{
  "cells": [
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "%gui qt"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\n# Picking Markers\n\nDemonstrates how to identify (pick) markers. Hover markers to change their\nsymbol and color.\n\nControls:\n* p  - Toggle picking view - shows the colors encoding marker ID\n* r  - Reset marker symbols and colors\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "import random\nimport time\nimport numpy as np\nfrom scipy.constants import golden as GOLDEN\n\nfrom vispy import app, scene\nfrom vispy.scene.visuals import Markers\nfrom vispy.visuals.filters import MarkerPickingFilter\n\ncanvas = scene.SceneCanvas(keys='interactive', bgcolor='black')\nview = canvas.central_widget.add_view(camera=\"panzoom\")\nview.camera.rect = (-1, -1, 2, 2)\n\n# floret pattern\nn = 10_000\nradius = np.linspace(0, 0.9, n)**0.6  # prevent extreme density at center\ntheta = np.arange(n) * GOLDEN\npos = np.column_stack([radius * np.cos(theta), radius * np.sin(theta)])\n\nCOLORS = [\n    (1, 0, 0, 1),  # red\n    (1, 0.5, 0, 1),  # orange\n    (1, 1, 0, 1),  # yellow\n    (0, 1, 0, 1),  # green\n    (0, 0, 1, 1),  # blue\n    (0.29, 0, 0.51, 1),  # indigo\n    (0.93, 0.51, 0.93, 1),  # violet\n]\n\ncolors = np.zeros((n, 4), dtype=np.float32)\ncolors[:, 0] = 1  # red\ncolors[:, -1] = 1  # alpha\n_colors = colors.copy()\n\nsymbols = list(Markers._symbol_shader_values.keys())\nsymbols_ring = dict(zip(symbols, symbols[1:]))\nsymbols_ring[symbols[-1]] = symbols[0]\n\nEDGE_COLOR = \"white\"\nMARKER_SIZE = 0.0125\nEDGE_WDITH = MARKER_SIZE / 10\n\nmarkers = Markers(\n    pos=pos,\n    edge_color=EDGE_COLOR,\n    face_color=colors,\n    size=MARKER_SIZE,\n    edge_width=EDGE_WDITH,\n    scaling=\"scene\",\n)\nmarkers.update_gl_state(depth_test=True)\nview.add(markers)\n\n# Use filters to affect the rendering of the mesh.\npicking_filter = MarkerPickingFilter()\nmarkers.attach(picking_filter)\n\n\n@view.events.connect\ndef on_viewbox_change(event):\n    # workaround for vispy/#2501\n    markers.update_gl_state(blend=not picking_filter.enabled)\n\n\nthrottle = time.monotonic()\n\n\n@canvas.events.mouse_move.connect\ndef on_mouse_move(event):\n    global throttle\n    # throttle mouse events to 50ms\n    if time.monotonic() - throttle < 0.05:\n        return\n    throttle = time.monotonic()\n\n    # adjust the event position for hidpi screens\n    render_size = tuple(d * canvas.pixel_scale for d in canvas.size)\n    x_pos = event.pos[0] * canvas.pixel_scale\n    y_pos = render_size[1] - (event.pos[1] * canvas.pixel_scale)\n\n    # render a small patch around the mouse cursor\n    restore_state = not picking_filter.enabled\n    picking_filter.enabled = True\n    markers.update_gl_state(blend=False)\n    picking_render = canvas.render(\n        crop=(x_pos - 2, y_pos - 2, 5, 5),\n        bgcolor=(0, 0, 0, 0),\n        alpha=True,\n    )\n    if restore_state:\n        picking_filter.enabled = False\n    markers.update_gl_state(blend=not picking_filter.enabled)\n\n    # unpack the face index from the color in the center pixel\n    marker_idx = (picking_render.view(np.uint32) - 1)[2, 2, 0]\n\n    if marker_idx >= 0 and marker_idx < len(pos):\n        new_symbols = list(markers.symbol)\n        new_symbol = symbols_ring[new_symbols[marker_idx]]\n        new_symbols[marker_idx] = new_symbol\n\n        colors[marker_idx] = random.choice(COLORS)\n        markers.set_data(\n            pos=pos,\n            edge_color=EDGE_COLOR,\n            face_color=colors,\n            size=MARKER_SIZE,\n            edge_width=EDGE_WDITH,\n            symbol=new_symbols,\n        )\n\n\n@canvas.events.key_press.connect\ndef on_key_press(event):\n    global colors\n    if event.key == 'p':\n        # toggle face picking view\n        picking_filter.enabled = not picking_filter.enabled\n        markers.update_gl_state(blend=not picking_filter.enabled)\n        markers.update()\n    if event.key == 'r':\n        # reset marker symbols\n        colors = _colors.copy()\n        markers.set_data(\n            pos=pos,\n            edge_color=EDGE_COLOR,\n            face_color=colors,\n            size=MARKER_SIZE,\n            edge_width=EDGE_WDITH,\n        )\n\n\ncanvas.show()\n\n\nif __name__ == \"__main__\":\n    print(__doc__)\n    app.run()"
      ]
    }
  ],
  "metadata": {
    "kernelspec": {
      "display_name": "Python 3",
      "language": "python",
      "name": "python3"
    },
    "language_info": {
      "codemirror_mode": {
        "name": "ipython",
        "version": 3
      },
      "file_extension": ".py",
      "mimetype": "text/x-python",
      "name": "python",
      "nbconvert_exporter": "python",
      "pygments_lexer": "ipython3",
      "version": "3.9.19"
    }
  },
  "nbformat": 4,
  "nbformat_minor": 0
}