{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 1. Image Functions"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Table of Contents\n",
    "* [1. Image Functions](#1.-Image-Functions)\n",
    "\t* [1.1 Pixel-based Drawing](#1.1-Pixel-based-Drawing)\n",
    "\t* [1.2 Image Flipping](#1.2-Image-Flipping)\n",
    "\t\t* [1.2.1 Horizontal Mirror](#1.2.1-Horizontal-Mirror)\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 1.1 Pixel-based Drawing"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "First, let's draw an image that we create:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "application/javascript": [
       "\n",
       "        var component = document.getElementById(\"sketch_1\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"state_1\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"controls_div_1\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "            // FIXME: Stop all previously running versions (?)\n",
       "            var processingInstance = Processing.getInstanceById(\"canvas_1\");\n",
       "            if (processingInstance != undefined && processingInstance.isRunning())\n",
       "                processingInstance.noLoop();\n",
       "        });\n",
       "\n",
       "\n",
       "        var output_area = this;\n",
       "        // find my cell element\n",
       "        var cell_element = output_area.element.parents('.cell');\n",
       "        // which cell is it?\n",
       "        var cell_idx = Jupyter.notebook.get_cell_elements().index(cell_element);\n",
       "        // get the cell object\n",
       "        var cell = Jupyter.notebook.get_cell(cell_idx);\n",
       "\n",
       "        function jyp_print(cell, newline) {\n",
       "            return function(message) {\n",
       "                cell.get_callbacks().iopub.output({header: {\"msg_type\": \"stream\"},\n",
       "                                                   content: {text: message + newline,\n",
       "                                                             name: \"stdout\"}});\n",
       "            }\n",
       "        }\n",
       "        window.jyp_println = jyp_print(cell, \"\\n\");\n",
       "        window.jyp_print = jyp_print(cell, \"\");\n",
       "\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "           Processing.logger.println = jyp_print(cell, \"\\n\");\n",
       "           Processing.logger.print = jyp_print(cell, \"\");\n",
       "        });\n",
       "\n",
       "\n",
       "        "
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "text/html": [
       "\n",
       "<div id=\"canvas_div_1\">\n",
       "  <b>Sketch #1:</b><br/>\n",
       "  <canvas id=\"canvas_1\"></canvas><br/>\n",
       "</div>\n",
       "<div id=\"controls_div_1\">\n",
       "  <button id=\"run_button_1\" onclick=\"startSketch('1');\">\n",
       "    <i class=\"fa fa-play-circle-o\" style=\"size: 2em;\"></i>\n",
       "        Run\n",
       "  </button>\n",
       "  <button id=\"pause_button_1\" onclick=\"pauseSketch('1');\">\n",
       "    <i class=\"fa fa-pause\" style=\"size: 2em;\"></i>\n",
       "        Pause\n",
       "  </button>\n",
       "  <button id=\"setup_button_1\" onclick=\"setupSketch('1');\">\n",
       "    setup()\n",
       "  </button>\n",
       "  <button id=\"draw_button_1\" onclick=\"drawSketch('1');\">\n",
       "    draw()\n",
       "  </button>\n",
       "</div>\n",
       "<b>Sketch #1 state:</b> <span id=\"state_1\">Loading...</span><br/>\n",
       "<script>\n",
       "\n",
       "function change_button(button, disable) {\n",
       "    button.disabled = disable;\n",
       "    if (disable) {\n",
       "        button.style.color = \"grey\";\n",
       "    } else {\n",
       "        button.style.color = \"black\";\n",
       "    }\n",
       "}\n",
       "\n",
       "function startSketch(id) {\n",
       "    switchSketchState(id, true);\n",
       "}\n",
       "\n",
       "function pauseSketch(id) {\n",
       "    switchSketchState(id, false);\n",
       "}\n",
       "\n",
       "function drawSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Drawing...\";\n",
       "            try {\n",
       "                processingInstance.redraw();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Drawing... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No drawing() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function setupSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.setup != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Setting up...\";\n",
       "            try {\n",
       "                processingInstance.setup();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Setting up... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No setup() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function switchSketchState(id, on) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (on) {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Running...\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"green\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id),  true);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), true);\n",
