javascript - "spawn"拖动 SVG 形状期间的鼠标处理程序

Question

我将继续完善我的小元素并学习 javascript 和 svg。

在我最后的代码中，我通过创建被点击对象的副本 (cloneNode(true)) 然后将其重新分配给可拖动对象来实现“点击生成元素并拖动它”。

既然我重构了整个代码以利用 javascript 对象工厂，我似乎一直在试图找出正确的“循环”；(

试试下面的片段:- 我设法创建了可拖动对象(库存形状)- 我设法添加了一些逻辑来识别它的库存类并复制并将类更改为“可拖动”- 现在有两个问题:-- 生成的对象并不是原始 Draggable 的真正完整副本，因此它们没有鼠标监听器，我不确定如何将监听器与原始对象分离...

你如何编写所有这些代码？

//var morphUIon = false;
var morphTarget = null;
var canvas = {};
var inventory = {};
canvas = document.getElementById("canvas");
inventory = document.getElementById("inventory");

window.onload = function() {	
  var src = document.querySelectorAll(".inventory");
    for (var h = 0; h < src.length; h++) {
      var o = new Draggable(src[h]);
      //inventory.push(o);
  }
}

function Draggable(elem) {
  this.target = elem
  this.clickPoint = this.target.ownerSVGElement.createSVGPoint()
  this.lastMove = this.target.ownerSVGElement.createSVGPoint()
  this.currentMove = this.target.ownerSVGElement.createSVGPoint()
  this.dpath = this.target.getAttribute("d")
  this.subclass = this.target.getAttribute("subclass")
  this.target.pathPoints = parsePathToPoints(this.dpath, this.subclass)
  this.target.addEventListener("dblclick", this)
  this.target.addEventListener("mousedown", this)
  this.handleEvent = function(evt) {
        switch (evt.type) {
            case 'mousedown':
                evt.preventDefault()
                if (this.target.classList.contains("inventory")) {
                  var spawned = this.target.cloneNode(true);
                  spawned.classList.remove("inventory");
                  spawned.classList.add("draggable");
                  canvas.appendChild(spawned);
                  this.target = spawned;
                  //return;
                }
                this.clickPoint = globalToLocalCoords(evt.clientX, evt.clientY)
                this.target.classList.add("dragged")
                this.target.ownerSVGElement.addEventListener("mousemove", this.move)
                this.target.ownerSVGElement.addEventListener("mouseup", this.endMove)
                //to ensure dblclick is "heard" we delay the pointer trick below by 200ms.
                //setTimeout(function() {this.target.setAttribute("pointer-events", "none")}, 200)
                break;
            case 'dblclick':
                evt.preventDefault()
                if (morphTarget) {
                  if (morphTarget!=this.target) {
                  morphTarget.classList.remove("morphed")
                  this.target.classList.add("morphed")
                  morphTarget = elem;
                  } else {
                    return;
                  }
                } else {
                  morphTarget = elem
                  this.target.classList.add("morphed")
                }
                Morph(this.target);
                break;
        }
  }
  this.move = function(evt) {
    evt.preventDefault()
    var p = globalToLocalCoords(evt.clientX, evt.clientY)
    this.currentMove.x = this.lastMove.x + (p.x - this.clickPoint.x)
    this.currentMove.y = this.lastMove.y + (p.y - this.clickPoint.y)
    this.target.setAttribute("transform", "translate(" + this.currentMove.x + "," + this.currentMove.y + ")")
  }.bind(this)
  this.endMove = function(evt) {
    this.lastMove.x = this.currentMove.x
    this.lastMove.y = this.currentMove.y
    this.target.classList.remove("dragged")
    //this.target.setAttribute("pointer-events", "all")
    this.target.ownerSVGElement.removeEventListener("mousemove", this.move)
    this.target.ownerSVGElement.removeEventListener("mouseup", this.endMove)
  }.bind(this)
  function globalToLocalCoords(x, y) {
    var p = elem.ownerSVGElement.createSVGPoint()
    var m = elem.parentNode.getScreenCTM()
    p.x = x
    p.y = y
    return p.matrixTransform(m.inverse())
  }
}

