ocr

type Box struct {
	Corners [4]Point
}

type DBOptions struct {
	Thresh      float64 // binarization threshold on the raw probability map
	BoxThresh   float64 // minimum mean probability inside a candidate box to keep it
	UnclipRatio float64 // box expansion factor
	MinSize     float64 // minimum shorter-side length (in resized-image pixels) to keep a box
}

type DetPreprocessOptions struct {
	LimitSideLen int
	// Mean/Std are per-channel in BGR order (index 0=B, 1=G, 2=R) - PaddleOCR
	// decodes images via OpenCV (cv2.imread, BGR by default) and normalizes
	// in that same channel order without ever converting to RGB, so the
	// model's input tensor channel 0 is normalized Blue, not Red. Confirmed
	// against the official PP-OCRv5_mobile_det inference.yml
	// (DecodeImage.img_mode: BGR). Getting this backwards silently swaps R
	// and B for every pixel - not a shape/crash bug, so nothing catches it
	// except comparing against a real model's actual behavior.
	Mean [3]float32
	Std  [3]float32
}

type Engine struct {
	// contains filtered or unexported fields
}

type Line struct {
	Text       string
	Confidence float32
	Box        Box
}

type Options struct {
	RuntimeLibPath string // onnxruntime.{dll,so,dylib}
	DetModelPath   string // PP-OCRv5 detection .onnx
	RecModelPath   string // PP-OCRv5 recognition .onnx

	// RecCharsetPath is the recognition model's dictionary file, one
	// character/token per line, in class-index order. Required - there is
	// no embedded default, because a wrong or mismatched charset produces
	// silently-wrong decoded text (plausible-looking output, no error),
	// which is worse than requiring the caller to supply the file that
	// actually matches their pinned model export.
	RecCharsetPath string

	// BlankIndex is the CTC blank class index in the recognition model's
	// output, and its position within RecCharsetPath's line order. Verify
	// against the actual pinned model/dictionary; PaddleOCR has used both
	// index-0 and last-index conventions across versions. Defaults to 0.
	BlankIndex int

	IntraOpNumThreads int

	// Zero-value Det/Rec/DB options fall back to their package defaults
	// (DefaultDetPreprocessOptions / DefaultRecPreprocessOptions /
	// DefaultDBOptions) - see those functions' docs for the caveat that
	// the defaults are PaddleOCR's documented values, not yet confirmed
	// against a specific pinned model export.
	DetOptions DetPreprocessOptions
	RecOptions RecPreprocessOptions
	DBOptions  DBOptions
}

type Point struct{ X, Y float32 }

type RecPreprocessOptions struct {
	TargetHeight int
	TargetWidth  int // max width; narrower resized images are right-zero-padded
}