Unfortunately, clip-path: path() is Still a No-Go

Initially, the prospect of clip-path: path() in Firefox was incredibly exciting. Imagine effortlessly creating a dynamic shape, like the breathing box shown below, using a single HTML element and minimal CSS – no SVGs or lengthy polygon point lists needed!

This potential thrilled Chris as well. The possibilities seemed endless.

However, my enthusiasm quickly waned upon closer inspection. While clip-path: path() functions in Firefox (versions 63-70 with a specific flag enabled, and 71 without), a significant limitation emerged: the path coordinates are pixel-based. This means they don't scale responsively.

The MDN examples, using pixel values within the path() function, highlighted this issue. The path() function accepts an SVG <path></path> string, whose coordinates, like the d attribute in SVG, are unitless pixels. Unlike SVG's viewBox, these pixels remain fixed within the CSS path() function, preventing responsive scaling.

This renders the function largely impractical for responsive design. A responsive element clipped with path() maintains a fixed clipped area regardless of its size. For instance, a square scaling with the viewport will have a statically sized clipped heart shape.

This limitation severely restricts the usefulness of clip-path: path(). SVG or polygon() approximations remain superior alternatives for most scenarios. Improvements are crucial to make clip-path: path() a viable option.

Amelia Bellamy-Royds proposed two solutions:

1. Support calc() values/units within path data. This would extend SVG path syntax.
2. Introduce a viewBox within the clip-path declaration, allowing scaling.

I favor the first option. The second, while eliminating the need for separate SVGs, offers limited advantage over using SVG directly, which enjoys broader support. The first option, however, would significantly enhance clip-path: path(), potentially surpassing SVG in convenience for certain applications.

Consider the breathing box example. The SVG implementation requires careful viewBox configuration to center the shape. The SCSS code, using viewBox and path commands (M, v, h), generates the necessary path string.

However, creating a breathing effect necessitates quadratic Bézier curves (q), requiring more complex path definitions for both "swollen" and "squished" states. This leads to lengthy, repetitive CSS.

Ideally, using clip-path: path() with calc() support and custom properties would allow dynamic control over the shape. A custom property, like --sgn, could control the sign within calc(), enabling animation between states with a single path definition. This would greatly simplify the code and ensure responsive scaling. Currently, however, clip-path: path() falls short of its potential.

The above is the detailed content of Unfortunately, clip-path: path() is Still a No-Go. For more information, please follow other related articles on the PHP Chinese website!