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Merge pull request #1921 from deirdreobyrne/widmp_fix 

Fixing the moon phase calculation
master
Gordon Williams 2022-06-06 12:03:51 +01:00 committed by GitHub
parent f78f13a85a 940241ce52
commit ab637c9b36
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3 changed files with 28 additions and 14 deletions
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1
apps/widmp/ChangeLog
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@ -2,3 +2,4 @@
0.02: Fix position and overdraw bugs
0.03: Better memory usage, theme support
0.04: Replace the 8 phases by a more exact drawing, see forum.espruino.com/conversations/371985
0.05: Fixed the algorithm for calculating the moon's phase

2
apps/widmp/metadata.json
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@ -1,7 +1,7 @@
{
"id": "widmp",
"name": "Moon Phase Widget",
"version": "0.04",
"version": "0.05",
"description": "Display the current moon phase in blueish for both hemispheres. In the southern hemisphere the 'My Location' app is needed.",
"icon": "widget.png",
"type": "widget",

39
apps/widmp/widget.js
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@ -1,19 +1,24 @@
WIDGETS["widmoon"] = { area: "tr", width: 24, draw: function() {
const CenterX = this.x + 12, CenterY = this.y + 12, Radius = 11;
var southernHemisphere = false; // when in southern hemisphere, use the "My Location" App
var lastCalculated = 0; // When we last calculated the phase
var phase = 0; // The last phase we calculated
const simulate = false; // simulate one month in one minute
const updateR = 1000; // update every x ms in simulation
function moonPhase() {
const d = Date();
var month = d.getMonth(), year = d.getFullYear(), day = d.getDate();
if (simulate) day = d.getSeconds() / 2 +1;
if (month < 3) {year--; month += 12;}
mproz = ((365.25 * year + 30.6 * ++month + day - 694039.09) / 29.5305882);
mproz = mproz - (mproz | 0); // strip integral digits, result is between 0 and <1
if (simulate) console.log(mproz + " " + day);
return (mproz);
// https://deirdreobyrne.github.io/calculating_moon_phases/
function moonPhase(millis) {
k = (millis - 946728000000) / 3155760000000;
mp = (8328.69142475915 * k) + 2.35555563685;
m = (628.30195516723 * k) + 6.24006012726;
d = (7771.37714483372 * k) + 5.19846652984;
t = d + (0.109764 * Math.sin (mp)) - (0.036652 * Math.sin(m)) + (0.022235 * Math.sin(d+d-mp)) + (0.011484 * Math.sin(d+d)) + (0.003735 * Math.sin(mp+mp)) + (0.00192 * Math.sin(d));
k = (1 - Math.cos(t))/2;
if (Math.sin(t) < 0) {
k = -k;
}
return (k); // Goes 0 -> 1 for waxing, and from -1 -> 0 for waning
}
function loadLocation() {
@ -44,11 +49,19 @@ WIDGETS["widmoon"] = { area: "tr", width: 24, draw: function() {
g.fillRect(CenterX - Radius, CenterY - Radius, CenterX + Radius, CenterY + Radius);
g.setColor(0x41f);
mproz = moonPhase(); // mproz = 0..<1
millis = (new Date()).getTime();
if ((millis - lastCalculated) >= 7200000) {
phase = moonPhase(millis);
lastCalculated = millis;
}
leftFactor = mproz * 4 - 1;
rightFactor = (1 - mproz) * 4 - 1;
if (mproz >= 0.5) leftFactor = 1; else rightFactor = 1;
if (phase < 0) { // waning - phase goes from -1 to 0
leftFactor = 1;
rightFactor = -1 - 2*phase;
} else { // waxing - phase goes from 0 to 1
rightFactor = 1;
leftFactor = -1 + 2*phase;
}
if (true == southernHemisphere) {
var tmp=leftFactor; leftFactor=rightFactor; rightFactor=tmp;
}