riv

A fast, precise, minimal image viewer for Windows.

 

Features

• Rendering
  • FP16 linear render pipeline, FP16 scRGB output
  • HDR passthrough on HDR displays, HDR tone-mapped on SDR displays
  • Native 10-bit output on deep-color displays
  • Output dither: Ordered or Fruit shader
  • Color management: Windows Advanced Color with WCG/HDR, PQ/HLG, embedded/display ICC profiles
• Browsing
  • Browse images inside archives (via archiveint.dll, shipped with Windows)
  • Open http/https image URLs (via curl.exe, shipped with Windows)
  • Animation playback with pause, frame stepping, speed control
  • Configurable preloading that follows the browsing direction
• Application
  • Customizable keyboard and mouse shortcuts
  • Per-extension file associations, reversible with no registry leftovers
  • Single portable executable (~7 MB), no installation
  • Settings stored in riv.json next to riv.exe

Running as administrator is blocked at startup.

Supported formats

Some formats need a codec extension from the Microsoft Store. Only those files fail without it; the error names the one to install:

Format	Required extension
HEIC †	HEVC Video Extensions (Microsoft Corporation)
HEIF ‡	HEIF Image Extension (Microsoft Corporation)
AVIF ‡	HEIF Image Extension + AV1 Video Extension (Microsoft Corporation)
JPEG XL ‡	JPEG XL Image Extension (Microsoft Corporation)
WebP (still) ‡	WebP Image Extensions (Microsoft Corporation)
Camera RAW ‡	Raw Image Extension (Microsoft Corporation)

† paid · ‡ free, no sign-in required

HEVC Video Extensions is optional; without it, the app uses its built-in decoder.

Decoded by built-in codecs:

Format	Decoder
HEIC / HEIF	libheif + libde265 §
SVG / SVGZ	resvg
EXR	OpenEXR
APNG	png
Animated WebP	libwebp

§ 8-bit output: 10-bit and HDR HEIC still decode, reduced to 8-bit. By contrast, HEVC Video Extensions keeps the full depth.

Decoded by Windows Imaging Component codecs:

Format	Notes
PNG, JPEG, GIF, BMP, ICO, TIFF
DDS	BC1–BC3

Archives browsable as image folders: zip, 7z, rar, tar, and cbz / cbr / cb7 / cbt.

Requirements

• Windows 11, x86-64
• Direct3D 12 capable GPU

Building

The build cross-compiles from Linux (tested on WSL) to x86_64-pc-windows-msvc.

Prerequisites:

• Rust with the x86_64-pc-windows-msvc target
• LLVM 21+: clang-cl, lld-link, llvm-lib, llvm-rc, llvm-mt
• A Windows CRT + SDK splat from xwin in ~/.xwin (override the location with XWIN_ROOT)
• CMake and Ninja, for static codec dependencies

On Ubuntu 26.04, everything but Rust and xwin comes from apt:

sudo apt-get install clang-21 lld-21 llvm-21 cmake ninja-build git

Rust and xwin:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup target add x86_64-pc-windows-msvc
cargo install xwin
xwin --accept-license splat --output ~/.xwin

./deps/build_deps.sh   # static build of the C/C++ codecs
cargo build --release

Acknowledgments

Inspired by qView. mpv and libplacebo served as references for context menu, dither, aspect ratio table.

License

GPL-3.0-only (see LICENSE).

THIRD-PARTY-NOTICES.md lists the statically linked third-party components and their licenses. The application icon is derived from Fluent UI System Icons (MIT).