traffic-laser/src/graphic/Renderer/Draw.js

import { dataService } from "../Service/DataService.js";
import { stateService } from "../Service/StateService.js";
import { coordinate } from "../Coordinate.js";
import Style from "@/graphic/CanvasStyle/index.js";
import VectorType from "../enum/VectorType.js";
import { mathUtil } from "../Util/MathUtil.js";
import ElementEvents from "../enum/ElementEvents.js";
import { elementService } from "../Service/ElementService.js";
import UIEvents from "@/graphic/enum/UIEvents.js";
import VectorCategory from "@/graphic/enum/VectorCategory.js";
import Settings from "@/graphic/Settings.js";

const imgCache = {};
const help = {
  getVectorStyle(vector, geoType = vector.geoType) {
    const geoId = vector?.vectorId;
    if (!geoId) {
      return [Style[geoType], undefined];
    }

    const itemsEntry = [
      [stateService.getSelectItem(), "Select"],
      [stateService.getDraggingItem(), "Dragging"],
      [stateService.getFocusItem(), "Focus"],
    ];
    let currentAttr;

    return [
      itemsEntry.reduce((prev, [item, attr]) => {
        if (!item) return prev
        const selected = geoId === item.vectorId || (
          item.parent && Object.keys(item.parent).some(id => id === geoId)
        );
        if (selected && Style[attr]) {
          const style = Style[attr][geoType] || Style[attr][vector.category]
          if (style) {
            currentAttr = attr;
            return style;
          }
        }

        return prev;
      }, Style[geoType]),
      currentAttr,
    ];
  },
  setStyle(ctx, styles) {
    for (const style in styles) {
      if (typeof styles[style] === "function") {
        styles[style](ctx, vector);
      } else {
        ctx[style] = styles[style];
      }
    }
  },
  setVectorStyle(ctx, vector, geoType = vector.geoType) {
    let styles, attr
    if (Array.isArray(geoType)) {
      for (const type of geoType) {
        [styles, attr] = help.getVectorStyle(vector, type);
        if (styles) {
          break;
        }
      }
    } else {
      [styles, attr] = help.getVectorStyle(vector, geoType);
    }
    help.setStyle(ctx, styles)
    return [styles, attr];
  },
  transformCoves(lines) {
    return lines.map((line) =>
      line.map((line) => ({
        start: coordinate.getScreenXY(line.start),
        end: coordinate.getScreenXY(line.end),
        controls: line.controls.map(coordinate.getScreenXY.bind(coordinate)),
      }))
    );
  },
  drawCoves(ctx, coves) {
    for (const curve of coves) {
      ctx.beginPath();
      ctx.moveTo(curve.start.x, curve.start.y);
      if (curve.controls.length === 1) {
        ctx.quadraticCurveTo(
          curve.controls[0].x,
          curve.controls[0].y,
          curve.end.x,
          curve.end.y
        );
      } else {
        ctx.bezierCurveTo(
          curve.controls[0].x,
          curve.controls[0].y,
          curve.controls[1].x,
          curve.controls[1].y,
          curve.end.x,
          curve.end.y
        );
      }
      ctx.stroke();
    }
  },
  getReal(data) {
    return (data * coordinate.ratio * coordinate.zoom) / coordinate.defaultZoom;
  },
  getImage(src) {
    if (imgCache[src]) {
      return imgCache[src];
    }
    const img = new Image();
    img.src = src;
    return (imgCache[src] = new Promise((resolve) => {
      img.onload = () => {
        resolve(img);
      };
    }));
  },
  getTextCenter(ctx, txt) {
    const text = ctx.measureText(txt);
    const height = text.actualBoundingBoxAscent + text.actualBoundingBoxDescent
    return {
      width: text.width,
      height,
      x: text.width / 2,
      y: -height / 2
    }
  },
  // 绘制圆角矩形
  roundRect(ctx, x, y, width, height, radius) {
    ctx.beginPath();
    ctx.moveTo(x + radius, y);
    ctx.lineTo(x + width - radius, y);
    ctx.quadraticCurveTo(x + width, y, x + width, y + radius);
    ctx.lineTo(x + width, y + height - radius);
    ctx.quadraticCurveTo(x + width, y + height, x + width - radius, y + height);
    ctx.lineTo(x + radius, y + height);
    ctx.quadraticCurveTo(x, y + height, x, y + height - radius);
    ctx.lineTo(x, y + radius);
    ctx.quadraticCurveTo(x, y, x + radius, y);
    ctx.closePath();
  },
  getRealDistance(p1, p2) {
    return Math.round(mathUtil.getDistance(p1, p2) * coordinate.res * 100) / 100
  },
  getPerpendicularPoint(p1, p2, p3, d) {
    if (p1.x === p2.x) {
      return {x: p3.x + d, y: p3.y}
    } else if (p1.y === p2.y) {
      return {x: p3.x, y: p3.y + d}
    }

