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今天就跟大家聊聊有關openlayers 3如何實現車輛軌跡回放,可能很多人都不太了解,為了讓大家更加了解,小編給大家總結了以下內容,希望大家根據這篇文章可以有所收獲。
利用 openlayers 3地圖的 postcompose 事件監聽地圖的重繪
注意:此代碼是我在Vue 的methods 里面寫的測試方法,并不能直接運行,請在理解的基礎上測試。
vm 為vue的this對象 注釋已經很豐富了,先做個備份,后期會編輯加入一點詳解。
實現代碼:
html:
<div id="menu"> <label for="speed" > 運動速度: <input id="speed" type="range" min="1" max="20" step="1" value="10" /> </label> <button id="start-animation"> 開始運動 </button> </div> <!-- 注:此代碼僅為上面速度條和按鈕--
核心代碼:
startMove:function () { var vm=this; var map=vm.map; vm.clearOverlayers("beijing_sq"); //中間站 var stops=[ [12909554.6597,4933234.84552], //14 [12909824.6852,4931594.7854], //43 [12910026.8837,4930523.89946], //63 [12910870.563,4929357.26511] //85 ]; var stopMakers = new Array(); for(var i=0;i<4;i++){ var s = new ol.Feature({ type: 'stop', geometry: new ol.geom.Point(stops[i]) }); stopMakers.push(s); } var Coordinates=vm.path; //將離散點構建成一條折線 var route = new ol.geom.LineString(Coordinates); //獲取直線的坐標 var routeCoords = route.getCoordinates(); var routeLength = routeCoords.length; var routeFeature = new ol.Feature({ type: 'route', geometry: route }); var geoMarker = new ol.Feature({ type: 'geoMarker', geometry: new ol.geom.Point(routeCoords[0]) }); var startMarker = new ol.Feature({ type: 'icon', geometry: new ol.geom.Point(routeCoords[0]) }); var endMarker = new ol.Feature({ type: 'icon', geometry: new ol.geom.Point(routeCoords[routeLength - 1]) }); var styles = { 'route': new ol.style.Style({ stroke: new ol.style.Stroke({ width: 6, color: '#F2C841' }), fill:new ol.style.Fill({ color:"#F6E3A3" }) }), /*'icon': new ol.style.Style({ image: new ol.style.Icon({ anchor: [0.5, 1], src: require() }) }),*/ 'geoMarker': new ol.style.Style({ /*image: new ol.style.Circle({ radius: 7, snapToPixel: false, fill: new ol.style.Fill({ color: 'black' }), stroke: new ol.style.Stroke({ color: 'white', width: 2 }) })*/ image: new ol.style.Icon({ src: require('../../assets/map/left_red_car.png'), rotateWithView: false, rotation: -Math.atan2(routeCoords[0][1]-routeCoords[1][1], routeCoords[0][0]-routeCoords[1][0]), scale:0.3, }) }), 'stop':new ol.style.Style({ image:new ol.style.Circle({ radius:10, snapToPixel:false, fill:new ol.style.Fill({ color:'red'}), stroke:new ol.style.Stroke({ color:'white', width:2 }) }) }) }; var animating = false; var speed, now; var speedInput = document.getElementById('speed'); var startButton = document.getElementById('start-animation'); var vectorLayer = new ol.layer.Vector({ id:'carLayer', source: new ol.source.Vector({ features: [routeFeature, geoMarker, startMarker, endMarker,stopMakers[0],stopMakers[1],stopMakers[2],stopMakers[3]] }), style: function (feature) { //如果動畫是激活的就隱藏geoMarker if (animating && feature.get('type') === 'geoMarker') { return null; } return styles[feature.get('type')]; } }); //var center = ol.proj.fromLonLat([115.981,40.451]); map.addLayer(vectorLayer); // 要素移動 var moveFeature = function (event) { var vectorContext = event.vectorContext; //HTML5 Canvas context,ol.render.canvas.Immediate的對象 var frameState = event.frameState; //freme 的狀態 if (animating) { var elapsedTime = frameState.time - now; //elapsedTime 已過時間 //通過增加速度,來獲得lineString坐標 var index = Math.round(speed * elapsedTime / 1000); //已經走了多少個點 //console.log("#########",routeCoords[index]); if (index >= routeLength) { stopAnimation(true); return; } //fixme --------------- if( index < 14){ flashFeature(0); } if( index == 14){ changeStyle(0, 1); } if(index > 14 && index <43){ flashFeature(1); } if(index == 43){ changeStyle(1, 2); } if(index > 43 && index <63){ flashFeature(2); } if(index == 63){ changeStyle(2, 3); } if(index > 63 && index <85){ flashFeature(3); } if(index == 85){ changeStyle(3, 3); } //fixme-------------------- var dx,dy,rotation,carStyle; if(routeCoords[index] && routeCoords[index+1]){ dx=routeCoords[index][0]-routeCoords[index+1][0]; dy=routeCoords[index][1]-routeCoords[index+1][1]; rotation = Math.atan2(dy,dx); //console.log("***********",rotation); carStyle= new ol.style.Style({ image: new ol.style.Icon({ src: require('../../assets/map/left_red_car.png'), rotateWithView: false, rotation: -rotation, scale:0.3, }) }); var currentPoint = new ol.geom.Point(routeCoords[index]); //當前點 var feature = new ol.Feature(currentPoint); //Render a feature into the canvas. // Note that any zIndex on the provided style will be ignored - features are rendered immediately in the order that this method is called. // If you need zIndex support, you should be using an ol.layer.Vector instead vectorContext.drawFeature(feature, carStyle); } } //繼續動畫效果 map.render(); }; function changeStyle(previous,next) { //console.log(stopMakers[previous]); stopMakers[previous].setStyle(new ol.style.Style({ image: new ol.style.Circle({ radius: 10, snapToPixel: false, fill: new ol.style.Fill({color: 'green'}), stroke: new ol.style.Stroke({ color: 'white', width: 2 }) }) })); } var colors=['red','green']; var colorIndex=0; function flashFeature(index) { var color; colorIndex++; colorIndex=colorIndex % 30; if(colorIndex < 15){ color=colors[0]; }else { color = colors[1]; } stopMakers[index].setStyle(new ol.style.Style({ image: new ol.style.Circle({ radius: 10, snapToPixel: false, fill: new ol.style.Fill({ color: color }), stroke: new ol.style.Stroke({ color: 'white', width: 2 }) }) })); } function startAnimation() { if (animating) { stopAnimation(false); } else { animating = true; now = new Date().getTime(); /** 開始時的時間*/ speed = speedInput.value; startButton.textContent = '結束運動'; //隱藏geoMarker geoMarker.setStyle(null); //設置顯示范圍 //map.getView().setCenter(center); map.on('postcompose', moveFeature); /** postcompose事件-- 地圖渲染時都會觸發 */ map.render(); } } /** * @param {boolean}結束動畫 */ function stopAnimation(ended) { animating = false; startButton.textContent = '開始運動'; //如果動畫取消就開始動畫 var coord = ended ? routeCoords[routeLength - 1] : routeCoords[0]; /** @type {ol.geom.Point} */ (geoMarker.getGeometry()).setCoordinates(coord); //移除監聽 map.un('postcompose', moveFeature); /** 解除postcompose 事件 */ } startButton.addEventListener('click', startAnimation, false); }
看完上述內容,你們對openlayers 3如何實現車輛軌跡回放有進一步的了解嗎?如果還想了解更多知識或者相關內容,請關注億速云行業資訊頻道,感謝大家的支持。
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