SegmentationMask class

A segmentation probability mask indicating foreground vs background.

Contains per-pixel probabilities (0.0-1.0) where higher values indicate greater likelihood that the pixel belongs to a person/foreground.

Memory Management

Mask data is stored as Float32List. For large images, prefer:

  • Use toBinary or toUint8 to reduce memory by 4x
  • Use upsample with maxSize parameter to limit output
  • Process masks promptly and let GC collect

Thread Safety

SegmentationMask is immutable. The underlying data buffer is exposed as an unmodifiable view.

Example

final mask = await segmenter(imageBytes);

// Get model-resolution mask values
final probability = mask.at(128, 128);

// Upsample to original image size (capped at 1080)
final fullMask = mask.upsample(maxSize: 1080);

// Convert to binary for compositing
final binary = fullMask.toBinary(threshold: 0.5);
Implementers

Constructors

SegmentationMask({required Float32List data, required int width, required int height, required int originalWidth, required int originalHeight, List<double> padding = const [0.0, 0.0, 0.0, 0.0]})
Creates a segmentation mask with validation.
factory
SegmentationMask.fromMap(Map<String, dynamic> map)
Creates a SegmentationMask from a serialized map (isolate deserialization).
factory

Properties

data → Float32List
Returns a copy of the raw probability data (row-major order).
no setter
hashCode → int
The hash code for this object.
no setterinherited
height → int
Mask height in pixels.
final
originalHeight → int
Original source image height.
final
originalWidth → int
Original source image width.
final
padding → List<double>
Padding applied during letterboxing [top, bottom, left, right]. All zeros if no letterboxing was used.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
width → int
Mask width in pixels.
final

Methods

at(int x, int y) → double
Returns probability at (x, y) in mask coordinates.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toBinary({double threshold = 0.5}) → Uint8List
Converts to binary mask (0 or 255) using threshold.
toMap() → Map<String, dynamic>
Serialization for isolate transfer.
toRgba({int foreground = 0xFFFFFFFF, int background = 0x00000000, PixelFormat format = PixelFormat.rgba, double threshold = 0.5}) → Uint8List
Converts to RGBA image with configurable colors.
toString() → String
A string representation of this object.
override
toUint8() → Uint8List
Converts to 8-bit grayscale mask (0-255).
upsample({int? targetWidth, int? targetHeight, int maxSize = 2048}) → SegmentationMask
Upsamples mask to target dimensions using bilinear interpolation.

Operators

operator ==(Object other) → bool
The equality operator.
inherited