fix: handle off-centre masks in convolver and blurring grid padding

When the mask is near the image edge, the PSF blurring region can extend
beyond the array boundary. The convolver now accounts for asymmetric
mask positions when computing fft_shape, and the blurring grid passes
allow_padding=True so off-centre datasets no longer raise MaskException.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

autoarray/operators/convolver.py

@@ -116,8 +116,14 @@ class determines how masked real-space data are embedded into a padded array,
             s1 + s2 - 1 for s1, s2 in zip(mask_shape, self.kernel.shape_native)
         )
         import scipy.fft
+        from autoarray.mask.mask_2d_util import required_shape_for_kernel
 
-        fft_shape = tuple(scipy.fft.next_fast_len(s, real=True) for s in full_shape)
+        min_blur_shape = required_shape_for_kernel(mask, self.kernel.shape_native)
+
+        fft_shape = tuple(
+            scipy.fft.next_fast_len(max(s, r), real=True)
+            for s, r in zip(full_shape, min_blur_shape)
+        )
 
         self.fft_shape = fft_shape
         self.mask = mask.resized_from(self.fft_shape, pad_value=1)

autoarray/structures/grids/uniform_2d.py

@@ -710,7 +710,7 @@ def blurring_grid_from(
         """
 
         blurring_mask = mask.derive_mask.blurring_from(
-            kernel_shape_native=kernel_shape_native
+            kernel_shape_native=kernel_shape_native, allow_padding=True
         )
 
         return cls.from_mask(