       "        processingInstance.loop();  // call Processing loop() function\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Paused.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "        processingInstance.noLoop(); // stop animation, call noLoop()\n",
       "    }\n",
       "}\n",
       "\n",
       "require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function () {\n",
       "    var processingCode = 'PImage img;\\n\\nvoid setup() {\\n    size(500, 500);\\n    img = new PImage(200, 300, RGB);\\n}\\n\\nvoid draw() {\\n    background(128);\\n    image(img, 0, 0);\\n    noLoop();\\n}\\n';\n",
       "    var cc;\n",
       "    var processingInstance;\n",
       "    var has_error = false;\n",
       "\n",
       "    try {\n",
       "        cc = Processing.compile(processingCode);\n",
       "    } catch (e) {\n",
       "        console.log(e);\n",
       "        cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "        document.getElementById(\"state_1\").innerHTML = e.toString();\n",
       "        document.getElementById(\"state_1\").style.color = \"red\";\n",
       "        has_error = true;\n",
       "    }\n",
       "    if (cc != undefined) {\n",
       "        try {\n",
       "            processingInstance = new Processing(\"canvas_1\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "        } catch (e) {\n",
       "            console.log(e);\n",
       "            cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "            document.getElementById(\"state_1\").innerHTML = e.toString();\n",
       "            document.getElementById(\"state_1\").style.color = \"red\";\n",
       "            processingInstance = new Processing(\"canvas_1\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "            has_error = true;\n",
       "        }\n",
       "    }\n",
       "    if (processingInstance != undefined) {\n",
       "        setTimeout(function () {\n",
       "            // Canvas:\n",
       "            if (processingInstance.externals.context === undefined) {\n",
       "                document.getElementById(\"canvas_div_1\").style.display = \"none\";\n",
       "            }\n",
       "        }, 100);\n",
       "        // Controls:\n",
       "        if (!(processingInstance.isRunning() && processingInstance.draw != undefined)) {\n",
       "            document.getElementById(\"controls_div_1\").style.display = \"none\";\n",
       "        }\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_1\").innerHTML = \"Running...\";\n",
       "                document.getElementById(\"state_1\").style.color = \"green\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_1\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_1\"), false);\n",
       "            change_button(document.getElementById(\"setup_button_1\"),  true);\n",
       "            change_button(document.getElementById(\"draw_button_1\"), true);\n",
       "        } else {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_1\").innerHTML = \"Done.\";\n",
       "                document.getElementById(\"state_1\").style.color = \"blue\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_1\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_1\"), true);\n",
       "            change_button(document.getElementById(\"setup_button_1\"),  processingInstance.setup == undefined);\n",
       "            change_button(document.getElementById(\"draw_button_1\"), true);\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"canvas_div_1\").style.display = \"none\";\n",
       "        document.getElementById(\"controls_div_1\").style.display = \"none\";\n",
       "        if (!has_error) {\n",
       "            document.getElementById(\"state_1\").innerHTML = \"Error.\";\n",
       "            document.getElementById(\"state_1\").style.color = \"red\";\n",
       "        }\n",
       "        change_button(document.getElementById(\"run_button_1\"), true);\n",
       "        change_button(document.getElementById(\"pause_button_1\"), true);\n",
       "        change_button(document.getElementById(\"setup_button_1\"),  true);\n",
       "        change_button(document.getElementById(\"draw_button_1\"), true);\n",
       "    }\n",
       "});\n",
       "\n",
       "</script>\n"
      ],
      "text/plain": [
       "<IPython.core.display.HTML object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "PImage img;\n",
    "\n",
    "void setup() {\n",
    "    size(500, 500);\n",
    "    img = new PImage(200, 300, RGB);\n",
    "}\n",
    "\n",
    "void draw() {\n",
    "    background(128);\n",
    "    image(img, 0, 0);\n",
    "    noLoop();\n",
