CSS Clip Path Generator

How CSS clip-path Works: Painting Boundaries with the Browser

The CSS clip-path property instructs the browser's rendering engine to restrict the paintable area of an element to a defined geometric shape. Conceptually, it is like applying a stencil over the element — anything outside the stencil boundary is simply not rendered, regardless of how the element's actual content or box model extends. This differs from overflow: hidden, which clips to the element's rectangle boundary and does create a new block formatting context that affects layout flow. The clip-path property, by contrast, never participates in layout — elements clipped by complex polygons still occupy their full rectangular grid space.

Under the hood, the browser evaluates the clip shape at paint time. For each pixel in the element's bounding box, the rendering engine tests whether that pixel's screen coordinates fall within the clip polygon using point-in-polygon math (the ray casting algorithm). Pixels that pass the test are painted normally; those that fail are discarded. This evaluation happens on the GPU for composited elements, making clip-path animations smooth and performant when combined with CSS transitions — the GPU simply re-evaluates the polygon boundary at each frame rather than sending repaint commands to the CPU.

Before & After: Square Section vs Diagonal Divider

.hero-section {
  background: #6366f1;
  /* Hard horizontal edge,
     no visual dynamism */
}

.hero-section {
  background: #6366f1;
  clip-path: polygon(
    0 0,
    100% 0,
    100% 88%,
    0 100%
  );
  /* Responsive diagonal cut */
}

Popular clip-path Shape Reference

Knowing a handful of common clip-path polygon values by heart can dramatically speed up your design workflow. These shapes are all fully responsive because they use percentage coordinates that scale with the element's bounding box. Each can be used as a starting template in this generator's preset panel.

Common Mistakes & Troubleshooting

• ✕
  Box shadow is clipped away: The clip-path masks the element's paint output entirely — including its box-shadow. If you need a shadow on a clip-path shaped element, apply the shadow to a wrapper parent element using filter: drop-shadow() instead of box-shadow, as filter effects are applied after the compositing stage.
• ✕
  Animating between different point counts: CSS transitions on clip-path only work when the number of polygon points is identical in both states. If your hover state polygon has a different number of vertices than the default state, the transition will not interpolate — it jumps. Add phantom points (redundant stacked coordinates) to equalize the point count.
• ✕
  Pixel coordinates break responsiveness: Using pixel values in polygon() (e.g., polygon(0 0, 200px 0, 200px 150px)) creates a fixed-size clip that does not scale with the element. Always use percentage coordinates for fluid responsive layouts.