Rendering Pipeline

MewUI uses a three-pass layout system:

Measure (calculate DesiredSize) → Arrange (set Bounds) → Render (draw via IGraphicsContext)

Key overrides in custom controls:

• MeasureContent(Size availableSize) → return desired size

• ArrangeContent(Rect bounds) → position children

• OnRender(IGraphicsContext context) → draw visuals

IGraphicsContext Essentials

protected override void OnRender(IGraphicsContext context) { var bounds = new Rect(0, 0, Bounds.Width, Bounds.Height);

// State management (always Save/Restore)
context.Save();
context.Translate(10, 10);
context.SetClip(clipRect);
// ... drawing ...
context.Restore();

// Drawing primitives
context.FillRectangle(bounds, Colors.Blue);
context.DrawRectangle(bounds, Colors.Black, thickness: 1);
context.FillRoundedRectangle(bounds, radiusX: 4, radiusY: 4, Colors.White);
context.DrawLine(start, end, Colors.Gray, thickness: 1);
context.FillEllipse(bounds, Colors.Red);

// Text - note parameter order: text, bounds, font, color, alignments, wrapping
context.DrawText("Hello", bounds, font, Colors.Black,
    TextAlignment.Center, TextAlignment.Center, TextWrapping.NoWrap);

// Images
context.DrawImage(image, destRect);

}

Text Measurement

protected override Size MeasureContent(Size availableSize) { var factory = GetGraphicsFactory(); using var ctx = factory.CreateMeasurementContext(GetDpi()); // uint dpi (96, 144, etc.) return ctx.MeasureText(Text, GetFont(), availableSize.Width); }

Graphics Backends

Application.DefaultGraphicsBackend = GraphicsBackend.Direct2D; // GPU (Windows) Application.DefaultGraphicsBackend = GraphicsBackend.Gdi; // Software (Windows) Application.DefaultGraphicsBackend = GraphicsBackend.OpenGL; // Cross-platform

Invalidation

InvalidateMeasure(); // Re-measure + re-arrange + re-render InvalidateArrange(); // Re-arrange + re-render InvalidateVisual(); // Re-render only

Detailed API: See graphics-api.md Pipeline details: See pipeline.md