    "}\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "We know that we can create shapes using the built-in Processing functions like rect(). But what are they doing at the deepest level? Could we do it ourselves?"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "application/javascript": [
       "\n",
       "        var component = document.getElementById(\"sketch_2\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"state_2\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"controls_div_2\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "            // FIXME: Stop all previously running versions (?)\n",
       "            var processingInstance = Processing.getInstanceById(\"canvas_2\");\n",
       "            if (processingInstance != undefined && processingInstance.isRunning())\n",
       "                processingInstance.noLoop();\n",
       "        });\n",
       "\n",
       "\n",
       "        var output_area = this;\n",
       "        // find my cell element\n",
       "        var cell_element = output_area.element.parents('.cell');\n",
       "        // which cell is it?\n",
       "        var cell_idx = Jupyter.notebook.get_cell_elements().index(cell_element);\n",
       "        // get the cell object\n",
       "        var cell = Jupyter.notebook.get_cell(cell_idx);\n",
       "\n",
       "        function jyp_print(cell, newline) {\n",
       "            return function(message) {\n",
       "                cell.get_callbacks().iopub.output({header: {\"msg_type\": \"stream\"},\n",
       "                                                   content: {text: message + newline,\n",
       "                                                             name: \"stdout\"}});\n",
       "            }\n",
       "        }\n",
       "        window.jyp_println = jyp_print(cell, \"\\n\");\n",
       "        window.jyp_print = jyp_print(cell, \"\");\n",
       "\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "           Processing.logger.println = jyp_print(cell, \"\\n\");\n",
       "           Processing.logger.print = jyp_print(cell, \"\");\n",
       "        });\n",
       "\n",
       "\n",
       "        "
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "text/html": [
       "\n",
       "<div id=\"canvas_div_2\">\n",
       "  <b>Sketch #2:</b><br/>\n",
       "  <canvas id=\"canvas_2\"></canvas><br/>\n",
       "</div>\n",
       "<div id=\"controls_div_2\">\n",
       "  <button id=\"run_button_2\" onclick=\"startSketch('2');\">\n",
       "    <i class=\"fa fa-play-circle-o\" style=\"size: 2em;\"></i>\n",
       "        Run\n",
       "  </button>\n",
       "  <button id=\"pause_button_2\" onclick=\"pauseSketch('2');\">\n",
       "    <i class=\"fa fa-pause\" style=\"size: 2em;\"></i>\n",
       "        Pause\n",
       "  </button>\n",
       "  <button id=\"setup_button_2\" onclick=\"setupSketch('2');\">\n",
       "    setup()\n",
       "  </button>\n",
       "  <button id=\"draw_button_2\" onclick=\"drawSketch('2');\">\n",
       "    draw()\n",
       "  </button>\n",
       "</div>\n",
       "<b>Sketch #2 state:</b> <span id=\"state_2\">Loading...</span><br/>\n",
       "<script>\n",
       "\n",
       "function change_button(button, disable) {\n",
       "    button.disabled = disable;\n",
       "    if (disable) {\n",
       "        button.style.color = \"grey\";\n",
       "    } else {\n",
       "        button.style.color = \"black\";\n",
       "    }\n",
       "}\n",
       "\n",
       "function startSketch(id) {\n",
       "    switchSketchState(id, true);\n",
       "}\n",
       "\n",
       "function pauseSketch(id) {\n",
       "    switchSketchState(id, false);\n",
       "}\n",
       "\n",
       "function drawSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Drawing...\";\n",
       "            try {\n",
       "                processingInstance.redraw();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Drawing... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No drawing() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function setupSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.setup != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Setting up...\";\n",
       "            try {\n",
       "                processingInstance.setup();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Setting up... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No setup() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function switchSketchState(id, on) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (on) {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Running...\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"green\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id),  true);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), true);\n",
       "        processingInstance.loop();  // call Processing loop() function\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Paused.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "        processingInstance.noLoop(); // stop animation, call noLoop()\n",
