javascript - HTML 5 Canvas 动画 - 一个接一个地移动多个对象

Question

我有这个动画，它将一行圆圈从 A(x,y) 移动到 B(x,y)。但是我在尝试将其复制到一个圆圈数组中时遇到了麻烦，其中每一行(一个接一个)从 A 移动到 B。但是，我还想保持数组的原始位置，以便从本质上说，它复制了行并移动副本。任何帮助将不胜感激!

编辑:我已经编辑了代码，现在有两行在移动时保持静止 - 但现在，我希望能够移动多行(如下例中所述)。

编辑 2:这里有一个 jsfiddle，这样更容易理解我的意思。

https://jsfiddle.net/vLvk1bsc/2/

例如，我想模拟这样的东西。

原始的 ------------------ 新的

1. r r r r r r。 -------------- A. g g g g g g g

2. p p p p p p ---------- B. r r r r r r

3. g g g g g g ---------- C. r r r r r r

因此动画的顺序如下:

1. 3 --- 一个。第3行的副本移动到A行

2. 1 --- b。第 1 行的副本移动到 B 行

3. 1 --- c。第 1 行的副本移动到 C 行

   var canvas = document.getElementById("canvas");
   var context = canvas.getContext("2d");
   
   window.requestAnimFrame = (function (callback) {
       return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function (callback) {
           window.setTimeout(callback, 1000 / 60);
       };
   })();
   
   setTimeout(function () {
       draw();
       animate(movingRow2);
   }, 100);
   
   var movingRow = [];
   var frozenRow = [];
   
   var cx = 50;
   var cy = 70;
   
   for (var i = 0; i < 6; i++) {
       movingRow.push({ x: cx, y: cy, borderWidth: 1, color: "orange"});
       frozenRow.push({ x: cx, y: cy, borderWidth: 1, color: "blue"});
   
       cx += 40;
   }
   
   var movingRow2 = [];
   var frozenRow2 = [];
   
   var cx = 50;
   var cy = 110;
   
   for (var i = 0; i < 6; i++) {
       movingRow2.push({ x: cx, y: cy, borderWidth: 1, color: "green"});
       frozenRow2.push({ x: cx, y: cy, borderWidth: 1, color: "pink"});
   
       cx += 40;
   }
   
   function drawCircle(myCircle, context) {
       context.beginPath();
       context.arc(myCircle.x, myCircle.y, 15, 0, 2 * Math.PI);
       context.fillStyle = myCircle.color;
       context.fill();
       context.stroke();
       context.closePath();
   }   
   
   function draw() {
       context.save();
       context.clearRect(0, 0, canvas.width, canvas.height);
   
       for (var i = 0; i < movingRow.length; i++) {
           drawCircle(movingRow[i], context);
           drawCircle(frozenRow[i], context);
   
           drawCircle(movingRow2[i], context);
           drawCircle(frozenRow2[i], context);
      }
   }
   
   var newX = 320;
   var newY = 70;
   
   var pathArray = [];
   
   pathArray.push({
       x: movingRow2[0].x,
       y: movingRow2[0].y
   });
   
   pathArray.push({
       x: newX,
       y: newY
   });
   
   var polyPoints = makePolyPoints(pathArray);
   
   var position = 0;
   var speed = 1;
   
   function animate(m) {
   
       // calculate the new position
       position += speed;
   
       if (position > polyPoints.length - 1) {
           return;
       }
   
       // a single point in the array
       var pt = polyPoints[position];
   
       var step = 0;
   
       // update x and y
       for (var i = 0; i < m.length; i++) {
           m[i].x = pt.x + step;
           m[i].y = pt.y;
   
           step += 40;
       }
   
       draw();
   
       // request new frame
       requestAnimationFrame(function() {
           animate(m);
       });
   }
   
   function makePolyPoints(pathArray) {
   
       // list of points for each frame of the shape
       var points = [];
       // how quickly the transition occurs
       var speed = 150;
   
       for (var i = 1; i < pathArray.length; i++) {
   
           var startPt = pathArray[i - 1];
           var endPt = pathArray[i];
   
           // calculate difference between start and end points 
           var dx = endPt.x - startPt.x;
           var dy = endPt.y - startPt.y;
   
           for (var n = 0; n <= speed; n++) {  
               // calculate the x and y positions for each frame
               var x = startPt.x + dx * n / speed;
               var y = startPt.y + dy * n / speed;
   
