ExplorerLens.io generates thumbnails for images, videos, documents, 3D models, fonts, archives, and more using multi-threaded processing with GPU acceleration planned for Phase 2. The project root directory is ExplorerLens.io, and this repository is the production codebase for the Explorer extension, engine, and manager UI.

Getting Started:

• Quick Start Guide — Developer onboarding: clone → build → register → test
• Build Quick Reference — Complete build instructions
• Installation Guide — Installation and setup
• Testing Guide — Validation and test procedures

Project Organization:

• System Overview — Architecture diagrams + cache layers
• Decode Pipeline — File → detect → route → decode → thumbnail
• Decoder Status — All 20 priority formats verified

Development:

• Developer Guide — Developer documentation
• Contributing — How to contribute
• Coding Standards — Code style and conventions
• Build Scripts — Build automation reference

Server & Ops:

• Dockerfile — Windows Container 2-stage build image for LensServer (Phase 4)

• Standard: .jpg, .jpeg, .png, .bmp, .gif, .tiff, .tif
• Modern: .webp (WebP), .avif (AV1 Image), .jxl (JPEG XL) ✅
• Mobile: .heif, .heic, .hif, .avci, .avcs (Apple HEIC/HEIF) ✅
• Implementation: JXL via libjxl 0.11.1 | HEIF via libheif 1.19.5 (with WIC fallback on Windows 11)

• Comic Books: .cbz, .cbr, .cb7, .cbt
• E-Books: .epub, .mobi, .azw, .azw3, .fb2
• Archives: .zip, .rar, .7z, .tar, .gz, .bz2, .xz

• RAW Photos: .cr2, .cr3, .nef, .arw, .orf, .dng, .rw2, .raf, .pef, .dcr, .mrw, .x3f and 100+ more camera formats (✅ LibRaw 0.21.3)
  • Features: Embedded JPEG thumbnail extraction (< 10ms), full RAW decode with demosaicing, EXIF orientation support, auto white balance
  • Cameras: Canon, Nikon, Sony, Olympus, Panasonic, Fujifilm, Pentax, Adobe DNG, Leica, Samsung, Hasselblad, Phase One, Sigma
• Modern Images: .jxl (JPEG XL) via libjxl 0.11.1, .heif/.heic (HEIF/HEIC) via libheif 1.19.5 + WIC fallback
  • JXL Features: Next-gen format support, better compression than WebP, wide color gamut
  • HEIF Features: Apple iPhone photos (iOS 11+), HDR support, 16-bit depth, wide color
• Design: .psd, .psb (Photoshop), .svg (vector graphics)
• HDR: .exr (OpenEXR), .hdr (Radiance RGBE)
• Texture: .dds (DirectX textures)
• Legacy: .tga (Targa), .ico (icons), .jp2 (JPEG2000)

• Video: .mp4, .mkv, .avi, .webm, .mov, .wmv, .flv, .mpg, .mpeg, .ts, .mts, .m2ts, .3gp, .vob, .ogv (22 extensions)
• Audio: .mp3, .flac, .m4a, .ogg, .wma, .wav, .opus - extracts album art or generates waveform

• Documents: .pdf, .docx, .xlsx, .pptx, .epub (Office/Edge required for Office formats)
• Fonts: .ttf, .otf, .ttc - renders font preview

• Models: .obj, .stl, .gltf, .glb - orthographic preview rendering

• SVG: .svg, .svgz - rasterizes vector graphics to thumbnail

• QOI: .qoi (Quite OK Image - fastest decode format)
• ICO: .ico, .cur (Windows icons/cursors)
• TGA: .tga (Targa)
• PPM: .ppm, .pgm, .pbm, .pnm, .pam, .pfm (Netpbm formats)
• DDS: .dds (DirectX textures)
• HDR: .hdr, .pic (Radiance RGBE)

Legend: ✅ = Production ready | ⚠️ = Requires external dependency | 📋 = Planned

• ⚡ Fast Decode — Multi-threaded CPU decode pipeline with GPU acceleration planned
• 🚀 Smart Caching — Instant display of cached thumbnails
• 📦 Multi-Format — Single extension for all formats
• 🎯 Low Memory — Efficient resource usage

• Windows 10 1809+ or Windows 11 (64-bit)
• Visual Studio 18 2026 BuildTools (MSVC v145 toolset)
• Administrator privileges for installation

# Canonical build command (sources vcvars64 automatically)
.\build-scripts\Build-MSVC.ps1

# Clean build + tests
.\build-scripts\Build-MSVC.ps1 -Clean -Test

See Build Quick Reference for detailed instructions.

REM Register DLL (as Administrator)
cd x64\Release
regsvr32 LENSShell.dll

Run LENSManager.exe to enable/disable file format categories.

