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Center Specs

This document captures design and implementation notes for Center.

For end-user usage and examples, see Center.

Overview

  • Status: Implemented
  • Primary purpose: Centers a single child within the available bounds.
  • Content model: Center is a ContentVisual and arranges only Content.

Public API surface

Type

  • Center : ContentVisual

Inherited properties

Center uses ContentVisual.Content (and the usual Visual sizing/alignment properties), but it does not introduce any new bindables of its own.

Layout & rendering

Center is purely a layout helper; it does not render anything itself.

Measure

  • If Content is null: DesiredSize = (0,0).
  • Otherwise: returns Content.Measure(constraints).

Arrange

  • If Content is null: no-op.
  • Otherwise:
    • clamps arranged width/height to the smaller of:
      • available size (finalRect)
      • Content.DesiredSize
    • centers the resulting rectangle within finalRect:
      • x = finalRect.X + (finalRect.Width - w) / 2
      • y = finalRect.Y + (finalRect.Height - h) / 2

This means:

  • the child is never stretched by Center
  • oversized children are arranged to a clipped rectangle (normal visual clipping rules apply)

Input & commands

Center does not handle input and does not expose commands.

Styling

There is no CenterStyle. Visual appearance is determined entirely by the child.

Tests & demos

There are no dedicated unit tests for Center at the time of writing.

Future / v2 ideas

  • Consider adding a small deterministic layout test if future changes introduce more behavior (e.g. margins or alignment overrides).