               // append the points to the array to be used in the animation
               points.push({
                   x: x,
                   y: y
               });
           }
       }
   
       return points;
   }
   

Answer 1

var canvas = document.getElementById("canvas");
var context = canvas.getContext("2d");

window.requestAnimFrame = (function (callback) {
    return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function (callback) {
        window.setTimeout(callback, 1000 / 60);
    };
})();



setTimeout(function () {
    draw();
    var a = anims[anims_i];
    animate(a[0], a[1]);
}, 100);

var rowA = [];
var rowB = [];
var rowC = [];

var cx = 50;
var cy = 70;

for (var i = 0; i < 6; i++) {
    rowA.push({ x: cx, y: cy-40, borderWidth: 1, color: "orange"});
    rowB.push({ x: cx, y: cy, borderWidth: 1, color: "blue"});
    rowC.push({ x: cx, y: cy+40, borderWidth: 1, color: "pink"});
    cx += 40;
}

var rowACopy1 = JSON.parse(JSON.stringify(rowA));
var rowACopy2 = JSON.parse(JSON.stringify(rowA));
var rowCCopy = JSON.parse(JSON.stringify(rowC));

var offsetX = 270;
var polyPointsA1 = makePolyPoints([
  {x: rowA[0].x, y: rowA[0].y},
  {x: rowB[0].x+offsetX, y: rowB[0].y}
]);

var polyPointsA2 = makePolyPoints([
  {x: rowA[0].x, y: rowA[0].y},
  {x: rowC[0].x+offsetX, y: rowC[0].y}
]);

var polyPointsC = makePolyPoints([
  {x: rowC[0].x, y: rowC[0].y},
  {x: rowA[0].x+offsetX, y: rowA[0].y}
]);

var anims = [
 [rowCCopy, polyPointsC],
 [rowACopy1, polyPointsA1],
 [rowACopy2, polyPointsA2]
];

var anims_i = 0;

function drawCircle(myCircle, context) {
    context.beginPath();
    context.arc(myCircle.x, myCircle.y, 15, 0, 2 * Math.PI);
    context.fillStyle = myCircle.color;
    context.fill();
    context.stroke();
    context.closePath();
}   

function draw() {
    context.save();
    context.clearRect(0, 0, canvas.width, canvas.height);

    for (var i = 0; i < rowA.length; i++) {
        drawCircle(rowA[i], context);
        drawCircle(rowB[i], context);
        drawCircle(rowC[i], context);

        drawCircle(rowACopy1[i], context);
        drawCircle(rowACopy2[i], context);
        drawCircle(rowCCopy[i], context);
   }
}

var position = 0;
var speed = 1;

function animate(m, polyPoints) {

    // calculate the new position
    position += speed;

    if (position > polyPoints.length - 1) {
      position = 0;
      anims_i++;
        if (anims_i < anims.length) {
          var a = anims[anims_i];
          requestAnimationFrame(function() {
            animate(a[0], a[1]);
          });
        }
        return;
    }

    // a single point in the array
    var pt = polyPoints[position];

    var step = 0;

    // update x and y
    for (var i = 0; i < m.length; i++) {
        m[i].x = pt.x + step;
        m[i].y = pt.y;

        step += 40;
    }

    draw();

    // request new frame
    requestAnimationFrame(function() {
        animate(m, polyPoints);
    });
}

function makePolyPoints(pathArray) {

    // list of points for each frame of the shape
    var points = [];
    // how quickly the transition occurs
    var speed = 150;

    for (var i = 1; i < pathArray.length; i++) {

        var startPt = pathArray[i - 1];
        var endPt = pathArray[i];

        // calculate difference between start and end points 
        var dx = endPt.x - startPt.x;
        var dy = endPt.y - startPt.y;

        for (var n = 0; n <= speed; n++) {  
            // calculate the x and y positions for each frame
            var x = startPt.x + dx * n / speed;
            var y = startPt.y + dy * n / speed;

            // append the points to the array to be used in the animation
            points.push({
                x: x,
                y: y
            });
        }
    }

    return points;
}

#canvas {
  border:1px solid red;
}

<canvas id="canvas" width="580"></canvas>