       "    }\n",
       "}\n",
       "\n",
       "require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function () {\n",
       "    var processingCode = 'PImage img;\\n\\nvoid setup() {\\n    size(500, 500);\\n    img = new PImage(500, 500, RGB);\\n}\\n\\nvoid draw() {\\n    myrect(10, 20, 200, 200, color(255, 0, 0));\\n    mycircle(300, 300, 75, color(0, 255, 0));\\n    image(img, 0, 0);\\n    noLoop();\\n}\\n\\nvoid myrect(int x, int y, int w, int h, color c) {\\n    // what would go here?\\n}\\n\\nvoid mycircle(int x, int y, int radius, color c) {\\n    // what would go here?\\n}\\n';\n",
       "    var cc;\n",
       "    var processingInstance;\n",
       "    var has_error = false;\n",
       "\n",
       "    try {\n",
       "        cc = Processing.compile(processingCode);\n",
       "    } catch (e) {\n",
       "        console.log(e);\n",
       "        cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "        document.getElementById(\"state_2\").innerHTML = e.toString();\n",
       "        document.getElementById(\"state_2\").style.color = \"red\";\n",
       "        has_error = true;\n",
       "    }\n",
       "    if (cc != undefined) {\n",
       "        try {\n",
       "            processingInstance = new Processing(\"canvas_2\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "        } catch (e) {\n",
       "            console.log(e);\n",
       "            cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "            document.getElementById(\"state_2\").innerHTML = e.toString();\n",
       "            document.getElementById(\"state_2\").style.color = \"red\";\n",
       "            processingInstance = new Processing(\"canvas_2\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "            has_error = true;\n",
       "        }\n",
       "    }\n",
       "    if (processingInstance != undefined) {\n",
       "        setTimeout(function () {\n",
       "            // Canvas:\n",
       "            if (processingInstance.externals.context === undefined) {\n",
       "                document.getElementById(\"canvas_div_2\").style.display = \"none\";\n",
       "            }\n",
       "        }, 100);\n",
       "        // Controls:\n",
       "        if (!(processingInstance.isRunning() && processingInstance.draw != undefined)) {\n",
       "            document.getElementById(\"controls_div_2\").style.display = \"none\";\n",
       "        }\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_2\").innerHTML = \"Running...\";\n",
       "                document.getElementById(\"state_2\").style.color = \"green\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_2\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_2\"), false);\n",
       "            change_button(document.getElementById(\"setup_button_2\"),  true);\n",
       "            change_button(document.getElementById(\"draw_button_2\"), true);\n",
       "        } else {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_2\").innerHTML = \"Done.\";\n",
       "                document.getElementById(\"state_2\").style.color = \"blue\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_2\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_2\"), true);\n",
       "            change_button(document.getElementById(\"setup_button_2\"),  processingInstance.setup == undefined);\n",
       "            change_button(document.getElementById(\"draw_button_2\"), true);\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"canvas_div_2\").style.display = \"none\";\n",
       "        document.getElementById(\"controls_div_2\").style.display = \"none\";\n",
       "        if (!has_error) {\n",
       "            document.getElementById(\"state_2\").innerHTML = \"Error.\";\n",
       "            document.getElementById(\"state_2\").style.color = \"red\";\n",
       "        }\n",
       "        change_button(document.getElementById(\"run_button_2\"), true);\n",
       "        change_button(document.getElementById(\"pause_button_2\"), true);\n",
       "        change_button(document.getElementById(\"setup_button_2\"),  true);\n",
       "        change_button(document.getElementById(\"draw_button_2\"), true);\n",
       "    }\n",
       "});\n",
       "\n",
       "</script>\n"
      ],
      "text/plain": [
       "<IPython.core.display.HTML object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "PImage img;\n",
    "\n",
    "void setup() {\n",
    "    size(500, 500);\n",
    "    img = new PImage(500, 500, RGB);\n",
    "}\n",
    "\n",
    "void draw() {\n",
    "    myrect(10, 20, 200, 200, color(255, 0, 0));\n",
    "    mycircle(300, 300, 75, color(0, 255, 0));\n",
    "    image(img, 0, 0);\n",
    "    noLoop();\n",
    "}\n",
    "\n",
    "void myrect(int x, int y, int w, int h, color c) {\n",
    "    // what would go here?\n",
    "}\n",
    "\n",
    "void mycircle(int x, int y, int radius, color c) {\n",
