Fx script - Problem with transition

Hi !

I have to do a transition script for Final Cut for college, and i've a problem : i want to have a transition like in this picture : http://pix.toile-libre.org/upload/original/1333312212.jpg. But i've only found how to do all these lines at the same time... I've tried to divide and multiply the variable "ratio", but the result isn't what i want... Can you help me ? I can't test my code except when i'm in class because i don't have a mac... Here is the code :

transition "Traits";

group "Balayage";

input nbLignes, "Nombre de lignes", slider, 10, 1, 100 label "lignes"

input direction, "Direction de départ", popup, 1, "gauche a droite", "droite a gauche", "haut vers bas", "bas vers haut"

code

float hauteur, largeur, dx, i;

region rgn, rgn2;

point poly[4];

for i = 0 to 3

poly[i] = {0, 0};

next

MakeRegion(poly, rgn);

DimensionsOf(dest, largeur, hauteur);

if (direction < 3)

dx = hauteur / nbLignes;

for i = 1 to nbLignes

poly[0] = {-largeur / 2, -hauteur / 2 + (i-1)*dx};

poly[1] = {-poly[0].x, poly[0].y};

poly[2] = {-poly[0].x, poly[0].y + dx};

poly[3] = {poly[0].x, poly[2].y};

scale(poly, poly[(i+direction) % 2], ratio, 1);

MakeRegion(poly, rgn2);

rgn += rgn2;

next

RegionCopy(src1, src2, dest, rgn, 0);

else

dx = largeur / nbLignes;

for i=1 to nbLignes

poly[0] = {-largeur / 2 + (i-1)*dx, -hauteur/2};

poly[1] = {poly[0].x + dx, poly[0].y};

poly[2] = {poly[1].x, -poly[0].y};

poly[3] = {poly[0].x, poly[2].y};

scale(poly, poly[(i+direction) % 2 + 1], 1, ratio);

MakeRegion(poly, rgn2);

rgn += rgn2;

next;

RegionCopy(src1, src2, dest, rgn, 0);

end if