README

<PinchZoom/> - a react component for pinch zooming DOM elements.

This is a migration of GoogleChromeLabs/pinch-zoom to React!

Demo

Simple image pinch-zoom. Although you can put any element in <PinchZoom/>.

Usage

yarn add pinch-zoom-element

import React, { useRef, useCallback } from "react";
import {
  PinchZoom,
  applyCssProperties,
  getTransform3DValue,
  getTransform2DValue,
} from "react-fast-pinch-zoom";

const App = () => {
  const ref = useRef(null);
  const onTransform = useCallback(({ x, y, scale }) => {
    // Use CSS Custom Properties (Variables)
    applyCssProperties(ref.current, { x, y, scale });

    // Or use literal transform value
    // ref.current.style.setProperty('transform',getTransform3DValue({x,y,scale}));
    // ref.current.style.setProperty('transform',getTransform2DValue({x,y,scale}));
  }, []);

  return (
    <PinchZoom onTransform={onTransform}>
      <img
        ref={ref}
        alt="two black cats look at you"
        src="https://cdn.glitch.com/d824d0c2-e771-4c9f-9fe2-a66b3ac139c5%2Fcats.jpg"
      />
    </PinchZoom>
  );
};

Now the above can be pinch-zoomed!

API

const App = () => {
  const pinchZoomRef = React.useRef();

  return (
    <PinchZoom ref={pinchZoomRef}>
      <img />
    </PinchZoom>
  );
};

Properties

pinchZoomRef.current.x; // x offset
pinchZoomRef.current.y; // y offset
pinchZoomRef.current.scale; // scale

Methods

Set the transform. All values are optional.

pinchZoomRef.current.setTransform({
  scale: 1,
  x: 0,
  y: 0,
});

Scale in/out of a particular point.

const scale = 2;

pinchZoomRef.current.scaleTo(scale, {
  // Transform origin. Can be a number, or string percent, eg "50%"
  originX: 0,
  originY: 0,
  // Should the transform origin be relative to the "container", or "content"?
  relativeTo: "content",
});

Usage no npm install needed!