    "    // what would go here?\n",
    "}\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Yes, we could. All we need to do is change the pixels ourselves, like this:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "application/javascript": [
       "\n",
       "        var component = document.getElementById(\"sketch_3\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"state_3\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"controls_div_3\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "            // FIXME: Stop all previously running versions (?)\n",
       "            var processingInstance = Processing.getInstanceById(\"canvas_3\");\n",
       "            if (processingInstance != undefined && processingInstance.isRunning())\n",
       "                processingInstance.noLoop();\n",
       "        });\n",
       "\n",
       "\n",
       "        var output_area = this;\n",
       "        // find my cell element\n",
       "        var cell_element = output_area.element.parents('.cell');\n",
       "        // which cell is it?\n",
       "        var cell_idx = Jupyter.notebook.get_cell_elements().index(cell_element);\n",
       "        // get the cell object\n",
       "        var cell = Jupyter.notebook.get_cell(cell_idx);\n",
       "\n",
       "        function jyp_print(cell, newline) {\n",
       "            return function(message) {\n",
       "                cell.get_callbacks().iopub.output({header: {\"msg_type\": \"stream\"},\n",
       "                                                   content: {text: message + newline,\n",
       "                                                             name: \"stdout\"}});\n",
       "            }\n",
       "        }\n",
       "        window.jyp_println = jyp_print(cell, \"\\n\");\n",
       "        window.jyp_print = jyp_print(cell, \"\");\n",
       "\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "           Processing.logger.println = jyp_print(cell, \"\\n\");\n",
       "           Processing.logger.print = jyp_print(cell, \"\");\n",
       "        });\n",
       "\n",
       "\n",
       "        "
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "text/html": [
       "\n",
       "<div id=\"canvas_div_3\">\n",
       "  <b>Sketch #3:</b><br/>\n",
       "  <canvas id=\"canvas_3\"></canvas><br/>\n",
       "</div>\n",
       "<div id=\"controls_div_3\">\n",
       "  <button id=\"run_button_3\" onclick=\"startSketch('3');\">\n",
       "    <i class=\"fa fa-play-circle-o\" style=\"size: 2em;\"></i>\n",
       "        Run\n",
       "  </button>\n",
       "  <button id=\"pause_button_3\" onclick=\"pauseSketch('3');\">\n",
       "    <i class=\"fa fa-pause\" style=\"size: 2em;\"></i>\n",
       "        Pause\n",
       "  </button>\n",
       "  <button id=\"setup_button_3\" onclick=\"setupSketch('3');\">\n",
       "    setup()\n",
       "  </button>\n",
       "  <button id=\"draw_button_3\" onclick=\"drawSketch('3');\">\n",
       "    draw()\n",
       "  </button>\n",
       "</div>\n",
       "<b>Sketch #3 state:</b> <span id=\"state_3\">Loading...</span><br/>\n",
       "<script>\n",
       "\n",
       "function change_button(button, disable) {\n",
       "    button.disabled = disable;\n",
       "    if (disable) {\n",
       "        button.style.color = \"grey\";\n",
       "    } else {\n",
       "        button.style.color = \"black\";\n",
       "    }\n",
       "}\n",
       "\n",
       "function startSketch(id) {\n",
       "    switchSketchState(id, true);\n",
       "}\n",
       "\n",
       "function pauseSketch(id) {\n",
       "    switchSketchState(id, false);\n",
       "}\n",
       "\n",
       "function drawSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Drawing...\";\n",
       "            try {\n",
       "                processingInstance.redraw();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Drawing... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No drawing() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function setupSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.setup != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Setting up...\";\n",
       "            try {\n",
       "                processingInstance.setup();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Setting up... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No setup() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function switchSketchState(id, on) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (on) {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Running...\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"green\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id),  true);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), true);\n",
       "        processingInstance.loop();  // call Processing loop() function\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Paused.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "        processingInstance.noLoop(); // stop animation, call noLoop()\n",
