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<!doctype html><html lang="en">
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
<meta content="width=device-width, initial-scale=1, shrink-to-fit=no" name="viewport">
<title>Compositing and Blending Level 1</title>
<meta content="ED" name="w3c-status">
<link href="https://www.w3.org/StyleSheets/TR/2021/W3C-ED" rel="stylesheet">
<meta content="Bikeshed version c3a8ac783, updated Wed Jul 24 12:20:06 2024 -0700" name="generator">
<link href="https://www.w3.org/TR/compositing-1/" rel="canonical">
<link href="https://drafts.csswg.org/csslogo.ico" rel="icon">
<meta content="9b96513f1950522941d4a948901244af0146e18a" name="revision">
<meta content="dark light" name="color-scheme">
<link href="https://www.w3.org/StyleSheets/TR/2021/dark.css" media="(prefers-color-scheme: dark)" rel="stylesheet" type="text/css">
<style type="text/css">
a[data-link-type=element]::before,span[data-link-type=element]::before {
content: '<';
}
a[data-link-type=element]::after,span[data-link-type=element]::after {
content: '>';
}
</style>
<style>/* Boilerplate: style-autolinks */
.css.css, .property.property, .descriptor.descriptor {
color: var(--a-normal-text);
font-size: inherit;
font-family: inherit;
}
.css::before, .property::before, .descriptor::before {
content: "‘";
}
.css::after, .property::after, .descriptor::after {
content: "’";
}
.property, .descriptor {
/* Don't wrap property and descriptor names */
white-space: nowrap;
}
.type { /* CSS value <type> */
font-style: italic;
}
pre .property::before, pre .property::after {
content: "";
}
[data-link-type="property"]::before,
[data-link-type="propdesc"]::before,
[data-link-type="descriptor"]::before,
[data-link-type="value"]::before,
[data-link-type="function"]::before,
[data-link-type="at-rule"]::before,
[data-link-type="selector"]::before,
[data-link-type="maybe"]::before {
content: "‘";
}
[data-link-type="property"]::after,
[data-link-type="propdesc"]::after,
[data-link-type="descriptor"]::after,
[data-link-type="value"]::after,
[data-link-type="function"]::after,
[data-link-type="at-rule"]::after,
[data-link-type="selector"]::after,
[data-link-type="maybe"]::after {
content: "’";
}
[data-link-type].production::before,
[data-link-type].production::after,
.prod [data-link-type]::before,
.prod [data-link-type]::after {
content: "";
}
[data-link-type=element],
[data-link-type=element-attr] {
font-family: Menlo, Consolas, "DejaVu Sans Mono", monospace;
font-size: .9em;
}
[data-link-type=element]::before { content: "<" }
[data-link-type=element]::after { content: ">" }
[data-link-type=biblio] {
white-space: pre;
}
@media (prefers-color-scheme: dark) {
:root {
--selflink-text: black;
--selflink-bg: silver;
--selflink-hover-text: white;
}
}
</style>
<style>/* Boilerplate: style-colors */
/* Any --*-text not paired with a --*-bg is assumed to have a transparent bg */
:root {
color-scheme: light dark;
--text: black;
--bg: white;
--unofficial-watermark: url(https://www.w3.org/StyleSheets/TR/2016/logos/UD-watermark);
--logo-bg: #1a5e9a;
--logo-active-bg: #c00;
--logo-text: white;
--tocnav-normal-text: #707070;
--tocnav-normal-bg: var(--bg);
--tocnav-hover-text: var(--tocnav-normal-text);
--tocnav-hover-bg: #f8f8f8;
--tocnav-active-text: #c00;
--tocnav-active-bg: var(--tocnav-normal-bg);
--tocsidebar-text: var(--text);
--tocsidebar-bg: #f7f8f9;
--tocsidebar-shadow: rgba(0,0,0,.1);
--tocsidebar-heading-text: hsla(203,20%,40%,.7);
