Resizable, movable minimap with quality scaling#106
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sjvrensburg merged 4 commits intomainfrom Apr 14, 2026
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The minimap was a fixed 180x240 docked bottom-right. Now: - Drag the top-edge grip to move it anywhere on the window - Drag the inner-corner handle (opposite the screen edge it's docked against) to resize. Aspect-locked to the page so the thumbnail never distorts. - Position and size persist via AppConfig (MinimapWidth, Height, MarginRight, MarginBottom). - Click/drag inside as before to navigate the primary view. Tier-1 quality: when the displayed thumbnail size exceeds the cached thumbnail bitmap by >10%, render from the primary's high-DPI SKImage (`CachedImage`) instead of the small thumbnail. No extra rendering work — reuses what the primary already has. Mitchell sampling at rest, Linear during drag. Implementation: - TabViewModel.MinimapImage wraps the thumbnail SKBitmap as SKImage (cached, disposed with the tab), so the canvas can use sampling- aware DrawImage uniformly across both source paths. - Drag-distance threshold (4px) preserves "click to navigate" UX — small movements still navigate; only intentional drags move/resize. - Resize handle position auto-flips to whichever corner points into the screen (handles non-default minimap docking). - Hover/drag chrome (move stripe, resize hash) only renders when needed; otherwise the minimap looks the same as before. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Three issues: 1. Drag/resize deltas were computed from e.GetPosition(this), relative to the moving control. As the control's origin moved during drag, subsequent pointer events saw a shifted relative position, feeding back into the next delta calculation — visible as resistance and jitter. Switched to window-coords for delta math; local coords still used for hit-zone detection and navigation. 2. Aspect-locked resize switched between width-driven and height-driven each frame based on which axis had the larger proportional drag. Mouse wobble flipped the dominant axis, jumping the size. Replaced with diagonal projection: project the drag vector onto the corner's aspect-ratio direction, derive both width and height from a single scalar. Continuous and aspect-preserving by construction. 3. Large minimap stuttered during rail scrolling because each redraw resampled the multi-megapixel CachedImage from scratch on the UI thread. Upload the source as a mipmapped GPU texture once (cached on the control, disposed on source change or detach) so subsequent draws are constant-cost regardless of downscale ratio. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
- Separate ThreadStatic SKPaint for resize-handle hash lines instead of mutating the shared grip-dot paint's Style back and forth (fragile with shared state). - Name PrimarySourceThreshold (1.1) and MaxViewportFraction (0.8). Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Summary
The minimap was a fixed 180×240 thumbnail in the bottom-right corner. This PR makes it a freely draggable, resizable, quality-scaling context view:
AppConfigacross sessionsQuality (tier 1)
When the displayed thumbnail exceeds the cached thumbnail's resolution by more than 10%, the minimap transparently switches its source to the primary view's high-DPI
CachedImage. The source is uploaded to the GPU as a mipmapped texture, cached per control, so enlarged minimaps stay crisp without re-sampling a multi-megapixel bitmap on every frame.Smoothness fixes landed during implementation
s_hashLinededicated ThreadStatic paint instead of mutating a shared paint's Style mid-render.Bumps to 3.10.0.0 (minor — user-visible enhancement, no API changes).
Test plan
dotnet build RailReader2.slnx -c ReleasecleanCtrl+Mtoggle still works, click-to-navigate unchanged🤖 Generated with Claude Code