Outline Filter Component

Overview

This component adds a visual outline effect to the UI object it is applied to.

WebGL Demo

Properties

Property	Type	Range	Default	Description
Distance
Method	Enum		DistanceMap	The algorithm to use for creating the outline. Options are: • DistanceMap - This is usually the best method as it has the best performance, especially for large outlines. • Dilate - This is a legacy method and is much slower than DistanceMap especially when Size is larger than 4.0, but it does have slightly smoother outline than DistanceMap. This enables the Blur property but doesn't enable some more advanced options that will be available in the DistanceMap method soon.
Shape	Enum		Circle	The shape that the outline grows in. Options are: • Square - Useful when you don't want rounded outlines. For example on a rectangular Image use this to keep the outline rectangular. • Diamond - Pointy sharper outlines. • Circle - Useful for rounded outlines and usually the best option.
Outline
Direction	Enum		Outside	The direction the outline grows in. Options are: • Both - Grow both inside and outside. • Inside - Only grow inside. • Outside - Only grow outside.
Size	Float	[0..256]	4.0	The radius of the outline in pixels.
Softness	Float	[0..128]	2.0	The radius of the falloff pixels. Best to keep this value below Size. Used to soften/anti-alias the outline. This option is only available when Method is set to DistanceMap mode.
Blur	Float	[0..4]	0.0	The radius of the blur filter in pixels. This option is only available when Method is set to Dilate mode.
Fill
Color	Color		Black	The color of the outline.
Apply
Source Alpha	Float	[0..1]	1.0	Fades the source Graphic.
Strength	Float	[0..1]	1.0	Strength of the effect.
Render Space	Enum		Canvas	Which coordinate system use when rendering this filter. Options are: • Canvas: Render the filter before any transforms (scale/rotation/translation etc) are applied. • Screen: Render the filter after transforms have been applied. Read more about this property here.

Usage

Add this component to any GameObject that contains a UI Graphic component (eg Text, Image, RawImage, etc). The object will now render with an outline.

Usage with TextMeshPro

To use this filter effect with TextMeshPro use the Filter Stack (TextMeshPro) component.

Render Space

The RenderSpace property effectively controls whether the Graphic filter is applied before or after the Transform is applied. There are two options:

• Canvas - This is the default mode for all filters. In this mode the filter is rendered to the Graphic before it is transformed into screen-space by the local Transform and by the Canvas. This means that any changes or animations to the transform (or it's parents) will not cause the filter to re-render (unless Canvas has per-pixel mode enabled), which is a performance benefit! This also means that when the Graphic is rotated, the filter will not be aware of this, so the filter will rotate as well. Imagine as drop-shadow effect.
• Screen - This was the default mode before version 1.8.0 was released. In this mode the filter is rendered to the Graphic after it is transformed into screne-space. This means that any changes or animations to the transform (or it's parents) will cause the filter to re-render which can become expensive. It has the advantage that it is possible to do some screen-aware options, such as clamping the filter to the edges of the screen, or extending an edge to the edge of the screen (for example in the Frame Filter component)

A summary of the differences:

Feature	Canvas	Screen
Adjusting transform causes filter re-render	No (unless Canvas has per-pixel mode enabled)	Yes