clip-path

clip-path: circle(40%);

clip-path: ellipse(130px 140px at 10% 20%);

clip-path: polygon(50% 0, 100% 50%, 50% 100%, 0 50%);

clip-path: path("M 0 200 L 0,75 A 5,5 0,0,1 150,75 L 200 200 z");

clip-path: rect(5px 145px 160px 5px round 20%);

clip-path: xywh(0 5px 100% 75% round 15% 0);

<section class="default-example" id="default-example">
  <div class="example-container">
    <img
      class="transition-all"
      id="example-element"
      src="/shared-assets/images/examples/balloon-small.jpg"
      width="150" />
    We had agreed, my companion and I, that I should call for him at his house,
    after dinner, not later than eleven o’clock. This athletic young Frenchman
    belongs to a small set of Parisian sportsmen, who have taken up “ballooning”
    as a pastime. After having exhausted all the sensations that are to be found
    in ordinary sports, even those of “automobiling” at a breakneck speed, the
    members of the “Aéro Club” now seek in the air, where they indulge in all
    kinds of daring feats, the nerve-racking excitement that they have ceased to
    find on earth.
  </div>
</section>

section {
  align-items: flex-start;
}

.example-container {
  text-align: left;
  padding: 20px;
}

#example-element {
  float: left;
  width: 150px;
  margin: 20px;
}

/* Keyword values */
clip-path: none;

/* <clip-source> values */
clip-path: url("resources.svg#c1");

/* <geometry-box> values */
clip-path: margin-box;
clip-path: border-box;
clip-path: padding-box;
clip-path: content-box;
clip-path: fill-box;
clip-path: stroke-box;
clip-path: view-box;

/* <basic-shape> values */
clip-path: inset(100px 50px);
clip-path: circle(50px at 0 100px);
clip-path: ellipse(50px 60px at 10% 20%);
clip-path: polygon(50% 0%, 100% 50%, 50% 100%, 0% 50%);
clip-path: path(
  "M0.5,1 C0.5,1,0,0.7,0,0.3 A0.25,0.25,1,1,1,0.5,0.3 A0.25,0.25,1,1,1,1,0.3 C1,0.7,0.5,1,0.5,1 Z"
);
clip-path: rect(5px 5px 160px 145px round 20%);
clip-path: shape(from 0% 0%, line to 100% 0%, line to 50% 100%, close);
clip-path: xywh(0 5px 100% 75% round 15% 0);

/* Box and shape values combined */
clip-path: padding-box circle(50px at 0 100px);

/* Global values */
clip-path: inherit;
clip-path: initial;
clip-path: revert;
clip-path: revert-layer;
clip-path: unset;

<div></div>
<div></div>

body {
  display: flex;
  gap: 20px;
  flex-flow: row wrap;
}

div {
  height: 200px;
  width: 200px;
  box-sizing: border-box;
  background-color: rebeccapurple;
  border: 20px solid magenta;

  clip-path: polygon(50% 0, 100% 100%, 0 100%);
}

div:last-of-type {
  clip-path: content-box polygon(50% 0, 100% 100%, 0 100%);
}

div {
  clip-path: path("M100 0 L200 200 L0 200 Z");
}

div:last-of-type {
  clip-path: shape(from 50% 0, line to 100% 100%, line to 0 100%, close);
}

div {
  width: 250px;
  height: 250px;
}

<svg height="0" width="0">
  <defs>
    <clipPath id="window">
      <rect y="0" x="0" width="80" height="80" />
      <rect y="0" x="120" width="80" height="80" />
      <rect y="120" x="0" width="80" height="80" />
      <rect y="120" x="120" width="80" height="80" />
    </clipPath>
    <clipPath id="cross">
      <rect y="0" x="80" width="40" height="200" />
      <rect y="80" x="0" width="200" height="40" />
    </clipPath>
  </defs>
</svg>

<div class="window">Window</div>
<div class="cross">Cross</div>

body {
  display: flex;
  gap: 20px;
  flex-flow: row wrap;
  font: 2em sans-serif;
}

div {
  width: 200px;
  height: 200px;
  background-image: conic-gradient(
    at center,
    rebeccapurple,
    green,
    lightblue,
    rebeccapurple
  );

  border: 5px solid;
  box-sizing: border-box;
}

.window {
  clip-path: url("#window");
}

.cross {
  clip-path: url("#cross");
  align-content: center;
}

<img
  id="clipped"
  src="https://mdn.github.io/shared-assets/images/examples/progress-pride-flag.jpg"
  alt="Pride flag" />
<svg height="0" width="0">
  <defs>
    <clipPath id="star">
      <path d="M100,0 42,180 196,70 4,70 158,180z" />
    </clipPath>
  </defs>
</svg>

<select id="clipPath">
  <option value="none">none</option>
  <option value="circle(100px at 110px 100px)">circle</option>
  <option value="url(#star)" selected>star</option>
  <option value="inset(20px round 20px)">inset</option>
  <option value="rect(20px 150px 200px 20px round 10%)">rect</option>
  <option value="xywh(0 20% 90% 67% round 0 0 5% 5px)">xywh</option>
  <option value="path('M 0 200 L 0,110 A 110,90 0,0,1 240,100 L 200 340 z')">
    path
  </option>
</select>

<pre id="log"></pre>

#clipped {
  margin-bottom: 20px;
  clip-path: url("#star");
}

const clipPathSelect = document.getElementById("clipPath");
clipPathSelect.addEventListener("change", (evt) => {
  const path = evt.target.value;
  document.getElementById("clipped").style.clipPath = path;
  log(`clip-path: ${path};`);
});

function log(text) {
  const logElement = document.querySelector("#log");
  logElement.innerText = `${text}`;
  logElement.scrollTop = logElement.scrollHeight;
}