diff --git a/Tests/test_image_resample.py b/Tests/test_image_resample.py index 73b25ed51..d4bd81559 100644 --- a/Tests/test_image_resample.py +++ b/Tests/test_image_resample.py @@ -165,6 +165,32 @@ class TestImagingCoreResampleAccuracy: for channel in case.split(): self.check_case(channel, self.make_sample(data, (8, 8))) + @pytest.mark.parametrize("mode", ("RGBX", "RGB", "La", "L")) + def test_reduce_mks2013(self, mode: str) -> None: + case = self.make_case(mode, (16, 16), 0xE1) + case = case.resize((8, 8), Image.Resampling.MKS2013) + # fmt: off + data = ("e1 e1 e9 dc" + "e1 e1 e9 dc" + "e9 e9 f1 e3" + "dc dc e4 d8") + # fmt: on + for channel in case.split(): + self.check_case(channel, self.make_sample(data, (8, 8))) + + @pytest.mark.parametrize("mode", ("RGBX", "RGB", "La", "L")) + def test_reduce_mks2021(self, mode: str) -> None: + case = self.make_case(mode, (16, 16), 0xE1) + case = case.resize((8, 8), Image.Resampling.MKS2021) + # fmt: off + data = ("e1 e1 e3 d7" + "e1 e1 e3 d7" + "e3 e3 e5 d9" + "d7 d7 d9 ce") + # fmt: on + for channel in case.split(): + self.check_case(channel, self.make_sample(data, (8, 8))) + @pytest.mark.parametrize("mode", ("RGBX", "RGB", "La", "L")) def test_enlarge_box(self, mode: str) -> None: case = self.make_case(mode, (2, 2), 0xE1) @@ -226,6 +252,36 @@ class TestImagingCoreResampleAccuracy: for channel in case.split(): self.check_case(channel, self.make_sample(data, (12, 12))) + @pytest.mark.parametrize("mode", ("RGBX", "RGB", "La", "L")) + def test_enlarge_mks2013(self, mode: str) -> None: + case = self.make_case(mode, (6, 6), 0xE1) + case = case.resize((12, 12), Image.Resampling.MKS2013) + data = ( + "e1 e1 e2 ef fb be" + "e1 e1 e2 ef fb be" + "e2 e2 e3 f1 fd bf" + "ef ef f0 ff ff c7" + "fb fb fc ff ff cf" + "be be bf c7 cf a8" + ) + for channel in case.split(): + self.check_case(channel, self.make_sample(data, (12, 12))) + + @pytest.mark.parametrize("mode", ("RGBX", "RGB", "La", "L")) + def test_enlarge_mks2021(self, mode: str) -> None: + case = self.make_case(mode, (6, 6), 0xE1) + case = case.resize((12, 12), Image.Resampling.MKS2021) + data = ( + "e3 e1 df e9 f5 bb" + "e1 df dd e7 f3 b9" + "df dd db e5 f1 b8" + "e9 e7 e5 ef fc be" + "f5 f3 f0 fc ff c5" + "bb ba b8 bf c6 a3" + ) + for channel in case.split(): + self.check_case(channel, self.make_sample(data, (12, 12))) + def test_box_filter_correct_range(self) -> None: im = Image.new("RGB", (8, 8), "#1688ff").resize( (100, 100), Image.Resampling.BOX @@ -309,6 +365,8 @@ class TestCoreResampleAlphaCorrect: self.run_levels_case(case.resize((512, 32), Image.Resampling.HAMMING)) self.run_levels_case(case.resize((512, 32), Image.Resampling.BICUBIC)) self.run_levels_case(case.resize((512, 32), Image.Resampling.LANCZOS)) + self.run_levels_case(case.resize((512, 32), Image.Resampling.MKS2013)) + self.run_levels_case(case.resize((512, 32), Image.Resampling.MKS2021)) @pytest.mark.xfail(reason="Current implementation isn't precise enough") def test_levels_la(self) -> None: @@ -318,6 +376,8 @@ class TestCoreResampleAlphaCorrect: self.run_levels_case(case.resize((512, 32), Image.Resampling.HAMMING)) self.run_levels_case(case.resize((512, 