flutter_pretext 1.1.0

A high-performance text dynamics engine and layout framework for native Flutter. mathematically wraps text natively around geometry, obstacles, and shapes.

Flutter Pretext

flutter_pretext is a blazingly fast, high-performance text dynamics engine and layout framework natively rebuilt for Flutter.

It is a direct Dart implementation and port of the groundbreaking JavaScript text dynamics library originally built by @chenglou. All credits for the underlying geometric abstractions, pure-code measuring mechanics, and cursor math layout capabilities go to chenglou/pretext.

This package natively migrates those massive layout capabilities to standard Flutter Widgets without bridging FFI or WebViews.

Why Pretext?

Flutter's standard Text widgets do an amazing job rendering strings, but custom geometry flow—like wrapping paragraphs beautifully around floating avatars, shrinking chat bubbles accurately, or splitting text evenly into a circular path—has historically been agonizing to compute cleanly on a device without dropping frames.

Pretext calculates lines mathematically behind the scenes before actually laying out the heavy rendering tree.

Features Available Today

1. ObstacleTextFlow

Pass in multiple UI widget bounds (like floating Positioned icons) and watch the text shatter and wrap flawlessly around them on both sides instantly.

2. ShrinkWrapText

Say goodbye to the "dead empty trailing space" bug in chat bubbles! ShrinkWrap computes the absolute geometric longest drawn string line and snaps your container size down perfectly.

3. BalancedText

Say goodbye to awkward orphaned words hanging off your H1 headlines. Drops in a binary-search container to ensure your multi-line headlines have geometrically balanced widths.

4. Custom Mathematical Shapes & 60 FPS Animations

You can bind your obstacle arrays to AnimationControllers or custom geometric algorithms like Circular mappings. Text will dynamically flow over moving surfaces without ever dropping a frame.

Quick Start

Obstacle Layout Flow

Got a square floating avatar taking up the top left edge? Let text handle it like Word or HTML float:left. Note: You can even use .wrapBothSides = true to drop the avatar in the exact middle of the paragraph!

final prepared = prepare("Your extremely long dynamic text here...", style);

ObstacleTextFlow(
    preparedText: prepared,
    textStyle: style,
    lineHeight: 18 * 1.2,
    obstacles: [ Rect.fromLTWH(0, 0, 100, 100) ], // Re-renders precisely around this square.
);

Typographic Balanced Headlines

Stop leaving one word hanging alone!

BalancedText(
  "This Super Long Title Will Splinter Awkwardly Unless You Use Pretext",
  titleStyle,
  /* lineHeight */ 40,
)

Special Thanks

This repository would not exist without the genius foundations of chenglou/pretext. His commitment to performance boundary pushing was instrumental.