How to draw a smooth oval in canvas

Question

I am trying to draw a smooth oval using ctx.clip property in my canvas.I have done with drawing part i am facing problem with oval arc line clarity.Any one have any idea regarding this just let me know? Here is my code.

<canvas id="c" width="400" height="400"></canvas>


var canvas = new fabric.Canvas('c');
var ctx = canvas.getContext('2d');
var cx=180;
var cy=200;
var w=300;
var h=250;
    // Quadratric curves example
    ctx.beginPath();
    var lx = cx - w/2,
        rx = cx + w/2,
        ty = cy - h/2,
        by = cy + h/2;
    var magic = 0.551784;
    var xmagic = magic*w/2;
    var ymagic = h*magic/2;
    ctx.moveTo(cx,ty);
    ctx.bezierCurveTo(cx+xmagic,ty,rx,cy-ymagic,rx,cy);
    ctx.bezierCurveTo(rx,cy+ymagic,cx+xmagic,by,cx,by);
    ctx.bezierCurveTo(cx-xmagic,by,lx,cy+ymagic,lx,cy);
    ctx.bezierCurveTo(lx,cy-ymagic,cx-xmagic,ty,cx,ty);

    ctx.fill();
    ctx.stroke();
    ctx.clip();



var text;
text = new fabric.Text('Honey', {
  fontSize: 50,
  left: 150,
  top: 150,
  lineHeight: 1,
  originX: 'left',
  fontFamily: 'Helvetica',
  fontWeight: 'bold'
});
canvas.add(text);

Here is my fiddle link

You can see this output over here the line border of oval not much clear.

Answer 1

try this it will help you //Script

var canvas = new fabric.Canvas('c');
 var w;
 var h;
 var ctx = canvas.getContext('2d');
 w=canvas.width / 4;
 h=canvas.height / 2.4;
canvas.clipTo = function(ctx) {
 ctx.save();
 ctx.scale(2, 1.2);
 ctx.arc(w, h, 90, 0, 2 * Math.PI, true);
 ctx.stroke();
 ctx.restore();
}

Fiddle Demo

Answer 2

One problem is in the nature of your display screen...

Since pixels are rectangles and you're drawing a curve, your result will have "jaggies" as the curve tries to fit itself in rectangular spaces.

You can use an optical illusion to trick the eye into seeing a less jagged oval.

An optical trick:

Reduce the contrast between the background color and the oval color.

This is not a cure...the jaggies are still there.

But the eye recognizes less contrast and perceives the oval as more smooth.

So if your design accommodates this style change, this optical illusion might help.

Here's code and a Fiddle: http://jsfiddle.net/m1erickson/vDWR3/

var cx=180;
var cy=200;
var w=300;
var h=250;

// Start with a less-contrasting background
ctx.fillStyle="#ddd";
ctx.fillRect(0,0,canvas.width,canvas.height);

ctx.beginPath();
var lx = cx - w/2,
    rx = cx + w/2,
    ty = cy - h/2,
    by = cy + h/2;
var magic = 0.551784;
var xmagic = magic*w/2;
var ymagic = h*magic/2;
ctx.moveTo(cx,ty);
ctx.bezierCurveTo(cx+xmagic,ty,rx,cy-ymagic,rx,cy);
ctx.bezierCurveTo(rx,cy+ymagic,cx+xmagic,by,cx,by);
ctx.bezierCurveTo(cx-xmagic,by,lx,cy+ymagic,lx,cy);
ctx.bezierCurveTo(lx,cy-ymagic,cx-xmagic,ty,cx,ty);

ctx.fillStyle="#555";
ctx.strokeStyle=ctx.fillStyle;
ctx.lineWidth=1.5;
ctx.stroke();