32), Image.Resampling.BICUBIC)) self.run_levels_case(case.resize((512, 32), Image.Resampling.LANCZOS)) + self.run_levels_case(case.resize((512, 32), Image.Resampling.MKS2013)) + self.run_levels_case(case.resize((512, 32), Image.Resampling.MKS2021)) def make_dirty_case( self, mode: str, clean_pixel: tuple[int, ...], dirty_pixel: tuple[int, ...] @@ -360,6 +420,12 @@ class TestCoreResampleAlphaCorrect: self.run_dirty_case( case.resize((20, 20), Image.Resampling.LANCZOS), (255, 255, 0) ) + self.run_dirty_case( + case.resize((20, 20), Image.Resampling.MKS2013), (255, 255, 0) + ) + self.run_dirty_case( + case.resize((20, 20), Image.Resampling.MKS2021), (255, 255, 0) + ) def test_dirty_pixels_la(self) -> None: case = self.make_dirty_case("LA", (255, 128), (0, 0)) @@ -368,6 +434,8 @@ class TestCoreResampleAlphaCorrect: self.run_dirty_case(case.resize((20, 20), Image.Resampling.HAMMING), (255,)) self.run_dirty_case(case.resize((20, 20), Image.Resampling.BICUBIC), (255,)) self.run_dirty_case(case.resize((20, 20), Image.Resampling.LANCZOS), (255,)) + self.run_dirty_case(case.resize((20, 20), Image.Resampling.MKS2013), (255,)) + self.run_dirty_case(case.resize((20, 20), Image.Resampling.MKS2021), (255,)) class TestCoreResamplePasses: @@ -453,6 +521,8 @@ class TestCoreResampleBox: Image.Resampling.HAMMING, Image.Resampling.BICUBIC, Image.Resampling.LANCZOS, + Image.Resampling.MKS2013, + Image.Resampling.MKS2021, ), ) def test_wrong_arguments(self, resample: Image.Resampling) -> None: diff --git a/Tests/test_image_resize.py b/Tests/test_image_resize.py index 270500a44..9e549cc71 100644 --- a/Tests/test_image_resize.py +++ b/Tests/test_image_resize.py @@ -72,6 +72,8 @@ class TestImagingCoreResize: Image.Resampling.HAMMING, Image.Resampling.BICUBIC, Image.Resampling.LANCZOS, + Image.Resampling.MKS2013, + Image.Resampling.MKS2021, ), ) def test_reduce_filters(self, resample: Image.Resampling) -> None: @@ -88,6 +90,8 @@ class TestImagingCoreResize: Image.Resampling.HAMMING, Image.Resampling.BICUBIC, Image.Resampling.LANCZOS, + Image.Resampling.MKS2013, + Image.Resampling.MKS2021, ), ) def test_enlarge_filters(self, resample: Image.Resampling) -> None: @@ -104,6 +108,8 @@ class TestImagingCoreResize: Image.Resampling.HAMMING, Image.Resampling.BICUBIC, Image.Resampling.LANCZOS, + Image.Resampling.MKS2013, + Image.Resampling.MKS2021, ), ) @pytest.mark.parametrize( @@ -154,6 +160,8 @@ class TestImagingCoreResize: Image.Resampling.HAMMING, Image.Resampling.BICUBIC, Image.Resampling.LANCZOS, + Image.Resampling.MKS2013, + Image.Resampling.MKS2021, ), ) def test_enlarge_zero(self, resample: Image.Resampling) -> None: diff --git a/docs/handbook/concepts.rst b/docs/handbook/concepts.rst index 46f612be3..0a4801af6 100644 --- a/docs/handbook/concepts.rst +++ b/docs/handbook/concepts.rst @@ -217,6 +217,23 @@ pixel, the Python Imaging Library provides different resampling *filters*. .. versionadded:: 1.1.3 +.. data:: Resampling.MKS2013 + :noindex: + + Calculate the output pixel value using the Magic Kernel Sharp 2013 filter + (a quadratic B-spline composed with a sharpening kernel) on all pixels that + may contribute to the output value. This filter can only