Core Features & User Guide

Text & Code Viewer

Engineered for software developers and technical readers, balancing high-fidelity syntax rendering for everyday source code with instant, zero-freeze opening of massive multi-megabyte logs.

Dual-View Architecture: Standard View vs Large File View

To eliminate out-of-memory crashes and interface freezes when viewing large files, Seer automatically adapts the view mode based on file size:

• Automatic Routing Threshold: Controlled via configuration, defaulting to 3 MiB (3,145,728 bytes).
  • ≤ 3 MiB: Opens in Standard View, providing full syntax styling, word wrap, code formatting, and quick rendering switches.
  • > 3 MiB: Automatically streams the document in Large File View to guarantee instant, freeze-free opening of multi-hundred-megabyte logs, database SQL dumps, or massive CSV files without memory exhaustion.

To maintain instant, freeze-free performance on massive files, the Large File View streams content using fixed row heights. As a result, certain compute-intensive features—such as dynamic word wrap, code formatting, and direct Markdown/HTML/SVG rendering—are unavailable in this mode. Both views fully support syntax highlighting, search (Ctrl + F), line numbers (N), whitespace visualization (W), overview minimap (M), and mouse text selection.

Single-Line Length Limit & Overflow Protection

When inspecting minified or bundled files (such as single-line minified JavaScript, monolithic JSON payloads, or Base64 data), a single row may contain tens or hundreds of thousands of characters. Calculating layout and line-wrapping for such enormous single lines causes severe application lag or freezes during window resizing.

• Default Single-Line Limit: 10,000 Characters: Seer caps single-line reading and layout at 10,000 characters by default (the configuration key enforces a strict minimum floor of 10,000).
• Capsule Truncated Badge: If a line exceeds 10,000 characters, the excess bytes are safely truncated, and an inline capsule badge is painted at the end of the line (e.g., … 500 B or … 14.5 KB).
• Omitted Byte Tooltip: Hovering your cursor over the badge displays an informative tooltip reporting the exact omitted byte count (e.g., Line truncated (14,848 bytes omitted)), maintaining silky-smooth interaction without silently discarding awareness of truncated content.

Complete Shortcut Reference

Custom Syntax Highlighting

Seer's code highlighting engine is powered by the open-source Kate syntax highlighting specification (the same standard shared by Kate, KWrite, Qt Creator, and KDevelop). When a specialized or custom file format is not covered out of the box, or when you want to customize syntax coloration, you can easily add .xml syntax definitions without writing code or compiling anything.

1. Syntax Reference & Examples

• Syntax Format Reference: Kate Highlight XML Format Documentation
• Official Example (hextxt.xml): ccseer/Seer-Controls/plugins/hex-viewer/syntax/hextxt.xml

The official Hex View control plugin uses this exact mechanism: it dumps hex data into files with a custom .hextxt extension and bundles syntax/hextxt.xml to provide custom syntax highlighting.

2. Storage Locations & Activation

Place your .xml definition files into one of Seer's syntax directories:

• Standard Installed Seer: %LocalAppData%\Corey\Seer\syntax\ (i.e., C:\Users\<YourUsername>\AppData\Local\Corey\Seer\syntax\; create the syntax folder if it does not already exist).
• Portable Seer (when portable.cfg exists in the application root): <SeerInstallDir>\data\syntax\.
• Extension Packages: Plugin packages can bundle and distribute syntax definitions under <packageRoot>\syntax\.

Activation: After placing the file, simply restart Seer. The host will automatically scan, validate, and register all conforming syntax files.

3. XML File Rules & Key Constraints

Syntax definitions follow the standard Kate Syntax XML specification. Below is the structure from the official hextxt.xml example:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE language>
<language name="HexDump" section="Other"
          extensions="*.hextxt" version="2" priority="100" kateversion="5.0"
          mimetype="text/x-hexdump" author="corey" license="MIT">
  <highlighting>
    <contexts>
      <context name="Dump" attribute="Normal" lineEndContext="#stay">
        <RegExpr String="^[0-9A-Fa-f]{8}(?=\s{5})" attribute="Offset" context="DataRow"/>
        <RegExpr String="^Offset\(h\).*$" attribute="ColumnHeader" context="#stay"/>
        <RegExpr String="^\[.*\]$" attribute="Banner" context="#stay"/>
      </context>
      <context name="DataRow" attribute="Normal" lineEndContext="#pop">
        <RegExpr String="\|.{16}\|$" attribute="Ascii" context="#stay"/>
        <RegExpr String="\b[0-9A-Fa-f]{2}\b" attribute="HexByte" context="#stay"/>
      </context>
    </contexts>
    <itemDatas>
      <itemData name="Normal" defStyleNum="dsNormal"/>
      <itemData name="Offset" defStyleNum="dsFunction"/>
      <itemData name="HexByte" defStyleNum="dsDataType"/>
      <itemData name="Ascii" defStyleNum="dsString"/>
      <itemData name="ColumnHeader" defStyleNum="dsComment"/>
      <itemData name="Banner" defStyleNum="dsAlert"/>
    </itemDatas>
  </highlighting>
</language>

