Convert geometry objects to & from JSON compatible dicts

extra_geom/__init__.py

@@ -35,8 +35,11 @@
 
 __version__ = "1.6.0"
 
-from .detectors import (AGIPD_1MGeometry, AGIPD_500K2GGeometry, DSSC_1MGeometry, Epix10KGeometry, Epix100Geometry,
-                        GenericGeometry, JUNGFRAUGeometry, LPD_1MGeometry, PNCCDGeometry, agipd_asic_seams)
+from .detectors import (
+    AGIPD_1MGeometry, AGIPD_500K2GGeometry, DSSC_1MGeometry, Epix10KGeometry, Epix100Geometry,
+    GenericGeometry, JUNGFRAUGeometry, LPD_1MGeometry, PNCCDGeometry, agipd_asic_seams,
+    geometry_from_dict,
+)
 
 __all__ = [
     'AGIPD_1MGeometry',
@@ -49,4 +52,5 @@
     'PNCCDGeometry',
     'Epix100Geometry',
     'Epix10KGeometry',
+    'geometry_from_dict',
 ]

extra_geom/base.py

@@ -35,6 +35,25 @@ def from_panel_dict(cls, d):
         fs_pixels = d['max_fs'] - d['min_fs'] + 1
         return cls(corner_pos, ss_vec, fs_vec, ss_pixels, fs_pixels)
 
+    @classmethod
+    def from_dict(cls, d):
+        return cls(
+            corner_pos=np.asarray(d['corner_pos']),
+            ss_vec=np.asarray(d['slow_scan_vector']),
+            fs_vec=np.asarray(d['fast_scan_vector']),
+            ss_pixels=d['slow_scan_pixels'],
+            fs_pixels=d['fast_scan_pixels'],
+        )
+
+    def to_dict(self):
+        return {
+            'corner_pos': self.corner_pos.tolist(),
+            'slow_scan_vector': self.ss_vec.tolist(),
+            'fast_scan_vector': self.fs_vec.tolist(),
+            'slow_scan_pixels': self.ss_pixels,
+            'fast_scan_pixels': self.fs_pixels,
+        }
+
     def corners(self):
         return np.stack([
             self.corner_pos,
@@ -73,6 +92,7 @@ def snap(self, px_shape):
 class DetectorGeometryBase:
     """Base class for detector geometry. Subclassed for specific detectors."""
     # Define in subclasses:
+    fixed_detector_type = False
     detector_type_name = ''
     pixel_size = 0.0
     frag_ss_pixels = 0
@@ -101,6 +121,37 @@ def __init__(self, modules, filename='No file', metadata=None):
         self.metadata = metadata if (metadata is not None) else {}
         self._snapped_cache = None
 
+    def to_dict(self):
+        if not self.fixed_detector_type:
+            raise NotImplementedError(
+                "to_dict() and from_dict() are currently only implemented for "
+                "specific fixed detector types"
+            )
+        return {
+            'detector': {'type': self.detector_type_name},
+            'modules': [
+                [t.to_dict() for t in mod]
+                for mod in self.modules
+            ]
+        }
+
+    @classmethod
+    def from_dict(cls, d):
+        if not cls.fixed_detector_type:
+            raise NotImplementedError(
+                "to_dict() and from_dict() are currently only implemented for "
+                "specific fixed detector types"
+            )
+        if d['detector']['type'] != cls.detector_type_name:
+            raise ValueError(
+                f"This class is for a {cls.detector_type_name} detector, but "
+                f"the data is for {d['detector']['type']}"
+            )
+        return cls([
+            [GeometryFragment.from_dict(d) for d in mod]
+            for mod in d['modules']
+        ])
+
     def _get_plot_scale_factor(self, axis_units):
         if axis_units == 'm':
             return 1

extra_geom/detectors.py

@@ -199,6 +199,7 @@ class AGIPD_1MGeometry(DetectorGeometryBase):
     use one of the constructor class methods to create or load a geometry.
     """
     detector_type_name = 'AGIPD-1M'
+    fixed_detector_type = True
     pixel_size = 2e-4  # 2e-4 metres == 0.2 mm
     frag_ss_pixels = 64
     frag_fs_pixels = 128
@@ -443,6 +444,7 @@ class AGIPD_500K2GGeometry(DetectorGeometryBase):
     use one of the constructor class methods to create or load a geometry.
     """
     detector_type_name = 'AGIPD-500K2G'
+    fixed_detector_type = True
     pixel_size = 2e-4  # 2e-4 metres == 0.2 mm
     frag_ss_pixels = 64
     frag_fs_pixels = 128
@@ -614,6 +616,7 @@ class LPD_1MGeometry(DetectorGeometryBase):
     use one of the constructor class methods to create or load a geometry.
     """
     detector_type_name = 'LPD-1M'
+    fixed_detector_type = True
     pixel_size = 5e-4  # 5e-4 metres == 0.5 mm
     frag_ss_pixels = 32
     frag_fs_pixels = 128
@@ -1024,6 +1027,7 @@ class DSSC_1MGeometry(DetectorGeometryBase):
     """
     # Hexagonal pixels, 236 μm step in fast-scan axis, 204 μm in slow-scan
     detector_type_name = 'DSSC-1M'
+    fixed_detector_type = True
     pixel_size = 236e-6
     frag_ss_pixels = 128
     frag_fs_pixels = 256
@@ -1447,6 +1451,7 @@ class JUNGFRAUGeometry(DetectorGeometryBase):
      dimension is x, so the data shape for one module is (y, x).
     """
     detector_type_name = 'JUNGFRAU'
+    fixed_detector_type = True
     pixel_size = 7.5e-5   # 7.5e-5 metres = 75 micrometer = 0.075 mm
     frag_ss_pixels = 256  # pixels along slow scan axis within tile
     frag_fs_pixels = 256  # pixels along fast scan axis within tile
@@ -2007,6 +2012,7 @@ class Epix100Geometry(EpixGeometryBase):
     array. This class assumes that calibration rows are cut.
     """
     detector_type_name = 'ePix100'
+    fixed_detector_type = True
     pixel_size = 50e-6
     inner_pixel_size = 175e-6
     asic_gap = 2 * (inner_pixel_size - pixel_size) / pixel_size
@@ -2084,6 +2090,7 @@ class Epix10KGeometry(EpixGeometryBase):
     array. This class assumes that calibration rows are cut.
     """
     detector_type_name = 'ePix10K'
+    fixed_detector_type = True
     pixel_size = 100e-6
     inner_pixel_size = 250e-6
     asic_gap = 2 * (inner_pixel_size - pixel_size) / pixel_size
@@ -2094,3 +2101,14 @@ class Epix10KGeometry(EpixGeometryBase):
         2 * frag_ss_pixels,
         2 * frag_fs_pixels
     )
+
+
+def geometry_from_dict(d: dict):
+    type_name = d['detector']['type']
+    for gcls in DetectorGeometryBase.__subclasses__():
+        if gcls.fixed_detector_type and gcls.detector_type_name == type_name:
+            return gcls.from_dict(d)
+
+    raise ValueError(
+        f"This version of EXtra-geom does not recognise a {type_name!r} detector"
+    )