.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "auto_examples/Interactive/plot_key_bindings.py"
.. LINE NUMBERS ARE GIVEN BELOW.

.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        :ref:`Go to the end <sphx_glr_download_auto_examples_Interactive_plot_key_bindings.py>`
        to download the full example code.

.. rst-class:: sphx-glr-example-title

.. _sphx_glr_auto_examples_Interactive_plot_key_bindings.py:


Key-Press Widget Placement
==========================

Demonstrates the ``key_down`` event handler API: press a key while the plot
is focused to add an overlay widget centred on the current cursor position,
or press **Backspace / Delete** to remove the last widget you clicked.

**Key bindings**

+-------------------------------+---------------------------+
| Key                           | Action                    |
+===============================+===========================+
| ``q``                         | Add a rectangle           |
+-------------------------------+---------------------------+
| ``w``                         | Add a circle              |
+-------------------------------+---------------------------+
| ``e``                         | Add an annulus            |
+-------------------------------+---------------------------+
| ``Backspace`` (macOS ⌫)       | Remove last-clicked       |
| ``Delete`` (Windows / Linux)  |                           |
+-------------------------------+---------------------------+

**Built-in 2-D shortcuts** (not overridden in this example):

+-------+---------------------------+
| Key   | Action                    |
+=======+===========================+
| ``r`` | Reset zoom / pan          |
+-------+---------------------------+
| ``c`` | Toggle colorbar           |
+-------+---------------------------+
| ``l`` | Toggle log scale          |
+-------+---------------------------+
| ``s`` | Toggle symlog scale       |
+-------+---------------------------+

The cursor coordinates are available as ``event.xdata`` and ``event.ydata``
in image-pixel space (column, row), so widgets are centred exactly where
the cursor was when the key was pressed.

.. note::
   Move the mouse over the image first so the plot panel receives focus,
   then press a key.  On macOS the backspace key (⌫) is used for deletion;
   on Windows / Linux use the **Delete** key.

.. GENERATED FROM PYTHON SOURCE LINES 47-129




.. raw:: html

    <div style="display:block;text-align:center;line-height:0;margin:12px 0;"><div id="sphx_glr_plot_key_bindings_001" class="awi-fig-wrap" data-awi-fig="sphx_glr_plot_key_bindings_001" style="display:inline-block;overflow:hidden;position:relative;width:536px;height:536px;"><iframe src="../../_static/viewer_widgets/sphx_glr_plot_key_bindings_001.html" data-awi-fig="sphx_glr_plot_key_bindings_001" frameborder="0" scrolling="no" style="width:536px;height:536px;border:none;overflow:hidden;display:block;transform-origin:top left;transform:scale(1);position:absolute;top:0;left:0;"></iframe><div class="awi-badge" data-awi-badge="sphx_glr_plot_key_bindings_001"><button class="awi-badge-icon awi-activate-btn" data-awi-fig="sphx_glr_plot_key_bindings_001" title="Make interactive (boots Pyodide — may take ~10 s)">&#x26A1;</button></div></div><script>(function(){var wrap=document.getElementById('sphx_glr_plot_key_bindings_001'),ifr=wrap.querySelector('iframe'),nw=536,nh=536;function r(){var avail=wrap.parentElement?wrap.parentElement.offsetWidth:0;if(!avail)return;var s=Math.min(1,avail/nw);wrap.style.width=Math.round(nw*s)+'px';wrap.style.height=Math.round(nh*s)+'px';ifr.style.transform='scale('+s+')';}requestAnimationFrame(r);window.addEventListener('resize',r);})()</script></div>