• File Size Limit: Each .xml file must strictly stay within 512 KB. Files exceeding 512 KB are discarded to guard against accidental non-syntax payloads.
• Required Attributes:
  • name (Mandatory): Unique display name for the language (e.g., name="HexDump").
  • section: Category under which the definition is grouped (e.g., Sources, Scripts, Markup, Other).
  • extensions (Mandatory): Semicolon-delimited wildcard patterns for matching filenames (e.g., extensions="*.hextxt").
  • ⚠️ Do not include spaces after semicolons: Writing *.foo; *.bar causes the second pattern to be read with a leading space (" *.bar"), which will never match any filename. Always write them cleanly without spaces as *.foo;*.bar.
  • priority: Must be a positive integer (e.g., priority="100").
  • version: Definition revision number (integer or float, e.g., version="2").
  • kateversion: Kate format version string. It must contain a dot (e.g., kateversion="5.0" or kateversion="6.0"). Files with missing, dotless, or incompatible kateversion attributes are skipped.

4. Conflict Resolution & Overrides

When multiple syntax definitions overlap, Seer applies deterministic precedence rules:

• Identical Names (name match): If a custom definition shares the same name as an existing or built-in definition, the one with the higher version takes precedence. If versions are tied, the first loaded definition is retained.
• Overlapping Extensions (extensions collision): When different language definitions claim the same file extension (such as two definitions both matching *.shader), the definition with the higher priority value wins.
• Overriding Built-in Highlighters: To replace Seer's built-in highlighting for a given file type with an updated community or custom rule, simply specify a higher positive integer in priority (e.g., priority="100"; built-in priorities are typically in the single digits), and Seer will seamlessly prioritize your custom rule.

Video & Audio Viewer

Provides GPU hardware decoding support (disabled out of the box) and real-time audio visualization for smooth playback across all popular media formats.

Decoding & OpenGL Rendering Requirements

• Decoding Backend: Hardware decoding is off by default — the Disable GPU decoding option under Settings > Types > Media is checked, so Seer starts with software decoding (FFmpeg, dav1d). Uncheck it to let Seer try the GPU decoders, and optionally pin the exact backend order in user.ini [Media] under decoders (D3D11, MFT:d3d=11, DXVA, CUDA, FFmpeg, dav1d, ...).
• ⚠️ OpenGL Hardware Rendering: Video frame display strictly requires an active OpenGL hardware rendering context from the GPU. In rare environments (such as virtual machines, remote desktop connections lacking GPU passthrough, or systems with outdated/corrupt display drivers), video playback may fail to render properly.

Playback Control & Volume Behaviors

• Playback Speed Lifecycle: Playback speed adjustments are runtime-only (held for the active application lifecycle) and automatically reset to 1.0x on the next launch of Seer.
• Volume Control (Standard Preview vs Standalone Window):
  • Standard Preview Window: Supports toggling Mute / Unmute (M or control bar button), without volume slider adjustment.
  • Standalone Window (SeerViewer.exe): Supports fine volume adjustment via mouse wheel or volume slider popup with an on-screen display (Volume OSD) badge, and automatically saves and persists the volume level across launches.
• Subtitle Track Selection & Auto-Discovery: For videos with embedded subtitle tracks, select or disable tracks via the right-click Subtitle menu. Seer also automatically detects external .srt, .ass, .ssa, and .vtt subtitle files sharing the same base name in the video's directory.
• Under 1-Second Media Protection: Media clips with a duration under 1 second (< 1,000 ms) do not have playback functionality: the progress slider, time indicator, play/pause button, speed button, and mute button are completely hidden, and timeline shortcuts are disabled. Looping is disabled to avoid pipeline restart oscillation; the clip plays once and pauses on its final frame, with a "No timeline" status displayed on the control bar.
• Video Chapters & Progress Bar Tooltip: For videos with embedded chapters (such as MP4 or MKV), the progress slider automatically paints visual chapter tick marks. Hovering your mouse along the progress bar displays a tooltip with the exact timestamp and chapter title (e.g., 04:15 | Introduction).
• Time Indicator Display Modes: Click the time label on the control bar to cycle between display modes (toggling between elapsed time / total duration and countdown remaining time). Your preferred display style is remembered automatically.
• Percent Seek: Press number keys 0 through 9 during playback to jump directly to 0% through 90% of the video duration.
• Frame Stepping: Press , / . to pause and step backward / forward by 1 frame (Shift + , / Shift + . steps by 5 frames). Also available via the right-click "Jump" menu.
• Playback Resume: Remembers playback progress for audio and video files when enabled in settings or user.ini (audio_remember_playback_pos and video_remember_playback_pos, disabled by default).