    // 计算通过 p1 和 p2 的直线的斜率和截距
    const slope = (p2.y - p1.y) / (p2.x - p1.x);
    const intercept = p1.y - slope * p1.x;

    // 计算垂直线的斜率和截距
    const perpendicularSlope = -1 / slope;
    const perpendicularIntercept = p3.y - perpendicularSlope * p3.x;

    // 计算垂足点 p0
    const x = (perpendicularIntercept - intercept) / (slope - perpendicularSlope);
    const y = slope * x + intercept;
    const p0 = { x, y };

// 计算点 p4
    const distance = d; // 指定距离
    const dx = distance / Math.sqrt(1 + perpendicularSlope ** 2);
    const dy = perpendicularSlope * dx;
    return { x: p0.x + dx, y: p0.y + dy };
  },
  drawLineText(ctx, start, end, text, style) {
    if (start.x > end.x) {
      [start, end] = [end, start]
    }

    const angle = Math.atan2(end.y - start.y, end.x - start.x) * 180 / Math.PI;
    const center = mathUtil.lineCenter(start, end)

    ctx.save();
    ctx.translate(center.x, center.y);
    ctx.rotate(angle * Math.PI / 180);
    const textCenter = help.getTextCenter(ctx, text)
    const padding = style.padding;
    help.roundRect(
      ctx,
      -textCenter.x - padding,
      textCenter.y - padding,
      textCenter.width + 2 * padding,
      textCenter.height + 2 * padding,
      (textCenter.height / 2) + padding
    )
    ctx.fillStyle = style.backColor
    ctx.fill()
    ctx.fillStyle = style.fillColor
    ctx.fillText(text, -textCenter.x, -textCenter.y);
    ctx.restore();
  }
};

export default class Draw {
  constructor() {
    this.canvas = null;
    this.context = null;
  }

  initContext(canvas) {
    if (canvas) {
      this.canvas = canvas;
      this.context = canvas.getContext("2d");
    } else {
      this.context = null;
      this.canvas = null;
    }
  }

  clear() {
    this.context.clearRect(
      0,
      0,
      this.context.canvas.width,
      this.context.canvas.height
    );
  }

  drawBackGroundImg(vector) {
    if (!vector.display) {
      return;
    }
    const img = vector.imageData;
    const width = help.getReal(img.width);
    const height = help.getReal(img.height);
    const center = coordinate.getScreenXY(vector.center);
    this.context.save();
    this.context.drawImage(
      img,
      center.x - width / 2,
      center.y - height / 2,
      width,
      height
    );
    this.context.restore();
  }

  drawGrid(startX, startY, w, h, step1, step2) {
    this.context.save();
    this.context.beginPath();
    for (var x = startX; x <= w; x += step1) {
      this.context.moveTo(x, 0);
      this.context.lineTo(x, h);
    }

    for (var y = startY; y <= h; y += step1) {
      this.context.moveTo(0, y);
      this.context.lineTo(w, y);
    }
    this.context.strokeStyle = "rgba(0,0,0,0.1)";
    this.context.lineWidth = 0.5 * coordinate.ratio;
    this.context.stroke();

    this.context.beginPath();
    for (var x = startX; x <= w; x += step2) {
      this.context.moveTo(x, 0);
      this.context.lineTo(x, h);
    }

    for (var y = startY; y <= h; y += step2) {
      this.context.moveTo(0, y);
      this.context.lineTo(w, y);
    }
    this.context.strokeStyle = "rgba(0,0,0,0.2)";
    this.context.lineWidth = 1 * coordinate.ratio;
    this.context.stroke();
    this.context.restore();
  }

