Tournament Matchup Wheel is a free spinner for drawing a casual opponent, practice pairing, or exhibition matchup from an eligible team list. It makes the selection visible while keeping seeded or regulated tournament rules separate.
Wheel of Names
Elimination: OFFAccumulation: OFFAuto-Spin: OFFFair Rotation: OFF
Add entries and spin the wheel.
(()=>{
const r=document.currentScript.closest(‘.wnx-spinner’);
if(!r||r.dataset.ready)return;
r.dataset.ready=’1′;
const $=s=>r.querySelector(s),$$=s=>[…r.querySelectorAll(s)];
const params=new URLSearchParams(location.search),cfg=document.querySelector(‘.wnx-config’);
const mode=cfg?.dataset.mode||r.dataset.mode||’standard’;
const title=cfg?.dataset.title||r.dataset.title||document.querySelector(‘.wn-page h1′)?.textContent||’Wheel of Names’;
const raw=params.get(‘wnitems’)||cfg?.dataset.items||r.dataset.items||’Alice~Bob~Charlie~David~Eve~Frank’;
const palettes=[
((cfg?.dataset.palette)||r.dataset.palette||”).split(‘,’).filter(Boolean),
[‘#6366f1′,’#8b5cf6′,’#ec4899′,’#f97316′,’#14b8a6′,’#3b82f6’],
[‘#ef476f’,’#f78c6b’,’#ffd166′,’#06d6a0′,’#118ab2′,’#7353ba’],
[‘#22c55e’,’#06b6d4′,’#3b82f6′,’#8b5cf6′,’#ec4899′,’#f59e0b’]
].filter(x=>x.length>2);
let colors=palettes[0];
let entries=raw.split(‘~’).map(v=>{try{return decodeURIComponent(v)}catch(e){return v}}).filter(Boolean).map(v=>{
const p=v.split(‘|’);
const weight=mode===’weighted’?Math.max(1,Number(p.pop())||1):1;
return{name:p.join(‘|’),weight,count:0,last:-999,image:”};
});
let angle=0,busy=false,history=[],undo=[],redo=[],spinNumber=0,lastReceipt=null,preSpin=[];
let backgroundImage=”,centerImage=”,backgroundOpacity=.45,centerRadius=76,pendingEntryImage=”,pendingEntryFilename=”;
const imageCache=new Map();
const canvas=$(‘.wnx-canvas’),ctx=canvas.getContext(‘2d’),spin=$(‘.wnx-spin’),result=$(‘.wnx-result’),list=$(‘.wnx-list’);
const elimination=$(‘.wnx-elimination’),accumulation=$(‘.wnx-accumulation’),auto=$(‘.wnx-auto’),winnerCount=$(‘.wnx-winner-count’),duration=$(‘.wnx-duration’);
const balance=$(‘.wnx-smart-balance’),cooldown=$(‘.wnx-smart-cooldown’);
$(‘.wnx-title’).textContent=title;
elimination.checked=mode===’norepeat’||params.get(‘wnremove’)===’1′;
winnerCount.value=mode===’multi’?Math.max(1,Number(cfg?.dataset.count||r.dataset.count)||3):1;
$(‘.wnx-multi-field’).classList.toggle(‘wnx-hidden’,mode!==’multi’);
const escapeHtml=s=>String(s).replace(/[&”‘]/g,m=>({‘&’:’&’,”:’>’,'”‘:’"’,”‘”:’'’}[m]));
const snapshot=()=>JSON.stringify(entries);
const save=()=>{undo.push(snapshot());if(undo.length>25)undo.shift();redo=[];};
const randomInt=n=>{if(n=limit);return a[0]%n;};
function getImage(src){
if(!src)return null;
if(imageCache.has(src))return imageCache.get(src);
const img=new Image();
img.onload=draw;
img.src=src;
imageCache.set(src,img);
return img;
}
function drawCover(img,x,y,w,h){
if(!img||!img.complete||!img.naturalWidth)return;
const scale=Math.max(w/img.naturalWidth,h/img.naturalHeight);
const dw=img.naturalWidth*scale,dh=img.naturalHeight*scale;
ctx.drawImage(img,x+(w-dw)/2,y+(h-dh)/2,dw,dh);
}
function readOptimizedImage(file,maxSize=1000){
return new Promise((resolve,reject)=>{