Instant Frame & Cover Copying

Press Ctrl + C at any time during playback or pause to copy visual media directly to your clipboard:

• Video Frame Capture: Copies the current video frame as a high-resolution lossless image into the system clipboard.
  • Pinpoint Specific Frames: If you want to copy an exact frame, simply pause playback and use frame-stepping (, for previous frame, . for next frame, or Shift + , / Shift + . for 5-frame leaps) to navigate to the precise frame, then press Ctrl + C.
• Audio Tracks:
  • With Embedded Cover Art: If the audio file contains album artwork (and the view is in Cover or Cover & Visualizer mode), Ctrl + C copies the original high-resolution album cover image directly to your clipboard.
  • Without Cover Art (or Visualizer-Only Mode): If the track has no embedded artwork or is displayed in Visualizer-Only mode, Ctrl + C captures the active dynamic audio waveform canvas and saves it to your clipboard as an image.
• A notification confirms the image has been saved to your clipboard upon every successful copy.

Audio Waveform Visualizer & Cinema RAW Formats

• Real-Time Audio Visualizer: Playing audio tracks (MP3, FLAC, WAV, etc.) provides a real-time visualizer accessible via the right-click menu:
  • 3 View Modes: Cover Only, Cover & Visualizer, Visualizer Only.
  • 4 Visualizer Styles: Mirrored Bars, Symmetrical Bars, Smooth Spectrum Curve, Dynamic Liquid Wave.
• Cinema RAW Video Formats: With the official mdkadapter plugin installed, Seer natively previews professional cinema raw footage including RED R3D (.r3d) and Blackmagic RAW (.braw).

Image Viewer

Engineered for precision design and photography inspection, combining GPU-accelerated rendering, deep gesture support, and instant opening of massive raw images.

Display Modes & Canvas Navigation

• Default Display Mode Setting: Configure your preferred opening size under Settings > Types > Image:
  • Auto Fit (default): Automatically scales down or up so the entire image fits within the viewer window without scrollbars.
  • Fit Short Side: Scales until the shorter side touches the window edge; scroll the longer side if needed (ideal for tall screenshots or panoramic banners).
  • Prefer Full Size: Always opens the image at 100% native unscaled physical resolution.
• Smart Expand (E): Press E (or select Expand from the right-click context menu) to intelligently optimize the preview window and zoom level:
  • For tall vertical images (e.g. mobile screenshots, long web captures): expands the image width to fill the available screen width while allowing smooth vertical scrolling.
  • For wide panoramic images: fits the height to the available screen height while allowing horizontal scrolling.
  • Seer automatically calculates the maximum readable dimension on your monitor and resizes the preview window accordingly.
• Direct Edge Fitting: Press W to fit the image to the window width, or press H to fit to the window height.
• Double-Click Toggle: Double-click anywhere on the canvas to instantly toggle between 1:1 actual pixel resolution and window-fitting mode.
• Mouse Wheel & Touchpad Gestures:
  • Wheel Action Mode: In Settings > Types > Image, choose whether spinning the mouse wheel scrolls the canvas vertically or zooms smoothly without holding Ctrl.
  • Shift + Wheel: Scrolls the canvas horizontally—effortlessly pan wide pictures without dragging scrollbars.
  • Windows Precision Touchpad: Native support for two-finger pinch-to-zoom and two-finger fluid canvas panning.
  • Click & Drag: When zoomed in, simply click and drag with the left mouse button to freely navigate the canvas.
• Overview Minimap (M): Press M to toggle the navigation minimap in the bottom-right corner. When zoomed in, click or drag the highlighted viewport box on the minimap to jump across large multi-thousand-pixel canvases with pinpoint precision.

Inspection Gems & Background Cycling

• Resolution Label & Live Zoom Tooltip: The resolution label on the bottom control bar displays the image's original native dimensions (e.g. 3840×2160). Hovering your cursor over the label reveals a real-time tooltip showing the currently rendered dimensions and exact scaling percentage (e.g. 1280×720 (33.33%)), making it easy to check the live zoom ratio at a glance.
• 5-Mode Canvas Background Cycling (B):
  • Press B (or use the right-click menu) to instantly cycle between No background (inherits app theme), Transparent checkerboard, Pure Black, Pure Gray, and Pure White.
  • Solving Transparency Inspection: Essential for viewing light/dark transparent PNGs, monochrome logos, or white vector SVGs—switch to black to inspect white highlights, or switch to white to check dark contours.
• Orientation & Flipping: Press R / L to rotate 90° clockwise / counter-clockwise; press X / Y to flip horizontally / vertically.
• Massive Image Fast-Opening (150 MiB Threshold):
  • Opening giant images (scanned archives, gigapixel aerial photography, or massive TIFF files exceeding 150 MiB) often freezes ordinary viewers.
  • Seer uses a two-stage pipeline: it extracts high-resolution embedded preview data in milliseconds for an instant zero-freeze preview on Spacebar, while allowing on-demand full uncompressed bitmap loading without memory exhaustion.

