Add kernel_radius properties (#17)

* Add kernel_size properties

* flake8

* Placebo._kernel_size: Use fallback, fix typing

* Change @Property to @stgpytools.classproperty

* Switch classproperty for inject_self.property

* Remove hack for spline

* Add kernel_size to Point

* Add kernel_size to base classes

* Add kernel_size to BicubicAuto

* Add abstract_kernels

Fix #45

* More code cleanup

* Fix Placebo default for kernel_size

* Remove unused import

* Fix EwaBicubic's radius

* Add kernel_size to FmtConv

* Add _static_kernel_size for kernel with static sizes

* Rename kernel_size to kernel_radius

* Fix typo

---------

Co-authored-by: Setsugennoao <[email protected]>

vskernels/kernels/abstract.py

@@ -19,6 +19,18 @@
 ]
 
 
+def _default_kernel_radius(cls, self) -> int:
+    if hasattr(self, '_static_kernel_radius'):
+        return ceil(self._static_kernel_radius)
+
+    try:
+        return super(cls, self).kernel_radius
+    except AttributeError:
+        ...
+
+    raise NotImplementedError
+
+
 class BaseScaler:
     @staticmethod
     def from_param(
@@ -120,6 +132,10 @@ def multi(
 
         return self.scale(clip, dst_width, dst_height, shift, **kwargs)
 
+    @inject_self.property
+    def kernel_radius(self) -> int:
+        return _default_kernel_radius(__class__, self)
+
 
 class Descaler(vs_object):
     @inject_self.cached
@@ -165,6 +181,10 @@ def ensure_obj(
     ) -> Descaler:
         return BaseScaler.ensure_obj(cls, Descaler, descaler, UnknownDescalerError, [], func_except)  # type: ignore
 
+    @inject_self.property
+    def kernel_radius(self) -> int:
+        return _default_kernel_radius(__class__, self)
+
 
 class Resampler(vs_object):
     @inject_self.cached
@@ -186,6 +206,10 @@ def ensure_obj(
     ) -> Resampler:
         return BaseScaler.ensure_obj(cls, Resampler, resampler, UnknownDescalerError, [], func_except)  # type: ignore
 
+    @inject_self.property
+    def kernel_radius(self) -> int:
+        return _default_kernel_radius(__class__, self)
+
 
 class Kernel(Scaler, Descaler, Resampler):
     """

vskernels/kernels/bicubic.py

@@ -3,7 +3,7 @@
 from math import acos, asinh, cos, sqrt
 from typing import TYPE_CHECKING, Any
 
-from vstools import CustomValueError, core, vs
+from vstools import CustomValueError, core, vs, inject_self
 
 from .complex import ComplexKernel
 
@@ -68,6 +68,12 @@ def get_params_args(
             return args | dict(b=self.b, c=self.c)
         return args | dict(filter_param_a=self.b, filter_param_b=self.c)
 
+    @inject_self.property
+    def kernel_radius(self) -> int:
+        if (self.b, self.c) == (0, 0):
+            return 1
+        return 2
+
 
 class BSpline(Bicubic):
     """Bicubic b=1, c=0"""
@@ -265,3 +271,7 @@ def _get_bc_args(self) -> tuple[float, float]:
             autoc = (self.target - self.b) / 2
 
         return autob, autoc
+
+    @inject_self.property
+    def kernel_radius(self) -> int:
+        return Bicubic(*self._get_bc_args()).kernel_radius

vskernels/kernels/fmtconv.py

@@ -1,12 +1,13 @@
 from __future__ import annotations
 
+from math import ceil
 from typing import Any, Callable, overload
 
 from vstools import VideoFormatT, VSFunction, core, inject_self, vs
 
 from .abstract import Resampler
-from .complex import ComplexScaler
 from .bicubic import Bicubic
+from .complex import ComplexScaler
 
 __all__ = [
     'FmtConv'
@@ -167,3 +168,12 @@ def _shift(shift_top: float | list[float] = 0.0, shift_left: float | list[float]
                 shifts_left = shifts_left[:n_planes]
 
         return _shift(shifts_top, shifts_left)
+
+    @inject_self.property
+    def kernel_radius(self) -> int:
+        taps_hv = self.kwargs.get('taps_h', self.kwargs.get('taps_v', None))
+
+        if taps_hv is None:
+            taps_hv = self.taps
+
+        return ceil(taps_hv)

vskernels/kernels/placebo.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from math import ceil
 from typing import TYPE_CHECKING, Any
 
 from vstools import Transfer, TransferT, core, inject_self, vs
@@ -82,3 +83,15 @@ def get_params_args(
             antiring=self.antiring, cutoff=self.cutoff,
             lut_entries=self.lut_entries, trc=curve.value_libplacebo
         )
+
+    @inject_self.property
+    def kernel_radius(self) -> int:
+        from .bicubic import Bicubic
+
+        if self.taps:
+            return ceil(self.taps)
+
+        if self.b or self.c:
+            return Bicubic(self.b, self.c).kernel_radius
+
+        return 2

vskernels/kernels/resize.py

@@ -1,8 +1,9 @@
 from __future__ import annotations
 
+from math import ceil
 from typing import Any
 
-from vstools import core, vs
+from vstools import core, vs, inject_self
 
 from .zimg import ZimgComplexKernel
 
@@ -17,13 +18,15 @@ class Point(ZimgComplexKernel):
     """Built-in point resizer."""
 
     scale_function = resample_function = descale_function = core.lazy.resize.Point
+    _static_kernel_radius = 1
 
 
 class Bilinear(ZimgComplexKernel):
     """Built-in bilinear resizer."""
 
     scale_function = resample_function = core.lazy.resize.Bilinear
     descale_function = core.lazy.descale.Debilinear
+    _static_kernel_radius = 1
 
 
 class Lanczos(ZimgComplexKernel):
@@ -51,3 +54,7 @@ def get_params_args(
         if is_descale:
             return args | dict(taps=self.taps)
         return args | dict(filter_param_a=self.taps)
+
+    @inject_self.property
+    def kernel_radius(self) -> int:
+        return ceil(self.taps)

vskernels/kernels/spline.py

@@ -4,8 +4,8 @@
 
 from vstools import core
 
-from .zimg import ZimgComplexKernel
 from .fmtconv import FmtConv
+from .zimg import ZimgComplexKernel
 
 __all__ = [
     'Spline',
@@ -35,6 +35,7 @@ class Spline16(ZimgComplexKernel):
 
     scale_function = resample_function = core.lazy.resize.Spline16
     descale_function = core.lazy.descale.Despline16
+    _static_kernel_radius = 2
 
 
 class Spline36(ZimgComplexKernel):
@@ -48,6 +49,7 @@ class Spline36(ZimgComplexKernel):
 
     scale_function = resample_function = core.lazy.resize.Spline36
     descale_function = core.lazy.descale.Despline36
+    _static_kernel_radius = 3
 
 
 class Spline64(ZimgComplexKernel):
@@ -61,3 +63,4 @@ class Spline64(ZimgComplexKernel):
 
     scale_function = resample_function = core.lazy.resize.Spline64
     descale_function = core.lazy.descale.Despline64
+    _static_kernel_radius = 4

vskernels/kernels/various.py

@@ -107,7 +107,9 @@ def __init__(self, b: float = 0.0, c: float = 0.5, radius: int | None = None, **
         radius = kwargs.pop('taps', radius)
 
         if radius is None:
-            radius = 1 if (b, c) == (0, 0) else 2
+            from .bicubic import Bicubic
+
+            radius = Bicubic(b, c).kernel_radius
 
         super().__init__(radius, b, c, **kwargs)