if(!file||!file.type.startsWith(‘image/’)){reject(new Error(‘Please choose an image file.’));return;}
const reader=new FileReader();
reader.onerror=()=>reject(new Error(‘The image could not be read.’));
reader.onload=()=>{
const img=new Image();
img.onerror=()=>reject(new Error(‘The image format is not supported.’));
img.onload=()=>{
const scale=Math.min(1,maxSize/Math.max(img.naturalWidth,img.naturalHeight));
const w=Math.max(1,Math.round(img.naturalWidth*scale)),h=Math.max(1,Math.round(img.naturalHeight*scale));
const temp=document.createElement(‘canvas’);temp.width=w;temp.height=h;
const t=temp.getContext(‘2d’);t.drawImage(img,0,0,w,h);
const type=file.type===’image/png’?’image/png’:’image/jpeg’;
resolve(temp.toDataURL(type,type===’image/jpeg’?.86:undefined));
};
img.src=String(reader.result||”);
};
reader.readAsDataURL(file);
});
}
const smartOn=()=>!elimination.checked&&(balance.checked||Number(cooldown.value)>0);
function eligibleEntries(){
let pool=[…entries];
if(!smartOn())return pool;
const cd=Number(cooldown.value);
if(cd>0){const cooled=pool.filter(e=>spinNumber-e.last>=cd);if(cooled.length)pool=cooled;}
if(balance.checked&&pool.length){const min=Math.min(…pool.map(e=>e.count));pool=pool.filter(e=>e.count===min);}
return pool.length?pool:[…entries];
}
function segments(){
const total=entries.reduce((s,e)=>s+e.weight,0)||1;
let used=0;
return entries.map(entry=>{const start=used/total*Math.PI*2;used+=entry.weight;return{entry,start,end:used/total*Math.PI*2};});
}
function draw(){
const size=900,center=450,radius=418,segs=segments(),allowed=new Set(eligibleEntries());
ctx.clearRect(0,0,size,size);
if(backgroundImage){
const img=getImage(backgroundImage);
ctx.save();ctx.beginPath();ctx.arc(center,center,radius,0,Math.PI*2);ctx.clip();ctx.globalAlpha=backgroundOpacity;drawCover(img,center-radius,center-radius,radius*2,radius*2);ctx.restore();
}
if(!segs.length){
ctx.beginPath();ctx.arc(center,center,radius,0,Math.PI*2);ctx.fillStyle=’#0b1628′;ctx.fill();ctx.strokeStyle=’rgba(129,140,248,.24)’;ctx.lineWidth=6;ctx.stroke();ctx.fillStyle=’#94a3b8′;ctx.font=’800 34px system-ui’;ctx.textAlign=’center’;ctx.fillText(‘Add entries’,center,center);return;
}
segs.forEach((seg,index)=>{
const dim=smartOn()&&!allowed.has(seg.entry);
const start=seg.start+angle,end=seg.end+angle;
ctx.save();
ctx.globalAlpha=dim?.2:1;
ctx.beginPath();ctx.moveTo(center,center);ctx.arc(center,center,radius,start,end);ctx.closePath();
if(seg.entry.image){
ctx.save();ctx.clip();drawCover(getImage(seg.entry.image),center-radius,center-radius,radius*2,radius*2);ctx.restore();
ctx.globalAlpha=dim?.12:.22;ctx.fillStyle=colors[index%colors.length];ctx.fill();ctx.globalAlpha=dim?.2:1;
}else{
ctx.fillStyle=colors[index%colors.length];
if(backgroundImage)ctx.globalAlpha=dim?.14:.72;
ctx.fill();ctx.globalAlpha=dim?.2:1;
}
ctx.strokeStyle=’rgba(255,255,255,.82)’;ctx.lineWidth=5;ctx.stroke();
const mid=(seg.start+seg.end)/2+angle;
ctx.translate(center,center);ctx.rotate(mid);ctx.textAlign=’right’;ctx.fillStyle=’#fff’;ctx.shadowColor=’rgba(0,0,0,.55)’;ctx.shadowBlur=8;
ctx.font=`850 ${Math.max(18,Math.min(33,350/entries.length+16))}px system-ui`;
