Function parse_polygon_coordinates_from_array

std/src/gfx/mod.rs:102–159

Parses an array reference that contains a variable-length sequence of X/Y coordinate pairs.

(scope: &Scope<'_>)

/// Parses an array reference that contains a variable-length sequence of X/Y coordinate pairs.
fn parse_polygon_coordinates_from_array(scope: &Scope<'_>) -> CallResult<Vec<PixelsXY>> {
    debug_assert_eq!(1, scope.nargs());

    let array = scope.get_ref(0);
    let pos = scope.get_pos(0);
    if array.vtype != ExprType::Integer {
        return Err(CallError::Syntax(pos, "Expected an INTEGER array".to_owned()));
    }

    let dimensions = array.array_dimensions();
    match dimensions {
        [ncoords] => {
            if !ncoords.is_multiple_of(2) {
                return Err(CallError::Syntax(
                    pos,
                    "Expected an even number of coordinates".to_owned(),
                ));
            }

            let mut points = Vec::with_capacity(*ncoords / 2);
            for i in (0..*ncoords).step_by(2) {
                let x = array
                    .deref_array_integer(&[i as i32])
                    .map_err(|e| CallError::Syntax(pos, e))?;
                let y = array
                    .deref_array_integer(&[(i + 1) as i32])
                    .map_err(|e| CallError::Syntax(pos, e))?;
                points.push(PixelsXY {
                    x: parse_coordinate_value(pos, x)?,
                    y: parse_coordinate_value(pos, y)?,
                });
            }
            Ok(points)
        }

        [npoints, 2] => {
            let mut points = Vec::with_capacity(*npoints);
            for i in 0..*npoints {
                let x = array
                    .deref_array_integer(&[i as i32, 0])
                    .map_err(|e| CallError::Syntax(pos, e))?;
                let y = array
                    .deref_array_integer(&[i as i32, 1])
                    .map_err(|e| CallError::Syntax(pos, e))?;
                points.push(PixelsXY {
                    x: parse_coordinate_value(pos, x)?,
                    y: parse_coordinate_value(pos, y)?,
                });
            }
            Ok(points)
        }

        _ => Err(CallError::Syntax(
            pos,
            "Expected a flat array of coordinates or an Nx2 array of points".to_owned(),
        )),
    }
}