Advanced Formats & Metadata

• Professional Adobe PSD Compatibility:
  • Full compatibility with native Adobe Photoshop .psd documents without launching Photoshop.
  • Comprehensive support for 8-bit, 16-bit, and 32-bit color depths.
  • Flawless color rendering across CMYK print colors, Duotone, Indexed color, and Multichannel modes.
• Camera RAW Lossless Negatives & EXIF:
  • Native direct decoding for professional camera RAW formats: Canon (.cr2, .cr3), Nikon (.nef), Sony (.arw), Fujifilm (.raf), Adobe (.dng), Olympus (.orf), Panasonic (.rw2), and more.
  • Prioritizes embedded full-resolution previews for sub-second opening; the Property Inspector (Ctrl + I) extracts camera bodies, lens optics, focal length, aperture, shutter speed, ISO, exposure bias, and embedded GPS coordinates.
• Smart Animation Detection:
  • Many .apng and .webp files contain only a single static frame. Seer inspects animation metadata to automatically choose the best viewing engine:
  • Single-Frame Static Files: Automatically routed to the static raster engine, enabling 1:1 pixel inspection, zooming, and EXIF extraction.
  • Animated Sequences (GIF / APNG / Animated WebP): Activates the playback engine with loop control, playback pause, and frame-stepping (, / .) for inspecting individual animation frames.
• Multi-Resolution Icon Containers (ICO / CUR / ICNS):
  • For Windows icons (.ico), cursors (.cur), or macOS icons (.icns) bundling multiple resolutions and bit-depths, the bottom control bar displays a selectable list of all bundled icon sizes (e.g., 16x16, 32x32, 48x48, 256x256).
  • Click Export Selected Image as PNG in the control bar to instantly export the active icon layer as a standalone transparent PNG file.
• Vector Graphics (SVG) & Source Inspection:
  • Renders vector drawings with infinite sharpness at any scale. The right-click menu provides a one-click shortcut to view the raw XML source structure directly in the text viewer.

PDF Document Viewer

Features a lightweight native rendering engine tailored for office documentation and technical whitepapers, with background streaming rendering and deep annotation support.

Reading Layouts & Tile Overview

• Two-Page Book Spread (P): Press P (or use the right-click menu) to toggle between continuous vertical scrolling and a realistic two-page book spread layout with binding gaps.
• Tile Overview Grid (Ctrl + G): Press Ctrl + G to enter the overview mode, rendering all document pages as an interactive thumbnail grid. Click any page thumbnail to jump directly to it.
• Rapid Navigation Shortcuts: Press [ / ] to flip to the previous / next page; press Home / End to jump straight to the first / last page. Press M to toggle the navigation minimap.
• Direct Sizing: Press W to fit page width, H to fit page height, or A to restore 1:1 original physical size.
• 3 Reading Color Themes (D): Press D to cycle between Default White, Dark Night Mode (high-contrast eye saver), and Warm Sepia (eye-care reading tone) without modifying document colors.
• Page Separator Styles (G): Press G to cycle between clean default gap, solid line, dashed line, and wavy separator lines.
• Orientation (R / L): Rotate document pages 90° clockwise (R) or counter-clockwise (L).

Default Zoom Modes & Sizing Rules

In addition to shortcuts (Ctrl + = / Ctrl + - or Ctrl + mouse wheel), Seer provides 4 configurable default opening zoom modes in the right-click menu and configuration:

• Four Default Zoom Modes:
  • Default / Actual Size: Opens pages at 1:1 original physical dimensions. Important history behavior: Only this default option recovers saved zoom levels from document history; other modes ignore history zoom upon opening.
  • Fit Width: Dynamically scales pages so the maximum width across all pages fits the viewer window. The initial zoom calculation references the window size base (default fit_w = 960, configurable in user.ini [PDF]).
  • Fit Height: Dynamically scales pages so the current page fits the viewer window height (in a two-page spread it uses the taller page of the facing pair). fit_h = 960 in user.ini [PDF] only provides the initial window height base.
  • Custom Zoom: Always opens documents at your preferred custom scaling ratio (e.g., 125%, 150%).
• Right-Click Zoom Menu & Custom Default Setting:
  • The right-click context menu displays the current live zoom percentage (e.g. Custom (135%)).
  • "Set Current Zoom as Custom Default": When you have adjusted a document to your ideal comfortable reading size, right-click and choose this option to instantly save that exact percentage as your global custom default.

