AnyBackground class final

Drawing over something you didn't choose: a wallpaper, a video frame, a gradient, a map.

A palette's background is one color the theme chose. AnyBackground is whatever is actually behind the UI, as real pixels. Build one per image, then ask it:

• AnyBackground.scrimFor: how to make text or an icon legible over it. Draw the answer as a rect (Scrim.paintArgb), around the glyph (Scrim.shadowsWithStroke), or as stacked shadows (Scrim.shadows).
• AnyBackground.sharedBorder: one border tone for surfaces drawn together over it, so they read at one elevation.

Everything here is ARGB ints; Flutter types live in theming/over_image_flutter.dart. See ADR-001. The pixels behind some UI, plus the contrast policy to judge them by.

The pixels are reduced lazily, once. Answers are cached, 64 per method.

Constructors

AnyBackground(List<int> _argbs, {required Algo algo, required double contrast})

argbs must be real sampled pixels from what's behind the UI. If downscaling first, use min/max pooling, never averaging: averaged black and white pixels make a mid-gray that hides both. Quantizer clusters are averages too. Alpha is ignored; every pixel is opaque.

AnyBackground.unknown({required Algo algo, required double contrast})

Nothing is known about what's behind.

Properties

algo → Algo

final

contrast → double

libmonet's 0..1 contrast dial; see Algo.getAbsoluteContrast.

final

hashCode → int

The hash code for this object.

late, final

isUnknown → bool

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

scrimFor(int contentArgb, {Usage usage = Usage.text, int? scrimArgb}) → Scrim

The minimum-opacity scrim that makes contentArgb meet usage's contrast against every pixel, and keeps meeting it at every opacity above, so callers may round up freely.

sharedBorder(List<int> surfaceArgbs, {Usage usage = Usage.border, ColorModel colorModel = ColorModel.kDefault}) → SharedBorder

One border tone for surfaces drawn together over this background, so they read at one elevation. Each border keeps its surface's hue.

toString() → String

A string representation of this object.

override

Operators

operator ==(Object other) → bool

The equality operator.

override