screensaver/huey/Huey.cpp

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

#include "Huey.hpp"
#include <libscscreensaver.hpp>
#include <string>

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

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

    private:
        double _hue {0};
};

ScreensaverPlugin* create_instance() {
    return new Huey;
}

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

void Huey::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);

    // show hue value
    std::string hue_text {std::to_string(static_cast<int>(_hue))};
    cairo_set_source_rgb(_c, 0, 0, 0);
    cairo_select_font_face(_c, "Helvetica", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
    cairo_set_font_size(_c, 24);
    cairo_move_to(_c, 30, 50);
    cairo_show_text(_c, hue_text.c_str());
    cairo_set_source_rgb(_c, 1, 1, 1);
    cairo_move_to(_c, 29, 49);
    cairo_show_text(_c, hue_text.c_str());

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