Tried to find the detailed implementation of ImageFilter

[anonymous530]

What did you do?

Tried to find the detailed implementation of ImageFilter, but I can't figure out where filterargs are used? That is, I can't figure out the implementation detail for image filter. I just saw the filter function in Image.py and ImageFilter in ImageFilter.py , but still could't find the detailed implementation. Could you help me?

What did you expect to happen?

Tried to find the detailed implementation of ImageFilter.

[anonymous530]

Is the ImageFilter implemented in libImaging/Filter.c ?

[radarhere]

Starting from code -

from PIL import Image, ImageFilter
im = Image.new("RGB", (100, 100), "#f00")
im.filter(ImageFilter.BLUR)

im.filter calls -

Pillow/src/PIL/Image.py

Line 1185 in 1699616

def filter(self, filter):

Which then calls this, or a similar line -

Pillow/src/PIL/Image.py

Line 1205 in 1699616

return self._new(filter.filter(self.im))

Since filter is ImageFilter.BLUR that was passed in, the filter method of ImageFilter.BLUR is called. Note that self.im is not a PIL.Image.Image instance, but an ImagingCore object.

ImageFilter.BLUR inherits ImageFilter.BuiltinFilter -

Pillow/src/PIL/ImageFilter.py

Line 212 in 1699616

class BLUR(BuiltinFilter):

Pillow/src/PIL/ImageFilter.py

Lines 36 to 40 in 1699616

	class BuiltinFilter(MultibandFilter):
	def filter(self, image):
	if image.mode == "P":
	raise ValueError("cannot filter palette images")
	return image.filter(*self.filterargs)

image being an ImagingCore object, this moves into the C code.

Pillow/src/_imaging.c

Line 3194 in 1699616

{"filter", (PyCFunction)_filter, 1},

Pillow/src/_imaging.c

Lines 1004 to 1005 in 1699616

	static PyObject*
	_filter(ImagingObject* self, PyObject* args)

This parses the filterargs that were passed in -

Pillow/src/_imaging.c

Lines 1014 to 1015 in 1699616

	if (!PyArg_ParseTuple(args, "(ii)ffO", &xsize, &ysize,
	&divisor, &offset, &kernel))

and calls -

Pillow/src/_imaging.c

Line 1032 in 1699616

ImagingFilter(self->image, xsize, ysize, kerneldata, offset)

leading to

Pillow/src/libImaging/Filter.c

Lines 316 to 317 in 1699616

	Imaging
	ImagingFilter(Imaging im, int xsize, int ysize, const FLOAT32* kernel,

So yes, src/libImaging/Filter.c

[anonymous530]

Thanks