從Ol3中的繪圖交互中刪除最后一點

Question

我試圖刪除esc鍵上的多邊形繪制功能中的最后一點。

以下代碼不起作用。 繪制區域部分時似乎已將其刪除，但頂點仍在那里。

var geom :ol.geom.Polygon = null;
draw.on("drawstart",(event) => {
    console.log(event);
    var feature :ol.Feature= event.feature;
    console.log(feature);
    geom = feature.getGeometry<ol.geom.Polygon>();
});

$(document).keyup((e)=> {
    if (e.keyCode === 27) {
        var coords = geom.getCoordinates()[0];
        if(coords.length>1)
            geom.setCoordinates([coords.slice(0, coords.length - 2)]);
    }
});

Answer 1

OpenLayers 3使用Draw.removeLastPoint（）方法對此有了新的解決方案。 奇跡般有效！

 draw = new ol.interaction.Draw({ source:source, type: /** @type (ol.geom.GeometryType) */ ('Polygon') }) draw.on('drawstart', function(evt){ $(document).on('keyup', function(event){ if(event.keyCode === 27){ draw.removeLastPoint(); } }); }); 

Answer 2

刪除最后一個線段后，需要在幾何元素上使用setCoordinates。

這是一個例子：

this.olDraw.on('drawstart',
  function (evt) {
    $(document).on('keyup', function (event) {
      if (event.keyCode === 27) {
        var feature = evt.feature;
        var geom = feature.getGeometry();
        if (geom.getType() === LINE_STRING) {
          geom.setCoordinates(geom.getCoordinates().slice(0,geom.getCoordinates().length - 1));
        }
      }
    });
  }, this);

Answer 3

這段代碼是對類似問題的另一個答案的修改版本（我再也找不到）。 使用此代碼段，您可以刪除lineString的最后插入點。 我認為它也應適用於多邊形。 試試看。

var lineStringdraw = new ol.interaction.Draw({
    features: features,
    type: "LineString",
    geometryFunction:geometryChange
});


function geometryChange(coordinates, geometry){
    if (!geometry) {
        console.info("what did you do?");
        geometry = new ol.geom.LineString(null);   
    } 
    var coords = geometry.getCoordinates();
    var diff = coordinates.length - coords.length;
    if (diff > 1) {
        coordinates.splice(coordinates.length - diff, diff - 1);
        if (coordinates.length === 1){
            lineStringdraw.finishDrawing();
            var emptyFeature = vector2.getSource().getFeatures()[vector2.getSource().getFeatures().length-1];
            vector2.getSource().removeFeature(emptyFeature);
        }
    }
    geometry.setCoordinates(coordinates);
    coordinates= geometry.getCoordinates();
    return geometry;    
}

var keydown = function(evt){
var charCode = (evt.which) ? evt.which : evt.keyCode;
if (charCode === 27 && drawing === true){ //esc key
    var geom = drawing_feature.getGeometry();
    geom.setCoordinates(geom.getCoordinates().slice(0, -1));
    undo=true;
}
};

var drawing=false,drawing_feature=null;

lineStringdraw.on('drawstart', function(e1) {
    drawing = true;
    drawing_feature = e1.feature;
    drawing_feature.setProperties({'FID': featureID})
    var featureGeom = drawing_feature.getGeometry();
});


lineStringdraw.on('drawend', function(e2) {
    drawing = false;
    drawing_feature = null;
});