--toclink-text: var(--text);
--toclink-underline: #3980b5;
--toclink-visited-text: var(--toclink-text);
--toclink-visited-underline: #054572;
--heading-text: #005a9c;
--hr-text: var(--text);
--algo-border: #def;
--del-text: red;
--del-bg: transparent;
--ins-text: #080;
--ins-bg: transparent;
--a-normal-text: #034575;
--a-normal-underline: #bbb;
--a-visited-text: var(--a-normal-text);
--a-visited-underline: #707070;
--a-hover-bg: rgba(75%, 75%, 75%, .25);
--a-active-text: #c00;
--a-active-underline: #c00;
--blockquote-border: silver;
--blockquote-bg: transparent;
--blockquote-text: currentcolor;
--issue-border: #e05252;
--issue-bg: #fbe9e9;
--issue-text: var(--text);
--issueheading-text: #831616;
--example-border: #e0cb52;
--example-bg: #fcfaee;
--example-text: var(--text);
--exampleheading-text: #574b0f;
--note-border: #52e052;
--note-bg: #e9fbe9;
--note-text: var(--text);
--noteheading-text: hsl(120, 70%, 30%);
--notesummary-underline: silver;
--assertion-border: #aaa;
--assertion-bg: #eee;
--assertion-text: black;
--advisement-border: orange;
--advisement-bg: #fec;
--advisement-text: var(--text);
--advisementheading-text: #b35f00;
--warning-border: red;
--warning-bg: hsla(40,100%,50%,0.95);
--warning-text: var(--text);
--amendment-border: #330099;
--amendment-bg: #F5F0FF;
--amendment-text: var(--text);
--amendmentheading-text: #220066;
--def-border: #8ccbf2;
--def-bg: #def;
--def-text: var(--text);
--defrow-border: #bbd7e9;
--datacell-border: silver;
--indexinfo-text: #707070;
--indextable-hover-text: black;
--indextable-hover-bg: #f7f8f9;
--outdatedspec-bg: rgba(0, 0, 0, .5);
--outdatedspec-text: black;
--outdated-bg: maroon;
--outdated-text: white;
--outdated-shadow: red;
--editedrec-bg: darkorange;
}
@media (prefers-color-scheme: dark) {
:root {
--text: #ddd;
--bg: black;
--unofficial-watermark: url("data:image/svg+xml,%3Csvg xmlns='http://www.w
2A1
3.org/2000/svg' width='400' height='400'%3E%3Cg fill='%23100808' transform='translate(200 200) rotate(-45) translate(-200 -200)' stroke='%23100808' stroke-width='3'%3E%3Ctext x='50%25' y='220' style='font: bold 70px sans-serif; text-anchor: middle; letter-spacing: 6px;'%3EUNOFFICIAL%3C/text%3E%3Ctext x='50%25' y='305' style='font: bold 70px sans-serif; text-anchor: middle; letter-spacing: 6px;'%3EDRAFT%3C/text%3E%3C/g%3E%3C/svg%3E");
--logo-bg: #1a5e9a;
--logo-active-bg: #c00;
--logo-text: white;
--tocnav-normal-text: #999;
--tocnav-normal-bg: var(--bg);
--tocnav-hover-text: var(--tocnav-normal-text);
--tocnav-hover-bg: #080808;
--tocnav-active-text: #f44;
--tocnav-active-bg: var(--tocnav-normal-bg);
--tocsidebar-text: var(--text);
--tocsidebar-bg: #080808;
--tocsidebar-shadow: rgba(255,255,255,.1);
--tocsidebar-heading-text: hsla(203,20%,40%,.7);
--toclink-text: var(--text);
--toclink-underline: #6af;
--toclink-visited-text: var(--toclink-text);
--toclink-visited-underline: #054572;
--heading-text: #8af;
--hr-text: var(--text);
--algo-border: #456;
--del-text: #f44;
--del-bg: transparent;
--ins-text: #4a4;
--ins-bg: transparent;
--a-normal-text: #6af;
--a-normal-underline: #555;
--a-visited-text: var(--a-normal-text);
--a-visited-underline: var(--a-normal-underline);
--a-hover-bg: rgba(25%, 25%, 25%, .2);
--a-active-text: #f44;
--a-active-underline: var(--a-active-text);
--borderedblock-bg: rgba(255, 255, 255, .05);
--blockquote-border: silver;
--blockquote-bg: var(--borderedblock-bg);
--blockquote-text: currentcolor;
