Do it now!

소개 (https://chobocho.tistory.com/2461396)
실행하기 http://www.chobocho.com/javascript/painter.html
전체 소스코드 https://github.com/chobocho/painter

6.1 원 그리기

원을 그리는 함수를 추가합니다.

circle = new Shape("Circle");
circle.mouseAction = new MouseAction(circleMouseUp, circleMouseDown, circleMouseMove);

function circleMouseDown(event) {
  console.log("circleMouseDown");
  if (painter.isDraw()) {
    return;
  }
  bufCtx.drawImage(canvas, 0, 0);
  var startPos = getMousePosition(event);
  painter.shape.point.x = startPos.X;
  painter.shape.point.y = startPos.Y;
  painter.setDrawMode(true);
}

function circleMouseMove(event) {
  if (!painter.isDraw()) {
    return;
  }
  var currentPos = getMousePosition(event);
  cvs.beginPath();
  // Need a delay
  cvs.clearRect(0, 0, canvas.width, canvas.height);
  cvs.drawImage(bufCanvas, 0, 0);

  cvs.strokeStyle = painter.getColor();

  var circle = {
    X: Math.round((painter.shape.point.x + currentPos.X) / 2),
    Y: Math.round((painter.shape.point.y + currentPos.Y) / 2),
    R: Math.round(Math.abs(currentPos.Y - painter.shape.point.y) / 2)
  };
  cvs.arc(circle.X, circle.Y, circle.R, 0, Math.PI * 2);
  cvs.closePath();
  cvs.stroke();
}

function circleMouseUp(event) {
  if (!painter.isDraw()) {
    return;
  }

  var currentPos = getMousePosition(event);
  bufCtx.beginPath();
  bufCtx.strokeStyle = painter.getColor();

  var circle = {
    X: Math.round((painter.shape.point.x + currentPos.X) / 2),
    Y: Math.round((painter.shape.point.y + currentPos.Y) / 2),
    R: Math.round(Math.abs(currentPos.Y - painter.shape.point.y) / 2)
  };
  bufCtx.arc(circle.X, circle.Y, circle.R, 0, Math.PI * 2);
  bufCtx.closePath();
  bufCtx.stroke();

  cvs.clearRect(0, 0, canvas.width, canvas.height);
  cvs.drawImage(bufCanvas, 0, 0);

  painter.setDrawMode(false);
}

6.2 도형의 선택

원과 선을 선택 할 수 있도록 html 파일에 함수를 연결 합니다.

[paint.js]

function selectShape(choosedShape) {
  console.log("selectShape:" + choosedShape);
  painter.setShape(choosedShape);
}

Painter 객체에 선, 원을 tools라는 자료형에 추가를 합니다.

Painter.prototype.init = function () {
  line = new Shape("Line");
  line.mouseAction = new MouseAction(lineMouseUp, lineMouseDown, lineMouseMove);
  this.tools[line.name] = line;

  circle = new Shape("Circle");
  circle.mouseAction = new MouseAction(circleMouseUp, circleMouseDown, circleMouseMove);
  this.tools[circle.name] = circle;

  this.shape = this.tools["Line"];
  this.color = "black";
}

function onLoadPage() {
  
  // ...

  painter = new Painter();
  painter.init();
}

6.3 기타 수정 사항

color 값은 모든 도형이 공통적으로 사용하므로,
shape 에서 painter 객체로 이동을 합니다.

Painter.prototype.init = function () {
  // ...
  this.color = "black";
}

여기까지 소스코드:

https://github.com/chobocho/painter/tree/master/doc/tutorial/006/src

공감과 댓글은 큰 도움이 됩니다.