Implements borderWidth and borderColor properties for Layer, matching CoreAnimation's API pattern.

Implementation

• Layer properties: Added border_width: f32 and border_color: [f32; 4] with RGBA support
• Shader rendering: Fragment shader detects border region using untransformed pixel positions (0..width, 0..height) and renders border color before base color/texture
• API methods:
  • set_border(width, r, g, b, a) - width auto-clamps to 0.0 minimum
  • border_width() / border_color() - property getters
• Uniforms extension: Extended GPU uniform buffer with border parameters and layer dimensions

Usage

let mut layer = Layer::new("layer".to_string(), 200, 200, None);
layer.set_background_color(1.0, 0.0, 0.0);
layer.set_border(5.0, 0.0, 0.0, 0.0, 1.0); // 5px black border

// Semi-transparent borders supported
layer.set_border(3.0, 1.0, 1.0, 1.0, 0.5); // 3px 50% opacity white border

Example added in examples/border_demo.rs demonstrating various border styles, widths, and nesting scenarios.

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.