Scientist, Designer, and Teacher. Assoc Prof of CompSci in visualization at Mississippi State University. Believes information wants to be seen. Loves Python. @dr_tj
function gappy_circle([xc, yc], r)
{
const pixel = (x,y) => [x,y].map(Math.round);
const pixels = [pixel(xc, yc+r), pixel(xc, yc-r)];
for(let i = 1; i <= r; ++i)
{
// Four pixels: [xc+i, y+sqrt], [xc+i, y-sqrt], and the xc-i versions of same
let sqrt_disc = Math.sqrt(r**2 - i**2);
pixels.splice(pixels.length, 0, ...[pixel(xc+i, yc+sqrt_disc),
pixel(xc+i, yc-sqrt_disc),
pixel(xc-i, yc+sqrt_disc),
pixel(xc-i, yc-sqrt_disc)]);
}
return pixels;
}
function midpoint_circle([xc, yc], r)
{
const pixel = (x,y) => [x,y].map(Math.round);
// Initial condition
let [ic, jc] = pixel(xc, yc);
r = Math.round(r);
let [i,j] = [0, r];
// Find the error
let d = 1 - r;
// Rasterize by octant; start w/ four cardinal points
const pixels = [pixel(ic, jc + r),
pixel(ic, jc - r),
pixel(ic + r, jc),
pixel(ic - r, jc)];
while(i < j)
{
// Update midpoint/error term
if(d >= 0)
{
j -= 1;
d -= 2 * j;
}
i += 1;
d += 2 * i + 1;
pixels.splice(pixels.length, 0, ...[pixel(ic + i, jc + j),
pixel(ic + i, jc - j),
pixel(ic - i, jc + j),
pixel(ic - i, jc - j),
pixel(ic + j, jc + i),
pixel(ic + j, jc - i),
pixel(ic - j, jc + i),
pixel(ic - j, jc - i)]);
}
return pixels;
}
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
