nevaforget
4026f6dafa
Security: prevent double unlock() when PAM and fingerprint succeed simultaneously (ext-session-lock protocol error). Fix PAM callback returning PAM_AUTH_ERR instead of PAM_BUF_ERR on calloc OOM. Performance: replace CPU-side Gaussian blur (image crate) with GPU blur via GskBlurNode + GskRenderer::render_texture(). Eliminates 500ms-2s main-thread blocking on cold cache for 4K wallpapers. Remove image and dirs dependencies (~15 transitive crates). Make fingerprint stop() fire-and-forget async to avoid 6s UI block after successful auth.
25 lines
2.0 KiB
Markdown
25 lines
2.0 KiB
Markdown
# Decisions
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Architectural and design decisions for Moonlock, in reverse chronological order.
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## 2026-03-28 – GPU blur via GskBlurNode replaces CPU blur
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- **Who**: Nyx, Dom
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- **Why**: CPU-side Gaussian blur (`image` crate) blocked the GTK main thread for 500ms–2s on 4K wallpapers at cold cache. Disk cache mitigated repeat starts but added ~100 lines of complexity.
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- **Tradeoffs**: GPU blur quality is slightly different (box-blur approximation vs true Gaussian), acceptable for wallpaper. Removes `image` and `dirs` dependencies entirely. No disk cache needed.
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- **How**: `Snapshot::push_blur()` + `GskRenderer::render_texture()` on `connect_realize`. Blur happens once on the GPU when the widget gets its renderer, producing a concrete `gdk::Texture`. Zero startup latency.
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## 2026-03-28 – Optional background blur via `image` crate (superseded)
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- **Who**: Nyx, Dom
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- **Why**: Consistent with moonset/moongreet — blurred wallpaper as lockscreen background is a common UX pattern
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- **Tradeoffs**: Adds `image` crate dependency (~15 transitive crates); CPU-side Gaussian blur at load time adds startup latency proportional to image size and sigma. Acceptable because blur runs once and the texture is shared across monitors.
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- **How**: `load_background_texture(bg_path, blur_radius)` loads texture, optionally applies `imageops::blur()`, returns `gdk::Texture`. Config option `background_blur: Option<f32>` in TOML.
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## 2026-03-28 – Shared wallpaper texture pattern (aligned with moonset/moongreet)
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- **Who**: Nyx, Dom
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- **Why**: Previously loaded wallpaper per-window via `Picture::for_filename()`. Multi-monitor setups decoded the JPEG redundantly. Blur feature requires texture pixel access anyway.
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- **Tradeoffs**: Slightly more code in main.rs (texture loaded before window creation), but avoids redundant decoding and enables the blur feature.
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- **How**: `load_background_texture()` in lockscreen.rs decodes once, `create_background_picture()` wraps shared `gdk::Texture` in `gtk::Picture`. Same pattern as moonset/moongreet.
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