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LeanMark 0.7.0

Read-only Markdown viewer with offline Mermaid rendering

filecart Windows Updated Nov 06, 2026
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About LeanMark

LeanMark is a focused, read-only Markdown viewer. It renders GitHub-flavored Markdown, local images and Mermaid diagrams entirely offline using the system WebView2 runtime rather than a bundled Chromium. Raw HTML is disabled, a strict Content Security Policy is enforced, and remote content is blocked.

License: MIT
Release info Update on Nov 06, 2026
Release notes LeanMark v0.4.2

LeanMark 0.4.2 removes a white flash when LeanMark opens on Windows with the
dark theme.

Release assets

| Platform | Artifact |
| --- | --- |
| Windows x64 | LeanMark-v0.4.2-windows-x64.zip |
| Ubuntu 24.04 / Debian-compatible x86-64 | LeanMark-v0.4.2-linux-x86_64.deb |
| macOS Intel and Apple silicon | LeanMark-v0.4.2-macos-universal-preview.zip |

Every artifact has an adjacent .sha256 sidecar in this release.

Fix
• No white flash at launch. With the dark theme, a new LeanMark window was
white for about a quarter second before the reader appeared. Two things
caused it. The window skipped painting its own background, so it kept
Windows' default white surface until WebView2 drew; it now fills that area
with the reader background. And WebView2 itself renders white before an
app's background color takes effect, which Microsoft documents along with
the fix: LeanMark now gives WebView2 the theme background through the
WEBVIEW2_DEFAULT_BACKGROUND_COLOR environment variable before it starts,
and clears the variable once the reader exists so programs LeanMark opens do
not inherit it.

How it was measured

Each build was launched five times with the dark theme and the diagram
showcase document, and the window's client area was screen-captured for 2.5
seconds after each launch. A frame counted as a flash when more than a fifth
of it was near white. 0.4.1 flashed in all five launches, with the whole
window white for 0.2 to 0.5 seconds. 0.4.2 flashed in none; the most white any
frame showed was 1.3 percent, which is the document's own light text. The
Windows verification suite, including the window launch and real-page checks,
passes on Windows 11.

Installing

On Windows, run the installer from the extracted ZIP:

powershell
powershell.exe -NoProfile -ExecutionPolicy Bypass -File .\installer\install.ps1 -OpenDefaultAppsSettings

For a portable copy, clear the downloaded-file mark once from the extracted
folder with Get-ChildItem -Recurse |…
Related tags markdown viewer mermaid offline reader
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