GoJs中导出图片或者SVG实现示例详解

//html
<button @click="image">image</button>
<button @click="svg">svg</button>
//data
nodes: [
    { key: "1", color: "#99FFFF", text: "三国", figure: "Rectangle" },
    { key: "1-1", color: "#FF0000", text: "魏", figure: "Circle" },
    { key: "1-2", color: "#FFFF66", text: "蜀", figure: "Circle" },
    { key: "1-3", color: "#0000FF", text: "吴", figure: "Circle" },
],
links: [
    {
      from: "1",
      to: "1-1",
    },
    {
      from: "1",
      to: "1-2",
    },
    {
      from: "1",
      to: "1-3",
    },
],
//methods
this.myDiagram = $$(Go.Diagram, "myDiagramDiv", {
    allowDelete: true,
    layout: $$(go.TreeLayout),
    });
this.myDiagram.nodeTemplate = $$(
go.Node,
"Vertical",
$$(
  go.Shape,
  "Circle",
  { width: 30, height: 30, name: "ICON" },
  new go.Binding("fill", "color"),
  new go.Binding("figure", "figure")
),
$$(go.TextBlock,new go.Binding("text", "text"))
);
this.myDiagram.model = new go.GraphLinksModel(this.nodes, this.links);

image(){
    this.myDiagram.makeImage({
        scale: 1.0,//放大倍数
        parts: this.myDiagram.links,//选中导出的图中元器件
        background: "#FFF",//导出图片的背景颜色
        type: "image/jpeg",//导出图片的格式
        detail: 1.0,//导出图片的详细程度
        size: new go.Size(NAN,NAN),//导出图片的尺寸
        position: new go.Point(0,0),导出图片的左上角在画布上的位置
        callback: img => {
            let a = document.createElement("a");
            a.style = "display: none";
            a.href = img.src;
            a.download = "导出图片";
            a.click();
        }
    })
},

image(){
    let blob = this.myDiagram.makeImageData({
        returnType: "blob",
        scale: 1.0,
        detail: 10.0,
        background: "#FFF",
        callback: this.myCallback,
    });
},
myCallback(blob) {
  let url = window.URL.createObjectURL(blob);
  let filename = "img.png";
  let a = document.createElement("a");
  a.style = "display: none";
  a.href = url;
  a.download = "导出图片";
  let file = new File([blob], filename, { type: "png" });
  // IE 11
  if (window.navigator.msSaveBlob !== undefined) {
    window.navigator.msSaveBlob(blob, filename);
    return;
  }
  document.body.appendChild(a);
  requestAnimationFrame(function () {
    a.click();
    window.URL.revokeObjectURL(url);
    document.body.removeChild(a);
  });
},

svg(){
    let svg = this.myDiagram.makeSvg({ 
        scale: 1.0,//放大倍数
        parts: this.myDiagram.links,//选中导出的图中元器件
        background: "#FFF",//导出图片的背景颜色
        type: "image/jpeg",//导出图片的格式
        detail: 1.0,//导出图片的详细程度
        size: new go.Size(NAN,NAN),//导出图片的尺寸
        position: new go.Point(0,0),//导出图片的左上角在画布上的位置
    });
    let svgstr = new XMLSerializer().serializeToString(svg);
    let blob = new Blob([svgstr], { type: "image/svg+xml" });
    this.myCallback(blob);
},
myCallback(blob) {
  let url = window.URL.createObjectURL(blob);
  let filename = "img.png";
  let a = document.createElement("a");
  a.style = "display: none";
  a.href = url;
  a.download = "导出图片";
  let file = new File([blob], filename, { type: "png" });
  // IE 11
  if (window.navigator.msSaveBlob !== undefined) {
    window.navigator.msSaveBlob(blob, filename);
    return;
  }
  document.body.appendChild(a);
  requestAnimationFrame(function () {
    a.click();
    window.URL.revokeObjectURL(url);
    document.body.removeChild(a);
  });
},