Home » Making a circle out of . (periods) [closed]

# Making a circle out of . (periods) [closed]

## Solutons:

Here’s the maths and even an example program in C:

http://pixwiki.bafsoft.com/mags/5/articles/circle/sincos.htm (link no longer exists).

And `position: absolute`, `left` and `top` will let you draw:

http://www.w3.org/TR/CSS2/visuren.html#choose-position

Any further questions?

I know you asked for just the circumference, but it seemed easier to do a filled circle.

``````<html>
<head>
<script type="text/javascript" src="http://www.google.com/jsapi"></script>
<script type="text/javascript">
google.load("jquery", "1");
</script>
</head>
<body>
<script type="text/javascript">
function drawCircle(left, top, radius) {
var pre = \$("<pre/>").css({position: "absolute", top: top, left: left}).appendTo(\$("body"));
var testSpan = \$("<span> </span>").appendTo(pre);
var cellWidth = testSpan.width();
var cellHeight = testSpan.height();
testSpan.remove();
var diameter = 2 * radius;
var dotArray = [];
for (var row = 0; row <= diameter / cellHeight; row++) {
for (var column = 0; column <= diameter / cellWidth; column++) {
var cellDY = Math.abs(row * cellHeight - radius) - cellHeight / 2;
var cellDX = Math.abs(column * cellWidth - radius) - cellWidth / 2;
var distance = Math.pow(cellDY, 2) + Math.pow(cellDX, 2);
if (distance < Math.pow(radius, 2)) {
dotArray.push(".");
} else {
dotArray.push(" ");
}
}
dotArray.push("<br/>");
}
pre.html(dotArray.join(""));
}
drawCircle(20, 20, 200);
</script>
</body>
</html>
``````

Yes, it is possible. Put the below code into an html file to see it in action.

A quick run through: The code generates an array of dots and spaces. It chooses to make a dot based on if the distance from the current x, y position to the center of the circle is less than or equal to the length of the radius via the distance formula ( http://www.purplemath.com/modules/distform.htm ).

``````<div id= "mydiv" style="font-family: monospace"> </div>

<script type="text/javascript">
var x = 2; //starting x,y position of circle
var y = 5;
var rad = 4; //radius of circle

var width = 10; //width and height of display
var height = 10;

var dotArray = "";

for (var i=0;i<width;i++){
for (var j=0;j<height;j++){
if (Math.sqrt( Math.pow(i-y, 2) + Math.pow(j-x, 2)) <= rad){
dotArray += (".");
} else {
dotArray += ("&nbsp;");
}
}
dotArray += "<br >";
}

document.getElementById('mydiv').innerHTML = dotArray;
</script>
``````

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