mapbox-gl-draw 绘制态势标绘-双箭头

CreateDoubleArrow.js

function getMid(t,e){return[(t[0]+e[0])/2,(t[1]+e[1])/2]}function getDistance(t,e){return Math.sqrt(Math.pow(t[0]-e[0],2)+Math.pow(t[1]-e[1],2))}function getAngle(t,e,i){let n=getAzimuth(e,t)-getAzimuth(e,i);return n<0?n+TWO_PI:n}function getAzimuth(t,e){let i,n=Math.asin(Math.abs(e[1]-t[1])/getDistance(t,e));return e[1]>=t[1]&&e[0]>=t[0]?i=n+Math.PI:e[1]>=t[1]&&e[0]<t[0]?i=TWO_PI-n:e[1]<t[1]&&e[0]<t[0]?i=n:e[1]<t[1]&&e[0]>=t[0]&&(i=Math.PI-n),i}function getSymetricPoint(t,e,i,n,r){let o=getAzimuth(t,e),c=r?o+i:o-i,g=n*Math.cos(c),a=n*Math.sin(c);return[e[0]+g,e[1]+a]}function calculateSymmetryPoint(t,e,i){let n,r,o,c,g=getMid(t,e),a=getDistance(g,i),P=getAngle(t,g,i);return P<HALF_PI?(r=a*Math.sin(P),o=a*Math.cos(P),c=getSymetricPoint(t,g,HALF_PI,r,!1),n=getSymetricPoint(g,c,HALF_PI,o,!0)):P>=HALF_PI&&P<Math.PI?(r=a*Math.sin(Math.PI-P),o=a*Math.cos(Math.PI-P),c=getSymetricPoint(t,g,HALF_PI,r,!1),n=getSymetricPoint(g,c,HALF_PI,o,!1)):P>=Math.PI&&P<1.5*Math.PI?(r=a*Math.sin(P-Math.PI),o=a*Math.cos(P-Math.PI),c=getSymetricPoint(t,g,HALF_PI,r,!0),n=getSymetricPoint(g,c,HALF_PI,o,!0)):(r=a*Math.sin(2*Math.PI-P),o=a*Math.cos(2*Math.PI-P),c=getSymetricPoint(t,g,HALF_PI,r,!0),n=getSymetricPoint(g,c,HALF_PI,o,!1)),n}function getBaseLength(t){return Math.pow(wholeDistance(t),.99)}function wholeDistance(t){let e=0;for(let i=0;i<t.length-1;i++)e+=getDistance(t[i],t[i+1]);return e}function getAngleOfThreePoints(t,e,i){let n=getAzimuth(e,t)-getAzimuth(e,i);return n<0?n+TWO_PI:n}function getArrowHeadPoints(t,e,i){let n=getBaseLength(t),r=n*hea