vtk-pure-rs 0.2.0

Pure Rust visualization toolkit — data structures, filters, I/O, rendering
Documentation 
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use crate::data::{AnyDataArray, DataArray, ImageData};

/// Extract a 1D profile along a row (fixed j, k) from ImageData.
pub fn image_profile_row(input: &ImageData, scalars: &str, row: usize, slice: usize) -> Vec<f64> {
    let arr = match input.point_data().get_array(scalars) { Some(a)=>a, None=>return vec![] };
    let dims = input.dimensions();
    let nx=dims[0] as usize; let ny=dims[1] as usize;
    let j=row.min(ny-1); let k=slice.min(dims[2] as usize-1);
    let mut buf=[0.0f64];
    (0..nx).map(|i| { arr.tuple_as_f64(k*ny*nx+j*nx+i, &mut buf); buf[0] }).collect()
}

/// Extract a 1D profile along a column (fixed i, k) from ImageData.
pub fn image_profile_column(input: &ImageData, scalars: &str, col: usize, slice: usize) -> Vec<f64> {
    let arr = match input.point_data().get_array(scalars) { Some(a)=>a, None=>return vec![] };
    let dims = input.dimensions();
    let nx=dims[0] as usize; let ny=dims[1] as usize;
    let i=col.min(nx-1); let k=slice.min(dims[2] as usize-1);
    let mut buf=[0.0f64];
    (0..ny).map(|j| { arr.tuple_as_f64(k*ny*nx+j*nx+i, &mut buf); buf[0] }).collect()
}

/// Extract a diagonal profile from corner to corner.
pub fn image_profile_diagonal(input: &ImageData, scalars: &str) -> Vec<f64> {
    let arr = match input.point_data().get_array(scalars) { Some(a)=>a, None=>return vec![] };
    let dims = input.dimensions();
    let nx=dims[0] as usize; let ny=dims[1] as usize;
    let n = nx.min(ny);
    let mut buf=[0.0f64];
    (0..n).map(|i| {
        let j = i * (ny-1) / (n-1).max(1);
        let ii = i * (nx-1) / (n-1).max(1);
        arr.tuple_as_f64(j*nx+ii, &mut buf); buf[0]
    }).collect()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn row_profile() {
        let mut img = ImageData::with_dimensions(4, 3, 1);
        let values: Vec<f64> = (0..12).map(|i| i as f64).collect();
        img.point_data_mut().add_array(AnyDataArray::F64(DataArray::from_vec("v", values, 1)));

        let profile = image_profile_row(&img, "v", 1, 0);
        assert_eq!(profile.len(), 4);
        assert_eq!(profile[0], 4.0); // row 1, col 0
    }

    #[test]
    fn column_profile() {
        let mut img = ImageData::with_dimensions(3, 4, 1);
        let values: Vec<f64> = (0..12).map(|i| i as f64).collect();
        img.point_data_mut().add_array(AnyDataArray::F64(DataArray::from_vec("v", values, 1)));

        let profile = image_profile_column(&img, "v", 1, 0);
        assert_eq!(profile.len(), 4);
        assert_eq!(profile[0], 1.0); // row 0, col 1
    }

    #[test]
    fn diagonal_profile() {
        let mut img = ImageData::with_dimensions(3, 3, 1);
        let values: Vec<f64> = (0..9).map(|i| i as f64).collect();
        img.point_data_mut().add_array(AnyDataArray::F64(DataArray::from_vec("v", values, 1)));

        let profile = image_profile_diagonal(&img, "v");
        assert_eq!(profile.len(), 3);
        assert_eq!(profile[0], 0.0); // (0,0)
        assert_eq!(profile[2], 8.0); // (2,2)
    }

    #[test]
    fn missing_array() {
        let img = ImageData::with_dimensions(3, 3, 1);
        assert!(image_profile_row(&img, "nope", 0, 0).is_empty());
    }
}