Add 3D plot example

Author: davidbrochart

environment.yml

@@ -5,3 +5,5 @@ dependencies:
   - branca
   - ipycanvas=0.7.0
   - ipyevents
+  - numpy
+  - matplotlib

examples/plot3d.ipynb

@@ -0,0 +1,165 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import matplotlib.pyplot as plt\n",
+    "from mpl_toolkits.mplot3d import Axes3D, proj3d\n",
+    "import numpy as np\n",
+    "from ipycanvas import Canvas, hold_canvas\n",
+    "from ipywidgets import FloatSlider, Output\n",
+    "from math import pi"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "out = Output(layout={'border': '1px solid black'})"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class Plot3d(Canvas):\n",
+    "    def __init__(self):\n",
+    "        super(Plot3d, self).__init__(size=(500, 500))\n",
+    "        \n",
+    "        self.width = 500\n",
+    "        self.height = 500\n",
+    "        \n",
+    "        plt.ioff()\n",
+    "        fig = plt.figure()\n",
+    "        self.ax = Axes3D(fig)\n",
+    "\n",
+    "        self.dragging = False\n",
+    "        self.n = 200\n",
+    "        self.x = np.random.rand(self.n)\n",
+    "        self.y = np.random.rand(self.n)\n",
+    "        self.z = np.random.rand(self.n)\n",
+    "        \n",
+    "        self.zoom = 4\n",
+    "        self.dx = 0\n",
+    "        self.dy = 0\n",
+    "        self.ax.view_init(elev=self.dx, azim=self.dy)\n",
+    "        self.x2, self.y2, _ = proj3d.proj_transform(self.x, self.y, self.z, self.ax.get_proj())\n",
+    "        self.draw()\n",
+    "            \n",
+    "        self.on_mouse_down(self.mouse_down_handler)\n",
+    "        self.on_mouse_move(self.mouse_move_handler)\n",
+    "        self.on_mouse_up(self.mouse_up_handler)\n",
+    "        self.on_mouse_out(self.mouse_out_handler)\n",
+    "\n",
+    "    #@out.capture()\n",
+    "    def draw(self):\n",
+    "        x = self.x2 * self.width * self.zoom + self.width / 2\n",
+    "        y = self.y2 * self.width * self.zoom + self.height / 2\n",
+    "        with hold_canvas(self):\n",
+    "            self.clear()\n",
+    "            self.save()\n",
+    "            for i in range(self.n):\n",
+    "                self.fill_arc(x[i], y[i], self.zoom, 0, 2*pi)\n",
+    "                self.stroke_arc(x[i], y[i], self.zoom, 0, 2*pi)\n",
+    "            self.restore()\n",
+    "\n",
+    "    def mouse_down_handler(self, pixel_x, pixel_y):\n",
+    "        self.dragging = True\n",
+    "        self.x_mouse = pixel_x\n",
+    "        self.y_mouse = pixel_y\n",
+    "\n",
+    "    def mouse_move_handler(self, pixel_x, pixel_y):\n",
+    "        if self.dragging:\n",
+    "            self.dx_new = self.dx + pixel_x - self.x_mouse\n",
+    "            self.dy_new = self.dy + pixel_y - self.y_mouse\n",
+    "            self.ax.view_init(elev=self.dy_new, azim=self.dx_new)\n",
+    "            self.x2, self.y2, _ = proj3d.proj_transform(self.x, self.y, self.z, self.ax.get_proj())\n",
+    "            self.draw()\n",
+    "    \n",
+    "    def mouse_up_handler(self, pixel_x, pixel_y):\n",
+    "        if self.dragging:\n",
+    "            self.dragging = False\n",
+    "            self.dx = self.dx_new\n",
+    "            self.dy = self.dy_new\n",
+    "    \n",
+    "    def mouse_out_handler(self, pixel_x, pixel_y):\n",
+    "        if self.dragging:\n",
+    "            self.dragging = False\n",
+    "            self.dx = self.dx_new\n",
+    "            self.dy = self.dy_new"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {
+    "scrolled": false
+   },
+   "outputs": [],
+   "source": [
+    "p = Plot3d()\n",
+    "p"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "slider = FloatSlider(description='Zoom:', value=p.zoom, min=1, max=10)\n",
+    "\n",
+    "def on_slider_change(change):\n",
+    "    p.zoom = slider.value\n",
+    "    p.draw()\n",
+    "\n",
+    "slider.observe(on_slider_change, 'value')\n",
+    "slider"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Drag the figure with the mouse to rotate, use the slider to zoom"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "out"
+   ]
+  }
+ ],
+ "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": "3.8.5"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}