A pure-C UI layout engine — currently under active development.

Project Xent is split into two repositories with a clear separation of concerns:

block-beta
  columns 1

  block:fluxent_block["fluxent"]
    columns 4
    A["Win32\nWindow"] B["Direct2D\nRendering"] C["DirectWrite\nText"] D["DirectComposition\nCompositing"]
    E["21 Controls"] F["Input\nSystem"] G["Theme\nEngine"] H["Animation\nSystem"]
  end

  space

  block:xent_block["xent-core"]
    columns 4
    I["Flex"] J["SwiftStack"] K["Grid"] L["Absolute"]
    M["Text\nMeasurement"] N["ISPC\nSIMD"] O["Semantics\n& A11y"] P["Plugin\nSystem"]
  end

  fluxent_block -- "XentNodeId / XentContext" --> xent_block

  style fluxent_block fill:#2d333b,stroke:#539bf5,color:#adbac7
  style xent_block fill:#2d333b,stroke:#57ab5a,color:#adbac7

Repository — github.com/Project-Xent/xent-core · Language — C11 · Build — xmake

graph LR
  subgraph Protocols
    direction TB
    F["<b>Flex</b><br/>row · column · wrap<br/>justify · align<br/>grow · shrink"]
    S["<b>SwiftStack</b><br/>priority-based stack<br/>spacers · layout_priority"]
    G["<b>Grid</b><br/>CSS Grid subset<br/>AUTO · PIXEL · STAR<br/>spans up to 16×16"]
    A["<b>Absolute</b><br/>explicit position/size"]
  end

  style F fill:#2d333b,stroke:#539bf5,color:#adbac7
  style S fill:#2d333b,stroke:#539bf5,color:#adbac7
  style G fill:#2d333b,stroke:#539bf5,color:#adbac7
  style A fill:#2d333b,stroke:#539bf5,color:#adbac7

Incremental layout is supported via dirty-flag propagation (DIRTY_SELF · DIRTY_SUBTREE · DIRTY_LAYOUT). The engine skips clean subtrees on re-layout.

Nodes are stored in a Structure-of-Arrays (XentNodeStore) for cache-friendly access. Fields cover tree topology, layout inputs/outputs, Flex and SwiftStack properties, Grid definitions, text attributes, accessibility semantics, and focus metadata (focusable, tab_index).

ISPC kernels with runtime SSE4 / AVX2 dispatch accelerate:

mindmap
  root((ISPC Kernels))
    Flex
      Line statistics<br/>four-way parallel reduction
      Grow / shrink distribution
    SwiftStack
      Spacer distribution<br/>masked add · FMA
      Proportional reduce
    Utility
      Dirty-flag batch OR / clear
      Pixel quantization

Pluggable XentTextBackend interface with a built-in Mono backend (zero external dependencies): word-wrap, char-wrap, multi-line measurement. Two-level cache: XentTextCache → XentShapeCache.

• Accessibility — semantic tree (role, label, checked, value, enabled, expanded, selected)
• Focus management — focusable, tab_index
• Node tagging — generic uint8_t per-node tag (xent_set/get_node_tag) for consumer-defined typing
• Plugin system — xent_plugins.h
• CLI tooling — JSON dump, demo scaffolding (xent_cli.h, opt-in include)
• Profiling — xent_profile_get() / xent_profile_dump()

xent.h · xent_types.h · xent_layout.h · xent_text.h · xent_plugins.h · xent_cli.h

Repository — github.com/Project-Xent/fluxent · Language — C17 · Platform — Windows 10/11 · Build — xmake

Two-phase rendering: collect (walk xent-core node tree → build render command list) → execute (dispatch to per-control renderers).

flowchart LR
  A["Node Tree\n(xent-core)"] -->|walk| B["Collect Phase"]
  B -->|render commands| C["Execute Phase"]
  C --> D["Direct2D"]
  C --> E["DirectWrite"]
  C --> F["DirectComposition"]

  subgraph Backdrop
    G["Mica"] ~~~ H["Mica Alt"] ~~~ I["Acrylic"]
  end

  F --> Backdrop

  style A fill:#2d333b,stroke:#57ab5a,color:#adbac7
  style B fill:#2d333b,stroke:#539bf5,color:#adbac7
  style C fill:#2d333b,stroke:#539bf5,color:#adbac7
  style D fill:#2d333b,stroke:#da3633,color:#adbac7
  style E fill:#2d333b,stroke:#da3633,color:#adbac7
  style F fill:#2d333b,stroke:#da3633,color:#adbac7

fluxent defines the XentControlType enum (flux_control_type.h) — 27 control types that drive renderer dispatch, input routing, and factory creation. 21 of these have dedicated renderers:

• Mouse — hit testing, hover, click, double/triple click, scroll wheel
• Keyboard — full WM_KEYDOWN routing to focused node
• IME — WM_IME_COMPOSITION with cursor position feedback
• Focus nav — Tab / Arrow key ordered by tab_index

Light / Dark / System (reads Windows preference) with 39 Fluent semantic color tokens. Version-number cache so controls refresh only when the theme changes.

Frame-driven FluxTween (float) and FluxColorTween (RGBA), no external dependencies.

Easing: ease_out_quad · ease_in_out_cubic

Both repositories use xmake.

git clone https://github.com/Project-Xent/xent-core.git
git clone https://github.com/Project-Xent/fluxent.git

cd fluxent
xmake
xmake run hello-fluxent