GUI Overview

BLine-GUI is a visual path editor for designing autonomous routines. It writes JSON files in your robot project's deploy/autos/ directory, which BLine-Lib loads at runtime. Paths can be iterated visually, simulated for rough timing and trajectory preview, and versioned in Git like any other source file.

The current release is BLine-GUI v0.5.0, which added macOS binaries, a new constraint editing experience, and a revamped selection/editor workflow.

Launching

Install method	How to start
Prebuilt binary (Windows / macOS / Linux)	Start Menu, Applications folder, or double-click the executable
Source install (pip/pipx)	Run bline from a terminal

See Installation if you haven't installed it yet. To create a desktop shortcut when using the legacy source install, run bline --create-shortcut.

Interface layout

Area	Purpose
Menu bar (top)	Project management, path operations, edit actions, settings. See Menu Bar.
Canvas (center)	The field with your path drawn on top. Drag elements, zoom/pan, scrub simulation. See Canvas.
Sidebar (right)	Element list, per-element properties, path constraints. See Sidebar.
Transport controls (bottom-left of canvas)	Play/pause simulation + timeline scrubber. See Simulation.

Project structure

BLine-GUI operates on a project directory — any directory containing a config.json and a paths/ subfolder. The idiomatic layout is to point it at your robot project's src/main/deploy/autos:

src/main/deploy/autos/
├── config.json         # Global constraints, robot footprint, protrusion settings
└── paths/
    ├── scoreFirst.json
    ├── toIntake.json
    └── ...

Every file in paths/ is a single path. BLine-Lib loads them by name (without the .json extension):

Path scoreFirst = new Path("scoreFirst");

Open your FRC project directly

Open the autos/ directory inside your robot project (not a separate folder). The JSONs that the GUI writes are the same JSONs BLine-Lib reads on the robot. No copy step.

Element colors on the canvas

Color	Element
🟠 Orange rectangle + rotation handle	Waypoint (position + rotation)
🔵 Blue circle	TranslationTarget (position only)
🟢 Green dashed rectangle + rotation handle	RotationTarget (rotation only)
🟡 Yellow line marker	EventTrigger (action at a t_ratio)
🟣 Magenta dashed circle around translation elements	Handoff radius
🟢 Green overlay	Ranged constraint domain (shown when slider focused)
🟧 Dashed orange/green offsets around waypoints/rotation targets	Protrusions (if enabled). See Protrusions.

Typical workflow

1. Open your project (Project → Open Project…), pointed at src/main/deploy/autos.
2. Configure the robot (Settings → Edit Config…): robot size, kinematic defaults, optional protrusions.
3. Create or open a path from the Path menu.
4. Add path elements — click Add element in the sidebar or use the canvas.
5. Position and rotate elements by dragging them on the canvas.
6. Add ranged constraints in the sidebar's Path Constraints section for per-section velocity/acceleration limits.
7. Preview using the transport controls at the bottom-left of the canvas.
8. Save — the GUI writes the JSON on save, so your path is immediately available to robot code.

Keyboard shortcuts

Shortcut	Context	Action
Ctrl/Cmd + Z	Global	Undo
Ctrl/Cmd + Y / Ctrl/Cmd + Shift + Z	Global	Redo
Ctrl/Cmd + S	Global	Save current path
Space	Canvas focus	Play / pause simulation
Delete / Backspace	Element selected	Remove the selected element
← / →	Constraint segment focused	Navigate between segments on a ranged constraint
Delete / Backspace	Constraint segment focused	Delete the selected constraint segment
S	Constraint segment focused	Split the selected constraint segment at its midpoint

The segment-bar shortcuts were added in v0.5.0 alongside the new constraint editor. The arrow/Delete behavior also works inside the pop-out constraint editor.

What was recently added

Highlights since the initial BLine-GUI release:

• v0.5.0 — macOS support + constraint editor overhaul. First macOS .dmg (Apple Silicon). Introduces the SegmentBar widget, pop-out constraint editor, sharper sidebar typography, and segment-bar keyboard shortcuts.
• v0.4.0 — Selection clarity. Animated selection indicator on the canvas. Better sync between canvas/sidebar selection. Clicking empty field space clears selection. Drag/reorder/undo preserve selection more reliably.
• v0.3.0 — Protrusions. New per-element protrusion rendering (left/right/front/back/none) with event-trigger-driven show/hide. Reorganized config dialog. See Protrusions.

For the full release history, see the Chief Delphi thread or the BLine Web releases page.

Learn more

• Menu Bar — project, path, edit, settings menus.
• Canvas — zoom/pan, dragging, rotation handles, selection.
• Sidebar — element properties, constraint editor, segment bar.
• Simulation — previewing robot motion and reading the timeline.
• Protrusions — visualizing bumpers, intakes, and appendages.