function Morph(elem) {
  console.log(elem); 
}

function parsePathToPoints(d, sub) {
  var darray = [];
  var pathPoints = {};
  switch (sub) {
            case 'circle':
              darray = d.replace(/M|A|Z/g, "").replace(/,/g, " ").split(" ").map(Number);
              pathPoints.p0 = {"x": darray[0], "y": darray[1]};
              pathPoints.p1 = {"x": darray[0]+darray[2], "y": darray[1]-darray[3]};
              pathPoints.p2 = {"x": darray[7], "y": darray[8]};
              pathPoints.p3 = {"x": darray[0]+darray[2], "y": darray[1]+darray[3]};
              pathPoints.p4 = {"x": darray[2], "y": darray[3]}; // = radius used in the circle path
              return pathPoints;
            break;
            case 'curve4':
              darray = d.replace(/M|Q/g, "").replace(/,/g, " ").split(" ").map(Number);
              for (i=0, j=1, o=9; i<darray.length-2; i+=2, j+=2, o++) {
                pathPoints["p"+(o-9)] = {"x": darray[i], "y": darray[j]};
                };
              return pathPoints;
            break;
            case 'curve3':
              darray = d.replace(/M|Q/g, "").replace(/,/g, " ").split(" ").map(Number)
              for (i=0, j=1, o=9; i<darray.length; i+=2, j+=2, o++) {
                pathPoints["p"+(o-9)] = {"x": darray[i], "y": darray[j]};
                }
              return pathPoints;
            break;
            case 'curve2':
              darray = d.replace(/M|Q/g, "").replace(/,/g, " ").split(" ").map(Number);
              for (i=0, j=1, o=9; i<darray.length; i+=2, j+=2, o++) {
                pathPoints["p"+(o-9)] = {"x": darray[i], "y": darray[j]};
                }
              return pathPoints;
            break; 
            case 'curve1':
              darray = d.replace(/M|Q/g, "").replace(/,/g, " ").split(" ").map(Number);
              for (i=0, j=1, o=9; i<darray.length; i+=2, j+=2, o++) {
                pathPoints["p"+(o-9)] = {"x": darray[i], "y": darray[j]};
                }
              return pathPoints;
            break;
            case 'cubic':
              darray = d.replace(/M|C/g, "").replace(/,/g, " ").split(" ").map(Number);
              for (i=0, j=1, o=9; i<darray.length; i+=2, j+=2, o++) {
                    pathPoints["p"+(o-9)] = {"x": darray[i], "y": darray[j]};
			            }
              return pathPoints;
            break; 
    }
}

function pointsToPath(pathPoints, pathSubclass) {
    console.log("joining "+pathPoints+"for a "+pathSubclass);
}

html, body {
	margin: 0;
	padding: 0;
	border: 0;
	overflow:hidden;
	background-color: #fff;	
}
svg {
    position: fixed; 
	  top:0%; 
	  left:0%; 
	  width:100%; 
	  height:100%;  
}
.inventory {
  fill: transparent;
	stroke: black;
  cursor: move;
}
.draggable {
  fill: transparent;
	stroke: blue;
  cursor: move;
}
.dragged {
  fill: transparent;
	stroke: green;
  cursor: move;
}
.morphed {
  fill: transparent;
	stroke: red;
  cursor: move;
}
.lines {
	stroke: green;
  stroke-dasharray: 8,5;
  stroke-width: 1;
  opacity: 0.5;
}
path
{
	stroke-width: 3;
	stroke: #000;
	stroke-linecap: round;
}
path.fill
{
	fill: #3ff;
}
#canvasBackground {
	fill: lightgrey;
}
#inventoryBackground {
	fill: grey;
}
#morphUIrect {
    fill: none; 
    stroke: blue;
    stroke-dasharray: 10,5;
    opacity: 0.1;
}
.label {
  fill: grey;
}

