pura-tiff

A pure Ruby TIFF decoder/encoder without additional image-processing libraries.

Part of the pura-* series — pure Ruby image codec gems.

Features

  • TIFF decoding and encoding (uncompressed)
  • Image resizing (bilinear / nearest-neighbor / fit / fill)
  • No image-specific native extension or FFI dependency
  • CLI tool included

Installation

gem install pura-tiff

Usage

require "pura-tiff"

# Decode
image = Pura::Tiff.decode("photo.tiff")
image.width      #=> 400
image.height     #=> 400
image.pixels     #=> Raw RGB byte string
image.pixel_at(x, y) #=> [r, g, b]

# Encode
Pura::Tiff.encode(image, "output.tiff")

# Resize
thumb = image.resize(200, 200)
fitted = image.resize_fit(800, 600)

CLI

pura-tiff decode input.tiff --info
pura-tiff resize input.tiff --width 200 --height 200 --out thumb.tiff

Benchmark

These historical measurements include ffmpeg process startup. They do not compare against an in-process C codec or establish Rails pipeline throughput.

400×400 image, Ruby 4.0.2 + YJIT.

Decode

Decoder Time
pura-tiff 14 ms
ffmpeg (C) 59 ms

Encode

Encoder Time vs ffmpeg Notes
pura-tiff 0.8 ms 0.01× — 73× faster than ffmpeg! Uncompressed
ffmpeg (C) 58 ms —

Why pure Ruby?

  • gem install and go — no brew install, no apt install, no C compiler needed
  • Part of pura-* — convert between JPEG, PNG, BMP, GIF, TIFF, WebP seamlessly
Gem Format Status
pura-jpeg JPEG ✅ Available
pura-png PNG ✅ Available
pura-bmp BMP ✅ Available
pura-gif GIF ✅ Available
pura-tiff TIFF ✅ Available
pura-ico ICO ✅ Available
pura-webp WebP ✅ Available
pura-image All formats ✅ Available

Pixel model and limitations

Images contain 8-bit RGB pixels. Only the first IFD is decoded. Supported input is 8-bit strip data with uncompressed, LZW, or PackBits compression; encoding is uncompressed. Alpha and extra samples are discarded.

crop(x, y, width, height) requires integer coordinates, positive dimensions, and a region entirely inside the image; invalid regions raise ArgumentError.

Decode limits

Pura::Tiff.decode(input, max_input_bytes: 64 * 1024 * 1024, max_pixels: 40_000_000, max_decoded_bytes: 256 * 1024 * 1024) accepts a path or binary data. All limits must be positive integers. These defaults bound input, pixel count, and decoded data size; they are not a cap on the Ruby process's total memory or CPU time.

Invalid image data raises Pura::Tiff::DecodeError; exceeding a configured limit raises its subclass Pura::Tiff::LimitExceeded. TIFF decoding validates directory/tag bounds and rejects truncated or oversized strip output.

License

MIT