--issue-border: #e05252;
--issue-bg: var(--borderedblock-bg);
--issue-text: var(--text);
--issueheading-text: hsl(0deg, 70%, 70%);
--example-border: hsl(50deg, 90%, 60%);
--example-bg: var(--borderedblock-bg);
--example-text: var(--text);
--exampleheading-text: hsl(50deg, 70%, 70%);
--note-border: hsl(120deg, 100%, 35%);
--note-bg: var(--borderedblock-bg);
--note-text: var(--text);
--noteheading-text: hsl(120, 70%, 70%);
--notesummary-underline: silver;
--assertion-border: #444;
--assertion-bg: var(--borderedblock-bg);
--assertion-text: var(--text);
--advisement-border: orange;
--advisement-bg: #222218;
--advisement-text: var(--text);
--advisementheading-text: #f84;
--warning-border: red;
--warning-bg: hsla(40,100%,20%,0.95);
--warning-text: var(--text);
--amendment-border: #330099;
--amendment-bg: #080010;
--amendment-text: var(--text);
--amendmentheading-text: #cc00ff;
--def-border: #8ccbf2;
--def-bg: #080818;
--def-text: var(--text);
--defrow-border: #136;
--datacell-border: silver;
--indexinfo-text: #aaa;
--indextable-hover-text: var(--text);
--indextable-hover-bg: #181818;
--outdatedspec-bg: rgba(255, 255, 255, .5);
--outdatedspec-text: black;
--outdated-bg: maroon;
--outdated-text: white;
--outdated-shadow: red;
--editedrec-bg: darkorange;
}
/* In case a transparent-bg image doesn't expect to be on a dark bg,
which is quite common in practice... */
img { background: white; }
}
</style>
<style>/* Boilerplate: style-counters */
body {
counter-reset: example figure issue;
}
.issue {
counter-increment: issue;
}
.issue:not(.no-marker)::before {
content: "Issue " counter(issue);
}
.example {
counter-increment: example;
}
.example:not(.no-marker)::before {
content: "Example " counter(example);
}
.invalid.example:not(.no-marker)::before,
.illegal.example:not(.no-marker)::before {
content: "Invalid Example" counter(example);
}
figcaption {
counter-increment: figure;
}
figcaption:not(.no-marker)::before {
content: "Figure " counter(figure) " ";
}
</style>
<style>/* Boilerplate: style-dfn-panel */
:root {
--dfnpanel-bg: #ddd;
--dfnpanel-text: var(--text);
--dfnpanel-target-bg: #ffc;
--dfnpanel-target-outline: orange;
}
@media (prefers-color-scheme: dark) {
:root {
--dfnpanel-bg: #222;
--dfnpanel-text: var(--text);
--dfnpanel-target-bg: #333;
--dfnpanel-target-outline: silver;
}
}
.dfn-panel {
position: absolute;
z-index: 35;
width: 20em;
width: 300px;
height: auto;
max-height: 500px;
overflow: auto;
padding: 0.5em 0.75em;
font: small Helvetica Neue, sans-serif, Droid Sans Fallback;
background: var(--dfnpanel-bg);
color: var(--dfnpanel-text);
border: outset 0.2em;
white-space: normal; /* in case it's moved into a pre */
}
.dfn-panel:not(.on) { display: none; }
.dfn-panel * { margin: 0; padding: 0; text-indent: 0; }
.dfn-panel > b { display: block; }
.dfn-panel a { color: var(--dfnpanel-text); }
.dfn-panel a:not(:hover) { text-decoration: none !important; border-bottom: none !important; }
.dfn-panel a:focus {
outline: 5px auto Highlight;
outline: 5px auto -webkit-focus-ring-color;
}
.dfn-panel > b + b { margin-top: 0.25em; }
.dfn-panel ul { padding: 0 0 0 1em; list-style: none; }
.dfn-panel li a {
max-width: calc(300px - 1.5em - 1em);
overflow: hidden;
text-overflow: ellipsis;
}
.dfn-panel.activated {
display: inline-block;
position: fixed;
left: 8px;
bottom: 2em;
margin: 0 auto;
max-width: calc(100vw - 1.5em - .4em - .5em);
max-height: 30vh;
transition: left 1s ease-out, bottom 1s ease-out;
}
