image

Documentation

Index

• type ImageEngine
  • func NewEngine() *ImageEngine
  • func (e *ImageEngine) DetectByExtension(path string) bool
  • func (e *ImageEngine) DetectByHeuristic(path string, header []byte) bool
  • func (e *ImageEngine) DetectByMagic(header []byte) bool
  • func (e *ImageEngine) Diff(ctx context.Context, oldPath string, oldReader io.Reader, newPath string, ...) (string, error)
  • func (e *ImageEngine) Metadata() *core.FileMetadata
  • func (e *ImageEngine) Name() string
  • func (e *ImageEngine) Preview(header []byte, size int64, reader io.Reader, maxLines int) (string, error)

Types

type ImageEngine

type ImageEngine struct {
	chunker.DefaultSelector
}

ImageEngine handles image files (PNG, JPEG, GIF, WebP, BMP, TIFF).

func NewEngine

func NewEngine() *ImageEngine

NewEngine creates a new ImageEngine.

func (*ImageEngine) DetectByExtension

func (e *ImageEngine) DetectByExtension(path string) bool

DetectByExtension checks if the path's extension is a known image type.

func (*ImageEngine) DetectByHeuristic

func (e *ImageEngine) DetectByHeuristic(path string, header []byte) bool

DetectByHeuristic returns false; images are not sniffed heuristically.

func (*ImageEngine) DetectByMagic

func (e *ImageEngine) DetectByMagic(header []byte) bool

DetectByMagic checks file header signatures for known image magic bytes.

func (*ImageEngine) Diff

func (e *ImageEngine) Diff(ctx context.Context, oldPath string, oldReader io.Reader, newPath string, newReader io.Reader) (string, error)

Diff compares two images streaming, without buffering either file wholly in memory. The leading core.HeaderPeekSize bytes are peeked for format and dimension detection; the remainder is hashed with BLAKE3 for an equality short-circuit. Priority of reported changes is:

format -> dimensions -> size -> content

Returns an empty string when the images are identical (same size and hash).

The full file bytes are never held in memory: only the fixed-size header buffer and the 32-byte hash digest are retained, so memory stays constant regardless of image size.

func (*ImageEngine) Metadata

func (e *ImageEngine) Metadata() *core.FileMetadata

Metadata returns the file metadata for image files. The MIME type is a generic octet-stream placeholder; per-format refinement (image/png, etc.) is a future enhancement tracked separately.

func (*ImageEngine) Name

func (e *ImageEngine) Name() string

Name returns "image".

func (*ImageEngine) Preview

func (e *ImageEngine) Preview(header []byte, size int64, reader io.Reader, maxLines int) (string, error)

Preview returns a one-line summary: format name, dimensions, and human-readable file size (e.g. "PNG 1920x1080 2.4 MB").

Only the header is inspected (for magic detection and dimension parsing) and size is taken from the caller; the content reader is never touched. This keeps memory constant for arbitrarily large images. Dimension parsing delegates to format.DecodeDimensions so that PNG, JPEG, GIF, WebP, BMP, and TIFF are all supported.