from pRegroup-done-2019 Zoom around the mouse pointer position
- Zooming is currently based on the center of the screen, but what is natural for humans is zooming centered on the mouse pointer position
Like this ts
export function zoomAroundMousePointer(
initZoom: number, initCenter: paper.Point,
zoomCenter: paper.Point, scale: number,
) {
const v = initCenter.subtract(zoomCenter);
let newZoom = initZoom * scale;
let newCenter = initCenter.add(v.multiply((1 - scale) / scale));
return [newZoom, newCenter];
}It was bracketed to support not only Shift+drag, but also mouse wheel and two-finger up/down swipes on MacBooks.
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