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JoBerkner/CBGestureHandlers.js

Created July 31, 2020 04:33
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Callbacks for the geesture handlers
Raw
CBGestureHandlers.js
const pinchStateHandler = event => {
if (event.nativeEvent.oldState === State.UNDETERMINED) {
setLastScaleOffset(-1 + scale);
};
};
const pinchGestureHandler = event => {
if (event.nativeEvent.scale + lastScaleOffset >= 1 && event.nativeEvent.scale + lastScaleOffset <= 5) {
setPrevScale(scale);
setScale(event.nativeEvent.scale + lastScaleOffset);
setTranslateX(
translateX - (
event.nativeEvent.focalX / scale -
event.nativeEvent.focalX / prevScale
)
);
setTranslateY(
translateY - (
event.nativeEvent.focalY / scale -
event.nativeEvent.focalY / prevScale
)
);
}
};
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