be used with the + :py:meth:`~PIL.Image.Image.resize` and :py:meth:`~PIL.Image.Image.thumbnail` + methods. + +.. data:: Resampling.MKS2021 + :noindex: + + Calculate the output pixel value using the Magic Kernel Sharp 2021 filter + (a quadratic B-spline composed with a sharpening kernel) on all pixels that + may contribute to the output value. This filter can only be used with the + :py:meth:`~PIL.Image.Image.resize` and :py:meth:`~PIL.Image.Image.thumbnail` + methods. Filters comparison table ~~~~~~~~~~~~~~~~~~~~~~~~ @@ -237,3 +254,7 @@ Filters comparison table +---------------------------+-------------+-----------+-------------+ |:data:`Resampling.LANCZOS` | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐ | +---------------------------+-------------+-----------+-------------+ +|:data:`Resampling.MKS2013` | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐ | ++---------------------------+-------------+-----------+-------------+ +|:data:`Resampling.MKS2021` | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐| ⭐ | ++---------------------------+-------------+-----------+-------------+ diff --git a/src/PIL/Image.py b/src/PIL/Image.py index 262b5478b..e1610272f 100644 --- a/src/PIL/Image.py +++ b/src/PIL/Image.py @@ -147,6 +147,8 @@ class Resampling(IntEnum): HAMMING = 5 BICUBIC = 3 LANCZOS = 1 + MKS2013 = 6 + MKS2021 = 7 _filters_support = { @@ -155,6 +157,8 @@ _filters_support = { Resampling.HAMMING: 1.0, Resampling.BICUBIC: 2.0, Resampling.LANCZOS: 3.0, + Resampling.MKS2013: 2.5, + Resampling.MKS2021: 4.5, } @@ -2211,7 +2215,8 @@ class Image: :param resample: An optional resampling filter. This can be one of :py:data:`Resampling.NEAREST`, :py:data:`Resampling.BOX`, :py:data:`Resampling.BILINEAR`, :py:data:`Resampling.HAMMING`, - :py:data:`Resampling.BICUBIC` or :py:data:`Resampling.LANCZOS`. + :py:data:`Resampling.BICUBIC`, :py:data:`Resampling.LANCZOS`, + :py:data:`Resampling.MKS2013`, or :py:data:`Resampling.MKS2021`. If the image has mode "1" or "P", it is always set to :py:data:`Resampling.NEAREST`. Otherwise, the default filter is :py:data:`Resampling.BICUBIC`. See: :ref:`concept-filters`. @@ -2243,6 +2248,8 @@ class Image: Resampling.LANCZOS, Resampling.BOX, Resampling.HAMMING, + Resampling.MKS2013, + Resampling.MKS2021, ): msg = f"Unknown resampling filter ({resample})." @@ -2255,6 +2262,8 @@ class Image: (Resampling.BICUBIC, "Image.Resampling.BICUBIC"), (Resampling.BOX, "Image.Resampling.BOX"), (Resampling.HAMMING, "Image.Resampling.HAMMING"), + (Resampling.MKS2013, "Image.Resampling.MKS2013"), + (Resampling.MKS2021, "Image.Resampling.MKS2021"), ) ] msg += f" Use {', '.join(filters[:-1])} or {filters[-1]}" @@ -2706,7 +2715,8 @@ class Image: :param resample: Optional resampling filter. This can be one of :py:data:`Resampling.NEAREST`, :py:data:`Resampling.BOX`, :py:data:`Resampling.BILINEAR`, :py:data:`Resampling.HAMMING`, - :py:data:`Resampling.BICUBIC` or :py:data:`Resampling.LANCZOS`. + :py:data:`Resampling.BICUBIC`, :py:data:`Resampling.LANCZOS`, + :py:data:`Resampling.MKS2013`, or :py:data:`Resampling.MKS2021`. If omitted, it defaults to :py:data:`Resampling.BICUBIC`. (was :py:data:`Resampling.NEAREST` prior