  drawRoad(vector, isTemp) {
    if (!isTemp && vector.display && vector.way !== "oneWay") {
      const ctx = this.context;
      const draw = (midDivide) => {
        const startScreen = coordinate.getScreenXY(midDivide.start);
        const endScreen = coordinate.getScreenXY(midDivide.end);
        ctx.beginPath();
        ctx.moveTo(startScreen.x, startScreen.y);
        ctx.lineTo(endScreen.x, endScreen.y);
        ctx.stroke();
      };

      ctx.save();
      help.setVectorStyle(ctx, vector);
      vector.midDivide.leftMidDivide && draw(vector.midDivide.leftMidDivide);
      vector.midDivide.rightMidDivide && draw(vector.midDivide.rightMidDivide);
      ctx.restore();
    }

    if (import.meta.env.DEV && !isTemp) {
      const startReal = isTemp
        ? vector.start
        : dataService.getRoadPoint(vector.startId);
      const endReal = isTemp
        ? vector.end
        : dataService.getRoadPoint(vector.endId);
      this.drawTextByInfo(
        { x: (startReal.x + endReal.x) / 2, y: (startReal.y + endReal.y) / 2 },
        vector.vectorId
      );
    }
    this.drawRoadEdge(vector, isTemp);
    vector.leftLanes && vector.leftLanes.forEach(this.drawLan.bind(this));
    vector.rightLanes && vector.rightLanes.forEach(this.drawLan.bind(this));
  }

  drawLan(lan) {
    const ctx = this.context;
    const start = coordinate.getScreenXY(lan.start);
    const end = coordinate.getScreenXY(lan.end);
    ctx.save();
    ctx.beginPath();
    help.setVectorStyle(ctx, null, "Lane");
    ctx.setLineDash(Style.Lane.dash);
    ctx.moveTo(start.x, start.y);
    ctx.lineTo(end.x, end.y);
    ctx.stroke();
    ctx.restore();

    if (import.meta.env.DEV) {
      this.drawPoint(lan.start);
      this.drawPoint(lan.end);
    }
  }

  drawRoadEdge(vector, isTemp) {
    //判断是否与road方向一致。角度足够小，路足够宽，有可能向量方向不一致
    const start = isTemp
      ? vector.start
      : dataService.getRoadPoint(vector.startId);
    const end = isTemp ? vector.end : dataService.getRoadPoint(vector.endId);

    const drawRoadEdgeChild = (edgeVector) => {
      const flag = mathUtil.isSameDirForVector(
        start,
        end,
        edgeVector.start,
        edgeVector.end
      );

      if (flag) {
        ctx.beginPath();
        const point1 = coordinate.getScreenXY(edgeVector.start);
        const point2 = coordinate.getScreenXY(edgeVector.end);
        ctx.moveTo(point1.x, point1.y);
        ctx.lineTo(point2.x, point2.y);
        ctx.stroke();
      }
      this.drawTextByInfo(
        {
          x: (edgeVector.start.x + edgeVector.end.x) / 2,
          y: (edgeVector.start.y + edgeVector.end.y) / 2,
        },
        edgeVector.vectorId
      );
    };

    const leftEdge = isTemp
      ? vector.leftEdge
      : dataService.getRoadEdge(vector.leftEdgeId);
    const rightEdge = isTemp
      ? vector.rightEdge
      : dataService.getRoadEdge(vector.rightEdgeId);
    const ctx = this.context;
    ctx.save();
    isTemp && (ctx.globalAlpha = 0.3);
    help.setVectorStyle(ctx, leftEdge);
    drawRoadEdgeChild(leftEdge);
    help.setVectorStyle(ctx, rightEdge);
    drawRoadEdgeChild(rightEdge);
    ctx.restore();

    if (import.meta.env.DEV) {
      this.drawPoint(leftEdge.start);
      this.drawPoint(leftEdge.end);
      this.drawPoint(rightEdge.start);
      this.drawPoint(rightEdge.end);
    }
  }