.. raw:: html

    <script type="text/x-python" data-fig-id="sphx_glr_plot_key_bindings_001" data-fig-index="0" data-src-file="plot_key_bindings" data-src="&quot;\&quot;\&quot;\&quot;\nKey-Press Widget Placement\n==========================\n\nDemonstrates the ``key_down`` event handler API: press a key while the plot\nis focused to add an overlay widget centred on the current cursor position,\nor press **Backspace / Delete** to remove the last widget you clicked.\n\n**Key bindings**\n\n+-------------------------------+---------------------------+\n| Key                           | Action                    |\n+===============================+===========================+\n| ``q``                         | Add a rectangle           |\n+-------------------------------+---------------------------+\n| ``w``                         | Add a circle              |\n+-------------------------------+---------------------------+\n| ``e``                         | Add an annulus            |\n+-------------------------------+---------------------------+\n| ``Backspace`` (macOS \u232b)       | Remove last-clicked       |\n| ``Delete`` (Windows / Linux)  |                           |\n+-------------------------------+---------------------------+\n\n**Built-in 2-D shortcuts** (not overridden in this example):\n\n+-------+---------------------------+\n| Key   | Action                    |\n+=======+===========================+\n| ``r`` | Reset zoom / pan          |\n+-------+---------------------------+\n| ``c`` | Toggle colorbar           |\n+-------+---------------------------+\n| ``l`` | Toggle log scale          |\n+-------+---------------------------+\n| ``s`` | Toggle symlog scale       |\n+-------+---------------------------+\n\nThe cursor coordinates are available as ``event.xdata`` and ``event.ydata``\nin image-pixel space (column, row), so widgets are centred exactly where\nthe cursor was when the key was pressed.\n\n.. note::\n   Move the mouse over the image first so the plot panel receives focus,\n   then press a key.  On macOS the backspace key (\u232b) is used for deletion;\n   on Windows / Linux use the **Delete** key.\n\&quot;\&quot;\&quot;\n\nimport numpy as np\nimport anyplotlib as apl\n\n# \u2500\u2500 Synthetic test image \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\nrng = np.random.default_rng(0)\nN = 256\nx = np.linspace(0, 4 * np.pi, N)\nXX, YY = np.meshgrid(x, x)\ndata = np.sin(XX) * np.cos(YY) + 0.15 * rng.standard_normal((N, N))\n\n# \u2500\u2500 Figure \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\nfig, ax = apl.subplots(figsize=(520, 520))\nplot = ax.imshow(data)\n\n# \u2500\u2500 Key handlers \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\n\n@plot.add_event_handler(\&quot;key_down\&quot;)\ndef add_rectangle(event):\n    \&quot;\&quot;\&quot;Press &#x27;q&#x27; \u2014 add a rectangle centred on the cursor.\&quot;\&quot;\&quot;\n    if event.key != &#x27;q&#x27;:\n        return\n    cx, cy = event.xdata, event.ydata\n    half_w, half_h = N * 0.08, N * 0.08\n    plot.add_widget(\n        \&quot;rectangle\&quot;,\n        x=cx - half_w, y=cy - half_h,\n        w=half_w * 2,  h=half_h * 2,\n        color=\&quot;#ffd54f\&quot;,\n    )\n\n\n@plot.add_event_handler(\&quot;key_down\&quot;)\ndef add_circle(event):\n    \&quot;\&quot;\&quot;Press &#x27;w&#x27; \u2014 add a circle centred on the cursor.\&quot;\&quot;\&quot;\n    if event.key != &#x27;w&#x27;:\n        return\n    plot.add_widget(\n        \&quot;circle\&quot;,\n        cx=event.xdata, cy=event.ydata,\n        r=N * 0.07,\n        color=\&quot;#80cbc4\&quot;,\n    )\n\n\n@plot.add_event_handler(\&quot;key_down\&quot;)\ndef add_annulus(event):\n    \&quot;\&quot;\&quot;Press &#x27;e&#x27; \u2014 add an annulus centred on the cursor.\&quot;\&quot;\&quot;\n    if event.key != &#x27;e&#x27;:\n        return\n    plot.add_widget(\n        \&quot;annular\&quot;,\n        cx=event.xdata, cy=event.ydata,\n        r_outer=N * 0.12,\n        r_inner=N * 0.06,\n        color=\&quot;#ce93d8\&quot;,\n    )\n\n\n# macOS sends &#x27;Backspace&#x27; for the \u232b key; Windows/Linux send &#x27;Delete&#x27;.\n# Register both so the example works cross-platform.\n@plot.add_event_handler(\&quot;key_down\&quot;)\ndef delete_last(event):\n    \&quot;\&quot;\&quot;Press Backspace/Delete \u2014 remove the last widget that was clicked.\&quot;\&quot;\&quot;\n    if event.key not in (&#x27;Backspace&#x27;, &#x27;Delete&#x27;):\n        return\n    wid = event.last_widget_id\n    if wid and wid in {w.id for w in plot.list_widgets()}:\n        plot.remove_widget(wid)\n\n\n# \u2500\u2500 Catch-all handler (optional) \u2014 log every registered key press \u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\n\n@plot.add_event_handler(\&quot;key_down\&quot;)\ndef log_key(event):\n    xdata = event.xdata\n    ydata = event.ydata\n    pos = f\&quot;({xdata:.1f}, {ydata:.1f})\&quot; if xdata is not None else \&quot;n/a\&quot;\n    print(f\&quot;[key_down] key={event.key!r}  img={pos}\&quot;\n          f\&quot;  last_widget={event.last_widget_id!r}\&quot;)\n\nfig  # Interactive\n&quot;"></script>