<body>
<svg id="svg"
  height="480"
  width="480"
	viewbox="0 0 480 580"
	preserveAspectRatio="xMinYMax meet"
	xmlns="http://www.w3.org/2000/svg"
	xmlns:xlink="http://www.w3.org/1999/xlink"
>
<rect id="canvasBackground" width="480" height="480" x="0" y="0" pointer-events="all"/>
<rect id="inventoryBackground" width="480" height="100" x="0" y="480" pointer-events="all"/>

<g id="inventory">
<path class="inventory" subclass="circle" d="M30,530 A35,35 1 1,1 100,530 A35,35 1 1,1 30,530" />
<path class="inventory" subclass="curve4" d="M125,500 Q155,490 185,500 Q195,530 185,560 Q155,570 125,560 Q115,530 125,500" />
<path class="inventory" subclass="curve3" d="M245,495 Q275,520 280,560 Q245,570 210,560 Q215,520 245,495" />
<path class="inventory" subclass="curve2" d="M305,515 Q345,475 385,515 Q345,555 305,515"/>
<path class="inventory" subclass="curve1" d="M305,550 Q345,580 385,550"/>
<path class="inventory" subclass="cubic" d="M420,495 C470,530 380,530 425,565"/>
</g>

<g id="canvas">
</g>
  
<g id="morphUI">
<rect id="morphUIrect" visibility = "visible" x="0" y="0" width="0" height="0"></rect>
<line id="l0" visibility = "hidden" class="lines" x1="0" y1="0" x2="0" y2="0"/>
<line id="l1" visibility = "hidden" class="lines" x1="0" y1="0" x2="0" y2="0"/>
<line id="l2" visibility = "hidden" class="lines" x1="0" y1="0" x2="0" y2="0"/>
<line id="l3" visibility = "hidden" class="lines" x1="0" y1="0" x2="0" y2="0"/>
<line id="l4" visibility = "hidden" class="lines" x1="0" y1="0" x2="0" y2="0"/>
<line id="l5" visibility = "hidden" class="lines" x1="0" y1="0" x2="0" y2="0"/>
<line id="l6" visibility = "hidden" class="lines" x1="0" y1="0" x2="0" y2="0"/>
<line id="l7" visibility = "hidden" class="lines" x1="0" y1="0" x2="0" y2="0"/>
<circle id="0" visibility = "hidden" class="control" cx="0" cy="0" r="8"/>
<circle id="1" visibility = "hidden" class="control" cx="0" cy="0" r="8"/>
<circle id="2" visibility = "hidden" class="control" cx="0" cy="0" r="8"/>
<circle id="3" visibility = "hidden" class="control" cx="0" cy="0" r="8"/>
<circle id="4" visibility = "hidden" class="control" cx="0" cy="0" r="8"/>
<circle id="5" visibility = "hidden" class="control" cx="0" cy="0" r="8"/>
<circle id="6" visibility = "hidden" class="control" cx="0" cy="0" r="8"/>
<circle id="7" visibility = "hidden" class="control" cx="0" cy="0" r="8"/>
<circle id="8" visibility = "hidden" class="control" cx="0" cy="0" r="10" _x="0" _y="0"/>
</g>
</svg>
</body>

Answer 1

通常最好不要将事件处理程序附加到单个 SVG 形状元素。如果您在拖动时快速移动，然后释放鼠标按钮，则 mouseup 事件可能会在您拖动的形状之外发生。你最终可能会得到“卡住”的形状。最好将 mouseup/mousedown 事件附加到根 <svg>元素并跟踪您在变量中拖动的元素。这还有一个好处，就是您不必一直在被拖动的元素中添加和删除事件处理程序。