cannot merge Alpha (from colormap) and Mask with different type

[vincentsarago]

reported in stac-utils/titiler-pgstac#79

import numpy

mask = numpy.zeros((256,256), dtype="uint8")
alpha = numpy.zeros((256,256), dtype="float32")

numpy.bitwise_and(alpha, mask)
>> TypeError: ufunc 'bitwise_and' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''

rio-tiler/rio_tiler/models.py

Line 488 in 0c9d4e5

numpy.bitwise_and(alpha, self.mask),

rio-tiler/rio_tiler/utils.py

Line 430 in 0c9d4e5

mask = numpy.bitwise_and(alpha, mask)

[vincentsarago]

after more 👀

It appears that the bug is in the mosaic methods

rio-tiler/rio_tiler/mosaic/methods/base.py

Line 36 in 0c9d4e5

return self.tile.data, (~self.tile.mask[0] * 255).astype(self.tile.dtype)

We shouldn't cast the mask to the data dtype