from glasscut.exceptions import MagnificationError
[docs]
def build_magnification_mapping(
base_magnification: int | float, num_levels: int
) -> list[int | float]:
"""Build a list of available magnifications from pyramid levels.
Parameters
----------
base_magnification : int | float
The magnification at level 0 (e.g., 40, 20)
num_levels : int
Number of pyramid levels in the slide
Returns
-------
list[int | float]
List of magnifications in descending order (e.g., [40.0, 20.0, 10.0, 5.0])
"""
magnifications: list[int | float] = []
for i in range(num_levels):
downsample = 2**i
mag = base_magnification / downsample
magnifications.append(mag)
return sorted(magnifications, reverse=True)
[docs]
def magnification_to_level(
magnification: int | float, available_magnifications: list[int | float]
) -> int:
"""Convert magnification to the pyramid level.
This function performs EXACT matching - the requested magnification must
be available in the slide, otherwise an error is raised.
Parameters
----------
magnification : int | float
Target magnification (e.g., 40, 20, 10, 5)
available_magnifications : list[int | float]
List of available magnifications for the slide (in descending order)
Returns
-------
int
The level index corresponding to the magnification
Raises
------
MagnificationError
If the requested magnification is not available on this slide
"""
if not available_magnifications:
raise MagnificationError("No available magnifications in slide")
# Check for exact match (with tolerance for floating point)
tolerance = 0.01
for level, available_mag in enumerate(available_magnifications):
if abs(available_mag - magnification) < tolerance:
return level
# No match found
raise MagnificationError(
f"Magnification {magnification}x is not available on this slide. "
f"Available magnifications: {available_magnifications}"
)
GlassCut