/* Keyword values */
shape-outside: none;
shape-outside: margin-box;
shape-outside: content-box;
shape-outside: border-box;
shape-outside: padding-box;

/* Function values */
shape-outside: circle();
shape-outside: ellipse();
shape-outside: inset(10px 10px 10px 10px);
shape-outside: polygon(10px 10px, 20px 20px, 30px 30px);
shape-outside: path("M100,0 A100,100 0 1,1 100,200 A100,100 0 1,1 100,0");

/* <url> value */
shape-outside: url(image.png);

/* <gradient> value */
shape-outside: linear-gradient(45deg, rgba(255, 255, 255, 0) 150px, red 150px);

/* Global values */
shape-outside: inherit;
shape-outside: initial;
shape-outside: revert;
shape-outside: revert-layer;
shape-outside: unset;

The shape-outside property is specified using the values from the list below, which define the float area for float elements. The float area determines the shape around which inline content (float elements) wrap.

none

The float area is unaffected. Inline content wraps around the element's margin box, like usual.

<shape-box>

The float area is computed according to the shape of a float element's edges (as defined by the CSS box model). This can be margin-box, border-box, padding-box, or content-box. The shape includes any curvature created by the border-radius property (behavior which is similar to background-clip).

margin-box

Defines the shape enclosed by the outside margin edge. The corner radii of this shape are determined by the corresponding border-radius and margin values. If the border-radius / margin ratio is 1 or more, then the margin box corner radius is border-radius + margin. If the ratio is less than 1, then the margin box corner radius is border-radius + (margin * (1 + (ratio-1)^3)).

border-box

Defines the shape enclosed by the outside border edge. The shape follows the normal border radius shaping rules for the outside of the border.

padding-box

Defines the shape enclosed by the outside padding edge. The shape follows the normal border radius shaping rules for the inside of the border.

content-box

Defines the shape enclosed by the outside content edge. Each corner radius of this box is the larger of 0 or border-radius - border-width - padding.

<basic-shape>

The float area is computed based on the shape created by of one of inset(), circle(), ellipse(), polygon() or, as added in the level 2 specification, path(). If a <shape-box> is also supplied, it defines the reference box for the <basic-shape> function. Otherwise, the reference box defaults to margin-box.

<image>

The float area is extracted and computed based on the alpha channel of the specified <image> as defined by shape-image-threshold.

When animating between one <basic-shape> and a second, the rules below are applied. The values in the shape functions interpolate as a simple list. The list values interpolate as <length>, <percentage>, or calc() where possible. If list values are not one of those types but are identical (such as finding nonzero in the same list position in both lists), those values do interpolate.

• Both shapes must use the same reference box.
• If both shapes are the same type, that type is ellipse() or circle(), and none of the radii use the closest-side or farthest-side keywords, interpolate between each value in the shape functions.
• If both shapes are of type inset(), interpolate between each value in the shape functions.
• If both shapes are of type polygon(), both polygons have the same number of vertices, and use the same <fill-rule>, interpolate between each value in the shape functions.
• In all other cases no interpolation occurs.

shape-outside = 
  none                              |
  [ <basic-shape> || <shape-box> ]  |
  <image>                           

<shape-box> = 
  <box>       |
  margin-box  

<image> = 
  <url>       |
  <gradient>  

<box> = 
  border-box   |
  padding-box  |
  content-box  

<url> = 
  url( <string> <url-modifier>* )  |
  src( <string> <url-modifier>* )  

HTML

<div class="main">
  <div class="left"></div>
  <div class="right"></div>
  <p>
    Sometimes a web page's text content appears to be funneling your attention
    towards a spot on the page to drive you to follow a particular link.
    Sometimes you don't notice.
  </p>
</div>

CSS

.main {
  width: 530px;
}

.left,
.right {
  width: 40%;
  height: 12ex;
  background-color: lightgray;
}

.left {
  shape-outside: polygon(0 0, 100% 100%, 0 100%);
  float: left;
  clip-path: polygon(0 0, 100% 100%, 0 100%);
}

.right {
  shape-outside: polygon(100% 0, 100% 100%, 0 100%);
  float: right;
  clip-path: polygon(100% 0, 100% 100%, 0 100%);
}

p {
  text-align: center;
}

Result

• CSS Shapes
• Overview of CSS Shapes
• Shapes from Box Values
• Basic Shapes
• Shapes from Images
• <basic-shape>
• shape-margin
• shape-image-threshold