slint/examples/orbit-animation/orbiter.slint

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: MIT

enum OrbiterState { front, back }

export component Orbiter {
    in property <OrbiterState> state: OrbiterState.front;
    in-out property source <=> img.source;
    in-out property colorize <=> img.colorize;
    in property <angle> orbit-rotation: 0deg;
    in property <angle> offset: 45deg;
    in property <length> radius: 220px;
    property <angle> internal-rotation: orbit-rotation + offset;
    in property <angle> orbit-attack: 180deg;
    in property <length> ball-size: 60px;
    property <length> zPos: sin(internal-rotation) * radius;
    out property <float> scale: 0.3 + 0.7 * (zPos + radius) / (2 * radius);
    property <bool> infront: internal-rotation.mod(360deg) < 180deg;

    function isVisible() -> bool {
        if (infront && state == OrbiterState.front) || (!infront && state == OrbiterState.back) {
            return true;
        } else   {
            return false;
        }
    }

    visible: isVisible();

    Rectangle {
        x: cos(orbit-attack) * cos(internal-rotation) * radius;
        y: sin(orbit-attack) * cos(internal-rotation) * radius;
        img := Image {
            width: root.ball-size * scale;
            height: root.ball-size * scale;
            source: @image-url("images/sphere-small.png");
        }
    }

}