Sidebar Navigation & Page Alignment

• Dynamic Inspection Sidebar (O): Press O to toggle the sidebar. To keep the interface clean, tabs appear dynamically based on document contents:
  • Page Thumbnails: Always available for every document, showing a continuous thumbnail strip with page numbers.
  • Document Outline / TOC: Appears only when the PDF contains embedded bookmarks/TOC data, displaying a multi-level collapsible tree for chapter jumping.
  • Annotations & Comments: Appears only when the PDF contains reader annotations, listing all highlights, strikethroughs, and notes across the document.
• Thumbnail Alignment (V): While reading in the main viewport, press V to automatically align and center the sidebar thumbnail list onto the currently visible page.
• Configurable Sidebar Docking: By default, the sidebar is docked on the right. You can configure it to dock on the left via user.ini [PDF] show_sidebar_left = true.

Interactive Hyperlinks, Search & Security

• Native Hyperlink Interaction: Fully supports clicking table-of-contents entries, internal page anchors, external web URLs (opens directly in your default browser), and mailto email links.
• Annotation Visibility (T): Press T to toggle the visibility of document highlight markings, underlines, and reader annotations.
• Full-Text Streaming Search (Ctrl + F):
  • Background asynchronous chunked search with an active loading ring indicator.
  • Supports case-sensitive matching (Aa), current match deep orange highlight, matching items yellow highlight, and F3 / Shift + F3 stepping across hyphenated line breaks.
• Password-Protected Documents: Encrypted PDF files automatically present a clean native password prompt to unlock and view contents safely.

Folder & Archive Viewer

Inspect folder structures and compressed archive contents instantly without disk decompression or temporary file clutter.

Three Distinct View Modes

• Hierarchical Tree View (Alt + T): Classical multi-level collapsible directory tree showing folders and files in a unified tree hierarchy with expand/collapse arrows.
• Multi-Column Navigation (Alt + C): macOS Finder-style drill-down columns, allowing deep filesystem navigation by clicking through subfolders without losing parent context.
• Gallery View (Alt + Y): Thumbnail grid layout optimized for photo, graphic, and asset directories, with keyboard arrow navigation and an integrated side preview pane.

Git Status Integration & In-Place Search

• Git Repository Status Badges:
  • When viewing folders inside a Git repository, Seer automatically detects repository status and displays color-coded badges next to file entries:
  • Modified (M): Tracked files with unstaged or staged modifications.
  • Added (A): Newly staged files.
  • Untracked (?): Newly created files not yet tracked by Git.
  • Renamed (R): Files that have been renamed.
  • Deleted (D): Tracked files that have been removed.
  • This feature can be toggled under Settings > Types > Folder (enabled by default).
• In-Place File Search (Ctrl + F):
  • Press Ctrl + F to search filenames in real time with case matching (Aa).
  • Matching names are highlighted and non-matching entries are dimmed instead of hidden, so the folder structure stays readable. Enter or F3 steps through the matches in all three views.
• Side Info View & Preview Pane (Alt + D):
  • Press Alt + D to toggle the right info pane to inspect file thumbnails, EXIF metadata, and file remarks directly without opening separate preview windows.

Archive Inspection & Fast Operations

• Instant Archive Inspection & Double Decompression:
  • Native direct reading for archives including .zip, .7z, .rar, .tar, .gz, .bz2, .xz, .zst, .iso, .cab, .chm, and .arj without extracting temporary files to disk.
  • Supports nested archives requiring secondary decompression.
• Background Folder Size Calculation: Opening a folder starts a size scan in a separate helper process, so the preview window stays responsive and the cumulative size of the folder appears in the Property Inspector once the scan finishes.
• Convenient Path Copying:
  • Right-click menu shortcuts allow one-click copying of absolute paths, relative paths, or the entire directory listing to your clipboard.

Web & Markdown Viewer

Modern offline rendering for .html, .mhtml, and .md documents.

Browser Engine & Security Considerations

Seer embeds the full Chrome (Chromium) browser engine, providing layout and execution capabilities identical to modern web browsers:

• Chrome (Chromium) Core: Full compatibility with HTML5, modern CSS3, JavaScript, Canvas, SVG, and hardware acceleration for offline single-page apps, reports, and .mhtml web archives.
• Local & Network Permissions:
  • To support rich local reports, offline documentation, and Markdown previews, web security boundaries are relaxed: local documents can load cross-directory local assets, fetch external CDN resources, and access the clipboard.
• Data Caching & Persistent Storage:
  • HTTP network cache is kept purely in memory (MemoryHttpCache), while persistent web storage (such as HTML5 localStorage, IndexedDB, and site data) is stored in %LocalAppData%\Corey\Seer\web.
• ⚠️ Security Warning:
  • Because previewed HTML documents are granted local file reading, network access, and script execution permissions, never preview untrusted, suspicious, or unverified .html files from unknown sources.