to version 2.5.0). See: :ref:`concept-filters`. @@ -2920,11 +2930,19 @@ class Image: Resampling.BILINEAR, Resampling.BICUBIC, ): - if resample in (Resampling.BOX, Resampling.HAMMING, Resampling.LANCZOS): + if resample in ( + Resampling.BOX, + Resampling.HAMMING, + Resampling.LANCZOS, + Resampling.MKS2013, + Resampling.MKS2021, + ): unusable: dict[int, str] = { Resampling.BOX: "Image.Resampling.BOX", Resampling.HAMMING: "Image.Resampling.HAMMING", Resampling.LANCZOS: "Image.Resampling.LANCZOS", + Resampling.MKS2013: "Image.Resampling.MKS2013", + Resampling.MKS2021: "Image.Resampling.MKS2021", } msg = unusable[resample] + f" ({resample}) cannot be used." else: diff --git a/src/libImaging/Imaging.h b/src/libImaging/Imaging.h index bfe67d462..675a68046 100644 --- a/src/libImaging/Imaging.h +++ b/src/libImaging/Imaging.h @@ -294,6 +294,8 @@ ImagingError_ValueError(const char *message); #define IMAGING_TRANSFORM_HAMMING 5 #define IMAGING_TRANSFORM_BICUBIC 3 #define IMAGING_TRANSFORM_LANCZOS 1 +#define IMAGING_TRANSFORM_MKS2013 6 +#define IMAGING_TRANSFORM_MKS2021 7 typedef int (*ImagingTransformMap)(double *X, double *Y, int x, int y, void *data); typedef int (*ImagingTransformFilter)(void *out, Imaging im, double x, double y); diff --git a/src/libImaging/Resample.c b/src/libImaging/Resample.c index b114e0023..ae0186c71 100644 --- a/src/libImaging/Resample.c +++ b/src/libImaging/Resample.c @@ -79,11 +79,55 @@ lanczos_filter(double x) { return 0.0; } +static inline double +mks_2013_filter(double x) { + /* https://johncostella.com/magic/ */ + if (x < 0) { + x = -x; + } + if (x < 0.5) { + return 17.0 / 16.0 - 7.0 / 4.0 * pow(x, 2); + } + if (x < 1.5) { + return (1.0 - x) * (7.0 / 4.0 - x); + } + if (x < 2.5) { + return -1.0 / 8.0 * pow(x - 5.0 / 2.0, 2); + } + return 0; +} + +static inline double +mks_2021_filter(double x) { + /* https://johncostella.com/magic/ */ + if (x < 0) { + x = -x; + } + if (x < 0.5) { + return 577.0 / 576.0 - 239.0 / 144.0 * pow(x, 2); + } + if (x < 1.5) { + return 35.0 / 36.0 * (x - 1.0) * (x - 239.0 / 140.0); + } + if (x < 2.5) { + return 1.0 / 6.0 * (x - 2.0) * (65.0 / 24.0 - x); + } + if (x < 3.5) { + return 1.0 / 36.0 * (x - 3.0) * (x - 15.0 / 4.0); + } + if (x < 4.5) { + return -1.0 / 288.0 * pow(x - 9.0 / 2.0, 2); + } + return 0; +} + static struct filter BOX = {box_filter, 0.5}; static struct filter BILINEAR = {bilinear_filter, 1.0}; static struct filter HAMMING = {hamming_filter, 1.0}; static struct filter BICUBIC = {bicubic_filter, 2.0}; static struct filter LANCZOS = {lanczos_filter, 3.0}; +static struct filter MKS2013 = {mks_2013_filter, 2.5}; +static struct filter MKS2021 = {mks_2021_filter, 4.5}; /* 8 bits for result. Filter can have negative areas. In one cases the sum of the coefficients will be negative, @@ -695,6 +739,12 @@ ImagingResample(Imaging imIn, int xsize, int ysize, int filter, float box[4]) { case IMAGING_TRANSFORM_LANCZOS: filterp = &LANCZOS; break; + case IMAGING_TRANSFORM_MKS2013: + filterp = &MKS2013; + break; + case IMAGING_TRANSFORM_MKS2021: + filterp = &MKS2021; + break; default: return (Imaging)ImagingError_ValueError("unsupported resampling filter"); }