I don't think that's true. Consider a simple case where the shape is a square and you are sampling in such a way that the closest edge point is closer to a corner of the square than the filter width. Using a function of distance you will get the same result as when sampling far from the corner. But the coverage is different in the two cases.

If you want to deal with pixels near multiple edges, it needs to be more complicated.

(And another way to do it is to simply allocate all your function call frames on the heap to begin with and not have a stack. Then call/cc is essentially free, but you need a really good incremental garbage collector because now every function call conses.)

    > (let ((x 0)) (list (call/cc (lambda (f) (set! x 1) (f 2))) x))
    (2 0)

    localhost:~/oort/examples% ../oort callcc2.nl 
    2
    1

The Oort program:

    typedef continuation_t = fn (p: int32) -> void;
    
    call_cc (fun: fn(k: continuation_t) -> void) -> int32
    {
        retval: int32;
    
        fun (fn (v: int32) -> void {
            retval = v;
            goto current_continuation;
        });
        
        // If fun returns without calling the continuation,
        // then just return 0
        return 0;
    
    @current_continuation:
        return retval;
    }
    
    x: int32 = 0;
    
    print call_cc (fn (k: continuation_t) {
        x = 1;
        k (2);
        });
    
    print x;

http://www.indiegogo.com/projects/mailpile-taking-e-mail-bac...

A potentially interesting way around this is to make the client open source and get it shipped by all the Linux distributions. That would give application developers an initial audience which would help solve the chicken-and-egg problem.

GTK+ uses the triangle technique along with a delay of 225 ms. When the pointer is inside the triangle, the delay is 1500 ms.

Firefox subscribes to the misguided "fake the look and feel of the default toolkit" idea, so on Linux it has a 225 ms delay, but without the triangle. Unfortunately 225 ms is way too short when there is no triangle.