---
name: "CT EXTENSION"
type: topic
source: https://community.bistudio.com/wiki/CT_EXTENSION
revid: 379124
updated: 2026-10-09T12:45:53Z
---

# CT EXTENSION

Arma 3 v2.20

### Introduction

> [!WARNING]
> This is a experimental feature currently available for testing on Development-Branch. It is not yet decided whether this will become available in Stable branch. Please provide Feedback on the [Arma Discord](https://discord.gg/arma)'s #dev_rc_branch channel.

Extension controls are controlled and rendered by [Extensions](../topics/Extensions.md). The constant *type* property for these controls usually is `CT_EXTENSION`.
All inputs to the control are forwarded to the Extension. And the Extension will render the UI into a prepared texture that will then be displayed.

#### Related commands & functions

- Commands: General
- Commands: UI Eventhandlers

#### Related User Interface Eventhandlers

- [Events: General](../topics/User_Interface_Event_Handlers.md#generic-events)

### Alphabetical Order

> [!NOTE]
> TokenNames common to most controls, such as x, y, w, h, text, idc... can be found [**here**](../topics/Arma~3A_GUI_Configuration.md#common-properties).

> [!WARNING]
> Not all of the listed attributes might have an effect nor might the list be complete. All attributes were gathered with [this](https://github.com/7erra/BIKI.VR/blob/master/fnc/generateCTPage.sqf) config crawler.

```cpp
#define CT_EXTENSION 107
```

#### C

##### colorBackground

**Type:** Array

**Description:** Color of the background (The backing texture gets cleared to this color before the Extension's OnDraw). If the UI is not created (Extension not found, or doesn't offer the uiClass), this color fills the whole control.

```cpp
colorBackground[] = {0,0,0,0};
```

#### E

##### extension

**Type:** String

**Description:** Name of the Extension that provides this UI Control.

```cpp
extension = "RVExtensionTest";
```

#### T

##### tileH

**Type:** Number, String

**Description:** Height of one tile. Used with ST_TILE_PICTURE to create a repeating wall of pictures, such as the fullscreen backgrounds in the Eden Editor. Uses [GUI Coordinates](../topics/GUI_Coordinates.md).

Number example:

```cpp
tileH = 1;
```

String example:

```cpp
tileH = "4 / (32 * pixelH)";
```

##### tileW

**Type:** Number, String

**Description:** Width of one tile. Used with ST_TILE_PICTURE to create a repeating wall of pictures, such as the fullscreen backgrounds in the Eden Editor. Uses [GUI Coordinates](../topics/GUI_Coordinates.md).

Number example:

```cpp
tileW = 1;
```

String example:

```cpp
tileW = "8 / (32 * pixelW)";
```

#### U

##### uiClass

**Type:** String

**Description:** "Classname" of the UI, gets passed to the Extension, the Extension has to interpret it and choose what UI to display (If the Extension offers multiple UI Elements).

```cpp
uiClass = "TestUI_123";
```

### Default Classes

> [!NOTE]
> **Arma 3:** **AddOns:** Classes need to be initialised first with `class SomeClass;`
>
> ---
>
> **Missions:** Since Arma 3 v2.02 one can use `import SomeClass;` to initialise a class (see the [import](../topics/import_~28Config~29.md) keyword).
>
> In older versions, use `"Default" call BIS_fnc_exportGUIBaseClasses;` and paste the result into the [description.ext](../topics/Description.ext.md).

#### RscExtension

Baseline RscExtension example

```cpp
class RscExtension
{
    type = CT_EXTENSION; // 107
    idc = -1;
    deletable = 0;
    style = 0;
    colorBackground[] = {0,0,0,0};
    x = 0;
    y = 0;
    w = 0.3;
    h = 0.3;
    extension = "ExtensionNameHere";
    uiClass = "ClassNameHere";
};
```

#### RscWebBrowser

Web Browser sample, utilizing https://github.com/arma3/RVExtensionImGui/blob/main/dllmain.cpp#L76

```cpp
class RscExtension
{
    type = CT_EXTENSION; // 107
    idc = -1;
    deletable = 0;
    style = 0;
    colorBackground[] = {0,0,0,0};
    x = 0;
    y = 0;
    w = 0.3;
    h = 0.3;
    extension = "RVExtensionTest";
    uiClass = "webbrowser_https://arma3.com/";
};
```

<sub>Source: [BI Community Wiki — CT EXTENSION](https://community.bistudio.com/wiki/CT_EXTENSION) (revision 379124).</sub>