transform-origin
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since 2015年9月.
CSS 內的**transform-origin**屬性可以設定元素變化的原點。
嘗試一下
transform-origin: center; transform-origin: top left; transform-origin: 50px 50px; /* 3D rotation with z-axis origin */ transform-origin: bottom right 60px; <section id="default-example"> <div id="example-container"> <div id="example-element">Rotate me!</div> <img alt="" id="crosshair" src="/shared-assets/images/examples/crosshair.svg" width="24px" /> <div id="static-element"></div> </div> </section> @keyframes rotate { from { transform: rotate(0); } to { transform: rotate(30deg); } } @keyframes rotate3d { from { transform: rotate3d(0); } to { transform: rotate3d(1, 2, 0, 60deg); } } #example-container { width: 160px; height: 160px; position: relative; } #example-element { width: 100%; height: 100%; display: flex; position: absolute; align-items: center; justify-content: center; background: #f7ebee; color: #000000; font-size: 1.2rem; text-transform: uppercase; } #example-element.rotate { animation: rotate 1s forwards; } #example-element.rotate3d { animation: rotate3d 1s forwards; } #crosshair { width: 24px; height: 24px; opacity: 0; position: absolute; } #static-element { width: 100%; height: 100%; position: absolute; border: dotted 3px #ff1100; } "use strict"; window.addEventListener("load", () => { function update() { const selected = document.querySelector(".selected"); /* Restart the animation https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Animations/Tips */ el.className = ""; window.requestAnimationFrame(() => { window.requestAnimationFrame(() => { el.className = el.style.transformOrigin.split(" ")[2] === "60px" ? "rotate3d" : "rotate"; }); }); const transformOrigin = getComputedStyle(el).transformOrigin; const pos = transformOrigin.split(/\s+/); crosshair.style.left = `calc(${pos[0]} - 12px)`; crosshair.style.top = `calc(${pos[1]} - 12px)`; } const crosshair = document.getElementById("crosshair"); const el = document.getElementById("example-element"); const observer = new MutationObserver(() => { update(); }); observer.observe(el, { attributes: true, attributeFilter: ["style"], }); update(); crosshair.style.opacity = "1"; }); 變化原點指的是應用變化的點。舉例來說， rotate()函數的原點為旋轉中心。 (This property is applied by first translating the element by the negated value of the property, then applying the element's transform, then translating by the property value.)
語法
/* One-value syntax */ transform-origin: 2px; transform-origin: bottom; /* x-offset | y-offset */ transform-origin: 3cm 2px; /* x-offset-keyword | y-offset */ transform-origin: left 2px; /* x-offset-keyword | y-offset-keyword */ transform-origin: right top; /* y-offset-keyword | x-offset-keyword */ transform-origin: top right; /* x-offset | y-offset | z-offset */ transform-origin: 2px 30% 10px; /* x-offset-keyword | y-offset | z-offset */ transform-origin: left 5px -3px; /* x-offset-keyword | y-offset-keyword | z-offset */ transform-origin: right bottom 2cm; /* y-offset-keyword | x-offset-keyword | z-offset */ transform-origin: bottom right 2cm; /* Global values */ transform-origin: inherit; transform-origin: initial; transform-origin: unset; transform-origin 屬性可以使用多次，每一次都代表著一個偏移量。若未設定偏移量，則重置為其對應的初始值。
If two or more values are defined and either no value is a keyword, or the only used keyword is center, then the first value represents the horizontal offset and the second represents the vertical offset.
-
One-value syntax:
- The value must be a
<length>, a<percentage>, or one of the keywordsleft,center,right,toporbottom.
- The value must be a
-
Two-value syntax:
- One value must be a
<length>, a<percentage>, or one of the keywordsleft,center, andright. - The other value must be a
<length>, a<percentage>, or one of the keywordstop,center, andbottom.
- One value must be a
-
Three-value syntax:
- The first two values are the same as for the two-value syntax.
- The third value must be a
<length>. It always represents the Z offset.
Values
- x-offset
-
Is a
<length>or a<percentage>describing how far from the left edge of the box the origin of the transform is set. - offset-keyword
-
Is one of the
left,right,top,bottom, orcenterkeyword describing the corresponding offset. - y-offset
-
Is a
<length>or a<percentage>describing how far from the top edge of the box the origin of the transform is set. - x-offset-keyword
-
Is one of the
left,right, orcenterkeyword describing how far from the left edge of the box the origin of the transform is set. - y-offset-keyword
-
Is one of the
top,bottom, orcenterkeyword describing how far from the top edge of the box the origin of the transform is set. - z-offset
-
Is a
<length>(and never a<percentage>which would make the statement invalid) describing how far from the user eye the z=0 origin is set.
The keywords are convenience shorthands and match the following <percentage> values:
| Keyword | Value |
|---|---|
left | 0% |
center | 50% |
right | 100% |
top | 0% |
bottom | 100% |
Formal syntax
transform-origin =
[ left | center | right | top | bottom | <length-percentage> ] |
[ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ] <length>? |
[ [ center | left | right ] && [ center | top | bottom ] ] <length>?
<length-percentage> =
<length> |
<percentage>
Examples
Specifications
| Specification |
|---|
| CSS Transforms Module Level 1 # transform-origin-property |
| 預設值 | 50% 50% 0 |
|---|---|
| Applies to | transformable elements |
| 繼承與否 | no |
| Percentages | refer to the size of bounding box |
| Computed value | for <length> the absolute value, otherwise a percentage |
| Animation type | simple list of length, percentage, or calc |
Browser compatibility
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