JFLAP 7.1 Better UI (Unofficial)

This repo builds a more modern, themeable UI for the original JFLAP 7.1 by wrapping it with a small launcher (Swing + FlatLaf) and applying a few runtime/bytecode tweaks for dark-mode readability.

The primary distributables in this folder are:

• JFLAP7.1.5.1.2-better-ui.jar (slim build)
• JFLAP7.1.5.1.2-better-ui-fat.jar (optional, build with -Fat)

Run

java -jar JFLAP7.1.5.1.2-better-ui.jar

Launcher options:

java -jar JFLAP7.1.5.1.2-better-ui.jar --help

• --theme=light|dark|intellij|darcula
• --uiScale=<number> (example: --uiScale=1.25)
• Short flags: --light, --dark, --intellij, --darcula
• --selftest (diagnose crashes / UI creation)
• Also supported: -Djflap.theme=<theme> or env var JFLAP_THEME=<theme>

What Changed

• Modern look & feel via FlatLaf (defaults to Darcula).
• View > Theme menu: IntelliJ / Darcula / Light / Dark (saved).
• View > Customize Theme...: RGB overrides for:
  • Accent color
  • App background
  • Canvas background (optional checkbox)
  • Selection box color (optional checkbox)
  • Node color (optional checkbox)
  • Arrow color (optional checkbox)
  • Final-state ring color (optional checkbox)
  • Start triangle color (optional checkbox)
  • Tip: you can also paste/type a hex color like #1e1e1e
• Ctrl+K: Command Palette for quick actions.
• Ctrl+C / Ctrl+V: canvas copy/paste for selected states/transitions (marquee selection supported, deterministic rename on paste).
• Delete / Backspace: delete selected states/transitions.
• Ctrl+Z / Ctrl+Y (or Ctrl+Shift+Z): undo/redo on the canvas.
• Ctrl+Mouse Wheel or Ctrl+Plus / Ctrl+Minus: zoom the canvas (auto-zoom is disabled when you manually zoom).
• CapsLock+R: Fast Run shortcut with an optional rerun prompt for another input.
• File > Export PNG... / File > Export SVG...: export the current automaton using the canvas background color, centered with a tight border.
• Removes the legacy menu-bar close button artifact (extra "X"); use the normal window close button or File > Close.
• Fixes a close-confirmation bug where clicking "Cancel" would still close the editor window.
• File dialogs: uses the native OS Open/Save dialog (java.awt.FileDialog) when possible (falls back to Swing JFileChooser).
• Canvas dark-mode fixes:
  • Transition arrows/labels stay visible on dark canvases.
  • Delete tool cursor is forced to a visible crosshair.
• Toolbar icons are recolored at runtime to match the current theme.
• Pumping Lemma readability fixes:
  • HTML panes stay readable on dark themes (no need to toggle the theme).
  • The "Explain" text area is taller so it doesn't clip as easily at higher UI scale.
• Help pages: ships minimal DOCS/ stubs so Help doesn't error in the slim build.

Command Palette

Open it with Ctrl+K (or Cmd+K on macOS) or via View > Command Palette....

• Type to search actions from the current window's menu bar (shows the full path like File > Open...).
• Use Up/Down arrows to select, Enter to run, Esc to close.

Screenshots & Demos

Theme customization:

Export example:

Copy/Paste + Undo/Redo demo:

Theme/color override demo:

Save-as-PNG demo:

Build

Requirements:

• A JDK on PATH (javac, jar)
• Internet access on first run (downloads FlatLaf + ASM to deps/)

Place the original JFLAP jar in the repo root (for example: JFLAP7.1.jar) or pass an explicit path via -InputJar.

Slim build:

.\build.ps1 -InputJar .\JFLAP7.1.jar -OutputJar JFLAP7.1.5.1.2-better-ui.jar

Fat build (keeps full reference jar contents):

.\build.ps1 -InputJar .\JFLAP7.1.jar -OutputJar JFLAP7.1.5.1.2-better-ui-fat.jar -Fat

Notes:

• First run downloads FlatLaf + ASM + Batik + xml-apis + xml-apis-ext into deps/ (Batik/xml-apis/xml-apis-ext are for SVG export).
• build.ps1 delegates to JFLAP7.1.5.1.2-better-ui.ps1 and repackages the input jar plus launcher sources.

Changelog

2026-02-15 (v7.1.5.1.2)

• Added shortcut for Fast Run and a dialog asking whether to run another input.
• Fixed the SVG export bug (missing SVG DOM runtime class).

2026-02-15 (v7.1.5.1)

• Fixed hex color paste/edit crashes in the theme customization dialog.
• Added node + arrow color overrides in the theme customization dialog.
• Export: tightened image borders and centered automata consistently for PNG/SVG output.
• Added overrides for final-state outer ring color and start triangle color.

2026-02-14 (v7.1.5.1)

• Undo/redo now guarded while transition-edit tables are open to prevent crashes.
• Transition edit tables cancel safely if the underlying states are no longer valid (prevents addTransition NPE).
• Fast Run shortcut (CapsLock+R) with a rerun prompt for another input.
• Theme: add a selection box color override.
• Export: add PNG/SVG export that respects the canvas background color.

2026-02-13 (v7.1.5)

• Canvas: added zoom controls (Ctrl+wheel, Ctrl+Plus, Ctrl+Minus).
• Canvas: delete selected items with Delete / Backspace.
• Canvas: undo/redo shortcuts (Ctrl+Z / Ctrl+Y / Ctrl+Shift+Z).
• Paste: clears selection after paste so new states are immediately editable.

2026-02-11

• Pumping Lemma: fixed dark-mode text + enlarged the "Explain" area.
• Help: added minimal DOCS/ stubs to avoid missing-doc popups in slim builds.
• Build: slim jar by default; -Fat keeps the full reference contents.
• Canvas: added copy/paste on editor canvases (Ctrl+C/Ctrl+V).

License / Redistribution Notes

Per the JFLAP 7.1 license, distributing modified copies requires (at minimum):

• Include the JFLAP license text.
• Do not charge a fee for any product that includes any part of JFLAP.
• Provide clear contact info for the modifications.
• If the maintainer asks, provide the modified source code without fee.

This build includes:

• JFLAP license text inside the jar as LICENSE
• MODIFICATIONS.txt (contact: egasudjali2@gmail.com)
• Source code for the modifications inside the jar under launcher-src/ and tools-src/
• FlatLaf license inside the jar as META-INF/LICENSE (Apache License 2.0)
• Convenience copies of both licenses in licenses/

Disclaimer: This is not an official JFLAP release and is not endorsed by the original author/maintainer.