Start the Canvas Clock at a designated location

On page load, I am looking to initiate the second hand of a clock at 15 hours.

function startClockFromSpecificPosition(ctx, radius){
    now = new Date();
    second = now.getSeconds();
    second=(second*Math.PI/30);
    console.log(second);
    drawHand(ctx, second, radius*0.9, radius*0.02);
  }

function drawHand(ctx, pos, length, width) {
    ctx.beginPath();
    ctx.lineWidth = width;
    ctx.lineCap = "round";
    ctx.moveTo(0,0);
    ctx.rotate(pos);
    ctx.lineTo(0, -(3*length/4));
    ctx.stroke();
    ctx.rotate(-pos);
    ctx.restore();
  }

Answer №1

To simulate the passage of time in your code, I have made adjustments to use a random time and date instead of real-time values. This emulation is achieved by utilizing the setInterval() function.

I have also included explanatory comments within the code for better comprehension of its functionality.

// The initial date and time are arbitrary; set to 15:00:00.
// Converting the time into milliseconds simplifies future calculations.
var currentTime = (new Date('2011-10-10T15:00:00')).getTime();

function drawTime(ctx, radius){
  var now = new Date(currentTime);
  var second = now.getSeconds();
  second = (second * Math.PI / 30);
  console.log(second);
  drawHand(ctx, second, radius * 0.9, radius * 0.02);
}

function drawHand(ctx, pos, length, width) {
  ctx.beginPath();
  ctx.lineWidth = width;
  ctx.lineCap = "round";
  ctx.moveTo(0,0);
  ctx.rotate(pos);
  ctx.lineTo(0, -(3*length/4));
  ctx.stroke();
  ctx.rotate(-pos);
  ctx.restore();
}

// Simulating clock movement: 1000 milliseconds = 1 second.
setInterval(function() {
  currentTime += 1000; 
}, 1000);

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