scratch-vm/src/io/mouse.js

const MathUtil = require('../util/math-util');

class Mouse {
    constructor (runtime) {
        this._x = 0;
        this._y = 0;
        this._isDown = false;
        /**
         * Reference to the owning Runtime.
         * Can be used, for example, to activate hats.
         * @type{!Runtime}
         */
        this.runtime = runtime;
    }

    /**
     * Activate "event_whenthisspriteclicked" hats if needed.
     * @param  {number} x X position to be sent to the renderer.
     * @param  {number} y Y position to be sent to the renderer.
     * @private
     */
    _activateClickHats (x, y) {
        if (this.runtime.renderer) {
            const drawableID = this.runtime.renderer.pick(x, y);
            for (let i = 0; i < this.runtime.targets.length; i++) {
                const target = this.runtime.targets[i];
                if (target.hasOwnProperty('drawableID') &&
                    target.drawableID === drawableID) {
                    this.runtime.startHats('event_whenthisspriteclicked',
                        null, target);
                    return;
                }
            }
        }
    }

    /**
     * Mouse DOM event handler.
     * @param  {object} data Data from DOM event.
     */
    postData (data) {
        if (data.x) {
            this._x = data.x - data.canvasWidth / 2;
        }
        if (data.y) {
            this._y = data.y - data.canvasHeight / 2;
        }
        if (typeof data.isDown !== 'undefined') {
            this._isDown = data.isDown;
            if (!this._isDown) {
                this._activateClickHats(data.x, data.y);
            }
        }
    }

    /**
     * Get the X position of the mouse.
     * @return {number} Clamped X position of the mouse cursor.
     */
    getX () {
        return MathUtil.clamp(this._x, -240, 240);
    }

    /**
     * Get the Y position of the mouse.
     * @return {number} Clamped Y position of the mouse cursor.
     */
    getY () {
        return MathUtil.clamp(-this._y, -180, 180);
    }

    /**
     * Get the down state of the mouse.
     * @return {boolean} Is the mouse down?
     */
    getIsDown () {
        return this._isDown;
    }
}

module.exports = Mouse;