how to get pixel coordinate XYpositions in a curve

General Discussion Other

witch_hehe

how to get pixel coordinate XYpositions in a curve

in General Discussion • Other • 10 months ago

Hi,

I wonder if there is a way to identify the array of the x and y positions of all the pixels in a curve, like a circle or a triangle?

I hst want the points in side the curves

Thanks

Replies(3)

asimes

Re: how to get pixel coordinate XYpositions in a curve

10 months ago

To test for the points inside of a circle use the Pythagorean Theorem:

int x, y, rad;
void setup() {
size(400, 400);
smooth();
x = width/2;
y = height/2;
rad = 300;
}
void draw() {
background(255);
ellipse(x, y, rad, rad);
}
void mousePressed() {
float clickDist = sqrt(sq(mouseX-x)+sq(mouseY-y));
if (clickDist < rad/2) println("Inside circle");
else println("Outside circle");
}

There are many ways to test for a point in a polygon. A Google search will give you many results, but it is generally more difficult than a point in a circle test, so it would be good to understand why the code above works first.

witch_hehe

Re: how to get pixel coordinate XYpositions in a curve

10 months ago

thankx alot

v.k.

Re: how to get pixel coordinate XYpositions in a curve

10 months ago

I love math solutions, but for more complicated shapes, sometimes is easier to test a color against a identical shape drawn in a not displayed PGraphics. Probably slower though...

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