feat: Add and test axis code loading

Author: effigies

src/files/nifti.ts

@@ -65,6 +65,7 @@ export async function loadHeader(file: BIDSFile): Promise<NiftiHeader> {
       },
       qform_code: header.qform_code,
       sform_code: header.sform_code,
+      axis_codes: axisCodes(header.affine),
     } as NiftiHeader
   } catch (err) {
     throw { code: 'NIFTI_HEADER_UNREADABLE' }

src/tests/local/nifti_rules.test.ts

@@ -0,0 +1,13 @@
+import { assertEquals, assertObjectMatch } from '@std/assert'
+import { loadHeader } from '../../files/nifti.ts'
+import { BIDSFileDeno } from '../../files/deno.ts'
+
+Deno.test('Test NIFTI-specific rules', async (t) => {
+  await t.step('Test reading NIfTI axis codes' , async () => {
+    for (const axcodes of [['R', 'A', 'S'], ['S', 'P', 'L'], ['A', 'I', 'R']]) {
+      const testfile = `tests/data/${axcodes.join('')}.nii.gz`
+      const header = await loadHeader(new BIDSFileDeno('', testfile))
+      assertEquals(header.axis_codes, axcodes)
+    }
+  })
+})