.. code-block:: Python


    import numpy as np
    import anyplotlib as apl

    # ── Synthetic test image ──────────────────────────────────────────────────────
    rng = np.random.default_rng(0)
    N = 256
    x = np.linspace(0, 4 * np.pi, N)
    XX, YY = np.meshgrid(x, x)
    data = np.sin(XX) * np.cos(YY) + 0.15 * rng.standard_normal((N, N))

    # ── Figure ────────────────────────────────────────────────────────────────────
    fig, ax = apl.subplots(figsize=(520, 520))
    plot = ax.imshow(data)

    # ── Key handlers ─────────────────────────────────────────────────────────────

    @plot.add_event_handler("key_down")
    def add_rectangle(event):
        """Press 'q' — add a rectangle centred on the cursor."""
        if event.key != 'q':
            return
        cx, cy = event.xdata, event.ydata
        half_w, half_h = N * 0.08, N * 0.08
        plot.add_widget(
            "rectangle",
            x=cx - half_w, y=cy - half_h,
            w=half_w * 2,  h=half_h * 2,
            color="#ffd54f",
        )


    @plot.add_event_handler("key_down")
    def add_circle(event):
        """Press 'w' — add a circle centred on the cursor."""
        if event.key != 'w':
            return
        plot.add_widget(
            "circle",
            cx=event.xdata, cy=event.ydata,
            r=N * 0.07,
            color="#80cbc4",
        )


    @plot.add_event_handler("key_down")
    def add_annulus(event):
        """Press 'e' — add an annulus centred on the cursor."""
        if event.key != 'e':
            return
        plot.add_widget(
            "annular",
            cx=event.xdata, cy=event.ydata,
            r_outer=N * 0.12,
            r_inner=N * 0.06,
            color="#ce93d8",
        )


    # macOS sends 'Backspace' for the ⌫ key; Windows/Linux send 'Delete'.
    # Register both so the example works cross-platform.
    @plot.add_event_handler("key_down")
    def delete_last(event):
        """Press Backspace/Delete — remove the last widget that was clicked."""
        if event.key not in ('Backspace', 'Delete'):
            return
        wid = event.last_widget_id
        if wid and wid in {w.id for w in plot.list_widgets()}:
            plot.remove_widget(wid)


    # ── Catch-all handler (optional) — log every registered key press ─────────────

    @plot.add_event_handler("key_down")
    def log_key(event):
        xdata = event.xdata
        ydata = event.ydata
        pos = f"({xdata:.1f}, {ydata:.1f})" if xdata is not None else "n/a"
        print(f"[key_down] key={event.key!r}  img={pos}"
              f"  last_widget={event.last_widget_id!r}")

    fig  # Interactive


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** (0 minutes 0.748 seconds)


.. _sphx_glr_download_auto_examples_Interactive_plot_key_bindings.py:

.. only:: html

  .. container:: sphx-glr-footer sphx-glr-footer-example

    .. container:: sphx-glr-download sphx-glr-download-jupyter

      :download:`Download Jupyter notebook: plot_key_bindings.ipynb <plot_key_bindings.ipynb>`

    .. container:: sphx-glr-download sphx-glr-download-python

      :download:`Download Python source code: plot_key_bindings.py <plot_key_bindings.py>`

    .. container:: sphx-glr-download sphx-glr-download-zip

      :download:`Download zipped: plot_key_bindings.zip <plot_key_bindings.zip>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_