Struct GammaSpline 

pub struct GammaSpline { /* private fields */ }

Spline-based gamma correction curve.

Port of C++ gamma_spline from ctrl/agg_gamma_spline.h. Takes 4 control parameters (kx1, ky1, kx2, ky2) each in [0.001..1.999] and generates a smooth gamma curve through 4 interpolation points:

• (0, 0)
• (kx1 * 0.25, ky1 * 0.25)
• (1 - kx2 * 0.25, 1 - ky2 * 0.25)
• (1, 1)

Produces a 256-entry lookup table (gamma()) and supports evaluation (y()). Also implements a vertex source interface for rendering the curve.

Implementations

impl GammaSpline

pub fn new() -> Self

pub fn set_values(&mut self, kx1: f64, ky1: f64, kx2: f64, ky2: f64)

Set the 4 control parameters and rebuild the spline and gamma table.

Each parameter should be in [0.001..1.999]; values are clamped.

pub fn get_values(&self) -> (f64, f64, f64, f64)

Get the 4 control parameters back from the stored spline points.

pub fn gamma(&self) -> &[u8; 256]

Get the 256-entry gamma lookup table.

pub fn y(&self, x: f64) -> f64

Evaluate the spline curve at x (0..1) → result clamped to [0..1].

pub fn set_box(&mut self, x1: f64, y1: f64, x2: f64, y2: f64)

Set the bounding box for vertex source rendering.

pub fn rewind(&mut self, _idx: u32)

Rewind vertex source iteration.

pub fn vertex(&mut self, vx: &mut f64, vy: &mut f64) -> u32

Get the next vertex of the gamma curve path.

Trait Implementations

impl Default for GammaSpline

fn default() -> Self

Returns the “default value” for a type.

impl GammaFunction for GammaSpline

fn call(&self, x: f64) -> f64