  drawCrossPoint(vector) {
    const start = coordinate.getScreenXY(
      dataService
        .getRoadEdge(vector.edgeInfo1.id)
        .getPosition(vector.edgeInfo1.dir)
    );
    const end = coordinate.getScreenXY(
      dataService
        .getRoadEdge(vector.edgeInfo2.id)
        .getPosition(vector.edgeInfo2.dir)
    );
    const pt2 = mathUtil.twoOrderBezier(
      0.5,
      start,
      coordinate.getScreenXY({ x: vector.x, y: vector.y }),
      end
    );
    const pt = mathUtil.twoOrderBezier2(0.5, start, pt2, end);
    const extremePoint = coordinate.getScreenXY(vector.extremePoint);
    const ctx = this.context;
    ctx.save();
    ctx.strokeStyle = "red";
    ctx.beginPath();
    ctx.arc(
      // pt.x,
      // pt.y,
      extremePoint.x,
      extremePoint.y,
      Style.CrossPoint.radius * coordinate.ratio,
      0,
      Math.PI * 2,
      true
    );
    ctx.stroke();
    ctx.fill();
    ctx.restore();

    ctx.save();
    ctx.beginPath();
    help.setVectorStyle(ctx, null, "RoadEdge");
    //曲线
    // ctx.moveTo(start.x, start.y);
    // ctx.quadraticCurveTo(pt.x, pt.y, end.x, end.y);

    const [coves] = help.transformCoves([vector.curves]);
    help.drawCoves(ctx, coves);
    ctx.restore();
  }

  drawCurveRoad(vector) {
    if (vector.display && vector.midDivide) {
      const covesArray = help.transformCoves([
        vector.midDivide.leftMidDivideCurves,
        vector.midDivide.rightMidDivideCurves,
      ]);
      const ctx = this.context;
      ctx.save();
      help.setVectorStyle(ctx, vector);
      for (let coves of covesArray) {
        help.drawCoves(ctx, coves);
      }
      ctx.restore();
    }

    this.drawCurveRoadEdge(dataService.getCurveRoadEdge(vector.rightEdgeId));
    this.drawCurveRoadEdge(dataService.getCurveRoadEdge(vector.leftEdgeId));
    vector.leftLanesCurves &&
      vector.leftLanesCurves.forEach(this.drawCurveLan.bind(this));
    vector.rightLanesCurves &&
      vector.rightLanesCurves.forEach(this.drawCurveLan.bind(this));

    if (import.meta.env.DEV) {
      vector.points.forEach(this.drawPoint.bind(this));
    }
  }

  drawCurveRoadEdge(vector, isTemp) {
    const [coves] = help.transformCoves([vector.curves]);
    const ctx = this.context;
    ctx.save();
    help.setVectorStyle(ctx, vector);
    help.drawCoves(ctx, coves);
    ctx.restore();

    if (import.meta.env.DEV) {
      vector.points.forEach(this.drawPoint.bind(this));
    }
  }

  drawCurveLan(lines) {
    const [coves] = help.transformCoves([lines]);
    const ctx = this.context;
    ctx.save();

    help.setVectorStyle(ctx, null, "CurveLan");
    ctx.setLineDash(Style.Lane.dash);
    help.drawCoves(ctx, coves);
    ctx.restore();

    if (import.meta.env.DEV) {
      lines.map((line) => {
        this.drawPoint(line.start);
        this.drawPoint(line.end);
      });
    }
  }

  drawRoadPoint(vector) {
    this.drawPoint(vector);
  }

  drawArrow(vector) {
    const startReal = dataService.getPoint(vector.startId);
    const start = coordinate.getScreenXY(startReal);
    const endReal = dataService.getPoint(vector.endId);
    const end = coordinate.getScreenXY(endReal);
    const ctx = this.context;

    ctx.save();

    const [style] = help.setVectorStyle(this.context, vector);
    if (vector.arrowColor) {
      ctx.strokeStyle = vector.arrowColor;
    }

    const dires =
      vector.category === UIEvents.MeasureLine
        ? [
            [start, end],
            [end, start],
          ]
        : [[start, end]];
    for (let [start, end] of dires) {
      const lines = mathUtil.getArrow(start, end);
      ctx.moveTo(lines[0].x, lines[0].y);
      ctx.lineTo(lines[1].x, lines[1].y);
      ctx.lineTo(lines[2].x, lines[2].y);
    }
    ctx.stroke();
    ctx.restore();
  }

  drawMagnifier(vector) {
    const ctx = this.context;
    this.drawPoint({
      ...vector,
      ...vector.position,
      radius: Style.Magnifier.radius,
    });
    const pt = coordinate.getScreenXY(vector.position);
    const target = coordinate.getScreenXY(vector.popPosition);
    const [style] = help.setVectorStyle(ctx, vector);
    const radius = help.getReal(vector.radius || style.radius);
    const offset = radius / 2;
    const targetPts =
      style === Style.Focus.Magnifier
        ? [mathUtil.translate(pt, target, pt, radius), target]
        : null;

