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CanvasRenderingContext2D.ellipse()

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This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The CanvasRenderingContext2D.ellipse() method of the Canvas 2D API adds an ellipse to the path which is centered at (x, y) position with the radii radiusX and radiusY starting at startAngle and ending at endAngle going in the given direction by anticlockwise (defaulting to clockwise).

Syntax

void ctx.ellipse(x, y, radiusX, radiusY, rotation, startAngle, endAngle, anticlockwise);

Parameters

x
The x axis of the coordinate for the ellipse's center.
y
The y axis of the coordinate for the ellipse's center.
radiusX
The ellipse's major-axis radius.
radiusY
The ellipse's minor-axis radius.
rotation
The rotation for this ellipse, expressed in radians.
startAngle
The starting point, measured from the x axis, from which it will be drawn, expressed in radians.
endAngle
The end ellipse's angle to which it will be drawn, expressed in radians.
anticlockwise Optional
An optional Boolean which, if true, draws the ellipse anticlockwise (counter-clockwise), otherwise in a clockwise direction.

Examples

Using the ellipse method

This is just a simple code snippet drawing an ellipse.

HTML

<canvas id="canvas"></canvas>

JavaScript

var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");

ctx.beginPath();
ctx.ellipse(100, 100, 50, 75, 45 * Math.PI/180, 0, 2 * Math.PI);
ctx.stroke();

Edit the code below and see your changes update live in the canvas (check your Browser support in the compatibility table, if no ellipse is drawn):

Playable code
<canvas id="canvas" width="400" height="200" class="playable-canvas"></canvas>
<div class="playable-buttons">
  <input id="edit" type="button" value="Edit" />
  <input id="reset" type="button" value="Reset" />
</div>
<textarea id="code" class="playable-code">
ctx.beginPath();
ctx.ellipse(100, 100, 50, 75, 45 * Math.PI/180, 0, 2 * Math.PI);
ctx.stroke();</textarea>
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var textarea = document.getElementById("code");
var reset = document.getElementById("reset");
var edit = document.getElementById("edit");
var code = textarea.value;

function drawCanvas() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
  eval(textarea.value);
}

reset.addEventListener("click", function() {
  textarea.value = code;
  drawCanvas();
});

edit.addEventListener("click", function() {
  textarea.focus();
})

textarea.addEventListener("input", drawCanvas);
window.addEventListener("load", drawCanvas);

Specifications

Specification Status Comment
WHATWG HTML Living Standard
The definition of 'CanvasRenderingContext2D.ellipse' in that specification.
Living Standard  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Edge Opera Safari
Basic support (Yes) 48 (48) No support 13 (Yes) (Yes)
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support (Yes) 48.0 (48) No support No support (Yes)

See also

Tag del documento e collaboratori

 Hanno collaborato alla realizzazione di questa pagina: Sebastianz, fscholz, cers, valtlait1, planktn, vegittoss15, aeschylus
 Ultima modifica di: Sebastianz,