Can someone with good mathematical logic help me out for thi kotlinlang #announcements

Can someone with good mathematical logic help me out for this? I'm drawing two concentric circles on the screen. The smaller one has a radius startRadius and the outer larger one's radius is endRadius. So, Now I want to get a randomly generated point, which lies in the region between the two concentric circles. Also, is there a way to get significant distance between the previously generated random point & the newly generated random point? I'll be adding imageviews on these points, so don't want overlapping images because the two randomly picked points are almost next to each other. Thanks.

Tim Malseed

03/06/2020, 10:46 AM

I would write a function that determines if a point lies inside a circle. Then I would test that the point falls withing the outer circle, and doesn’t fall within the inner circle

A point is considered inside a circle, if the distance from the center of the circle to the point is less than the radius of the circle

Something like:

Copy code

fun isPointInCircle(point: Point, circleCenter: Point, radius: Int) : Boolean {

    return sqrt((point.x - circleCenter.x).pow(2) + (point.y - circleCenter.y).pow(2)) < radius

}

pedro

03/06/2020, 10:51 AM

Assuming the centre of the circles is

(0,0)

, and radius is r1 and r2 (r1 is smaller), generate a random value for an angle (0-360 degrees or use radians straight away as usually that’s what the drawing primitives will ask you)and generate a random value for the radius, which has to be between r1 and r2. Now use simple trigonometry to get the

(x, y)

position (

x = radius * cos angle;  y = radius * sin angle

)

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