weex-gcanvas+animation子產品實作雷達掃描效果

內建weex-gcanvas請參考Weex Gcanves內建和使用

先上圖

示例圖

上代碼： 

<template>
    <div ref="test" style="background-color: #ffffff">
        <gcanvas  @touchstart="touchstart" @touchmove="touchmove" @touchend="touchend" ref="areas"
                 style="width: 400px;height:400px;margin-left: 150px;
              margin-top: 150px;border-radius: 200px;"></gcanvas>
        <div style="width: 750px;flex-direction: row;align-items: center;justify-content: center">
            <div class="button_start" @click="animation(1)">
                <text style="color: white;font-size: 34px">start</text>
            </div>
            <div style="margin-left: 50px" class="button_stop" @click="animation(0)">
                <text style="color: white;font-size: 34px">stop</text>
            </div>
        </div>

    </div>
</template>
<style type="text/css" scoped>
    .button_start{
        height: 70px;width: 150px;background-color: #006ce7;margin-top: 100px;
        border-radius: 35px;
        align-items: center;
        justify-content: center;
    }
    .button_stop{
        height: 70px;width: 150px;background-color: #ff0000;margin-top: 100px;
        border-radius: 35px;
        align-items: center;
        justify-content: center;
      }

</style>
<script>
    var libGCanvas=require("weex-gcanvas")
    var animation=weex.requireModule('animation');
    var modal=weex.requireModule("modal");
    module.exports = {
        data:{
            startX:0,
            startY:0,
            currentX:0,
            currentY:0,
            context:{},
            canvasObj:{},
            angle:1,
            doAnimation:0,
        },
        methods:{
            animation(p){
                this.doAnimation=p;
                if(this.doAnimation){
                    this.exeAnimation();
                }
            },
            touchstart(event){
                this.startX=event.changedTouches[0].pageX;
                this.startY=event.changedTouches[0].pageY;
                this.context.strokeStyle = "#17acf6" ;  //設定線的顔色狀态
                this.context.lineWidth = 10;          //設定線寬狀态
            },
            touchmove(event){
                this.currentX=event.changedTouches[0].pageX;
                this.currentY=event.changedTouches[0].pageY;
                //進行繪制
                this.context.moveTo(this.startX,this.startY);
                this.context.lineTo(this.currentX,this.currentY);
                this.context.stroke();

                this.startX=event.changedTouches[0].pageX;
                this.startY=event.changedTouches[0].pageY;

            },
            touchend(event){

               // this.$navigator.push('login.js');
            },
            exeAnimation(){
                let self=this;
                animation.transition(self.$refs.areas,{
                    styles:{
                        transform:`rotate(${Math.PI*2*this.angle})`
                    },
                    duration:1000,
                    delay:0,
                    needLayout:false,
                    timingFunction:"linear"
                },function () {
                    if(self.doAnimation){
                        self.angle++;
                        self.exeAnimation();
                    }
                })
            }
        },
        created: function () {
            var self=this;
            var globalEvent = weex.requireModule('globalEvent');
            globalEvent.addEventListener("onPageInit", function (e) {
                /*擷取元素引用*/
                var ref=self.$refs.areas;
                /*通過元素引用擷取canvas對象*/
                self.canvasObj =libGCanvas.start(ref);
                /*擷取繪圖所需的上下文，目前不支援3d*/
                self.context =  self.canvasObj.getContext('2d');

                //繪制圓形
                self.context.beginPath();
                self.context.arc(200,200,200,0,2*Math.PI);
                self.context.fillStyle="#268cf0";
                self.context.fill();

                //繪制漸變的扇形區域
                self.context.beginPath();
                self.context.moveTo(200,200);
                self.context.arc(200,200,200,0,0.5*Math.PI);
                var gradient=self.context.createLinearGradient(200,300,200,200);
                gradient.addColorStop("0","#176cf0");
                gradient.addColorStop("1.0","#268cf0");
                self.context.fillStyle=gradient;
                self.context.fill();
            })
        }
    };
</script>