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Merged
elemeng merged 2 commits into from
Aug 27, 2025
Merged

Header improvements #4

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8e6349f
Mark Header exhaustive
akx Aug 25, 2025
acb0d0e
Adapt documentation for header fields from https://www.ccpem.ac.uk/mr…
akx Aug 25, 2025
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80 changes: 56 additions & 24 deletions src/header.rs
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Original file line number Diff line number Diff line change
@@ -1,40 +1,72 @@
use core::f32;

#[repr(C, align(4))]
#[derive(Debug, Clone, Copy, PartialEq)]
#[non_exhaustive]
pub struct Header {
/// number of columns in 3D data array (fast axis)
pub nx: i32,
/// Number of rows in 3D data array (medium axis)
pub ny: i32,
/// Number of sections in 3D data array (slow axis)
pub nz: i32,
/// Mode value (see `Mode` enum)
pub mode: i32,
/// Location of first column in unit cell
pub nxstart: i32,
/// Location of first row in unit cell
pub nystart: i32,
/// Location of first section in unit cell
pub nzstart: i32,
/// Sampling along X axis of unit cell
pub mx: i32,
/// Sampling along Y axis of unit cell
pub my: i32,
/// Sampling along Z axis of unit cell
pub mz: i32,
pub xlen: f32, // Unit cell edge length along X (Å).
pub ylen: f32, // Unit cell edge length along Y (Å).
pub zlen: f32, // Unit cell edge length along Z (Å).
pub alpha: f32, // Angle between Y and Z axes (degrees).
pub beta: f32, // Angle between X and Z axes (degrees).
pub gamma: f32, // Angle between X and Y axes (degrees).
pub mapc: i32, // 1-based index of column axis (1 = X, 2 = Y, 3 = Z).
pub mapr: i32, // 1-based index of row axis.
pub maps: i32, // 1-based index of section axis.
pub dmin: f32, // Minimum density value.
pub dmax: f32, // Maximum density value.
pub dmean: f32, // Mean density value.
pub ispg: i32, // Space-group number (1 = P1).
pub nsymbt: i32, // Bytes of symmetry data following the header.
pub extra: [u8; 100], // Reserved; bytes 8–11 hold EXTTYP, 12–15 NVERSION.
pub origin: [f32; 3], // Volume origin in voxels.
pub map: [u8; 4], // Magic bytes “MAP ”.
pub machst: [u8; 4], // Machine stamp (little-endian: 0x44 0x44 0x00 0x00).
pub rms: f32, // RMS deviation of density values.
pub nlabl: i32, // Number of valid labels (0–10).
pub label: [u8; 800], // Ten 80-byte text labels.
/// CELLA: Cell dimensions (unit cell edge length) in Angstroms (Å) along X axis
pub xlen: f32,
/// CELLA: Cell dimensions (unit cell edge length) in Angstroms (Å) along Y axis
pub ylen: f32,
/// CELLA: Cell dimensions (unit cell edge length) in Angstroms (Å) along Z axis
pub zlen: f32,
/// CELLB: Cell angles in degrees between the crystallographic axes Y and Z axes
pub alpha: f32,
/// CELLB: Cell angles in degrees between the crystallographic axes X and Z axes
pub beta: f32,
/// CELLB: Cell angles in degrees between the crystallographic axes X and Y axes
pub gamma: f32,
/// 1-based index of column axis (1,2,3 for X,Y,Z)
pub mapc: i32,
/// 1-based index of row axis (1,2,3 for X,Y,Z)
pub mapr: i32,
/// 1-based index of section axis (1,2,3 for X,Y,Z)
pub maps: i32,
/// Minimum density value
pub dmin: f32,
/// Maximum density value
pub dmax: f32,
/// Mean density value
pub dmean: f32,
/// Space group number; 0 implies 2D image or image stack.
/// For crystallography, represents the actual spacegroup.
/// For volume stacks, conventionally ISPG = spacegroup number + 400.
pub ispg: i32,
/// Size of extended header record ("symmetry data") in bytes.
pub nsymbt: i32,
/// Extra space used for anything.
/// Bytes 8–11 hold EXTTYP, 12–15 NVERSION.
pub extra: [u8; 100],
/// Volume/phase origin (pixels/voxels) or origin of subvolume
pub origin: [f32; 3],
/// Must contain "MAP " to identify file type
pub map: [u8; 4],
/// Machine stamp that encodes byte order of data
/// (little-endian: 0x44 0x44 0x00 0x00)
pub machst: [u8; 4],
/// RMS deviation of map from mean density
pub rms: f32,
/// Number of valid labels in `label` field (0–10)
pub nlabl: i32,
/// 10 text labels of 80 bytes each
pub label: [u8; 800],
}

impl Default for Header {
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