如何从二维几何中获得真实的线宽？

Question

如何从 2D 图纸中获取线宽以创建具有正确宽度或相对原始线宽的自定义线。

VertexBufferReader 返回的是没有线宽的两点。

Answer 1

你在找这个吗？

• onLineSegment(x1, y1, x2, y2, vpId, lineWidth) 在函数参数的末尾有一个lineWidth 参数

• onTexQuad(centerX, centerY, width, height, rotation, vpId) 在函数参数中有一个width 参数

快照：

演示代码：

function GeometryCallback(viewer,copiedGeometryName,curveMaterial) {

  this.viewer = viewer;   
  this.opiedGeometryName = copiedGeometryName;

  // linewidth does not take effect in Chrome and Firefox 
  // It is a known issue with OpenGL core
  // try with Safari
  this.curveMaterial = curveMaterial;
  this.is2PITimes = function(angle1,angle2){
    return Math.abs(angle1-angle2)/Math.PI % 2 == 0
  }

}

GeometryCallback.prototype.onLineSegment = function(x1, y1, x2, y2, vpId, lineWidth) {

  var vpXform = this.viewer.model.getPageToModelTransform(vpId);
  //if in CAD coordinate system, applyMatrix4 with vpXform
  var pt1 = new THREE.Vector3().set(x1, y1, 0)//.applyMatrix4(vpXform);
  var pt2 = new THREE.Vector3().set(x2, y2, 0)//.applyMatrix4(vpXform); 

  console.log('Line segment vertices coordinates: ', {
        pointX1: pt1.x,
        pointY1: pt1.y,
        pointX2: pt2.x,
        pointY2: pt2.y
    },
    'width:', lineWidth
  ); 
  
  //add overlay geometry 
  var geometry = new THREE.Geometry () 
  geometry.vertices.push (new THREE.Vector3 ( pt1.x,  pt1.y, 0))
  geometry.vertices.push (new THREE.Vector3 ( pt2.x,  pt2.y, 0))

  var lines = new THREE.Line (geometry,
                              this.curveMaterial,
                              THREE.LinePieces)
  this.viewer.impl.addOverlay (this.opiedGeometryName, lines) 
  this.viewer.impl.invalidate (false,false,true)   
}

GeometryCallback.prototype.onCircularArc = function(cx, cy, start, end, radius, vpId) {

  var vpXform = this.viewer.model.getPageToModelTransform(vpId);
  //if in CAD coordinate system, applyMatrix4 with vpXform
  var center = new THREE.Vector3().set(cx, cy, 0)//.applyMatrix4(vpXform);

  console.log('CircleArc segment: ', {
    centerX: center.x,
    centerY: center.y,
    radius: radius,
    startAngle: start,
    endAngle: end
  }); 

  //add overlay geometry
  var curve = new THREE.EllipseCurve(
    center.x, center.y,            
    radius, radius,     
    start, end,  
    false            
  );
  var path = new THREE.Path(curve.getPoints(50));
  var geometry = path.createPointsGeometry(50);
  //remove last vertex if it an arc
  if(!this.is2PITimes(start,end))
    geometry.vertices.pop();
  var circularArc = new THREE.Line(geometry, this.curveMaterial);
  this.viewer.impl.addOverlay (this.opiedGeometryName, circularArc) 
  this.viewer.impl.invalidate (false,false,true)  
};

GeometryCallback.prototype.onEllipticalArc = function(cx, cy, start, end, major, minor, tilt, vpId) {
  var vpXform = this.viewer.model.getPageToModelTransform(vpId);
  //if in CAD coordinate system, applyMatrix4 with vpXform
  var center = new THREE.Vector3().set(cx, cy, 0)//.applyMatrix4(vpXform);

  console.log('EllipticalArc segment: ', {
    centerX: center.x,
    centerY: center.y,
    radius: radius,
    startAngle: start,
    endAngle: end
  }); 

