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2020
10-01

QML实现钟表效果

Qt5以后的版本，主要加大的对Qt Quick的改进。现实最新的版本可以利用Qt Quick实现很多的绚丽的效果。此里只是利用画布Canvas简单钟表的效果。效果如下：

源码如下

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import QtQuick 2.6
import QtQuick.Window 2.2
 
 
 
Window {
  visible: true
  width: 740
  height: 680
  title: qsTr("Hello World")
  id:window
  //color: "red";
 
 
  Canvas
  {
    id : canvas
    anchors.fill: parent
    width: 740
    height: 680
    onPaint:
    {
      var ctx = getContext("2d");
      drawBack(ctx);
      drawDot(ctx);
 
 
      var date = new Date();
      var hours = date.getHours()
      hours = hours%12;
      var minutes = date.getMinutes()
      var seconds = date.getUTCSeconds();
      var timestr =date.toLocaleString("yyyy-MM-dd hh:mm:ss");
      console.log(date.toLocaleString("yyyy-MM-dd hh:mm:ss"));
      drawSecond(seconds,ctx);
 
      drawHour(hours,minutes,ctx);
      drawMinute(minutes,seconds,ctx);
      drawSecond(seconds,ctx);
 
     }
 
  }
 
 
  function drawBack(ctx)
  {
    var r = 200;
 
    ctx.save();
    ctx.beginPath();
    ctx.translate(width/2,height/2);
    ctx.clearRect(-r,-r,r*2,r*2);
    ctx.lineWidth = 10;
    ctx.arc(0,0,r-5,0,Math.PI*2,false); //外圆
    ctx.stroke();
 
    //画文本
    var numbers = [1,2,3,4,5,6,7,8,9,10,11,12];
    ctx.font = "18px Arial";
    ctx.textAlign = "center";
    ctx.textBaseline = "middle";
    for(var i = 0; i < 12; ++i)
    {
      var rad = 2*Math.PI/12*numbers[i]-3.14/2;
      var x = Math.cos(rad)*(r-30);
      var y = Math.sin(rad)*(r-30);
      ctx.fillText(numbers[i],x,y);
    }
 
    //画刻度
    ctx.lineWidth = 2;
 
    for (var i = 0; i <60; ++i)
    {
      ctx.beginPath();
      var rad = 2*Math.PI/60*i;
      var x = Math.cos(rad)*(r-15);
      var y = Math.sin(rad)*(r-15);
      var x2 = Math.cos(rad)*(r-10);
      var y2 = Math.sin(rad)*(r-10);
 
 
      //通过画线也可以
      if (i%5 === 0)
         {ctx.strokeStyle="#000000";}
      else
        { ctx.strokeStyle = "#989898";}
       ctx.moveTo(x,y);
       ctx.lineTo(x2,y2);
       ctx.stroke();
 
      //画圆实现
//        if (i%5 === 0)
//           {ctx.fillStyle="#000000";}
//        else
//          { ctx.fillStyle = "#FFFFFF";}
//        ctx.arc(x,y,2,0,3.15*2,false);
//        ctx.fill();
    }
    ctx.restore();
  }
 
  function drawHour(hour, minute, ctx)
  {
    var r = 200;
    ctx.save();
    ctx.beginPath(); //必须写
    ctx.lineWidth = 7;
    ctx.lineCap = "round";
    ctx.translate(width/2,height/2);
 
    var rad = Math.PI*2/12*hour+Math.PI*2*minute/12/60-Math.PI;
    ctx.rotate(rad);
    ctx.moveTo(0,-10);
    ctx.lineTo(0,r/2-10);
    ctx.stroke();  //必须写（填充方式）
    ctx.restore();
  }
  function drawMinute(minute,second,ctx)
  {
    var r = 200;
    ctx.save();
    ctx.beginPath(); //必须写
    ctx.lineWidth = 5;
    ctx.lineCap = "round";
    ctx.translate(width/2,height/2);
 
    var rad = Math.PI*2*minute/60 + Math.PI*2*second/60/60 -Math.PI;
    ctx.rotate(rad);
    ctx.moveTo(0,-10);
    ctx.lineTo(-10,r*3/5-10);
    ctx.stroke();  //必须写（填充方式）
    ctx.restore();
  }
  function drawSecond(second,ctx)
  {
    var r = 200;
    ctx.save();
    ctx.beginPath(); //必须写
    ctx.lineWidth = 3;
    ctx.lineCap = "round";
    ctx.translate(width/2,height/2);
    ctx.strokeStyle="#ff0000";
    var rad = Math.PI*2*second/60-Math.PI;
    ctx.rotate(rad);
    ctx.moveTo(0,-20);
    ctx.lineTo(0,r*4/5-10);
    ctx.stroke();  //必须写（填充方式）
    ctx.restore();
  }
  function drawDot(ctx)
  {
    ctx.save();
    ctx.beginPath(); //必须写
    ctx.translate(width/2,height/2);
    ctx.fillStyle="#ffffff";
    ctx.arc(0,0,3,0,Math.PI*2);
    ctx.fill();  //必须写（填充方式）
    ctx.restore();
  }
  //定时器
 
 
  Timer {
       interval: 1000; running: true; repeat: true
       onTriggered: canvas.requestPaint();
     }
}

利用定时器实现动态效果。

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