    ctx.save();
    ctx.beginPath();
    ctx.moveTo(pt.x - offset, pt.y);
    ctx.lineTo(pt.x + offset, pt.y);
    ctx.stroke();
    ctx.beginPath();
    ctx.moveTo(pt.x, pt.y - offset);
    ctx.lineTo(pt.x, pt.y + offset);
    ctx.stroke();

    if (targetPts) {
      ctx.beginPath();
      ctx.moveTo(targetPts[0].x, targetPts[0].y);
      ctx.lineTo(targetPts[1].x, targetPts[1].y);
      ctx.stroke();

      let img, imgBound;
      if (vector.photoImage) {
        img = vector.photoImage;
        imgBound = [0, 0, img.width, img.height];
      } else {
        const size = help.getReal(style.target.realRadius);
        const backImg = dataService.getBackgroundImg();
        img = backImg.imageData;
        const imgCenter = coordinate.getScreenXY(backImg.center);
        const start = {
          x: imgCenter.x - help.getReal(img.width) / 2,
          y: imgCenter.y - help.getReal(img.height) / 2,
        };
        const ro = img.width / help.getReal(img.width);
        imgBound = [
          (pt.x - start.x - size) * ro,
          (pt.y - start.y - size) * ro,
          size * 2 * ro,
          size * 2 * ro,
        ];
      }
      const size = help.getReal(style.target.radius);
      ctx.beginPath();
      ctx.arc(target.x, target.y, size, 0, 2 * Math.PI);
      ctx.clip();
      ctx.drawImage(
        img,
        ...imgBound,
        target.x - size,
        target.y - size,
        size * 2,
        size * 2
      );
      ctx.strokeStyle = style.target.strokeStyle;
      ctx.lineWidth = style.target.lineWidth;
      ctx.stroke();
    }
    ctx.restore();
  }

  drawCircle(element) {
    this.drawPoint({
      ...element,
      geoType: "Circle",
      ...element.center,
    });

    element.points.forEach((point) => this.drawPoint(point));
  }

  drawPoint(vector) {
    if (vector.category === VectorCategory.Point.TestBasePoint) {
      return;
    }
    const pt = coordinate.getScreenXY({ x: vector.x, y: vector.y });
    const ctx = this.context;
    let [style, attr] = help.setVectorStyle(
      ctx,
      vector,
      [vector.category, vector.geoType, "Point"]

    );
    if (vector.category === VectorCategory.Point.NormalPoint) {
      const lineid = Object.keys(vector.parent)[0]
      let line, style
      if (!(lineid && (line = dataService.getLine(lineid)))) {
        return;
      }
      const [_, attr] = help.getVectorStyle(line)
      if (!attr) {
        return;
      }
    }

    if (vector.color) {
      ctx.strokeStyle = vector.color;
    }
    const draw = (style) => {
      const radius = vector.radius || style.radius;
      ctx.save();
      ctx.beginPath();
      ctx.arc(pt.x, pt.y, radius, 0, Math.PI * 2, true);
      help.setStyle(ctx, style)
      ctx.stroke();
      ctx.fill();
      ctx.restore();
    }

    if (Settings.selectBasePointId === vector.vectorId) {
      style = {
        ...style,
        fillStyle: "red",
        out: style.out && {
          ...style.out,
          strokeStyle: "red",
        }
      }
    }
    draw(style)
    if (style.out) {
      draw(style.out)
    }

    if (import.meta.env.DEV) {
      if (vector.vectorId) {
        this.drawTextByInfo(vector, vector.vectorId);
      }
    }
  }

  drawTextByInfo(position, txt, angle, setStyle = true) {
    const ctx = this.context;
    ctx.save();
    setStyle && help.setVectorStyle(ctx, null, "Text");

    const pt = coordinate.getScreenXY(position);
    const textCenter = help.getTextCenter(ctx, txt);
    pt.x -= textCenter.x;
    pt.y -= textCenter.y;

    if (angle) {
      ctx.translate(pt.x, pt.y);
      ctx.rotate(angle);
      ctx.fillText(txt, 0, 0);
    } else {
      ctx.fillText(txt, pt.x, pt.y);
    }
    ctx.restore();
  }

