88 |
| 0x44 0x49 0x83 0x87 0x88 0x88 0x88 0x88 |
| 0x49 0x83 0x88 0x88 0x88 0x88 0x88 0x88 |
| 0x83 0x88 0x88 0x88 0x88 0x88 0x88 0x88` |
| |
| // image2NoEdgesAbove0xAA is the result of zeroing out all pixels in image2 where the Sobel |
| // operator value for the corresponding pixel in image1 is above 0xAA. |
| // |
| // It differs from image1NoEdgesAbove0xAA by 5 pixels, with a maximum per-channel delta sum of 15. |
| const image2NoEdgesAbove0xAA = `! SKTEXTSIMPLE |
| 8 8 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x49 0x83 |
| 0x44 0x44 0x44 0x44 0x44 0x00 0x00 0x88 |
| 0x44 0x44 0x47 0x49 0x00 0x00 0x88 0x88 |
| 0x44 0x44 0x49 0x00 0x00 0x87 0x88 0x88 |
| 0x44 0x44 0x00 0x00 0x88 0x88 0x88 0x88 |
| 0x44 0x00 0x00 0x87 0x88 0x88 0x88 0x88 |
| 0x49 0x00 0x88 0x88 0x88 0x88 0x88 0x88 |
| 0x83 0x88 0x88 0x88 0x88 0x88 0x88 0x88` |
| |
| // image2NoEdgesAbove0x66 is the result of zeroing out all pixels in image2 where the Sobel |
| // operator value for the corresponding pixel in image1 is above 0x66. |
| // |
| // It differs from image1NoEdgesAbove0x66 by 1 pixel, with a maximum per-channel delta sum of 9. |
| const image2NoEdgesAbove0x66 = `! SKTEXTSIMPLE |
| 8 8 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x49 0x83 |
| 0x44 0x44 0x44 0x44 0x00 0x00 0x00 0x88 |
| 0x44 0x44 0x47 0x00 0x00 0x00 0x00 0x88 |
| 0x44 0x44 0x00 0x00 0x00 0x00 0x88 0x88 |
| 0x44 0x00 0x00 0x00 0x00 0x88 0x88 0x88 |
| 0x44 0x00 0x00 0x00 0x88 0x88 0x88 0x88 |
| 0x49 0x00 0x00 0x88 0x88 0x88 0x88 0x88 |
| 0x83 0x88 0x88 0x88 0x88 0x88 0x88 0x88` |
| |
| // image2NoEdgesAbove0x00 is the result of zeroing out all pixels in image2 where the Sobel |
| // operator value for the corresponding pixel in image1 is above 0. |
| // |
| // It is identical to image1NoEdgesAbove0x00. |
| const image2NoEdgesAbove0x00 = `! SKTEXTSIMPLE |
| 8 8 |
| 0x44 0x44 0x44 0x44 0x44 0x44 0x49 0x83 |
| 0x44 0x44 0x44 0x00 0x00 0x00 0x00 0x88 |
| 0x44 0x44 0x00 0x00 0x00 0x00 0x00 0x88 |
| 0x44 0x00 0x00 0x00 0x00 0x00 0x00 0x88 |
| 0x44 0x00 0x00 0x00 0x00 0x00 0x88 0x88 |
| 0x44 0x00 0x00 0x00 0x00 0x88 0x88 0x88 |
| 0x49 0x00 0x00 0x00 0x88 0x88 0x88 0x88 |
| 0x83 0x88 0x88 0x88 0x88 0x88 0x88 0x88` |
| |
| // assertImagesEqual asserts that the two given images are equal, and prints out the actual image |
| // encoded as SKTEXT if the assertion is false. |
| func assertImagesEqual(t *testing.T, expected, actual image.Image) { |
| assertImagesEqualWithMessage(t, expected, actual, "") |
| } |
| |
| // assertImagesEqualWithMessage asserts that the two given images are equal, and prints out the |
| // actual image encoded as SKTEXT if the assertion is false, along with the given message if it is |
| // not empty. |
| func assertImagesEqualWithMessage(t *testing.T, expected, actual image.Image, msg string) { |
| // No need for newline if message is empty. |
| if msg != "" { |
| msg = msg + "\n" |
| } |
| |
| assert.Equal(t, expected, actual, fmt.Sprintf("%sSKTEXT-encoded expected output:\n%s\nSKTEXT-encoded actual output:\n%s", msg, imageToText(t, expected), imageToText(t, actual))) |
| } |
| |
| // imageToText returns the given image as an SKTEXT-encoded string. |
| func imageToText(t *testing.T, img image.Image) string { |
| // Convert image to NRGBA. |
| nrgbaImg := image.NewNRGBA(img.Bounds()) |
| draw.Draw(nrgbaImg, img.Bounds(), img, img.Bounds().Min, draw.Src) |
| |
| // Encode and return image as SKTEXTSIMPLE. |
| buf := &bytes.Buffer{} |
| err := text.Encode(buf, nrgbaImg) |
| require.NoError(t, err) |
| return buf.String() |
| } |
| |
| // readPngAsGray reads a PNG image from the file system, converts it to grayscale and returns it as |
| // an *image.Gray. |
| func readPngAsGray(t *testing.T, filename string) *image.Gray { |
| return imageToGray(readPng(t, filename)) |
| } |
| |
| // readPng reads a PNG image from the file system and returns it as an *image.NRGBA. |
| func readPng(t *testing.T, filename string) *image.NRGBA { |
| // Read image. |
| imgBytes, err := ioutil.ReadFile(filename) |
| require.NoError(t, err) |
| |
| // Decode image. |
| img, err := png.Decode(bytes.NewReader(imgBytes)) |
| require.NoError(t, err) |
| |
| // Convert to NRGBA. |
| nrgbaImg := image.NewNRGBA(img.Bounds()) |
| draw.Draw(nrgbaImg, img.Bounds(), img, img.Bounds().Min, draw.Src) |
| |
| return nrgbaImg |
| } |
