mohan-bee/stm32-midi-keys

clip-ground-outline.ts

PCB

Schematic

type Point = {x:number,y:number}
/** Clip the source's rectangular ground regions inside the rounded board edge. */
export function clipGroundOutline(subject:Point[], board:Point[]):Point[] {
  const clip=board.map(p=>({x:p.x*169.4/170,y:p.y*59.4/60}))
  const cross=(a:Point,b:Point,p:Point)=>(b.x-a.x)*(p.y-a.y)-(b.y-a.y)*(p.x-a.x)
  const area=clip.reduce((sum,p,i)=>sum+p.x*clip[(i+1)%clip.length].y-clip[(i+1)%clip.length].x*p.y,0)
  const sign=Math.sign(area)
  let output=subject
  for(let i=0;i<clip.length;i++) {
    const a=clip[i],b=clip[(i+1)%clip.length], input=output
    output=[]
    if(!input.length) break
    for(let j=0;j<input.length;j++) {
      const p=input[j],q=input[(j+1)%input.length]
      const dp=sign*cross(a,b,p),dq=sign*cross(a,b,q)
      if(dp>=-1e-9) output.push(p)
      if((dp>=0)!==(dq>=0)) {const t=dp/(dp-dq);output.push({x:p.x+t*(q.x-p.x),y:p.y+t*(q.y-p.y)})}
    }
  }
  return output
}