# filter proc

Source: https://ref.dm-lang.org/proc/filter
Added in BYOND 512.

### Format
> `filter(type = Type, parameter = Value, ...)`

Creates a graphical filter that can be assigned or added to a list of filters on an atom or image.

This proc uses named arguments, and the "type" value must always be included. To see which types of filters are available and what parameters they accept, see [Filter effects](https://ref.dm-lang.org/notes/filters/index.md).

```dm /filter/
atom/proc/Highlight(apply)
    if(apply)
        filters = filter(type="outline", size=1, color=rgb(255,0,0))
    else
        filters = null
```

A filter created with this proc is an *abstract* filter; it is not associated with any atom. When you add it to atom's filters, the atom gets a copy of this filter, so changing the abstract filter's values afterward will not change the atom's filters. For the same reason, an abstract filter can't be animated.

A filter that is part of an atom's filters list, like obj.filters[1], is an *attached* filter. Changing the values for an attached filter will change how that atom is displayed, and attached filters can be animated.

## Named Filters

Filters can also be given a `name` argument, and can be referred to in an atom's `filters` list via that name (e.g. as `filters["shadow"]`) instead of a numeric index.

### See also
- [filters var (atom)](https://ref.dm-lang.org/atom/var/filters.md)
- [Filter effects](https://ref.dm-lang.org/notes/filters/index.md)