drip_flutter

Flutter render layer for the DRIP framework.

Provides direct RenderObject bindings that update the UI with zero widget rebuilds, optional scoped business-logic helpers via DripNode, and high-performance granular reactive lists via DripItems and DripItemBuilder.

API frozen for alpha: 0.7.0-alpha is the frozen pre-1.0 Flutter surface. Removals now require a documented deprecation cycle.

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Features

• Zero Rebuilds — State changes call markNeedsPaint() / markNeedsLayout() directly on RenderObjects, bypassing the Widget → Element → RenderObject traversal entirely.
• Reactive Builder Widgets — Scoped, optimized builders (DripBuilder, DripSelect, DripAsyncBuilder) for complex UI updates when rebuilding widgets is necessary.
• DripReadable<T> binding — All render widgets accept both DripState<T> and DripComputed<T> via the shared DripReadable<T> interface.
• DripLifecycle & DripNode — Explicit, context-free management of business logic modules. No InheritedWidget magic.
• DripSemantics — Full accessibility support with zero-rebuild reactivity.

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Render Widgets

Widget	Bound Property	RenderObject call
DripText	DripReadable<String>	markNeedsLayout()
DripOpacity	DripReadable<double>	markNeedsPaint()
DripColor	DripReadable<Color>	markNeedsPaint()
DripTransform	DripReadable<Matrix4>	markNeedsPaint()
DripImage	DripReadable<ImageProvider>	async image resolution
DripCustomBinding<T>	any	developer-defined

Builder Widgets

When you need to rebuild a subtree conditionally or construct new widgets, use DRIP's reactive builders:

Widget	Purpose
DripBuilder<T>	Rebuilds its subtree whenever the bound DripReadable<T> changes.
DripSelect	Combines multiple sources via an internal DripComputed and rebuilds only when the evaluated combination changes.
DripAsyncBuilder<T>	Handles exhaustive sealed-class state rendering for DripAsync<T> (loading, data, error), automatically passing previousData to handlers.

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Usage

1. Zero-rebuild UI

import 'package:drip_flutter/drip_flutter.dart';

final label = dripState('Hello');
final opacity = DripComputed(() => label.value.isEmpty ? 0.0 : 1.0);

// In build() — no setState ever:
Column(children: [
  DripText(label, style: TextStyle(fontSize: 24)),
  DripOpacity(opacity: opacity, child: Text('visible!')),
])

// Anywhere in business logic:
label.write('World'); // → 0 widget builds

2. Business logic with DripNode

class CounterNode extends DripNode {
  late final DripState<int> count;
  late final DripComputed<String> displayText;
  late final DripComputed<double> opacity;

  @override
  void onInit() {
    count = state(0);
    displayText = computed(() => count.value.toString());
    opacity = computed(() => count.value == 0 ? 0.4 : 1.0);
  }

  void increment() => count.write(count.value + 1);
  void decrement() => count.write(count.value - 1);
}

Provide and consume (Context-Free):

// Explicit dependency injection via constructor
DripLifecycle<CounterNode>(
  create: () => CounterNode(),
  builder: (node) => Column(children: [
      DripText(node.displayText),
      DripOpacity(opacity: node.opacity, child: ElevatedButton(
        onPressed: node.increment,
        child: Icon(Icons.add),
      )),
    ]),
)

3. Accessibility with DripSemantics

DripSemantics<int>(
  value: node.count,
  label: (value) => "Current count is $value",
  child: DripText(node.displayText),
)

4. Reactive Lists

For highly-granular reactive collections, use DripItems<T> in combination with DripItemBuilder<T>. This ensures that individual element updates do not trigger a full list rebuild, keeping element-level updates isolated and performant:

final items = DripItems<String>(['item A', 'item B']);

// In build():
ListView.builder(
  itemCount: items.length,
  itemBuilder: (context, index) {
    return DripItemBuilder<String>(
      items: items,
      index: index,
      builder: (context, value) => ListTile(title: Text(value)),
    );
  },
);

// Writing to an element updates ONLY that specific index tile — zero list-level rebuilds:
items[0].write('Updated Item A');

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Architecture Invariants

1. Zero setState(): No setState() calls exist in the binding code path. DripFrame is the sole intentional exception, explicitly documented.
2. Binding Lifecycle: All bindings are synchronously deregistered in didUnmountRenderObject — zero subscriber leaks.
3. Context-Free Lifecycle: DripLifecycle creates nodes in initState, passes them explicitly through its builder, and disposes them in dispose.

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Benchmarking

Run the demo_grid app in profile mode to observe the zero-rebuild guarantee:

cd apps/demo_grid
flutter run --profile

Open Flutter DevTools → Performance → Track Widget Builds: 1,000 DripText cells update every 16 ms — widget build count stays at 0.

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Installation

dependencies:
  drip_flutter: ^0.7.0-alpha

Requires Flutter >=3.10.0 and drip_core ^1.0.0.

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Part of the DRIP Framework.