ScannerCv class

Static Methods

adjust(RgbaImage src, {double brightness = 0, double contrast = 1, double sharpness = 0}) → RgbaImage

Brightness -100..100, contrast 0.4..2.5, sharpness 0..2.

analyzeFrame(Uint8List bytes, int width, int height, int stride, {required bool isBgra, int cannyPasses = 2, bool useHoughFallback = true, bool refineCorners = true}) → FrameAnalysis

One-call live-frame analysis: quad detection + luma + focus, with a single downscale and a single buffer copy across the FFI boundary. bytes is a tightly packed luma plane (isBgra=false) or a 4-byte-per- pixel BGRA/RGBA buffer (isBgra=true), with stride bytes per row.

applyFilter(RgbaImage src, ScanFilter filter) → RgbaImage

Apply a named document filter, returning a new buffer.

compositeOver(RgbaImage dst, RgbaImage overlay) → void

Alpha-composite overlay over dst in place (must be same size).

detectDocument(RgbaImage src) → Quad?

Detect the document in a full-resolution RGBA still.

detectQuad(Uint8List gray, int width, int height, int stride) → Quad?

Detect the document quad in a grayscale (luma) frame. Returns normalized corners or null when nothing convincing was found.

encodeJpeg(RgbaImage src, int quality) → Uint8List

Encode RGBA pixels as a baseline JPEG (4:2:0).

frameStats(Uint8List gray, int width, int height, int stride) → FrameStats

Mean luma + focus (variance of Laplacian) for a grayscale frame.

limitSize(RgbaImage src, int maxDim) → RgbaImage

Resize so the long side is at most maxDim (no-op when small enough).

resize(RgbaImage src, int dw, int dh) → RgbaImage

Bilinear resize.

rgbaToGray(Uint8List rgba, int width, int height, int stride) → Uint8List

Convert an RGBA/BGRA buffer to grayscale.

rotateFlip(RgbaImage src, int quarterTurns, bool flipH) → RgbaImage

Rotate clockwise by quarter turns, then optionally mirror horizontally.

version() → int

warp(RgbaImage src, Quad pixelQuad) → RgbaImage

Perspective-warp src so that pixelQuad maps to a straight rectangle.