transform-origin - SVG: Scalable Vector Graphics 编辑

The transform-origin SVG attribute sets the origin for an item’s transformations. 

Note: As a presentation attribute in SVG, transform-origin corresponds in syntax and behavior to the transform-origin property in CSS, and can be used as CSS property to style SVG. See the CSS transform-origin property for more information. 

Usage notes

The default value of transform-origin is 0 0 for all SVG elements except for root <svg> elements and <svg> elements that are a direct child of a foreignObject, and whose transform-origin is 50% 50%, like other CSS elements.

The transform-origin property may be specified using one, two, or three values, where each value represents an offset. Offsets that are not explicitly defined are reset to their corresponding initial values.

If a single <length> or <percentage> value is defined, it represents the horizontal offset.

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 keywords left, center, right, top, and bottom.
• Two-value syntax:
  • One value must be a <length>, a <percentage>, or one of the keywords left, center, and right.
  • The other value must be a <length>, a <percentage>, 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>. It always represents the Z offset.

Specifications