  //add overlay geometry
  var curve = new THREE.EllipseCurve(
    center.x, center.y,            
    major, minor,     
    start, end,  
    false            
  );
  var path = new THREE.Path(curve.getPoints(50));
  var geometry = path.createPointsGeometry(50);
  //remove last vertex if it an arc
  if(!this.is2PITimes(start,end))
    geometry.vertices.pop();
  var ellipticalArc = new THREE.Line(geometry, this.curveMaterial);
  this.viewer.impl.addOverlay (this.opiedGeometryName, ellipticalArc) 
  this.viewer.impl.invalidate (false,false,true)  
};
GeometryCallback.prototype.onOneTriangle = function(x1, y1, x2, y2, x3, y3, vpId){
  //Similar logic as above
};
GeometryCallback.prototype.onTexQuad = function(centerX, centerY, width, height, rotation, vpId){
  //from VertexBufferReader.js:
  //Currently this case does not actually come up
};

//extension of MyShow2dCurve
function MyShow2dCurve(viewer, options) {

    Autodesk.Viewing.Extension.call(this, viewer, options)

    var _viewer = this.viewer 
    var _copiedGeometryName = 'copiedGeometryName'

    // linewidth does not take effect in Chrome and Firefox 
    // It is a known issue with OpenGL core
    // try with Safari
    var _curveMaterial = new THREE.LineBasicMaterial ({
      color: new THREE.Color (0xFF0000),
      transparent: true,
      depthWrite: false,
      depthTest: false,
      linewidth: 5,
      opacity: 1.0
      }) 

    //when extension is loaded
    this.load = function() {
        console.log('MyShow2dCurve is loaded!'); 
        //bind keyup event
        $(document).bind('keyup', onKeyUp); 
        _viewer.impl.invalidate(true);  
        return true;
    };

    //when extension is unloaded 
    this.unload = function() {
        console.log('MyShow2dCurve is now unloaded!');
        //unbind keyup event
        $(document).unbind('keyup', this.onKeyUp);
        return true;
    }; 

    //when key up
    function onKeyUp(evt) {  
        console.log('onKeyUp:' + evt.keyCode); 
  
        //when key 'S' is pressed
        if(evt.keyCode == 83){   
          //create overlay
          _viewer.impl.createOverlayScene (_copiedGeometryName, _curveMaterial)   
           //start to monitor select event 
          _viewer.addEventListener(Autodesk.Viewing.SELECTION_CHANGED_EVENT, onSelectObj) 
        }
      
        //when key 'Q' is pressed
        if(evt.keyCode == 81){ 
          //undelegate selection event
          _viewer.removeEventListener(Autodesk.Viewing.SELECTION_CHANGED_EVENT, onSelectObj) 
          //remove overlay
          _viewer.impl.removeOverlayScene(_copiedGeometryName);
          _viewer.impl.invalidate(false, false, true);  
          }
      
        return true;
      } 

      //when selecting object
      function onSelectObj(evt){ 
            console.log(evt) 
            //selected object id
            var dbId = evt.dbIdArray[0] 
            //get instance tree
            var it = _viewer.model.getData().instanceTree;
            //dump fragments of the object
            it.enumNodeFragments( dbId, function( fragId ) {
                //get each fragment
                var m = _viewer.impl.getRenderProxy(_viewer.model, fragId);
                //initialize VertexBufferReader
                var vbr = new Autodesk.Viewing.Private.VertexBufferReader(m.geometry, _viewer.impl.use2dInstancing);
                //dump geometry of this fragment
                vbr.enumGeomsForObject(dbId, new GeometryCallback(_viewer,_copiedGeometryName, _curveMaterial));
            }); 
      }    
}

MyShow2dCurve.prototype = Object.create(Autodesk.Viewing.Extension.prototype);
MyShow2dCurve.prototype.varructor = MyShow2dCurve; 
  
Autodesk.Viewing.theExtensionManager.registerExtension('MyShow2dCurve', MyShow2dCurve); 

修改自：https://forge.autodesk.com/blog/dump-geometries-2d-curve