Floating FindBar & Table of Contents

• Floating FindBar Over WebEngine:
  • The FindBar floats above the page in its own window, so it stays crisp and fully transparent over the hardware-accelerated web viewport instead of being covered by it.
  • Press Ctrl + F to open in-page keyword search, supporting case-sensitive matching (Aa) and F3 / Shift + F3 jumping.
• Floating Table of Contents (T): Press T to toggle a dynamic floating TOC on the side that tracks reading scroll progress in real time.
• Content Zoom: Hold Ctrl and scroll the mouse wheel, or press Ctrl + = / Ctrl + - to zoom in or out.

Markdown Themes, Math & Diagrams

• 100% Offline & Self-Contained: All Markdown rendering assets—including theme stylesheets, KaTeX math fonts, and the Mermaid diagram engine—are bundled directly within Seer. Markdown previews work completely offline with zero dependencies on external CDNs or online CSS/JS.
• Theme Library: Curated built-in themes including default, github_light, github_dark, obsidian, studio, papyrus, amethyst, prism, evergreen, sahara, nordic, and more. Custom external CSS files can also be specified under Settings > Types > HTML.
• LaTeX Math (KaTeX): Native rendering for inline $math$ and display block $$math$$ formulas.
• Technical Diagrams (Mermaid): Native rendering for flowcharts, sequence diagrams, and Gantt charts.
• GitHub Alerts: Native styling for [!NOTE], [!TIP], [!WARNING], [!IMPORTANT], and [!CAUTION] blockquotes.
• Save as PDF: The bottom control bar includes a "Save as PDF" action, allowing one-click export of styled Markdown or web pages into vector PDF documents.

System Previewer & Thumbnail

For proprietary or specialized file formats not covered by Seer's built-in viewers and without dedicated Seer plugins installed, Seer leverages the Windows operating system ecosystem via a two-tier fallback mechanism.

Concepts & How It Works

To understand this module, it is important to clarify what these two capabilities represent and where their underlying data originates:

• System Previewer:
  • Corresponds directly to the content displayed in Windows File Explorer's built-in Preview Pane (toggled with Alt + P in Windows File Explorer).
  • It is an interactive preview component registered with the OS by third-party applications (e.g., scrollable document views, interactive sheet previews).
• System Thumbnail:
  • Extracts the system-generated or application-generated file icon/thumbnail and renders it enlarged and centered in the preview window. When an interactive preview handler is unavailable, the enlarged high-resolution thumbnail ensures the file is still immediately identifiable.
• Data Source: Provided by Installed Applications: Windows does not natively know how to preview every specialized proprietary file format. These capabilities are provided and registered into Windows by third-party software you install (for example, installing Adobe Photoshop provides .psd previews, Microsoft Office provides .docx / .xlsx / .pptx previews, and 3D/CAD suites provide engineering model previews).
• Seer's Role: Reading and Hosting the Existing Data:
  • Seer simply attempts to read and host this data from the operating system. Seer does not bundle proprietary decoders for these closed formats itself; instead, it bridges into the Windows shell using standard system preview and thumbnail interfaces.
  • If the relevant application is not installed on the computer, or if that software did not register shell preview components with Windows, Seer cannot fabricate a preview out of thin air.

Two-Tier Loading & Graceful Fallback

When encountering a non-built-in format, Seer follows a prioritized sequential fallback:

graph TD
    A["Proprietary / Non-Built-in File (Press Spacebar)"] --> B{"Is preview support available in Windows or installed apps?"}
    B -- "Available and loaded" --> C["Host System Previewer (Embedded native interactive viewport)"]
    B -- "Unavailable or failed to load" --> D{"Is Thumbnail Fallback enabled?"}
    D -- "Enabled and thumbnail exists" --> E["Extract Shell Thumbnail (Enlarged and centered)"]
    D -- "Disabled or no thumbnail found" --> F["Show unsupported file notice"]

1. First Priority: System Previewer: Searches for and activates the preview component provided by Windows or installed software, embedding the identical native interactive view that would appear in File Explorer's preview pane.
2. Second Priority: System Thumbnail: If no preview handler is registered or initialization fails, Seer fetches the highest-resolution shell thumbnail and scales it up smoothly to fit the window.

Keyboard Shortcut Reliability & Cloud Protection

• Keyboard Closure: When Seer itself has focus, Space and Esc close the preview as usual. When an embedded third-party previewer (such as a Microsoft Office or Adobe preview handler) takes keyboard focus, the keystroke no longer reaches Seer directly, so Seer falls back to its low-level keyboard hook. Space is handled by the hook out of the box; Esc forwarding is controlled by enable_esc_key in user.ini [General] and is off by default — enable it if you want Esc to dismiss the window while an external previewer holds focus.
• Cloud Files on Demand Protection: For online-only cloud files (such as OneDrive or cloud-synced placeholder files not yet downloaded locally), Seer automatically avoids activating preview handlers or metadata extraction, preventing unwanted background file downloads.