.dfn-panel .link-item:hover {
text-decoration: underline;
}
.dfn-panel .link-item .copy-icon {
opacity: 0;
}
.dfn-panel .link-item:hover .copy-icon,
.dfn-panel .link-item .copy-icon:focus {
opacity: 1;
}
.dfn-panel .copy-icon {
display: inline-block;
margin-right: 0.5em;
width: 0.85em;
height: 1em;
border-radius: 3px;
background-color: #ccc;
cursor: pointer;
}
.dfn-panel .copy-icon .icon {
width: 100%;
height: 100%;
background-color: #fff;
display: flex;
justify-content: center;
align-items: center;
position: relative;
}
.dfn-panel .copy-icon .icon::before {
content: "";
position: absolute;
top: 0;
left: 0;
width: 100%;
height: 100%;
border: 1px solid black;
background-color: #ccc;
opacity: 0.25;
transform: translate(3px, -3px);
}
.dfn-panel .copy-icon:active .icon::before {
opacity: 1;
}
.dfn-paneled[role="button"] { cursor: help; }
.highlighted {
animation: target-fade 3s;
}
@keyframes target-fade {
from {
background-color: var(--dfnpanel-target-bg);
outline: 5px solid var(--dfnpanel-target-outline);
}
to {
color: var(--a-normal-text);
background-color: transparent;
outline: transparent;
}
}
</style>
<style>/* Boilerplate: style-issues */
a[href].issue-return {
float: right;
float: inline-end;
color: var(--issueheading-text);
font-weight: bold;
text-decoration: none;
}
</style>
<style>/* Boilerplate: style-md-lists */
/* This is a weird hack for me not yet following the commonmark spec
regarding paragraph and lists. */
[data-md] > :first-child {
margin-top: 0;
}
[data-md] > :last-child {
margin-bottom: 0;
}
</style>
<style>/* Boilerplate: style-mdn-anno */
:root {
--mdn-bg: #EEE;
--mdn-shadow: #999;
--mdn-nosupport-text: #ccc;
--mdn-pass: green;
--mdn-fail: red;
}
@media (prefers-color-scheme: dark) {
:root {
--mdn-bg: #222;
--mdn-shadow: #444;
--mdn-nosupport-text: #666;
--mdn-pass: #690;
--mdn-fail: #d22;
}
}
.mdn-anno {
background: var(--mdn-bg, #EEE);
border-radius: .25em;
box-shadow: 0 0 3px var(--mdn-shadow, #999);
color: var(--text, black);
font: 1em sans-serif;
hyphens: none;
max-width: min-content;
overflow: hidden;
padding: 0.2em;
position: absolute;
right: 0.3em;
top: auto;
white-space: nowrap;
word-wrap: normal;
z-index: 8;
}
.mdn-anno.unpositioned {
display: none;
}
.mdn-anno.overlapping-main {
opacity: .2;
transition: opacity .1s;
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.mdn-anno[open] {
opacity: 1;
z-index: 9;
min-width: 9em;
}
.mdn-anno:hover {
opacity: 1;
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}
.mdn-anno > summary {
font-weight: normal;
text-align: right;
cursor: pointer;
display: block;
}
.mdn-anno > summary > .less-than-two-engines-flag {
color: var(--mdn-fail);
padding-right: 2px;
}
.mdn-anno > summary > .all-engines-flag {
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padding-right: 2px;
}
.mdn-anno > summary > span {
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font-weight: normal;
font-family: zillaslab, Palatino, "Palatino Linotype", serif;
padding: 2px 3px 0px 3px;
line-height: 1.3em;
vertical-align: top;
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.mdn-anno > .feature {
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}
.mdn-anno > .feature:not(:first-of-type) {
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margin-top: 6px;
padding-top: 2px;
}
.mdn-anno > .feature > .less-than-two-engines-text {
color: var(--mdn-fail);
}
.mdn-anno > .feature > .all-engines-text {
color: var(--mdn-pass);
}
.mdn-anno > .feature > p {
