UXGradientStop

UXGradientStop is a colour pinned to a position on a UXGradient’s axis.

#use <UXKit>            // or #import "UXGradient.xc"

Overview

class UXGradientStop : Object {
    i32      pos;      // 0..255 along the gradient
    UXColor* color;
}

addStop makes stops and keeps them in position order. You read them back through stopAt, for example to serialise a theme or draw the handles of a gradient editor.

Position is a byte, not a fraction

i32 pos      // 0..255

The range is 0–255 rather than 0.0–1.0 because the whole gradient uses integer arithmetic. The same stops sample to the same colours on every backend, with no float to round differently.

256 positions is finer than the eye resolves in a ramp, and finer than most displays can show without banding. If you need more steps than the axis has, add stops. The resolution that matters is the number of distinct colours, not the number of positions between them.

addStop clamps out-of-range positions to the ends instead of rejecting them, so a stop at -50 becomes a stop at 0.

Two stops at one position make a hard edge

A new stop is inserted after any existing stop at the same position. Two stops sharing a position have zero span between them, so colorAt jumps instead of ramping:

g.addStop(128, red);
g.addStop(128, blue);      // colour switches at 128, with no blend

Use this for a stepped ramp or a two-tone fill. It follows from the ordering rule, so no flag is needed.

The colour is shared, not copied

UXColor* color

The stop keeps the pointer you passed to addStop. The toolkit treats a UXColor as immutable, and every operation returns a new one, so sharing a colour between stops, gradients and controls is normal and safe.

Changing a UXColor’s fields in place would change every stop that holds it. lightened, darkened and blend all return new colours, so you never need to.

init leaves color null, but a stop in a gradient always has a colour, because addStop is the only way to add one.

Fields

pos

i32 pos      // 0..255

color

UXColor* color

Conforms to

Inherits Object