我的解決方案考慮了環(huán)繞并適用于任何角度。即使輸入范圍超出標(biāo)準(zhǔn)范圍 0°...360° 和 -180° ... +180°（就像示例中的 -195 值一樣）或者如果值是浮點(diǎn)數(shù)而不是整數(shù)。我現(xiàn)在修復(fù)了程序并用適當(dāng)?shù)?javascript 編寫了它 - 并在https://playcode.io/上對其進(jìn)行了測試
θi = -26;
ai = [-15, 15, -165, -195];
// loop test: ai = [-161.5, -82.6, +53.7, +174.8]; // array of angles
a = [0, 0, 0, 0]
for (i = 0; i < ai.length; i++)
{
a[i] = getValueBetween0And360(ai[i]);
}
console.log(`a = ${ai} (${a})`);
// loop test: for(θi = -400; θi <= +400; θi += 33.3) // new angle
{
θ = getValueBetween0And360(θi);
//console.log(`θi = ${θi}, θ = ${θ}`);
ccw = ai[getIndexOfNearestAngle(a, θ, -1)]; // closest angle anticlockwise to θ from array
cw = ai[getIndexOfNearestAngle(a, θ, +1)]; // closest angle clockwise to θ from array
console.log(`θ = ${θi.toFixed(1)} (${θ.toFixed(1)}),\tccw = ${ccw.toFixed(1)} (${getValueBetween0And360(ccw).toFixed(1)}),\tcw = ${cw.toFixed(1)} (${getValueBetween0And360(cw).toFixed(1)})`);
}
function getValueBetween0And360(input)
{
if (input < 0)
{
return (input + (Math.trunc(-input / 360) + 1.0) * 360.0) % 360.0;
}
return input % 360.0;
}
function getValueBetweenPlusMinus180(input)
{
in360 = getValueBetween0And360(input);
return 180 < in360
? in360 - 360
: in360;
}
// sign = +1 for clock wise (cw), -1 for counter clock wise (ccw)
// starting from angle θ towards found angle in array a
function getIndexOfNearestAngle(a, θ, sign)
{
var iF = -1;
var diffF = 1000;
for (var i = 0; i < a.length; i++)
{
var diff = sign * getDiffClockWise(a[i], θ);
var diffPos = getValueBetween0And360(diff);
//console.log(`start a[${i}] = ${a[i]}, diffPos = ${diffPos}, iF = ${iF}, diffF = ${diffF}, sign = ${sign}`);
if (diffPos < diffF)
{
diffF = diffPos;
iF = i;
}
//console.log(`end a[${i}] = ${a[i]}, diffPos = ${diffPos}, iF = ${iF}, diffF = ${diffF}`);
}
return iF;
}
function getDiffClockWise(a, θ)
{
//console.log(`diff = ${a - θ}, a = ${a}, θ = ${θ}`)
return a - θ;
}
結(jié)果是：
a = -15,15,-165,-195 (345,15,195,165)
θ = -26.0 (334.0), ccw = -165.0 (195.0), cw = -15.0 (345.0)
如果// loop test:在代碼中沒有替換，它會報(bào)告這些示例顯示環(huán)繞和浮動工作：
a = -161.5,-82.6,53.7,174.8 (198.5,277.4,53.7,174.8)
θ = -400.0 (320.0), ccw = -82.6 (277.4), cw = 53.7 (53.7)
θ = -366.7 (353.3), ccw = -82.6 (277.4), cw = 53.7 (53.7)
θ = -333.4 (26.6), ccw = -82.6 (277.4), cw = 53.7 (53.7)
θ = -300.1 (59.9), ccw = 53.7 (53.7), cw = 174.8 (174.8)
θ = -266.8 (93.2), ccw = 53.7 (53.7), cw = 174.8 (174.8)
θ = -233.5 (126.5), ccw = 53.7 (53.7), cw = 174.8 (174.8)
θ = -200.2 (159.8), ccw = 53.7 (53.7), cw = 174.8 (174.8)
θ = -166.9 (193.1), ccw = 174.8 (174.8), cw = -161.5 (198.5)
θ = -133.6 (226.4), ccw = -161.5 (198.5), cw = -82.6 (277.4)
θ = -100.3 (259.7), ccw = -161.5 (198.5), cw = -82.6 (277.4)
θ = -67.0 (293.0), ccw = -82.6 (277.4), cw = 53.7 (53.7)
θ = -33.7 (326.3), ccw = -82.6 (277.4), cw = 53.7 (53.7)
θ = -0.4 (359.6), ccw = -82.6 (277.4), cw = 53.7 (53.7)
θ = 32.9 (32.9), ccw = -82.6 (277.4), cw = 53.7 (53.7)
θ = 66.2 (66.2), ccw = 53.7 (53.7), cw = 174.8 (174.8)
θ = 99.5 (99.5), ccw = 53.7 (53.7), cw = 174.8 (174.8)
θ = 132.8 (132.8), ccw = 53.7 (53.7), cw = 174.8 (174.8)
θ = 166.1 (166.1), ccw = 53.7 (53.7), cw = 174.8 (174.8)
θ = 199.4 (199.4), ccw = -161.5 (198.5), cw = -82.6 (277.4)
θ = 232.7 (232.7), ccw = -161.5 (198.5), cw = -82.6 (277.4)
θ = 266.0 (266.0), ccw = -161.5 (198.5), cw = -82.6 (277.4)
θ = 299.3 (299.3), ccw = -82.6 (277.4), cw = 53.7 (53.7)
θ = 332.6 (332.6), ccw = -82.6 (277.4), cw = 53.7 (53.7)
θ = 365.9 (5.9), ccw = -82.6 (277.4), cw = 53.7 (53.7)
θ = 399.2 (39.2), ccw = -82.6 (277.4), cw = 53.7 (53.7)
