an angle

java三点求⾓度_Java：计算两点之间的⾓度（以度为单位）

我从johncarls解决⽅案开始，但需要对其进⾏调整以完全满⾜我的需求。主要是，当⾓度增加时，我需要它顺时针旋转。我还需要0度才

能指向北。他的解决⽅案使我接近了，但是我决定也发布我的解决⽅案，以防其他⼈受益。

我添加了⼀些其他注释，以帮助解释我对功能的理解，以防您需要进⾏简单的修改。

/**

*CalculatestheanglefromcenterPttotargetPtindegrees.

*Thereturnshouldrangefrom[0,360),rotatingCLOCKWISE,

*0and360degreesreprentsNORTH,

*90degreesreprentsEAST,etc...

*

*arenot,

*tPointToScreenorequivalent

*onallargumentsbeforepassingthemtothisfunction.

*

*@paramcenterPtPointwearerotatingaround.

*@paramtargetPtPointwewanttocalcuatetheangleto.

*@theanglefromcenterPttotargetPt.

*/

publicstaticdoublecalcRotationAngleInDegrees(PointcenterPt,PointtargetPt)

{

//calculatetheanglethetafromthedeltaYanddeltaXvalues

//(atan2returnsradiansvaluesfrom[-PI,PI])

//0currentlypointsEAST.

//NOTE:ByprervingYandXparamordertoatan2,weareexpecting

//aCLOCKWISEangledirection.

doubletheta=2(targetPt.y-centerPt.y,targetPt.x-centerPt.x);

//rotatethethetaangleclockwiby90degrees

//(thismakes0pointNORTH)

//NOTE:addingtoananglerotatesitclockwi.

//subtractingwouldrotateitcounter-clockwi

theta+=/2.0;

//convertfromradianstodegrees

//thiswillgiveyouananglefrom[0->270],[-180,0]

doubleangle=ees(theta);

//converttopositiverange[0-360)

//sincewewanttopreventnegativeangles,adjustthemnow.

//wecanassumethatatan2willnotreturnanegativevalue

//greaterthanonepartialrotation

if(angle<0){

angle+=360;

}

returnangle;

}