screensaver/skembo/Skembo.cpp

//
// Skembo.cpp
// screensaver
//
// Created by Bob Polis at 2020-10-26
// Copyright (c) 2020 SwiftCoder. All rights reserved.
//

#include "Skembo.hpp"
#include <libscscreensaver.hpp>

class Skembo : public ScreensaverPlugin {
    public:
        Skembo() = default;
        ~Skembo() = default;

        int fps() const override;
        void draw_frame() override;

    private:
        double _hue {0};
};

ScreensaverPlugin* create_instance() {
    return new Skembo;
}

int Skembo::fps() const {
    return 40;
}

void Skembo::draw_frame() {
    // next color
    HSB hsb;
    hsb.h = _hue;
    hsb.s = 1.0;
    hsb.b = 0.4;

    // convert to rgb
    Color color {hsb};
    RGB rgb {RGB(color)};

    // setup color, fill whole window
    cairo_set_source_rgb(_c, rgb.r, rgb.g, rgb.b);
    cairo_rectangle(_c, _r.x, _r.y, _r.width, _r.height);
    cairo_fill(_c);

    // update for next frame
    _hue += 0.5;
    if (_hue > 360.0) {
        _hue -= 360.0;
    }
}