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.mdn-anno > .feature > p + p {
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.mdn-anno > .feature > .support {
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.mdn-anno > .feature > .support + div {
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.mdn-anno > .feature > .support > hr {
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.mdn-anno > .feature > .support > span::before {
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background-image: url(https://resources.whatwg.org/browser-logos/firefox.png);
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background-image: url(https://resources.whatwg.org/browser-logos/edge_legacy.svg);
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background-image: url(https://resources.whatwg.org/browser-logos/firefox.png);
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background-image: url(https://resources.whatwg.org/browser-logos/ie.png);
}
.mdn-anno > .feature > .support > .safari_ios::before {
background-image: url(https://resources.whatwg.org/browser-logos/safari-ios.svg);
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.mdn-anno > .feature > .support > .nodejs::before {
background-image: url(https://nodejs.org/static/images/favicons/favicon.ico);
}
.mdn-anno > .feature > .support > .opera_android::before {
background-image: url(https://resources.whatwg.org/browser-logos/opera.svg);
}
.mdn-anno > .feature > .support > .opera::before {
background-image: url(https://resources.whatwg.org/browser-logos/opera.svg);
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.mdn-anno > .feature > .support > .safari::before {
background-image: url(https://resources.whatwg.org/browser-logos/safari.png);
}
.mdn-anno > .feature > .support > .samsunginternet_android::before {
background-image: url(https://resources.whatwg.org/browser-logos/samsung.svg);
}
.mdn-anno > .feature > .support > .webview_android::before {
background-image: url(https://resources.whatwg.org/browser-logos/android-webview.png);
}
.name-slug-mismatch {
color: red;
}
.caniuse-status:hover {
z-index: 9;
}
/* dt, li, .issue, .note, and .example are "position: relative", so to put annotation at right margin, must move to right of containing block */;
.h-entry:not(.status-LS) dt > .mdn-anno, .h-entry:not(.status-LS) li > .mdn-anno, .h-entry:not(.status-LS) .issue > .mdn-anno, .h-entry:not(.status-LS) .note > .mdn-anno, .h-entry:not(.status-LS) .example > .mdn-anno {
right: -6.7em;
}
.h-entry p + .mdn-anno {
margin-top: 0;
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h2 + .mdn-anno.after {
margin: -48px 0 0 0;
}
h3 + .mdn-anno.after {
margin: -46px 0 0 0;
}
h4 + .mdn-anno.after {
margin: -42px 0 0 0;
}
h5 + .mdn-anno.after {
margin: -40px 0 0 0;
}
h6 + .mdn-anno.after {
margin: -40px 0 0 0;
}
</style>
<style>/* Boilerplate: style-ref-hints */
:root {
--ref-hint-bg: #ddd;
--ref-hint-text: var(--text);
}
@media (prefers-color-scheme: dark) {
:root {
--ref-hint-bg: #222;
--ref-hint-text: var(--text);
}
}
.ref-hint {
display: inline-block;
position: absolute;
z-index: 35;
width: 20em;
width: 300px;
height: auto;
max-height: 500px;
overflow: auto;
padding: 0.5em 0.5em;
font: small Helvetica Neue, sans-serif, Droid Sans Fallback;
background: var(--ref-hint-bg);
color: var(--ref-hint-text);
border: outset 0.2em;
white-space: normal; /* in case it's moved into a pre */
}
