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function rad2deg(x) {
return x * 180 / Math.PI;
}
function ellipseUsingArc(context, x, y, radiusX, radiusY, rotation, startAngle, endAngle, anticlockwise)
{
var transform = new WebKitCSSMatrix();
transform = transform.translate(x, y);
transform = transform.rotate(rad2deg(rotation));
transform = transform.scale(radiusX, radiusY);
/*
Use WebKitCSSMatrix instead of as follows, because using WebKitCSSMatrix computes float values more precisely.
It is because we don't want to fail pixel comparison due to float precision.
context.translate(x, y);
context.rotate(rotation);
context.scale(radiusX, radiusY);
*/
context.save();
context.transform(transform.a, transform.b, transform.c, transform.d, transform.e, transform.f);
context.arc(0, 0, 1, startAngle, endAngle, anticlockwise);
context.restore();
}
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