closest distance between a circle and a line in matlab

main.m
function dist = closestDistCircleLine(cx, cy, r, x1, y1, x2, y2)
    % Find the closest point on the line to the center of the circle
    vx = x2 - x1;
    vy = y2 - y1;
    wx = cx - x1;
    wy = cy - y1;
    c1 = vx * wx + vy * wy;
    if c1 <= 0
        % Closest point on the line is x1, y1
        dist = sqrt((cx - x1)^2 + (cy - y1)^2) - r;
        return;
    end
    c2 = vx * vx + vy * vy;
    if c2 <= c1
        % Closest point on the line is x2, y2
        dist = sqrt((cx - x2)^2 + (cy - y2)^2) - r;
        return;
    end
    frac = c1 / c2;
    qx = x1 + frac * vx;
    qy = y1 + frac * vy;

    % Find the distance between the closest point on the line and the center of the circle
    dist = sqrt((cx - qx)^2 + (cy - qy)^2) - r;

    % If the distance is negative, then the circle intersects the line
    if dist < 0
        dist = 0;
    end
end
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