# Filter effects

Source: https://ref.dm-lang.org/notes/filters/
Added in BYOND 512.

Filters are a way of adding special effects to an icon, or a group of icons (see `KEEP_TOGETHER` in [appearance_flags](https://ref.dm-lang.org/atom/var/appearance_flags.md)), by post-processing the image. A filter object describes a specific form of image processing, like for instance a blur or a drop shadow. Filters can be added or removed at will, and can even be animated.

A filter is created by using the [filter proc](https://ref.dm-lang.org/proc/filter.md) like so:

```dm
// halo effect
mob.filters += filter(type="drop_shadow", x=0, y=0,\
                      size=5, offset=2, color=rgb(255,255,170))
```

These are the filters currently supported:

* [Alpha mask](https://ref.dm-lang.org/notes/filters/alpha.md)
* [Angular blur](https://ref.dm-lang.org/notes/filters/angular_blur.md)
* [Bloom](https://ref.dm-lang.org/notes/filters/bloom.md)
* [Color matrix](https://ref.dm-lang.org/notes/filters/color.md)
* [Displacement map](https://ref.dm-lang.org/notes/filters/displace.md)
* [Drop shadow](https://ref.dm-lang.org/notes/filters/drop_shadow.md)
* [Gaussian blur](https://ref.dm-lang.org/notes/filters/blur.md)
* [Layering (composite)](https://ref.dm-lang.org/notes/filters/layer.md)
* [Motion blur](https://ref.dm-lang.org/notes/filters/motion_blur.md)
* [Outline](https://ref.dm-lang.org/notes/filters/outline.md)
* [Radial blur](https://ref.dm-lang.org/notes/filters/radial_blur.md)
* [Rays](https://ref.dm-lang.org/notes/filters/rays.md)
* [Ripple](https://ref.dm-lang.org/notes/filters/ripple.md)
* [Wave](https://ref.dm-lang.org/notes/filters/wave.md)

### See also
- [filters var (atom)](https://ref.dm-lang.org/atom/var/filters.md)
- [appearance_flags var (atom)](https://ref.dm-lang.org/atom/var/appearance_flags.md)
- [filter proc](https://ref.dm-lang.org/proc/filter.md)
- [animate proc](https://ref.dm-lang.org/proc/animate.md)
- [Understanding the renderer](https://ref.dm-lang.org/notes/renderer.md)

## Pages

- [Alpha mask filter](https://ref.dm-lang.org/notes/filters/alpha.md)
- [Angular blur filter](https://ref.dm-lang.org/notes/filters/angular_blur.md)
- [Bloom filter](https://ref.dm-lang.org/notes/filters/bloom.md)
- [Gaussian blur filter](https://ref.dm-lang.org/notes/filters/blur.md)
- [Color matrix filter](https://ref.dm-lang.org/notes/filters/color.md)
- [Displacement map filter](https://ref.dm-lang.org/notes/filters/displace.md)
- [Drop shadow filter](https://ref.dm-lang.org/notes/filters/drop_shadow.md)
- [Layering (composite) filter](https://ref.dm-lang.org/notes/filters/layer.md)
- [Motion blur filter](https://ref.dm-lang.org/notes/filters/motion_blur.md)
- [Outline filter](https://ref.dm-lang.org/notes/filters/outline.md)
- [Radial blur filter](https://ref.dm-lang.org/notes/filters/radial_blur.md)
- [Rays filter](https://ref.dm-lang.org/notes/filters/rays.md)
- [Ripple filter](https://ref.dm-lang.org/notes/filters/ripple.md)
- [Wave filter](https://ref.dm-lang.org/notes/filters/wave.md)