simple_parallax 1.2.0

Parallax widgets for Flutter, with a container mode and a per-item mode, vertical or horizontal. Pure Dart, no dependencies, any ImageProvider.

SimpleParallax Versions

1.2.0

Both scroll views move to slivers.

Added

• SimpleParallaxContainer.slivers, which takes the content as a list of slivers instead of a single child. The content then builds as it scrolls, and a SliverAppBar or a SliverGrid can ride over the background. On a long list prefer a fixed speed: autoSpeed spreads the travel overscan allows over the whole extent, so the drift becomes imperceptible.
• A fifth example screen, ContainerSliversDemo.

Changed

• SimpleParallaxContainer builds a CustomScrollView rather than a SingleChildScrollView. The default constructor puts child in a SliverToBoxAdapter, which lays it out exactly as before.
• SimpleParallaxWidget builds a CustomScrollView over one SliverList rather than a SingleChildScrollView over a Column or a Row, so its blocks build as they come into view. Two consequences, both of them ListView behaviour: a block is laid out across the full cross axis instead of being centred on it, and a block outside the viewport is not in the tree. Pass a block that must keep a narrower cross extent through an Align or a Center.

1.1.1

Documentation and example, no library change.

• The example covers all four combinations, two modes by two axes, behind a menu. They share example/lib/main.dart because that is the only file pub.dev renders on the example tab, so the three separate entry points only ever showed one of them there.
• The four preview animations are redone in one format, 520x260 at 25 frames a second, and laid out as a grid: modes in rows, axes in columns. 1.1.0 shipped before they were regenerated, so its README sized the vertical pair as portrait.

1.1.0

Horizontal parallax.

Added

• SimpleParallaxContainer.scrollDirection and SimpleParallaxWidget.scrollDirection. The background drifts along the scrolled axis, and overscan sizes it on that axis.
• SimpleParallaxItem reads the axis from the scrollable it sits in, so it slides sideways in a horizontal list with nothing to pass. Its height and width defaults swap accordingly: the scrolled axis falls back to the screen extent, the cross axis to the incoming constraints.
• SimpleParallaxContainer.width, the horizontal counterpart of height.
• A horizontal example, example/lib/main_horizontal.dart, and horizontal previews in the README.

Fixed

• SimpleParallaxContainer ignores scroll notifications from a nested scrollable running on the other axis, which used to drag the background along.

1.0.2

Add animated previews in to README.md

1.0.1

Improve example and comments.

1.0.0

Rewrite. Breaking changes, see the migration table below.

Changed

• The package is no longer a Flutter plugin. The android, ios, linux, macos and windows folders held nothing but the flutter create --template=plugin scaffold, whose only method was never called from Dart. They are gone, along with the flutter: plugin: declaration and lib/simple_parallax_web.dart.
• No dependencies left beyond the Flutter SDK. provider was replaced by ValueListenableBuilder and by Flow, both from the SDK, and flutter_web_plugins went with the plugin declaration.
• Both widgets now take an ImageProvider instead of an asset path, so network images, files and raw bytes work.
• decal is renamed overscan, which is what it actually controls.
• SimpleParallaxItem finds the enclosing Scrollable on its own. It works inside a ListView, a CustomScrollView or any other scroll view, and no longer throws when used outside SimpleParallaxWidget.
• SimpleParallaxItem.speed is now a 0..1 fraction of the available travel, default 1.0.
• autoSpeed derives the speed from the real scroll extent instead of requiring the caller to put a GlobalKey on their child, which was undocumented and silently did nothing when absent.
• SimpleParallaxWidget gained controller, padding and physics.

Fixed

• Scrolling rebuilt the whole subtree, content included, on every frame: the Consumer wrapped the user's widgets. Container mode now rebuilds only the background transform, behind a RepaintBoundary, and item mode repaints without rebuilding anything at all.
• Two ChangeNotifier instances were never disposed, one per parallax item and one per parallax widget.
• _key.currentContext!.findRenderObject()! in a post-frame callback crashed when the item left the tree before the next frame. The measurement now happens at paint time, with no force-unwrap.
• setState was called from a post-frame callback without checking mounted.
• The scroll notification was swallowed by returning true, so an ancestor listener never saw it.
• A non-finite scroll metric could place the background nowhere.
• The background could travel past its overscan and uncover its bottom edge; the offset is clamped.

Removed

• provider and flutter_web_plugins dependencies.
• Dead code: ScrollNotifier.speed and setSpeed, never called, and the unused scroll offset on the per-item notifier.
• Two lints removed from Dart years ago, still listed in analysis_options.yaml.

Added

• A test suite. There was none.

Migration

Before	Now
imagePath: 'assets/a.webp'	image: AssetImage('assets/a.webp')
decal: 1.5	overscan: 1.5
SimpleParallaxItem(speed: 0.3)	speed is a 0..1 fraction, default 1.0
SimpleParallaxItem only inside SimpleParallaxWidget	works inside any scrollable

0.1.1

• Improved README.md

0.1.0

• Add parallax mods container and widget.
• Rename all classes

0.0.2

• Add comments
• Update depedencies

0.0.1

• Initial release