LunaIcon.qml

/**

    Copyright (C) 2024 Samuel Jimenez <therealsamueljimenez@gmail.com>
          Ported the Luna Plasmoid to Plasma 6.

    Copyright 2016,2017 Bill Binder <dxtwjb@gmail.com>
    Copyright (C) 2011, 2012, 2013 Glad Deschrijver <glad.deschrijver@gmail.com>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, see <http://www.gnu.org/licenses/>.

*/

import "../code/shadowcalcs.js" as ShadowCalcs
import Qt5Compat.GraphicalEffects
import QtQuick 2.1
import org.kde.ksvg as KSvg
import org.kde.plasma.core as PlasmaCore
import org.kde.plasma.plasmoid

Item {
    id: lunaIcon

    property int phaseNumber: 0
    property int latitude: 90 //Degrees: 0=Equator, 90=North Pole, -90=South Pole
    property bool showShadow: true
    property bool transparentShadow: true
    property string lunarImage: ''
    property color diskColor: '#ffffff'
    property int lunarImageTweak: 0
    property bool showGrid: false
    property bool showTycho: false
    property bool showCopernicus: false
    // Degrees. 0= new moon, 90= first quarter, 180= full moon, 270= third quarter
    property int theta: 45

    KSvg.Svg {
        id: lunaSvg

        imagePath: lunarImage === '' ? '' : Qt.resolvedUrl("../data/" + lunarImage)
    }

    KSvg.SvgItem {
        id: lunaSvgItem

        visible: false
        anchors.centerIn: parent
        width: Math.min(parent.width, parent.height)
        height: Math.min(parent.width, parent.height)
        svg: lunaSvg
        // Rotation to compensate the moon's image basic position to a north pole view
        // FIXME: Somehow it does not work when applied to OpacityMask or Blend
        transformOrigin: Item.Center
        rotation: -lunarImageTweak
    }

    Canvas {
        id: shadow

        property int latitude: lunaIcon.latitude
        property int theta: lunaIcon.theta
        property bool showShadow: lunaIcon.showShadow
        property string lunarImage: lunaIcon.lunarImage
        property string diskColor: lunaIcon.diskColor
        property bool showGrid: lunaIcon.showGrid
        property bool showTycho: lunaIcon.showTycho
        property bool showCopernicus: lunaIcon.showCopernicus

        function radians(deg) {
            return deg / 180 * Math.PI;
        }

        function marker(radius, latitude, longitude) {
            var dy = radius * Math.sin(radians(latitude));
            var dx = radius * Math.cos(radians(latitude)) * Math.sin(radians(longitude));
            // console.log("dx: " + dx.toString());
            // console.log("dy: " + dy.toString());
            context.beginPath();
            context.strokeStyle = "#FF0000";
            context.arc(dx, -dy, 5, 0, 2 * Math.PI);
            context.moveTo(dx - 5, -dy - 5);
            context.lineTo(dx + 5, -dy + 5);
            context.moveTo(dx - 5, -dy + 5);
            context.lineTo(dx + 5, -dy - 5);
            context.stroke();
        }

        function grid(radius) {
            context.beginPath();
            context.strokeStyle = "#FF4040";
            context.moveTo(0, -radius);
            context.lineTo(0, radius);
            context.moveTo(-radius, 0);
            context.lineTo(radius, 0);
            context.stroke();
            context.beginPath();
            context.strokeStyle = "#40FF40";
            for (var ll = 10; ll < 65; ll += 10) {
                var dy = radius * Math.sin(radians(ll));
                context.moveTo(-radius, dy);
                context.lineTo(radius, dy);
                context.moveTo(-radius, -dy);
                context.lineTo(radius, -dy);
            }
            context.stroke();
        }

        width: lunaSvgItem.width
        height: lunaSvgItem.height
        visible: false
        anchors.centerIn: parent
        contextType: "2d"
        onLatitudeChanged: requestPaint()
        onThetaChanged: requestPaint()
        onLunarImageChanged: requestPaint()
        onDiskColorChanged: requestPaint()
        onShowGridChanged: requestPaint()
        onShowTychoChanged: requestPaint()
        onShowCopernicusChanged: requestPaint()
        onPaint: {
            context.reset();
            context.globalAlpha = 0.9;
            context.fillStyle = '#000000';
            var ct = Math.cos(theta / 180 * Math.PI);
            var radius = ShadowCalcs.setup(Math.floor(shadow.height / 2));
            context.translate(radius, radius);
            // These two determine which side of the center meridian to draw
            // the two arcs enclosing the shadow area.
            var terminator = (theta <= 180) ? 1 : -1;
            var edge = (theta <= 180) ? -1 : 1;
            if (lunarImage === '') {
                context.beginPath();
                context.fillStyle = diskColor;
                context.arc(0, 0, radius, 0, 2 * Math.PI);
                context.closePath();
                context.fill();
            }
            if (showShadow) {
                context.beginPath();
                context.fillStyle = '#000000';
                context.moveTo(ShadowCalcs.get(-radius), -radius);
                for (var z = -radius; z < radius; z++) {
                    context.lineTo(terminator * ShadowCalcs.get(z) * ct, z);
                }
                for (var z = radius; z > -radius; z--) {
                    context.lineTo(edge * ShadowCalcs.get(z), z);
                }
                context.closePath();
                context.stroke();
                context.fill();
            } else {
                // Calibration markers
                if (showGrid)
                    grid(radius);

                // Tycho
                if (showTycho)
                    marker(radius, -43, -11.5);

                // Copernicus
                if (showCopernicus)
                    marker(radius, 9.6, -20);

            }
        }
    }

    // Shadow acts as a transparency mask
    OpacityMask {
        anchors.fill: lunaSvgItem
        source: lunaSvgItem
        maskSource: shadow
        invert: true
        rotation: latitude - 90
        visible: transparentShadow
    }

    // Shadow is printed on top of the moon image
    Blend {
        anchors.fill: lunaSvgItem
        source: lunaSvgItem
        foregroundSource: shadow
        rotation: latitude - 90
        mode: "normal"
        visible: !transparentShadow
    }

}