@jupyterlab/cells/lib/resizeHandle.js

/*
 * Copyright (c) Jupyter Development Team.
 * Distributed under the terms of the Modified BSD License.
 */
import { Throttler } from '@lumino/polling';
import { Widget } from '@lumino/widgets';
const RESIZE_HANDLE_CLASS = 'jp-CellResizeHandle';
const CELL_RESIZED_CLASS = 'jp-mod-resizedCell';
/**
 * A handle that allows to change input/output proportions in side-by-side mode.
 */
export class ResizeHandle extends Widget {
    constructor(targetNode) {
        super();
        this.targetNode = targetNode;
        this._isActive = false;
        this._isDragging = false;
        this.addClass(RESIZE_HANDLE_CLASS);
        this._resizer = new Throttler(event => this._resize(event), 50);
    }
    /**
     * Dispose the resizer handle.
     */
    dispose() {
        this._resizer.dispose();
        super.dispose();
    }
    /**
     * Handle the DOM events for the widget.
     *
     * @param event - The DOM event sent to the widget.
     *
     */
    handleEvent(event) {
        var _a, _b;
        switch (event.type) {
            case 'dblclick':
                (_a = this.targetNode.parentNode) === null || _a === void 0 ? void 0 : _a.childNodes.forEach(node => {
                    node.classList.remove(CELL_RESIZED_CLASS);
                });
                document.documentElement.style.setProperty('--jp-side-by-side-output-size', `1fr`);
                this._isActive = false;
                break;
            case 'mousedown':
                this._isDragging = true;
                if (!this._isActive) {
                    (_b = this.targetNode.parentNode) === null || _b === void 0 ? void 0 : _b.childNodes.forEach(node => {
                        node.classList.add(CELL_RESIZED_CLASS);
                    });
                    this._isActive = true;
                }
                window.addEventListener('mousemove', this);
                window.addEventListener('mouseup', this);
                break;
            case 'mousemove': {
                if (this._isActive && this._isDragging) {
                    void this._resizer.invoke(event);
                }
                break;
            }
            case 'mouseup':
                this._isDragging = false;
                window.removeEventListener('mousemove', this);
                window.removeEventListener('mouseup', this);
                break;
            default:
                break;
        }
    }
    /**
     * Handle `after-attach` messages.
     */
    onAfterAttach(msg) {
        this.node.addEventListener('dblclick', this);
        this.node.addEventListener('mousedown', this);
        super.onAfterAttach(msg);
    }
    /**
     * Handle `before-detach` messages.
     */
    onBeforeDetach(msg) {
        this.node.removeEventListener('dblclick', this);
        this.node.removeEventListener('mousedown', this);
        super.onBeforeDetach(msg);
    }
    _resize(event) {
        // Gate the output size ratio between {0.05, 50} as sensible defaults.
        const { width, x } = this.targetNode.getBoundingClientRect();
        const position = event.clientX - x;
        const ratio = width / position - 1;
        if (0 < ratio) {
            const normalized = Math.max(Math.min(Math.abs(ratio), 50), 0.05);
            document.documentElement.style.setProperty('--jp-side-by-side-output-size', `${normalized}fr`);
        }
    }
}
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