Thanks for response - did make me smile! 2009/10/1 François Chaplais <[email protected]>
> > The drawing of the Bezier curves boils down to this: > 1) you compute the matrix A > 2) you invert it > 3) the parameters x of the unknown cubic polynomials are given by x > =A^(-1)b > 4) once your know the cubic polynomial, you can compute its value at any > point [the operation is referred as interpolation] > > HTH > > François > > P.S I have de Boor's book, it is unreadable > Maybe someone can suggest a hack :) I'm thinking something along the lines of calculating the bezier curves for each pair of points along the curve: this is the function I have courtesy Alejandro: function graph_BezierLine listOfPoints, zdt > put item 1 of listOfPoints into x1 > put item 2 of listOfPoints into y1 > put item 3 of listOfPoints into xa > put item 4 of listOfPoints into ya > put item 5 of listOfPoints into xb > put item 6 of listOfPoints into yb > put item 7 of listOfPoints into x2 > put item 8 of listOfPoints into y2 > put 0 into v1 > > if zdt is empty then put 32 into zdt > repeat with i = 1 TO zdt -- zdt is a integer number like 32 > put i * 1/zdt into v1 > put 1 - v1 into v2 > put (x1 * (v2 * v2 * v2) + (3 * xa * v1 * v2 * v2) + (3 * xb * v1 * > v1 * v2) + (x2 * (v1 ^ 3))) into x > put (y1 * (v2 * v2 * v2) + (3 * ya * v1 * v2 * v2) + (3 * yb * v1 * > v1 * v2) + (y2 * (v1 ^ 3))) into y > if (x div 1 & "," & y div 1) <> last line of variablezxc then put (x > div 1 & "," & y div 1) & CR after variablezxc > end repeat > > -- if x1,y1 <> first line of variablezxc then put x1,y1 & return before > variablezxc > if x2,y2 <> last line of variablezxc then put x2,y2 & CR after > variablezxc > put x1,y1 & CR before variablezxc > -- put x2,y2 & CR after variablezxc > return variablezxc > end graph_BezierLine > Then doing something like working out the perpendicular to the curve at each point.... hmmmm think it would be a nice little utility handler to have? _______________________________________________ use-revolution mailing list [email protected] Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
