Enum BandExpression 

pub enum BandExpression {
    Band(usize),
    Constant(f32),
    Add(Box<BandExpression>, Box<BandExpression>),
    Sub(Box<BandExpression>, Box<BandExpression>),
    Mul(Box<BandExpression>, Box<BandExpression>),
    Div(Box<BandExpression>, Box<BandExpression>),
    Sqrt(Box<BandExpression>),
    Abs(Box<BandExpression>),
    Neg(Box<BandExpression>),
    Min(Box<BandExpression>, Box<BandExpression>),
    Max(Box<BandExpression>, Box<BandExpression>),
    Pow(Box<BandExpression>, Box<BandExpression>),
    Log(Box<BandExpression>),
    Exp(Box<BandExpression>),
    Clamp {
        value: Box<BandExpression>,
        lo: Box<BandExpression>,
        hi: Box<BandExpression>,
    },
}

A composable expression tree for multi-band raster math.

Leaf nodes are either a Band index or a scalar Constant. Interior nodes are arithmetic operators.

Variants

Band(usize)

Reference to band at the given index.

Constant(f32)

Scalar constant.

Add(Box<BandExpression>, Box<BandExpression>)

Addition: A + B

Sub(Box<BandExpression>, Box<BandExpression>)

Subtraction: A - B

Mul(Box<BandExpression>, Box<BandExpression>)

Multiplication: A * B

Div(Box<BandExpression>, Box<BandExpression>)

Division: A / B (errors on divide-by-zero)

Sqrt(Box<BandExpression>)

Square root: sqrt(max(0, A))

Abs(Box<BandExpression>)

Absolute value: |A|

Neg(Box<BandExpression>)

Negation: -A

Min(Box<BandExpression>, Box<BandExpression>)

Element-wise minimum: min(A, B)

Max(Box<BandExpression>, Box<BandExpression>)

Element-wise maximum: max(A, B)

Pow(Box<BandExpression>, Box<BandExpression>)

Power: A ^ B (uses pow(A, B) in WGSL).

Log(Box<BandExpression>)

Natural logarithm: ln(A).

Exp(Box<BandExpression>)

Exponential: exp(A).

Clamp

Clamp: clamp(A, lo, hi) — equivalent to min(max(A, lo), hi).

Fields

value: Box<BandExpression>

lo: Box<BandExpression>

hi: Box<BandExpression>

Implementations

impl BandExpression

pub fn evaluate(&self, bands: &[f32]) -> Result<f32, GpuError>

Evaluate the expression for one pixel given per-band values.

Errors

Returns GpuError::InvalidKernelParams when a Band index is out of range or a Div node encounters a zero denominator.

Trait Implementations

impl Clone for BandExpression

fn clone(&self) -> BandExpression

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BandExpression

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.