Configuration & Management

All settings for this module are managed under Settings > Types > System:

• Global Toggle: Enable or disable the fallback module entirely under Settings > Types > System.
• Toggle Thumbnail Fallback Independently: If you prefer interactive previewers only and wish to avoid enlarged static thumbnails, uncheck the option Use system thumbnails for files without a preview handler under Settings > Types > System.
• File Extension Exclusion List: Exclude specific problematic or slow third-party preview handlers by configuring exclude in user.ini [SystemViewer].

Known Limitations & Important Tips

1. File Locked While Preview Is Open

• Observed Behavior: While the preview window remains open, attempting to rename, move, overwrite, or delete the file in Windows File Explorer or another program will trigger the Windows message: "The action can't be completed because the file is open in another program".
• Resolution:
  • Simply close the Seer preview window (by pressing Space or Esc) or navigate to any other file in your file explorer. Seer immediately closes the third-party preview component and releases the file, allowing rename or deletion operations to proceed normally.
• Comparison with Thumbnails:
  • In contrast, when fallback Shell Thumbnails or Seer's native built-in viewers are active, files are read quickly and released immediately, without locking the file.

2. Data Caching & Manual Refresh

• Behavior after Software Changes: When you install or uninstall software (e.g., installing Photoshop, Office, or CAD tools), Windows updates its configuration, but Seer may continue reading its cached data and might not immediately recognize the new preview capabilities.
• How to Refresh:
  • Simply restart Seer, or toggle any viewer option in Seer Settings and click OK to trigger a full runtime reload.
  • How it works: A viewer runtime reload automatically clears the local system previewer cache, prompting Seer to rescan Windows and recognize newly installed preview components.

Settings & Preferences

Press Ctrl + , (or right-click the system tray icon and select Settings) to open the Seer configuration dialog. Here is a guided tour of the key options across the settings panels:

1. General Settings

• Language: Choose your preferred user interface language. Seer ships with full localized interfaces for over 15 languages.
• Appearance Theme: Switch between Light, Dark, and Auto (automatically matches your Windows system color mode).
• Run Seer When System Boots:
  • Desktop Version: Uses the standard Windows registry startup by default. You can also opt into Use Task Scheduler for Startup under Settings > System for higher reliability and elevated privileges.
  • Microsoft Store Version: Click the Open System Settings button to jump directly to Windows Settings -> Apps -> Startup to enable automatic startup.
• Run as Administrator: Relaunches Seer with elevated administrative privileges, allowing Seer to intercept keystrokes and preview files within applications running as Administrator (such as Total Commander, Directory Opus, or Everything run with admin rights).
• Check for Updates Automatically: Toggle whether Seer automatically checks for new software releases on startup.

2. File Types

Manage associations, view modes, and feature toggles for each format category under Settings > Types:

• Category Tabs: Switch between dedicated panels for Text, Image, Media, Folder, PDF, HTML, System, Unknown (the property-inspector viewer used when no other viewer claims the file), and Disabled.
• Master Toggles & Custom Extensions: Every category has an enable/disable switch. Extra extensions for a viewer are added through its extra_support key in user.ini (for example [Text] extra_support); the Disabled panel is the only one with a tag editor, and it holds the global exclusion list.
• Category-Specific Options:
  • Image: Configure default view style (Auto Fit, Fit Short Side, Prefer Full Size) and mouse wheel behavior (scroll vs zoom). Minimap visibility is not on this page — it is show_minimap in user.ini [Image].
  • Folder: Toggle Git repository status badges (M, A, ?, R, D).
  • HTML: Select the default Markdown theme and optionally specify a custom external CSS file.
  • System: Toggle thumbnail fallback for unsupported formats.
  • Disabled: Blacklist specific file extensions that Seer should never preview.

