CrtTextBox

CrtTextBox is an Avalonia C# project that enhances a standard TextBox control with a custom SKSL shader, giving it the appearance of a retro CRT screen. This effect adds a nostalgic touch to your UI with features like fish-eye distortion, scan lines, vignette, screen jitter, background noise, and a scrolling electron bar.

It makes use of a custom ShaderControl control, allowing any SKSL shader code to be applied to a source Avalonia UI control. The CrtTextBox example demonstrate how to use it with a TextBox, but any other source control can be used.

Features

• Retro CRT Look: The shader applies various effects to create a convincing retro CRT display, including:

  • Fish-eye distortion
  • Scan lines
  • Vignette effect
  • Screen jitter
  • Background noise
  • Scrolling electron bar
  • Monitor 'surround' with screen reflection

• Cross-Platform Compatibility: Built with Avalonia, ensuring compatibility across Windows, MacOS, and Linux.

• Customizable: The shader can be easily integrated into any Avalonia application and modified to suit different visual styles.

Getting Started

Prerequisites

• .NET compatible IDE such as JetBrains Rider or Visual Studio 2022.
• Basic knowledge of C# and Avalonia UI.

Building From Source

1. Clone the repository from GitHub.
2. Open the solution in your IDE.
3. Build and run the project.

Using the Text Editor

The main view is taken up with the shader code itself. Feel free to modify it and press F5 to apply changes. Right-click outside of the text area to switch Themes.

Create Your Own Theme

Check out the Themes folder in the source tree. Modify the code to toggle features, or create your own theme from scratch.

Using the ShaderControl

The ShaderControl object is a standalone class and can be copied into your own project, and applied to any control with any shader code.

1. Add ShaderControl to your AXAML.
2. From the code-behind, set the ControlSource property to the UI control you wish to apply the shader to.
3. Set the FPS property, which determines the frequency the source control is sampled.
4. Set ShaderUri to point to the location of your SKSL shader code. Use crt.sksl as a reference.

Custom uniform values can be passed into the shader code using ShaderControl.AddUniform(name, value).

Contribution and Improvements

CrtTextBox is an open-source project, and contributions are welcome. If you have ideas for new features, improvements, or bug fixes, feel free to submit a pull request. Please note that this is a side project, so responses might not be immediate.

Credits

• Created with help from the blog: Avalonia with Fragment Shaders
• ...based on work by Wiesław Šoltés.

The project is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

Useful Resources

• Avalonia UI Documentation
• SKSL Shader Language
• The Oldschool PC Font Resource

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