@jbrowse/plugin-linear-genome-view/esm/LinearGenomeView/components/useRangeSelect.js

JBrowse 2 linear genome view

import { useEffect, useState } from 'react';
import { getRelativeX } from './util';
export function useRangeSelect(ref, model, shiftOnly) {
    const [startX, setStartX] = useState();
    const [currentX, setCurrentX] = useState();
    const [anchorPosition, setAnchorPosition] = useState();
    const [guideX, setGuideX] = useState();
    const mouseDragging = startX !== undefined && anchorPosition === undefined;
    useEffect(() => {
        function computeOffsets(offsetX) {
            if (startX === undefined) {
                return;
            }
            const leftPx = Math.min(startX, offsetX);
            const rightPx = Math.max(startX, offsetX);
            return {
                leftOffset: model.pxToBp(leftPx),
                rightOffset: model.pxToBp(rightPx),
            };
        }
        function globalMouseMove(event) {
            if (ref.current && mouseDragging) {
                const relativeX = getRelativeX(event, ref.current);
                setCurrentX(relativeX);
            }
        }
        function globalMouseUp(event) {
            if (startX !== undefined && ref.current) {
                const { clientX, clientY } = event;
                const offsetX = getRelativeX(event, ref.current);
                setAnchorPosition({
                    offsetX,
                    clientX,
                    clientY,
                });
                const args = computeOffsets(offsetX);
                if (args) {
                    model.setOffsets(args.leftOffset, args.rightOffset);
                }
                setGuideX(undefined);
            }
        }
        if (mouseDragging) {
            window.addEventListener('mousemove', globalMouseMove);
            window.addEventListener('mouseup', globalMouseUp);
            return () => {
                window.removeEventListener('mousemove', globalMouseMove);
                window.removeEventListener('mouseup', globalMouseUp);
            };
        }
        return () => { };
    }, [startX, mouseDragging, model, ref]);
    useEffect(() => {
        if (!mouseDragging &&
            currentX !== undefined &&
            startX !== undefined &&
            Math.abs(currentX - startX) <= 3) {
            handleClose();
        }
    }, [mouseDragging, currentX, startX]);
    function mouseDown(event) {
        if (shiftOnly && !event.shiftKey) {
            return;
        }
        event.preventDefault();
        event.stopPropagation();
        const relativeX = getRelativeX(event, ref.current);
        setStartX(relativeX);
        setCurrentX(relativeX);
    }
    function mouseMove(event) {
        if (shiftOnly) {
            if (event.shiftKey) {
                setGuideX(getRelativeX(event, ref.current));
            }
            else {
                setGuideX(undefined);
            }
        }
        else {
            setGuideX(getRelativeX(event, ref.current));
        }
    }
    function mouseOut() {
        setGuideX(undefined);
    }
    function handleClose() {
        setAnchorPosition(undefined);
        setStartX(undefined);
        setCurrentX(undefined);
    }
    function handleMenuItemClick(_, callback) {
        callback();
        handleClose();
    }
    const open = Boolean(anchorPosition);
    if (startX === undefined) {
        return {
            open,
            guideX,
            mouseDown,
            mouseMove,
            mouseOut,
            handleMenuItemClick,
        };
    }
    const right = anchorPosition ? anchorPosition.offsetX : currentX || 0;
    const left = Math.min(right, startX);
    const width = Math.abs(right - startX);
    const leftBpOffset = model.pxToBp(left);
    const rightBpOffset = model.pxToBp(left + width);
    const numOfBpSelected = Math.ceil(width * model.bpPerPx);
    return {
        open,
        rubberbandOn: true,
        mouseDown,
        mouseMove,
        mouseOut,
        handleClose,
        handleMenuItemClick,
        leftBpOffset,
        rightBpOffset,
        anchorPosition,
        numOfBpSelected,
        width,
        left,
    };
}