SHAPE / 195
Mask composition
マスクを引き算して輪郭を残す
二つのマスクの重なる部分を除き、内側が透けた輪郭をつくります。背景に画像があっても中を塗りつぶす必要がありません。
見本の中を操作して変化を試してください。
実装コードを見る
<!doctype html><html lang="ja"><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1"><style>body{margin:0;min-height:300px}.sample{box-sizing:border-box;min-height:210px;width:100%;height:100%;display:grid;place-items:center;align-content:center;gap:18px;padding:24px;background:#efeee9;color:#202020;font-family:Arial,Meiryo,sans-serif;overflow:hidden}.sample *{box-sizing:border-box}.sample button{min-height:40px;border:1px solid #777;border-radius:999px;background:transparent;padding:9px 17px;font:12px Arial,Meiryo,sans-serif;color:inherit;cursor:pointer}.sample label{font-size:11px;display:grid;gap:8px;width:min(100%,220px)}.sample input{width:100%;accent-color:#222}.sample small{font-size:10px;line-height:1.6}.sample :focus-visible{outline:2px solid #222;outline-offset:4px}@media(prefers-reduced-motion:reduce){.sample *{animation:none!important;transition:none!important}}.mask-scene{width:180px;height:140px;position:relative;display:grid;place-items:center;background:repeating-linear-gradient(45deg,transparent 0 9px,#ddd 9px 10px)}.mask-scene b{font-size:36px;z-index:1}.mask-ring{position:absolute;inset:0;border-radius:40px;padding:14px;background:linear-gradient(130deg,#111,#aaa);mask:linear-gradient(#fff 0 0) content-box,linear-gradient(#fff 0 0);mask-composite:exclude}</style><div class="sample"><div class="mask-scene"><div class="mask-ring"></div><b>g*e</b></div><label>輪郭の厚み <output>14</output>px<input type="range" aria-label="輪郭の厚み" min="2" max="35" value="14" data-target=".mask-ring" data-prop="padding" data-unit="px"></label></div><script>const controller=(function controls(root){const abort=new AbortController();for(const input of root.querySelectorAll('[data-target]')){const update=()=>{const target=root.querySelector(input.dataset.target);if(input.dataset.attr)target.setAttribute(input.dataset.attr,input.value+(input.dataset.unit||''));else target.style.setProperty(input.dataset.prop,input.value+(input.dataset.unit||''));const output=input.closest('label')?.querySelector('output');if(output)output.textContent=input.value};input.addEventListener('input',update,{signal:abort.signal});update()}for(const button of root.querySelectorAll('[data-toggle]'))button.addEventListener('click',()=>{const target=root.querySelector(button.dataset.toggle),on=target.classList.toggle('changed');button.setAttribute('aria-pressed',String(on));},{signal:abort.signal});return {destroy(){abort.abort()},setAuto(){}}})(document);addEventListener('pagehide',()=>controller.destroy(),{once:true});</script></html>