  // 文字
  drawText(vector) {
    help.setVectorStyle(this.context, vector);
    this.context.fillStyle = vector.color;
    const oldFont = this.context.font;
    this.context.font = `${vector.fontSize * coordinate.ratio}px Microsoft YaHei`;
    this.drawTextByInfo(vector.center, vector.value, 0, false);

    const ctx = this.context;
    const pt = coordinate.getScreenXY(vector.center);
    const text = ctx.measureText(vector.value);
    pt.x -= text.width / 2;
    pt.y += (text.actualBoundingBoxAscent + text.actualBoundingBoxDescent) / 2;

    this.context.font = oldFont;
  }

  drawLineText(vector, style) {
    const startReal = dataService.getPoint(vector.startId);
    const endReal = dataService.getPoint(vector.endId);
    help.drawLineText(
      this.context,
      coordinate.getScreenXY(startReal),
      coordinate.getScreenXY(endReal),
      help.getRealDistance(startReal, endReal) + "m",
      style
    )
  }

  drawBaseLineLabel(vector) {
    const startReal = dataService.getPoint(vector.startId);
    const start = coordinate.getScreenXY(startReal);
    const endReal = dataService.getPoint(vector.endId);
    const end = coordinate.getScreenXY(endReal);
    const point = mathUtil.translate(
      end, start, end, mathUtil.getDistance(start, end) / 3
    )
    const p4 = help.getPerpendicularPoint(start, end, point, 30 * coordinate.ratio)
    const ctx = this.context
    ctx.beginPath();
    const [style] = help.setVectorStyle(
      this.context,
      vector,
      vector.category || vector.geoType
    );
    ctx.moveTo(point.x, point.y);
    ctx.lineTo(p4.x, p4.y);
    ctx.stroke();

    const p5 = help.getPerpendicularPoint(start, end, point, 35 * coordinate.ratio)
    this.context.font = `${10 * coordinate.ratio}px Microsoft YaHei`;
    help.drawLineText(
      this.context,
      help.getPerpendicularPoint(point, p5, p5, 10 * coordinate.ratio),
      help.getPerpendicularPoint(point, p5, p5, -10 * coordinate.ratio),
      "基准线",
      {
        padding: 6 * coordinate.ratio,
        backColor: "rgba(0,0,0,0)",
        fillColor: style.strokeStyle
      }
    )
  }

  drawLine(vector) {
    const startReal = dataService.getPoint(vector.startId);
    const start = coordinate.getScreenXY(startReal);
    const endReal = dataService.getPoint(vector.endId);
    const end = coordinate.getScreenXY(endReal);

    this.context.save();
    const [style, attr] = help.setVectorStyle(
      this.context,
      vector,
      [vector.category, vector.geoType, 'BaseLine']
    );
    if (style.dash) {
      this.context.setLineDash(style.dash);
    }

    this.context.beginPath();
    this.context.moveTo(start.x, start.y);
    this.context.lineTo(end.x, end.y);
    this.context.stroke();
    this.context.restore();

    const drawPoints = () => {
      // if (attr) {
      //   this.drawPoint(dataService.getPoint(vector.startId))
      //   this.drawPoint(dataService.getPoint(vector.endId))
      // }
    }

    switch (vector.category) {
      case VectorCategory.Line.ArrowLine:
        this.drawArrow(vector);
        drawPoints()
        break
      case VectorCategory.Line.BaseLine:
        this.drawBaseLineLabel(vector)
        drawPoints()
        break;
      case VectorCategory.Line.MeasureLine:
      case VectorCategory.Line.PositionLine:
        this.drawLineText(vector, style.text)
        break;

    }

  }

  drawElementLine(element) {
    let start = elementService.getPoint(element.startId);
    start = coordinate.getScreenXY(start);
    let end = elementService.getPoint(element.endId);
    end = coordinate.getScreenXY(end);

    this.context.save();
    const [style] = help.setVectorStyle(
      this.context,
      element,
      element.category || element.geoType
    );

    if (style.dash) {
      this.context.setLineDash(style.dash);
    }
    this.context.beginPath();
    this.context.moveTo(start.x, start.y);
    this.context.lineTo(end.x, end.y);
    this.context.stroke();
    this.context.restore();
  }
}

const draw = new Draw();
export { draw };