Menu-less companion - minimal example

This notebook shows the shortest possible companion:

No menu: no menu_spec() / build() required
No hidden graphics helper: OpenGL drawing is explicit
Single responsibility: right click -> add a point

The whole class fits in about twenty lines.

What `AbstractUICompanion` does for you

API	Role
`self.proxy.register_action(...)`	Registers handlers on the viewer
`self.proxy.start_action(id, hint)`	Activates the action and shows the hint
`self.proxy.end_action()`	Deactivates the current action
`self.proxy.action_id(local)`	Returns a namespaced id (`namespace.local`)
`self.proxy._viewer.Refresh()`	Forces a redraw
`self.destroy()`	Unregisters all companion actions

1 - Start wx

[1]:

import sys
%gui wx

2 - Create the viewer

[ ]:

from wolfhece.PyDraw import WolfMapViewer

viewer = WolfMapViewer(None, title="Menu-less companion", w=1200, h=800)
viewer.Show()

INFO:root:Importing wolfhece modules
INFO:root:wolfhece modules imported
INFO:root:Plugin manager init: skipping auto-discovery because no global configuration is available yet.

False

3 - The companion class

The only requirement is to implement start() (required by AbstractUICompanion).

Everything else is optional.

[ ]:

from wolfhece.plugins.abc import AbstractUICompanion
from wolfhece._viewer_plugin_handlers import MouseContext
from OpenGL.GL import glBegin, glEnd, glVertex2f, glColor4f, glLineWidth, GL_LINES


class DotCompanion(AbstractUICompanion):
    """Collect right-clicks and draw them on the map.

    No menu, no boilerplate - the minimal companion.
    """

    def __init__(self):
        #: Collected points - readable from the notebook.
        self.points: list[tuple[float, float]] = []

    def start(self) -> None:
        """Register handlers and activate the action."""
        self.proxy.register_action('pick', rdown=self._rdown, paint=self._paint)
        self.proxy.start_action('pick', 'Right-click to add a point...')

    def _rdown(self, ctx: MouseContext) -> None:
        self.points.append((ctx.x_snap, ctx.y_snap))
        print(f'#{len(self.points):3d}  X={ctx.x_snap:.3f}  Y={ctx.y_snap:.3f}')
        self.proxy._viewer.Refresh()

    def _paint(self) -> None:
        half = (self.proxy._viewer.xmax - self.proxy._viewer.xmin) * 0.01
        glLineWidth(2.0)
        glColor4f(0.0, 1.0, 0.0, 1.0)
        glBegin(GL_LINES)
        for (x, y) in self.points:
            glVertex2f(x - half, y); glVertex2f(x + half, y)
            glVertex2f(x, y - half); glVertex2f(x, y + half)
        glEnd()

4 - Instantiate and start

No build() to call - start directly.

[ ]:

comp = DotCompanion()
viewer.attach_companion(comp)
comp.start()

print(comp)
print('Action active - right-click on the map to add points.')

INFO:root:ACTION : Clic droit pour ajouter un point…

<DotCompanion ns='dotcompanion' menu=not built actions=[dotcompanion.pick]>
Action active — clic droit sur la carte pour ajouter des points.

5 - Inspect collected points

[5]:

print(f"{len(comp.points)} point(s) :")
for i, (x, y) in enumerate(comp.points, 1):
    print(f"  {i:3d}.  X={x:.3f}   Y={y:.3f}")

0 point(s) :

6 - Stop and clean up

[ ]:

viewer.detach_companion(comp)

print("Companion destroyed.")
print(comp)

INFO:root:ACTION : End of action

Compagnon détruit.
<DotCompanion ns='dotcompanion' menu=not built actions=[—]>

The Kernel crashed while executing code in the current cell or a previous cell.

Please review the code in the cell(s) to identify a possible cause of the failure.

Click <a href='https://aka.ms/vscodeJupyterKernelCrash'>here</a> for more info.

View Jupyter <a href='command:jupyter.viewOutput'>log</a> for further details.

Summary - full class

from wolfhece.plugins.abc import AbstractUICompanion
from wolfhece._viewer_plugin_handlers import MouseContext
from OpenGL.GL import glBegin, glEnd, glVertex2f, glColor4f, glLineWidth, GL_LINES

class DotCompanion(AbstractUICompanion):
    def __init__(self):_()
        self.points: list[tuple[float, float]] = []

    def start(self) -> None:
        self.proxy.register_action('pick', rdown=self._rdown, paint=self._paint)
        self.proxy.start_action('pick', 'Right-click to add a point...')

    def _rdown(self, ctx: MouseContext) -> None:
        self.points.append((ctx.x_snap, ctx.y_snap))
        self.proxy._viewer.Refresh()

    def _paint(self) -> None:
        half = (self.proxy._viewer.xmax - self.proxy._viewer.xmin) * 0.01
        glLineWidth(2.0)
        glColor4f(0.0, 1.0, 0.0, 1.0)
        glBegin(GL_LINES)
        for (x, y) in self.points:
            glVertex2f(x - half, y); glVertex2f(x + half, y)
            glVertex2f(x, y - half); glVertex2f(x, y + half)
        glEnd()