Latest web development tutorials
 

Canvas Clock Face


Part II - Draw a Clock Face

The clock needs a clock face. Create a JavaScript function to draw a clock face:

JavaScript:

function drawClock() {
    drawFace(ctx, radius);
}

function drawFace(ctx, radius) {
    var grad;

    ctx.beginPath();
    ctx.arc(0, 0, radius, 0, 2*Math.PI);
    ctx.fillStyle = 'white';
    ctx.fill();

    grad = ctx.createRadialGradient(0,0,radius*0.95, 0,0,radius*1.05);
    grad.addColorStop(0, '#333');
    grad.addColorStop(0.5, 'white');
    grad.addColorStop(1, '#333');
    ctx.strokeStyle = grad;
    ctx.lineWidth = radius*0.1;
    ctx.stroke();

    ctx.beginPath();
    ctx.arc(0, 0, radius*0.1, 0, 2*Math.PI);
    ctx.fillStyle = '#333';
    ctx.fill();
}
Try it Yourself »

Code Explained

Create a drawFace() function for drawing the clock face:

function drawClock() {
    drawFace(ctx, radius);
}

function drawFace(ctx, radius) {
}

Draw the white circle:

ctx.beginPath();
ctx.arc(0, 0, radius, 0, 2*Math.PI);
ctx.fillStyle = 'white';
ctx.fill();

Create a radial gradient (95% and 105% of original clock radius):

grad = ctx.createRadialGradient(0,0,radius*0.95, 0,0,radius*1.05);

Create 3 color stops, corresponding with the inner, middle, and outer edge of the arc:

grad.addColorStop(0, '#333');
grad.addColorStop(0.5, 'white');
grad.addColorStop(1, '#333');

The color stops create a 3D effect.

Define the gradient as the stroke style of the drawing object:

ctx.strokeStyle = grad;

Define the line width of the drawing object (10% of radius):

ctx.lineWidth = radius * 0.1;

Draw the circle:

ctx.stroke();

Draw the clock center:

ctx.beginPath();
ctx.arc(0, 0, radius*0.1, 0, 2*Math.PI);
ctx.fillStyle = '#333';
ctx.fill();