# transform var (atom)

Source: https://ref.dm-lang.org/atom/var/transform
Added in BYOND 500.

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](https://ref.dm-lang.org/matrix/index.md) to do this for you.

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

## Examples:

```dm
// 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
- [vars (atom)](https://ref.dm-lang.org/atom/var/index.md)
- [matrix](https://ref.dm-lang.org/matrix/index.md)