transform var (atom)

An atom can be made to appear rotated, scaled, and/or translated (moved) by using affine transforms. This takes a matrix and multiplies the x and y positions of the icon’s corners like so:

a d 0
x y 1  *  b e 0  =  x' y' 1
          c f 1

This is equivalent to:

x' = a*x + b*y + c
y' = d*x + e*y + f

You do not need to understand matrix math to use transforms, because you can use the matrix datum to do this for you.

Transformations are relative to the center of the icon. They do not apply to maptext.

Examples:

// Rotate the atom by 45° clockwise
src.transform = turn(src.transform, 45)
 
// OR
var/matrix/M = matrix()
M.Turn(45)
src.transform = M
 
// Scale the atom by 2x2
src.transform *= 2
 
// OR
var/matrix/M = matrix()
M.Scale(2,2)
src.transform = M

Whenever you read the atom.transform var, you will get a copy of the atom’s current transformation. Whenever you assign a value to the var, you will update the transformation.

Assigning null to atom.transform will revert the atom to using no transformation at all. It is also legal to assign a list with six values, which is equivalent to using a matrix.

See also

matrix