Mirror Effect (Symmetry and Kaleidoscope)

Mirroring half of a photo onto the other half creates perfect symmetry: surreal landscapes, symmetrical faces, reflections in water, or patterns for backgrounds. This tool mirrors the left, right, top or bottom half, mirrors one quarter four ways, or folds a slice of the picture into a 6, 8 or 12-segment kaleidoscope. You can move the mirror line to choose exactly which part is kept. Everything happens in your browser.

How to use this tool

1. Choose one or more images.
2. Pick the effect: a half mirror, a four-way quarter mirror or a kaleidoscope.
3. Move the mirror line with the position setting, or set the kaleidoscope centre and source angle.
4. Download the result; kaleidoscopes are saved as PNG with a transparent background.

Formula

half mirror: output width = 2 × mirror line; pixel x right of the line shows source pixel 2 × line − 1 − x. Kaleidoscope: angle θ → θ mod (360° ÷ n), mirrored in every other segment

The mirror line sits at the centre plus the offset (a percentage of the width or height), and the kept part is copied exactly. For a kaleidoscope with n segments, each output pixel is measured from the centre; its angle is folded into the first segment of 360° ÷ n degrees, every other segment is flipped so that neighbours meet without a seam, and the colour is read from the source at the same distance with bilinear interpolation. The circle's radius is the distance from the centre to the nearest edge.

Example

A 4000 × 3000 photo mirrored left to right with the line at the centre stays 4000 × 3000 px: the left 2000 columns are kept and column 3999 repeats column 0. With an offset of +10% the line moves to 2400 px and the result is 4800 × 3000. An 8-segment kaleidoscope around the centre uses a radius of 1500 px, so it is 3000 × 3000 px with 45° segments.