Chapter 2. Actors
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# Chapter 2. Actors

An actor's a guy who if you ain't talkin' about him, ain't listening.

—Edmon Gween, actor, on his deathbed

## 1. Introduction

When building a User Interface with Clutter, the visible part of the UI — that is, what is displayed on the screen — is commonly referred to as "the scene graph". Like every graph, a scene graph is composed by nodes.

Every node on the Clutter scene graph is an actor. Every actor has a single relationship with the others: it can be the parent of another actor, or a child of another actor.

### Note

The stage is an actor that can have children but cannot have any parent.

Actors have different attributes: a position, a size, a scale factor, a rotation angle on each axis (relative to a specific center on the normal plane for that axis), an opacity factor.

The scene graph is not fixed: it can be changed, not only by adding or removing actors, but also by changing the parent-child relationship: it is possible, for instance, to move an entire section of the scene graph from one parent actor to another.

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4. Where to get Clutter | Home | 2. Implementing a simple custom actor