STYLUS_STUDIO

Stylus Studio & Hardware Pen Integration

Stylus Studio is designed specifically for mathematical derivation, paper annotation, and freeform research sketching on modern Android tablets.

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🖊️ Hardware Stylus Support (Xiaomi Smart Pen & S-Pen)

ResearchLoom features native barrel button support optimized for the Xiaomi Smart Pen 2 / Focus Pen (Xiaomi Pad 7 / Pad 6 series) and Samsung S-Pen:

Button Actions

• Primary Barrel Button (Button 1 / PageUp 92):
  • Single click: Cycles active tools (Pen $\to$ Highlighter $\to$ Stroke Eraser $\to$ Pixel Eraser $\to$ Pen).
  • Hold down: Temporarily activates eraser while held; returns to previous writing tool upon release.
• Secondary Barrel Button (Button 2 / PageDown 93):
  • Instant undo / secondary tool trigger.

OEM Gesture Neutralization

On Xiaomi HyperOS / MIUI tablets:

• Long-pressing the pen button normally triggers the native Xiaomi Notes app.
• Pressing the second button triggers the partial screenshot editor.
• ResearchLoom's MainActivity.java intercepts these hardware keycodes when the app is in the foreground, consuming the event so your drawing flow is never interrupted. Standard system 3-finger swipe screenshots continue working normally.

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🧹 Dual Eraser Modes

1. Stroke Eraser (Vector):
   • Uses line-segment distance computation (distToSegment).
   • Any stroke intersected by the eraser path is deleted in its entirety with a single swipe.
2. Pixel Eraser (Raster):
   • Uses HTML5 canvas destination-out blending.
   • Cleans up exact touched pixels without deleting the surrounding stroke, ideal for fine mathematical corrections.

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📐 Geometric Shape Auto-Snap

Toggle the Snap button on the top toolbar:

• Sketch a rough circle, ellipse, rectangle, triangle, or straight line.
• The engine computes the isoperimetric quotient and corner angles.
• Upon pen lift, the rough sketch is automatically replaced with a clean geometric shape.