Set Component Color.md

Set Component Color

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Overview

The Set Component Color command writes Fusion's per-component Component.componentColor (the value read by View → Color Cycling Toggle) on every selected component. Two ways to pick a color:

• A rainbow swatch palette — 34 colors sourced live from Fusion's own ColorCycleTable (in RiverRubicon.xml, located dynamically inside the running install) and sorted by hue across four button rows.
• A Custom color… button that launches the OS-native color picker — NSColorPanel via osascript on macOS, tkinter.colorchooser running in a fresh Python subprocess on Windows.

The command is selection-driven: it operates on whichever Components or Occurrences are currently selected when invoked. It is exposed only from the right-click context menu; the toolbar registration is left in the source but commented out.

Capabilities

Capability	Details
Browser context-menu integration	Right-click any component node (including the root) → menu item appears immediately after Fusion's built-in Cycle Component Color
Selection-driven, multi-target	Iterates every Component or Occurrence in ui.activeSelections; dedupes by component id
componentColor only	Writes Component.componentColor exclusively; never touches Appearance
Rainbow swatch palette	34 colors loaded from RiverRubicon.xml, HSV-sorted across four button rows; selection coordinates globally
OS-native custom picker	macOS: AppleScript choose color via /usr/bin/osascript (NSColorPanel). Windows: subprocess tkinter.colorchooser (Win32 ChooseColor)
No HTML / no PIL	Avoids in-process Tk (Cocoa run-loop conflict on macOS) and avoids PIL (not bundled with Fusion's Python)

Prerequisites

• A Fusion design must be open.
• One or more Components or Occurrences must be selected before invoking the command. The command shows an explanatory dialog and exits if the selection is empty.

Notes

• Path discovery: RiverRubicon.xml is found by walking up from adsk.__file__ until a known relative sub-path resolves. Tracks the current webdeploy hash automatically across Fusion updates.
• XML repair: a handful of shipped Fusion versions have malformed RGB values (missing decimal points, e.g. "5412" instead of ".5412"). The loader repairs the obvious cases and silently drops anything it cannot interpret.
• Rainbow sort key: HSV-based with neutrals (saturation < 0.18) pushed to the end so the rainbow band stays clean.
• Session-only state: last-used color is held in a module-level variable; not persisted across Fusion restarts.
• Visibility: componentColor only renders when View → Color Cycling Toggle is enabled. With cycling off, the assignment is still stored and will appear next time cycling is on.
• macOS Sequoia gotcha: spawning Fusion's bundled python3.14 shim from inside Fusion fails with posix_spawn: Undefined error: 0 (Gatekeeper blocks the re-exec into Python.app). osascript is system-signed at a fixed path and is always allowed — that's why the macOS picker uses it.
• Modal subprocess: the picker process blocks Fusion's main thread until the user picks or cancels. Same UX as any modal dialog.

Access

Right-click a Component or Occurrence in the browser (or any component-mode pick on the canvas) → Set Component Color appears in the context menu directly after Cycle Component Color.

Architecture

Command ID

PTND-changeActiveColor

Module layout

commands/changeactivecolor/
  __init__.py
  entry.py                          # command lifecycle, menu hook, dialog, picker dispatch, apply
  fusion_install.py                 # locate RiverRubicon.xml relative to running install
  colors.py                         # parse ColorCycleTable, hex helpers, rainbow sort
  swatches.py                       # pure-Python PNG generator (solid + 4-quadrant)
  _color_picker_subprocess.py       # standalone tkinter.colorchooser script (Windows path)

Execution flow

1. start() registers the CommandDefinition and subscribes a handler to ui.markingMenuDisplaying. The toolbar panel registration block is left in source but commented out.
2. Marking-menu hook (_on_marking_menu_displaying) runs on every right-click. It walks args.selectedEntities, calls _entity_to_component() to test for a Component or Occurrence, and — if any qualifies — calls args.linearMarkingMenu.controls.addCommand(cmd_def, "CycleComponentColorCmd", isBefore=False) to insert directly after Fusion's built-in cycle command. Failures are caught so the rest of the menu always renders.
3. command_created validates that app.activeProduct is a Design, calls _collect_selected_components() to gather unique target Components from ui.activeSelections, and aborts with an explanatory dialog if the selection is empty. On success it caches the rainbow-sorted swatches (one-time per session), builds the dialog (target description + four ButtonRowCommandInputs + custom-color button + colored preview), and subscribes inputChanged, execute, destroy handlers.
4. command_input_changed keeps single-selection coordinated across all four swatch rows (a click in one row clears isSelected on every item in the other three) and refreshes the preview chip. The Custom-color button trips _enter_custom_color_flow.
5. _enter_custom_color_flow invokes _pick_color_native(initial_hex). On confirm, it iterates the captured targets and writes componentColor, then sets _skip_normal_execute = True and calls cmd.doExecute(True) to dismiss the swatch dialog. On cancel it returns; the swatch dialog stays open.
6. _pick_color_native dispatches by sys.platform:
   • macOS → _pick_color_macos: spawns osascript running choose color default color {r16, g16, b16}. Components are AppleScript's 0–65535 range; we scale to 0–255 on return.
   • Other → _pick_color_subprocess_python: locates Fusion's bundled Python via sys.exec_prefix + /bin/python3.X, spawns _color_picker_subprocess.py with the initial hex argument. The script runs tkinter.colorchooser.askcolor in its own clean run loop and prints the chosen hex.
7. command_execute checks _skip_normal_execute (set by the custom-color flow) and returns early if it's set. Otherwise it iterates _pending_targets and calls _set_component_color(comp, rgb) on each, where rgb comes from the selected swatch. Per-target success/failure is logged; total failure surfaces a deferred warning, partial failure surfaces a softer "succeeded on N, failed on X" message.
8. _set_component_color writes target.componentColor = adsk.core.Color.create(r, g, b, 255) and returns True/False. Wrapped in hasattr so older Fusion API versions degrade gracefully.
9. command_destroy clears local_handlers, _pending_targets, _active_command, and surfaces any deferred error via messageBox.

