transform-origin

CSS 內的**transform-origin**屬性可以設定元素變化的原點。

嘗試一下

變化原點指的是應用變化的點。舉例來說， rotate() (en-US)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

css

/* 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;

The transform-origin p 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 (en-US)。

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> (en-US), a <percentage> (en-US), or one of the keywords left, center, right, top or bottom.
Two-value syntax:
- One value must be a <length> (en-US), a <percentage> (en-US), or one of the keywords left, center, and right.
- The other value must be a <length> (en-US), a <percentage> (en-US), or one of the keywords top, center, and bottom.
Three-value syntax:
- The first two values are the same as for the two-value syntax.
- The third value must be a <length> (en-US). It always represents the Z offset.

Values

x-offset: Is a <length> (en-US) or a <percentage> (en-US) 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, or center keyword describing the corresponding offset.
y-offset: Is a <length> (en-US) or a <percentage> (en-US) 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, or center keyword 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, or center keyword describing how far from the top edge of the box the origin of the transform is set.
z-offset: Is a <length> (en-US) (and never a <percentage> (en-US) 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> (en-US) values:

Keyword	Value
`left`	`0%`
`center`	`50%`
`right`	`100%`
`top`	`0%`
`bottom`	`100%`

Formal syntax

transform-origin = 
  [ (en-US) left | (en-US) center | (en-US) right | (en-US) top | (en-US) bottom | (en-US) <length-percentage> ] (en-US)  | (en-US)
  [ (en-US) left | (en-US) center | (en-US) right | (en-US) <length-percentage> ] (en-US) [ (en-US) top | (en-US) center | (en-US) bottom | (en-US) <length-percentage> ] (en-US) <length> (en-US)? (en-US)  | (en-US)
  [ (en-US) [ (en-US) center | (en-US) left | (en-US) right ] (en-US) && (en-US) [ (en-US) center | (en-US) top | (en-US) bottom ] (en-US) ] (en-US) <length> (en-US)? (en-US)  

<length-percentage> = 
  <length> (en-US)      | (en-US)
  <percentage> (en-US)

Examples

<div class="container">
  <div class="example">
    <div class="box box1">&nbsp;</div>
    <div class="box original">&nbsp;</div>
  </div>

  <pre>
transform: none;
</pre
  >

  <div class="example">
    <div class="box box2">&nbsp;</div>
    <div class="box original">&nbsp;</div>
  </div>

  <pre>
transform: rotate(30deg);
</pre
  >

  <div class="example">
    <div class="box box3">&nbsp;</div>
    <div class="box original">&nbsp;</div>
  </div>

  <pre>
transform: rotate(30deg);
transform-origin: 0 0;
</pre
  >

  <div class="example">
    <div class="box box4">&nbsp;</div>
    <div class="box original">&nbsp;</div>
  </div>

  <pre>
transform: rotate(30deg);
transform-origin: 100% 100%;
</pre
  >

  <div class="example">
    <div class="box box5">&nbsp;</div>
    <div class="box original">&nbsp;</div>
  </div>

  <pre>
transform: rotate(30deg);
transform-origin: -1em -3em;
</pre
  >

  <div class="example">
    <div class="box box6">&nbsp;</div>
    <div class="box original">&nbsp;</div>
  </div>

  <pre>
transform: scale(1.7);
</pre
  >

  <div class="example">
    <div class="box box7">&nbsp;</div>
    <div class="box original">&nbsp;</div>
  </div>

  <pre>
transform: scale(1.7);
transform-origin: 0 0;
</pre
  >

  <div class="example">
    <div class="box box8">&nbsp;</div>
    <div class="box original">&nbsp;</div>
  </div>

  <pre>
transform: scale(1.7);
transform-origin: 100% -30%;
</pre
  >

  <div class="example">
    <div class="box box9">&nbsp;</div>
    <div class="box original">&nbsp;</div>
  </div>

  <pre>
transform: skewX(50deg);
transform-origin: 100% -30%;
</pre
  >

  <div class="example">
    <div class="box box10">&nbsp;</div>
    <div class="box original">&nbsp;</div>
  </div>

  <pre>
transform: skewY(50deg);
transform-origin: 100% -30%;
</pre
  >
</div>

.container {
  display: grid;
  grid-template-columns: 200px 100px;
  gap: 20px;
}

.example {
  position: relative;
  margin: 0 2em 4em 5em;
}

.box {
  display: inline-block;
  width: 3em;
  height: 3em;
  border: solid 1px;
  background-color: palegreen;
}

.original {
  position: absolute;
  left: 0;
  opacity: 20%;
}

.box1 {
  transform: none;
}

.box2 {
  transform: rotate(30deg);
}

.box3 {
  transform: rotate(30deg);
  transform-origin: 0 0;
}

.box4 {
  transform: rotate(30deg);
  transform-origin: 100% 100%;
}

.box5 {
  transform: rotate(30deg);
  transform-origin: -1em -3em;
}

.box6 {
  transform: scale(1.7);
}

.box7 {
  transform: scale(1.7);
  transform-origin: 0 0;
}

.box8 {
  transform: scale(1.7);
  transform-origin: 100% -30%;
}

.box9 {
  transform: skewX(50deg);
  transform-origin: 100% -30%;
}

.box10 {
  transform: skewY(50deg);
  transform-origin: 100% -30%;
}

Specifications

Specification
CSS Transforms Module Level 1 # transform-origin-property

預設值 (en-US)	`50% 50% 0`
Applies to	transformable elements
繼承與否	no
Percentages	refer to the size of bounding box
Computed value (en-US)	for `length` (en-US) the absolute value, otherwise a percentage
Animation type (en-US)	simple list of length, percentage, or calc

Browser compatibility

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