See all 13 architecture SVGs in docs/architecture/

GPU Render Pipeline: GDI+ (current) → D3D11 compute (Phase 2) → D3D12/Vulkan (Phase 3+)

COM interfaces implemented: IThumbnailProvider, IInitializeWithStream, IPropertyStore, IPropertyStoreCapabilities, IExtractImage2, IPersistFile, IQueryInfo

CLSID: {9E6ECB90-5A61-42BD-B851-D3297D9C7F39}

graph TD
    ROOT["📁 <b>ExplorerLens.io</b>"]

    ROOT --> SHELL["🔌 <b>LENSShell/</b><br/>COM Shell Extension DLL"]
    ROOT --> MGR["🖥️ <b>LENSManager/</b><br/>WTL Admin GUI"]
    ROOT --> ENG["⚙️ <b>Engine/</b><br/>Core Decode + Render Library"]
    ROOT --> BS["🔨 <b>build-scripts/</b><br/>PowerShell Build Automation"]
    ROOT --> EXT["📦 <b>external/</b><br/>Statically Linked Libraries"]
    ROOT --> DOCS["📚 <b>docs/</b><br/>Architecture &amp; Guides"]
    ROOT --> SDK["🧩 <b>SDK/</b><br/>Plugin SDK · C ABI"]
    ROOT --> PKG["📋 <b>packaging/</b><br/>MSI · WiX · Portable ZIP"]
    ROOT --> SLN["📄 <b>LENSShell.sln</b><br/>Visual Studio 18 2026 Solution"]

    ENG --> CORE["🏗️ <b>Core/</b><br/>Pipeline · Detection · SIMD"]
    ENG --> DEC["🖼️ <b>Decoders/</b><br/>25+ Format Decoders"]
    ENG --> GPU["⚡ <b>GPU/</b><br/>D3D11 · D3D12 · Vulkan"]
    ENG --> CACHE["💾 <b>Cache/</b><br/>Multi-tier Caching"]
    ENG --> MEM["🧠 <b>Memory/</b><br/>BitmapPool · Pressure Ctrl"]
    ENG --> PLUGIN["🔩 <b>Plugin/</b><br/>Plugin Ecosystem · Sandbox"]
    ENG --> AI["🤖 <b>AI/</b><br/>Smart Crop · IQA · Scene"]
    ENG --> TESTS["✅ <b>Tests/</b><br/>4,877 Unit Tests · 5 Benchmarks"]

    style ROOT fill:#1e3a5f,color:#fff,stroke:#4a9eff,stroke-width:2px
    style ENG  fill:#1b4332,color:#fff,stroke:#40916c,stroke-width:2px
    style SHELL fill:#2d2d2d,color:#fff,stroke:#888
    style MGR   fill:#2d2d2d,color:#fff,stroke:#888
    style BS    fill:#2d2d2d,color:#fff,stroke:#888
    style EXT   fill:#2d2d2d,color:#fff,stroke:#888
    style DOCS  fill:#2d2d2d,color:#fff,stroke:#888
    style SDK   fill:#2d2d2d,color:#fff,stroke:#888
    style PKG   fill:#2d2d2d,color:#fff,stroke:#888
    style SLN   fill:#2d2d2d,color:#fff,stroke:#888
    style CORE   fill:#1a3d2b,color:#d8f3dc,stroke:#52b788
    style DEC    fill:#1a3d2b,color:#d8f3dc,stroke:#52b788
    style GPU    fill:#1a3d2b,color:#d8f3dc,stroke:#52b788
    style CACHE  fill:#1a3d2b,color:#d8f3dc,stroke:#52b788
    style MEM    fill:#1a3d2b,color:#d8f3dc,stroke:#52b788
    style PLUGIN fill:#1a3d2b,color:#d8f3dc,stroke:#52b788
    style AI     fill:#1a3d2b,color:#d8f3dc,stroke:#52b788
    style TESTS  fill:#1a3d2b,color:#d8f3dc,stroke:#52b788

We welcome contributions! See CONTRIBUTING.md for guidelines.

• 🐛 Report bugs and issues
• 💡 Suggest features
• 🔧 Submit pull requests
• 📝 Improve documentation
• 🧪 Write tests

Current Version: 40.0.1 "Procyon" Build Status: 0 errors / 0 warnings Test Status: 4,877 unit tests, 5 benchmarks (100% pass rate) Codename: Procyon

Platform scope: ExplorerLens is a Windows-only Shell Extension (IThumbnailProvider). macOS Quick Look and Linux Nautilus extensions are on the roadmap (Phase 5 and Phase 6 respectively) but are not yet implemented. See ROADMAP.md §16 for the cross-platform plan.

See CHANGELOG.md for the complete development history.

REM Restart Windows Explorer
taskkill /f /im explorer.exe && start explorer.exe

REM Clear Windows thumbnail cache
del /f /s /q "%LocalAppData%\Microsoft\Windows\Explorer\thumbcache_*.db"

reg query "HKCR\CLSID\{9E6ECB90-5A61-42BD-B851-D3297D9C7F39}\InprocServer32"

See Troubleshooting Guide for more troubleshooting.

Compression: zlib 1.3.1, LZ4 1.10.0, zstd 1.5.7, LZMA 26.00, minizip-ng 4.0.10 Images: libwebp 1.5.0, libavif 1.3.0 (dav1d 1.5.1), libjxl 0.11.1, LibRaw 0.21.3 Archives: UnRAR 7.2.1, minizip-ng 4.0.10 Video: Windows Media Foundation (system API) Rendering: DirectX 11, GDI+

MIT License — See LICENSE for details.

Note: MuPDF (PDF rendering) is AGPL-3.0 licensed. See ADR-009 for our compliance strategy and planned migration to PDFium (BSD). All other 17 external libraries use MIT/BSD/zlib/public-domain licenses.

• Repository: Internal project repository
• Issues: Use project issue tracker configured for this workspace
• Discussions: Use team discussion channel

Built with ❤️ using C++23, DirectX 11/12, and Vulkan — Windows Shell Extension for 200+ formats

Last Updated: March 29, 2026 (v25.0.0 "Rigel")