.ref-hint * { margin: 0; padding: 0; text-indent: 0; }
.ref-hint ul { padding: 0 0 0 1em; list-style: none; }
</style>
<style>/* Boilerplate: style-selflinks */
:root {
--selflink-text: white;
--selflink-bg: gray;
--selflink-hover-text: black;
}
.heading, .issue, .note, .example, li, dt {
position: relative;
}
a.self-link {
position: absolute;
top: 0;
left: calc(-1 * (3.5rem - 26px));
width: calc(3.5rem - 26px);
height: 2em;
text-align: center;
border: none;
transition: opacity .2s;
opacity: .5;
}
a.self-link:hover {
opacity: 1;
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.heading > a.self-link {
font-size: 83%;
}
.example > a.self-link,
.note > a.self-link,
.issue > a.self-link {
/* These blocks are overflow:auto, so positioning outside
doesn't work. */
left: auto;
right: 0;
}
li > a.self-link {
left: calc(-1 * (3.5rem - 26px) - 2em);
}
dfn > a.self-link {
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left: auto;
opacity: 0;
width: 1.5em;
height: 1.5em;
background: var(--selflink-bg);
color: var(--selflink-text);
font-style: normal;
transition: opacity .2s, background-color .2s, color .2s;
}
dfn:hover > a.self-link {
opacity: 1;
}
dfn > a.self-link:hover {
color: var(--selflink-hover-text);
}
a.self-link::before { content: "¶"; }
.heading > a.self-link::before { content: "§"; }
dfn > a.self-link::before { content: "#"; }
</style>
<style>/* Boilerplate: style-wpt */
:root {
--wpt-border: hsl(0, 0%, 60%);
--wpt-bg: hsl(0, 0%, 95%);
--wpt-text: var(--text);
--wptheading-text: hsl(0, 0%, 30%);
}
@media (prefers-color-scheme: dark) {
:root {
--wpt-border: hsl(0, 0%, 30%);
--wpt-bg: var(--borderedblock-bg);
--wpt-text: var(--text);
--wptheading-text: hsl(0, 0%, 60%);
}
}
.wpt-tests-block {
list-style: none;
border-left: .5em solid var(--wpt-border);
background: var(--wpt-bg);
color: var(--wpt-text);
margin: 1em auto;
padding: .5em;
}
.wpt-tests-block summary {
color: var(--wptheading-text);
font-weight: normal;
text-transform: uppercase;
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.wpt-tests-block summary::marker{
color: var(--wpt-border);
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.wpt-tests-block summary:hover::marker{
color: var(--wpt-text);
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/*
The only content of a wpt test block in its closed state is the <summary>,
which contains the word TESTS,
and that is absolutely positioned.
In that closed state, wpt test blocks are styled
to have a top margin whose height is exactly equal
to the height of the absolutely positioned <summary>,
and no other background/padding/margin/border.
The wpt test block elements will therefore allow the maring
of the previous/next block elements
to collapse through them;
if this combined margin would be larger than its own top margin,
it stays as is,
and therefore the pre-existing vertical rhythm of the document is undisturbed.
If that combined margin would be smaller, it is grown to that size.
This means that the wpt test block ensures
that there's always enough vertical space to insert the summary,
without adding more than is needed.
*/
.wpt-tests-block:not([open]){
padding: 0;
border: none;
background: none;
font-size: 0.75em;
line-height: 1;
position: relative;
margin: 1em 0 0;
}
.wpt-tests-block:not([open]) summary {
position: absolute;
right: 0;
bottom: 0;
}
/*
It is possible that both the last child of a block element
and the block element itself
would be annotated with a <wpt> block each.