const label=seg.entry.name.length>22?seg.entry.name.slice(0,20)+’…’:seg.entry.name;
ctx.fillText(label,radius-34,10);ctx.restore();
});
ctx.save();ctx.beginPath();ctx.arc(center,center,centerRadius,0,Math.PI*2);ctx.clip();
if(centerImage){drawCover(getImage(centerImage),center-centerRadius,center-centerRadius,centerRadius*2,centerRadius*2);}else{ctx.fillStyle=’#0b1628′;ctx.fillRect(center-centerRadius,center-centerRadius,centerRadius*2,centerRadius*2);}
ctx.restore();ctx.beginPath();ctx.arc(center,center,centerRadius,0,Math.PI*2);ctx.strokeStyle=’rgba(255,255,255,.24)’;ctx.lineWidth=10;ctx.stroke();
}
function updateBadges(){
[[ $(‘.wnx-badge-elimination’),elimination,’Elimination’],[$(‘.wnx-badge-accumulation’),accumulation,’Accumulation’],[$(‘.wnx-badge-auto’),auto,’Auto-Spin’],[$(‘.wnx-badge-smart’),{checked:smartOn()},’Fair Rotation’]].forEach(([el,input,label])=>{el.textContent=`${label}: ${input.checked?’ON’:’OFF’}`;el.classList.toggle(‘is-on’,input.checked);});
}
function balanceScore(){
if(!entries.length)return 100;
const total=entries.reduce((s,e)=>s+e.count,0),mean=total/entries.length;
if(!mean)return 100;
const deviation=entries.reduce((s,e)=>s+Math.abs(e.count-mean),0)/entries.length;
return Math.max(0,Math.round(100-deviation/mean*100));
}
function updateDashboard(){
$(‘.wnx-balance-score’).textContent=balanceScore()+’%’;$(‘.wnx-smart-spins’).textContent=String(spinNumber);
$(‘.wnx-smart-counts’).innerHTML=[…entries].sort((a,b)=>a.count-b.count||a.name.localeCompare(b.name)).map(e=>`
${escapeHtml(e.name)}${e.count}
`).join(”)||’
No entries yet.
‘;
const status=$(‘.wnx-smart-status’);
if(elimination.checked&&(balance.checked||Number(cooldown.value)>0))status.textContent=’Smart Fair Rotation is paused while Elimination mode is active.’;
else if(!smartOn())status.textContent=’Pure random mode is active.’;
else{const parts=[];if(balance.checked)parts.push(‘least-selected priority’);if(Number(cooldown.value)>0)parts.push(`${cooldown.value}-spin cooldown`);status.textContent=`Smart mode active: ${parts.join(‘ + ‘)}. Dimmed slices are temporarily ineligible.`;}
}
function render(){
list.innerHTML=entries.map((entry,index)=>`
A tournament matchup wheel selects one team or participant from the eligible pool. For complete pairings, remove each selected entry and spin again, or use two identical pools and document every draw.
How to use the Tournament Matchup Wheel
Replace the sample entries with your eligible options.
Review the list, explain the selection rule, and press Spin the Wheel.
Confirm the result, record it when accountability matters, and remove it before another spin when repeats are not allowed.
Best uses for this Tournament Matchup Wheel
Practice rounds
Create varied opponent pairings for training sessions.
Casual tournaments
Draw transparent matchups when all teams have equal status.
Exhibition events
Select featured pairings from a pre-approved eligible pool.
Tournament Matchup Wheel setup tips
Publish eligibility, byes, rematch rules, and draw order before spinning.
Do not mix seeded and unseeded teams unless the event rules explicitly allow it.
Save the draw sequence so organizers can reproduce the bracket decisions.
`:”}