3. Advanced Settings

• Double-Click to Open with Default Program: When enabled, double-clicking anywhere inside the preview viewport instantly launches the file in its default registered application (same as pressing Ctrl + O).
• Load Cloud Files: Controls whether Seer automatically triggers on-demand background downloads when previewing unhydrated cloud placeholder files (e.g. OneDrive files-on-demand). Keeping this unchecked preserves your network bandwidth and disk space.
• Tracking File: Automatically follows your selection in File Explorer; navigating with arrow keys updates the preview window in real time without repeatedly pressing Space.
• Auto-Reload on External Modification: When enabled (disabled by default), modifying and saving a previewed file in an external program reloads the view in place (the text viewer restores its saved reading position). For folders, it monitors 1st-level directory changes.
• Preview Window Focus: Decides whether the preview window takes keyboard focus away from your file manager. This is the setting to look at when shortcuts seem to "not work" right after pressing Space:
  • Never take focus (default): The preview never steals focus from Explorer or your file manager, so typing and arrow keys keep working there. Pressing Space again closes the preview immediately, but viewer-level shortcuts (Z, M, Ctrl + F, ...) only respond after you click inside the window.
  • Every time a file is previewed: Each new preview activates the window, so viewer shortcuts work right away. The trade-off is that focus leaves the file manager after every Space.
  • Only when the window opens: Focus is taken once when the preview window appears, but switching files while it stays open does not grab focus again.
• Trigger on Software-Generated Key Events: Off by default. Seer's keyboard hook deliberately ignores keystrokes that Windows flags as injected/simulated, so a macro, a virtual keyboard or a remote-control session does not accidentally pop up previews while you work. Turn it on when Seer is driven by automation — AutoHotkey/AutoIt scripts, on-screen keyboards, accessibility tools, or remote desktop/KVM setups that replay keystrokes. The option covers both the trigger key and the Delete/Esc handling below.
• Window Size and Position Mode:
  • Auto Size & Position (default): Adapts the window dimensions dynamically based on each file's native aspect ratio and the viewer's optimal scale.
  • Keep Window Size & Position: Remembers the exact geometry and screen coordinates of the last closed preview window.
  • Center Window on Open: Always centers the preview window in the middle of your active monitor.
• Titlebar Button Action: Choose what happens when clicking the primary button in the titlebar:
  • Separate Window (default): Detaches the current preview into its own floating window. It still belongs to the running Seer instance, so quitting Seer closes it.
  • Pinned Window: Keeps the preview pinned on top without dismissing when focus is lost.
  • Standalone Window: Launches a completely isolated viewer process (SeerViewer.exe).
• Enable Delete Key: Lets Delete cooperate with Seer's file handles instead of fighting them. What actually happens depends on which window has focus:
  • Preview window focused: Seer closes the preview (and any detached window showing the same file), then moves the file to the Windows Recycle Bin. Nothing happens while the file is still loading, and pinned windows are left open — they are only closed by you.
  • File manager focused: Seer does not delete anything itself. It just hides the preview and releases the file handles, so the deletion you requested in Explorer, Total Commander or Directory Opus does not fail with "The action can't be completed because the file is open in another program".
  • Leave this off if you keep Seer open while reorganizing files and would rather no key press could ever remove a file.
• Hide System Tray Icon: Hides Seer from the Windows system tray for maximum minimalism. If hidden, Seer provides an 8-second safety window on startup where the icon remains visible, allowing you to access settings.
• Open user.ini: Click the user.ini button at the bottom to open user.ini in your default editor for manual fine-tuning (hover the button to see the full path; refer to Custom Configuration Guide for field references).

4. System

• Use Task Scheduler for Startup: Toggle between Windows Task Scheduler (recommended, immune to UAC privilege blocks) and the legacy registry startup method.
• Context Menu Integration: Adds the "Open with SeerViewer" action to Windows File Explorer's right-click context menu for all files and directories, launching the file directly into a standalone SeerViewer.exe process.
• Register in "Open With" Menu: Registers SeerViewer in the native Windows "Open With" application list for all supported file formats.
• Set as Default App: Opens the Windows Default apps page so you can point a file type at SeerViewer yourself. Seer cannot silently take over associations — Windows requires that confirmation.
• File Remarks Master Switch: Toggle Seer's personal file note system on or off globally.

5. Keyboard Shortcuts

• Trigger Keys: Customize the primary trigger key and modifier combination (e.g. Space, Alt + Space, Ctrl + Space, Shift + Space).
• Separate Window Trigger: Set an alternative modifier combination to launch the preview directly into a detached window.
• Action Rebinding: Rebind any global or viewer-specific shortcut (e.g., Rotate, Mute, Word Wrap, FindBar, Fullscreen) to match your personal muscle memory.

6. Backup, Import & Reset

The three buttons at the bottom of Advanced move a whole configuration between machines or back to factory state:

• Export: Writes a snapshot of the current settings to a .ini file you choose. The file is Seer's own export format (versioned, not intended for hand editing), so keep it as a backup rather than opening it in an editor. The snapshot covers the settings stored in config.ini (appearance, shortcuts, per-type options, plugin switches, ...). It does not include user.ini tweaks, and it deliberately skips activation data, recent lists (PDF / Media history, per-page zoom memory), window positions, and the multi-viewer assignment map.
• Import: Applies a previously exported snapshot and then restarts Seer immediately, because several settings only take effect on a fresh start. Values are copied as-is — including any absolute paths inside them (see below). Files that are not Seer exports, or that were written by a different export format version, are refused with an error.
• Reset to default: Clears config.ini back to defaults and restarts. Activation and license data are preserved, and hand-edited values in user.ini are not touched, so you keep your own advanced tweaks. The button first turns into a confirm/cancel pair — a second click is required.