If the block element has a padding or a border,
that's fine, but otherwise
the bottom margin of the block and of its last child would collapse
and both <wpt> elements would overlap, being both placed there.
To avoid that, add 1px of padding to the <wpt> element annotating the last child
to prevent the bottom margin of the block and of its last child from collapsing
(and as much negative margin,
as wel only want to prevent margin collapsing,
but are not trying to actually take more space).
*/
.wpt-tests-block:not([open]):last-child {
padding-bottom: 1px;
margin-bottom: -1px;
}
/*
Exception to the previous rule:
don't do that in non-last list items,
because it's not necessary,
and would therefore consume more space than strictly needed.
Lists must have list items as children, not <wpt> elements,
so a <wpt> element cannot be a sibling of a list item,
and the collision that the previous rule avoids cannot happen.
*/
li:not(:last-child) > .wpt-tests-block:not([open]):last-child,
dd:not(:last-child) > .wpt-tests-block:not([open]):last-child {
padding-bottom: 0;
margin-bottom: 0;
}
.wpt-tests-block:not([open]):not(:hover){
opacity: 0.5;
}
.wpt-tests-list {
list-style: none;
display: grid;
margin: 0;
padding: 0;
grid-template-columns: 1fr max-content auto auto;
grid-column-gap: .5em;
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.wpt-tests-block hr:last-child {
display: none;
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.wpt-test {
display: contents;
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.wpt-test > .wpt-results { grid-column: 2; }
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.wpt-test .wpt-result {
display: inline-block;
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width: 1em;
border-radius: 50%;
position: relative;
}
</style>
<body class="h-entry">
<div class="head">
<p data-fill-with="logo"><a class="logo" href="https://www.w3.org/"> <img alt="W3C" height="48" src="https://www.w3.org/StyleSheets/TR/2021/logos/W3C" width="72"> </a> </p>
<h1>Compositing and Blending Level 1</h1>
<p id="w3c-state"><a href="https://www.w3.org/standards/types#ED">Editor’s Draft</a>, <time class="dt-updated" datetime="2024-07-31">31 July 2024</time></p>
<details open>
<summary>More details about this document</summary>
<div data-fill-with="spec-metadata">
<dl>
<dt>This version:
<dd><a class="u-url" href="https://drafts.fxtf.org/compositing-1/">https://drafts.fxtf.org/compositing-1/</a>
<dt>Latest published version:
<dd><a href="https://www.w3.org/TR/compositing-1/">https://www.w3.org/TR/compositing-1/</a>
<dt>Previous Versions:
<dd><a href="https://www.w3.org/TR/2015/CR-compositing-1-20150113/" rel="prev">https://www.w3.org/TR/2015/CR-compositing-1-20150113/</a>
<dt>Implementation Report:
<dd><a href="https://wpt.fyi/results/css/compositing">https://wpt.fyi/results/css/compositing</a>
<dt>Feedback:
<dd><a href="https://github.com/w3c/csswg-drafts/labels/compositing-1">CSSWG Issues Repository</a>
<dd><a href="https://github.com/w3c/fxtf-drafts/labels/compositing-1">GitHub</a>
<dd>https://github.com/w3c/fxtf-drafts/labels/compositing-1
<dt class="editor">Editor:
<dd class="editor p-author h-card vcard" data-editor-id="90243"><a class="p-name fn u-email email" href="mailto:chrishtr@chromium.org">Chris Harrelson</a> (<span class="p-org org">Google</span>)
<dt class="editor">Former Editors:
<dd class="editor p-author h-card vcard" data-editor-id="106988"><span class="p-name fn">Rik Cabanier</span> (<span class="p-org org">then of Adobe Systems Inc.</span>)
<dd class="editor p-author h-card vcard"><a class="p-name fn u-email email" href="mailto:Nikos.Andronikos@cisra.canon.com.au">Nikos Andronikos</a> (<span class="p-org org">Canon Information Systems Research Australia</span>)
