image_quality_gate_io library

Classes

ContrastCheck: Low contrast, measured as RMS contrast: the standard deviation of luminance normalised to 0..1 (Peli, 1990). 0 is a flat image, 0.5 is the maximum (half black, half white).
DocumentFillCheck: A heuristic for "the document is too small in the frame".
ExposureCheck: Exposure: mean luminance and clipped highlights and shadows.
GlareCheck: Glare: saturated near-white pixels, as left by a flash or a lamp reflecting off glossy paper or a laminated card.
ImageQualityGate: Measures a photo and decides whether it is good enough to use.
PixelRect: An axis-aligned rectangle in pixel coordinates.
QualityConfig: Which checks run, with which thresholds, on which part of the frame.
QualityIssue: One failed check, with the value that was measured and the limit it broke.
QualityMessages: User-facing messages for each QualityIssueCode.
QualityMetrics: Every raw measurement taken, whether or not a check used it.
QualityReport: The outcome of evaluating one image.
RegionOfInterest: The part of the frame that sharpness, exposure, glare, contrast and document-fill checks look at. Resolution checks always use the full image.
ResolutionCheck: Resolution and shape of the full image (the region of interest is not used here). A limit of 0 or null is not checked.
SharpnessCheck: Blur detection.

IssueSeverity: How serious an issue is. Only error makes QualityReport.passed false.
QualityCheck: The individual checks, used by QualityConfig.copyWith to disable them.
QualityIssueCode: What went wrong with a photo. Each code maps to one actionable message in QualityMessages.
ThresholdKind: Whether the threshold that was crossed is a lower or an upper bound.

evaluateInIsolate(Uint8List bytes, [QualityConfig config = QualityConfig.document]) → Future<QualityReport>: Decodes and evaluates bytes on a short-lived background isolate (Isolate.run), so a large photo does not block the UI isolate.

UndecodableImageException: Thrown by ImageQualityGate.evaluate when the bytes are not an image format package:image can decode.