User flow (sequence)

sequenceDiagram
    autonumber
    actor User
    participant Browser as Fusion Browser
    participant Menu as ui.markingMenuDisplaying
    participant Cmd as Set Component Color
    participant Picker as OS-native picker
    participant Comp as Component.componentColor

    User->>Browser: Right-click Component / Occurrence
    Browser->>Menu: markingMenuDisplaying fires
    Menu->>Menu: _entity_to_component() filter
    Menu-->>Browser: addCommand(cmd_def, after CycleComponentColorCmd)
    Browser-->>User: Linear menu shows "Set Component Color"

    User->>Cmd: Click menu item
    Cmd->>Cmd: command_created<br/>_collect_selected_components()
    Cmd-->>User: Swatch dialog (4 rainbow rows + Custom color…)

    alt Pick a swatch
        User->>Cmd: Click swatch + Apply
        Cmd->>Cmd: command_execute<br/>iterate _pending_targets
        Cmd->>Comp: target.componentColor = Color.create(r,g,b,255)
        Comp-->>Cmd: write OK
        Cmd-->>User: Dialog closes
    else Custom color
        User->>Cmd: Click "Custom color…"
        Cmd->>Cmd: _enter_custom_color_flow()
        Cmd->>Picker: subprocess.run([osascript|python, ...])
        Picker-->>User: NSColorPanel / ChooseColor dialog (modal)
        alt User picks
            User->>Picker: Pick + OK
            Picker-->>Cmd: stdout = '#RRGGBB' / 'r16,g16,b16'
            Cmd->>Comp: write componentColor on every target
            Cmd->>Cmd: _skip_normal_execute = True<br/>cmd.doExecute(True)
            Cmd-->>User: Both dialogs gone
        else User cancels
            User->>Picker: Cancel
            Picker-->>Cmd: stdout = ''
            Cmd-->>User: Swatch dialog remains open
        end
    end

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Component diagram (C4)

C4Component
    title Set Component Color – Component Architecture

    Person(user, "Designer", "Fusion user working on a 3D design")

    System_Boundary(addin, "PowerTools Add-In") {
        Component(menuHook, "Marking-menu hook", "ui.markingMenuDisplaying", "Inserts command after Cycle Component Color when Component/Occurrence selected")
        Component(cmd, "Set Component Color", "changeactivecolor/entry.py", "Validates selection, builds dialog, dispatches custom-color picker, writes componentColor")
        Component(install, "Install discovery", "fusion_install.py", "Walks up from adsk.__file__ to locate RiverRubicon.xml")
        Component(colorsLoader, "Palette loader", "colors.py", "Parses ColorCycleTable, repairs RGB typos, HSV rainbow sort")
        Component(swatches, "Swatch icon gen", "swatches.py", "Pure-Python PNG: solid swatches + 4-quadrant Custom-color icon")
        Component(pickerScript, "tkinter picker", "_color_picker_subprocess.py", "Standalone Tk colorchooser — used as the Windows native-picker subprocess")
    }

    System_Ext(fusion, "Autodesk Fusion", "Fusion application + API surface")
    System_Ext(xmlSrc, "RiverRubicon.xml", "Fusion install resource — ColorCycleTable")
    System_Ext(osPicker, "OS-native color picker", "macOS NSColorPanel via osascript / Win32 ChooseColor via tkinter")
    System_Ext(comp, "Component.componentColor", "Per-component color value read by Color Cycling Toggle")

    Rel(user, menuHook, "Right-clicks a Component / Occurrence")
    Rel(menuHook, fusion, "Reads selectedEntities, mutates linearMarkingMenu")
    Rel(menuHook, cmd, "Invokes via shared CommandDefinition")
    Rel(user, cmd, "Picks a swatch or clicks Custom color…")
    Rel(cmd, install, "Resolve XML path on first invocation")
    Rel(install, xmlSrc, "Reads")
    Rel(cmd, colorsLoader, "load_color_cycle + sort_rainbow")
    Rel(cmd, swatches, "ensure_all + ensure_quadrant_icon")
    Rel(cmd, osPicker, "subprocess.run (osascript or pickerScript)", "modal")
    Rel(cmd, pickerScript, "Spawns on Windows", "subprocess")
    Rel(pickerScript, osPicker, "tkinter.colorchooser.askcolor")
    Rel(cmd, comp, "Writes componentColor on each selected target")
    Rel(comp, fusion, "Read by View → Color Cycling Toggle")

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