i want to bound circle within a box

[Indranil_Mondal9509]

src=wiggle(2,200);
boundary = [135,135]; // size of boundinglayer/2
clamp(src, value - boundary, value + boundary)
how i do this in dynamic way , means if shape layer is rectangle and i want when ever i change height and weidth and bound upadated , balls are bounded inside the inner box because the box have stroke. bound also updated with stroke changes ,how can  ido that , can anyone give me idea?

[Hani ElTiby]

highlight this value [135,135] and use expression pickwip and choose the rectangle size then add /2

src=wiggle(2,200);
boundary = thisComp.layer("Shape Layer 1").content("Rectangle 1").content("Rectangle Path 1").size / 2; // size of boundinglayer/2
clamp(src, value - boundary, value + boundary)

[Hani ElTiby]

To respect the rectangle stroke width, you need to subtract it from the rectangle size,
As the size data is a 2D vector [x,y] and the stroke width is a single dimension float value you can put it twice in a 2D vector then subtract it from the size
var temp = << pickwip to insert it's code >> ;
var strokeWidth = [temp.temp] ;

then do the subtraction in parentheses before deviding by 2 (size - strokeWidth) /2

[Indranil_Mondal9509]

also i need to minus circle redius also ?

[Hani ElTiby]

Sure, if you want to always keep the circle boundary inside the rectangle then you shoud subtract the circle size too.
(rectngleSize - circleSize - strokeWidth) / 2
but this assumes that the initial circle position is at the center of the rectangle, if not then you should calculate the clamp in a different way.

[Hani ElTiby]

it's usefull to control the wiggle parameters by slider controllers on a null layer to be able to change it once for all circles.

[Indranil_Mondal9509]

src=wiggle(2,200);
boundary = thisComp.layer("Shape Layer 1").content("Rectangle 1").content("Rectangle Path 1").size ; // size of boundinglayer/2
var t = thisComp.layer("Shape Layer 1").content("Rectangle 1").content("Stroke 1").strokeWidth
var strokeWidth = [t,t] ;
r = content("Ellipse 1").content("Ellipse Path 1").size;
B = (boundary - strokeWidth - r )/2
clamp(src, value - B, value + B);
is this expression correct , with this my ball slightly excessed

[Indranil_Mondal9509]

is because of the result comes in decimal value ?

[Hani ElTiby]

does the circle have stroke?
does any of the layers has none 100% scale?

[Hani ElTiby]

it looks fine, but for good practice use ; at the end of each line

[Hani ElTiby]

both the rectangle and circle should have 100% scale

[Indranil_Mondal9509]

thanks it works

[Hani ElTiby]

Great! Happy Animating : )

[Indranil_Mondal9509]

but is it possible if cicle start from anywhere in the box and then behave like this , basically can we make this expression dynamic to there position ?

[Hani ElTiby]

sure, it just needs a different math
now you have the main idea, on a paper you can draw a line (as if it is the x axis) layout the boundaries and the circle and figure out the new formula 

[Hani ElTiby]

@Indranil_Mondal9509 Did it work?