<dt>Suggest an Edit for this Spec:
<dd><a href="https://github.com/w3c/csswg-drafts/blob/main/compositing-1/Overview.bs">GitHub Editor</a>
<dt>Test Suite:
<dd class="wpt-overview"><a href="https://wpt.fyi/results/css/compositing/">https://wpt.fyi/results/css/compositing/</a>
</dl>
</div>
</details>
<div data-fill-with="warning"></div>
<p class="copyright" data-fill-with="copyright"><a href="https://www.w3.org/policies/#copyright">Copyright</a> © 2024 <a href="https://www.w3.org/">World Wide Web Consortium</a>. <abbr title="World Wide Web Consortium">W3C</abbr><sup>®</sup> <a href="https://www.w3.org/policies/#Legal_Disclaimer">liability</a>, <a href="https://www.w3.org/policies/#W3C_Trademarks">trademark</a> and <a href="https://www.w3.org/copyright/software-license/" rel="license" title="W3C Software and Document License">permissive document license</a> rules apply. </p>
<hr title="Separator for header">
</div>
<div class="p-summary" data-fill-with="abstract">
<h2 class="no-num no-toc no-ref heading settled" id="abstract"><span class="content">Abstract</span></h2>
<p>Compositing describes how shapes of different elements are combined into a single image. There are various possible approaches for compositing. Previous versions of SVG and CSS used <a href="https://www.w3.org/TR/SVG11/masking.html#SimpleAlphaBlending">Simple Alpha Compositing</a>. In this model, each element is rendered into its own buffer and is then merged with its <a data-link-type="dfn" href="#backdrop" id="ref-for-backdrop">backdrop</a> using the Porter Duff <span class="css">source-over</span> operator. This specification will define a new compositing model that expands upon the Simple Alpha Compositing model by offering:</p>
<ul>
<li>additional Porter Duff compositing operators
<li>advanced blending modes which allow control of how colors mix in the areas where shapes overlap
<li>compositing groups
</ul>
In addition, this specification will define CSS properties for blending and group isolation and the properties of the <code class="idl"><a data-link-type="idl" href="https://html.spec.whatwg.org/multipage/canvas.html#dom-context-2d-globalcompositeoperation" id="ref-for-dom-context-2d-globalcompositeoperation">globalCompositeOperation</a></code> attribute. <a href="https://www.w3.org/TR/CSS/">CSS</a> is a language for describing the rendering of structured documents
(such as HTML and XML)
on screen, on paper, etc.
</div>
<h2 class="no-num no-toc no-ref heading settled" id="sotd"><span class="content">Status of this document</span></h2>
<div data-fill-with="status">
<p> This is a public copy of the editors’ draft.
It is provided for discussion only and may change at any moment.
Its publication here does not imply endorsement of its contents by W3C.
Don’t cite this document other than as work in progress. </p>
<p>Please send feedback
by <a href="https://github.com/w3c/csswg-drafts/issues">filing issues in GitHub</a> (preferred),
including the spec code “compositing” in the title, like this:
“[compositing] <i>…summary of comment…</i>”.
All issues and comments are <a href="https://lists.w3.org/Archives/Public/public-css-archive/&quo
D3C
t;>archived</a>.
Alternately, feedback can be sent to the (<a href="https://lists.w3.org/Archives/Public/www-style/">archived</a>) public mailing list <a href="mailto:www-style@w3.org?Subject=%5Bcompositing%5D%20PUT%20SUBJECT%20HERE">www-style@w3.org</a>. </p>
<p>This document is governed by the <a href="https://www.w3.org/policies/process/20231103/" id="w3c_process_revision">03 November 2023 W3C Process Document</a>. </p>
<p></p>