       "    }\n",
       "}\n",
       "\n",
       "require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function () {\n",
       "    var processingCode = 'PImage img;\\n\\nvoid setup() {\\n    size(500, 500);\\n    img = new PImage(500, 500, RGB);\\n}\\n\\nvoid draw() {\\n    myrect(10, 20, 200, 200, color(255, 0, 0));\\n    mycircle(300, 300, 75, color(0, 255, 0));\\n    image(img, 0, 0);\\n    noLoop();\\n}\\n\\nvoid myrect(int x, int y, int w, int h, color c) {\\n    // what would go here?\\n    img.loadPixels();\\n    for (int i=x; i < x + w; i++) {\\n        for (int j=y; j < y + h; j++) {\\n            img.pixels[i + j * img.width] = c;\\n        }\\n    }\\n    img.updatePixels();\\n}\\n\\nvoid mycircle(int x, int y, int radius, color c) {\\n    // what would go here?\\n    img.loadPixels();\\n    for (int i=x-radius; i < x + radius; i++) {\\n        for (int j=y-radius; j < y + radius; j++) {\\n            img.pixels[i + j * img.width] = c;\\n        }\\n    }\\n    img.updatePixels();\\n}';\n",
       "    var cc;\n",
       "    var processingInstance;\n",
       "    var has_error = false;\n",
       "\n",
       "    try {\n",
       "        cc = Processing.compile(processingCode);\n",
       "    } catch (e) {\n",
       "        console.log(e);\n",
       "        cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "        document.getElementById(\"state_3\").innerHTML = e.toString();\n",
       "        document.getElementById(\"state_3\").style.color = \"red\";\n",
       "        has_error = true;\n",
       "    }\n",
       "    if (cc != undefined) {\n",
       "        try {\n",
       "            processingInstance = new Processing(\"canvas_3\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "        } catch (e) {\n",
       "            console.log(e);\n",
       "            cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "            document.getElementById(\"state_3\").innerHTML = e.toString();\n",
       "            document.getElementById(\"state_3\").style.color = \"red\";\n",
       "            processingInstance = new Processing(\"canvas_3\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "            has_error = true;\n",
       "        }\n",
       "    }\n",
       "    if (processingInstance != undefined) {\n",
       "        setTimeout(function () {\n",
       "            // Canvas:\n",
       "            if (processingInstance.externals.context === undefined) {\n",
       "                document.getElementById(\"canvas_div_3\").style.display = \"none\";\n",
       "            }\n",
       "        }, 100);\n",
       "        // Controls:\n",
       "        if (!(processingInstance.isRunning() && processingInstance.draw != undefined)) {\n",
       "            document.getElementById(\"controls_div_3\").style.display = \"none\";\n",
       "        }\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_3\").innerHTML = \"Running...\";\n",
       "                document.getElementById(\"state_3\").style.color = \"green\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_3\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_3\"), false);\n",
       "            change_button(document.getElementById(\"setup_button_3\"),  true);\n",
       "            change_button(document.getElementById(\"draw_button_3\"), true);\n",
       "        } else {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_3\").innerHTML = \"Done.\";\n",
       "                document.getElementById(\"state_3\").style.color = \"blue\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_3\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_3\"), true);\n",
       "            change_button(document.getElementById(\"setup_button_3\"),  processingInstance.setup == undefined);\n",
       "            change_button(document.getElementById(\"draw_button_3\"), true);\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"canvas_div_3\").style.display = \"none\";\n",
       "        document.getElementById(\"controls_div_3\").style.display = \"none\";\n",
       "        if (!has_error) {\n",
       "            document.getElementById(\"state_3\").innerHTML = \"Error.\";\n",
       "            document.getElementById(\"state_3\").style.color = \"red\";\n",
       "        }\n",
       "        change_button(document.getElementById(\"run_button_3\"), true);\n",
       "        change_button(document.getElementById(\"pause_button_3\"), true);\n",
       "        change_button(document.getElementById(\"setup_button_3\"),  true);\n",
       "        change_button(document.getElementById(\"draw_button_3\"), true);\n",
       "    }\n",
       "});\n",
       "\n",
       "</script>\n"
      ],
      "text/plain": [
       "<IPython.core.display.HTML object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "PImage img;\n",
    "\n",
    "void setup() {\n",
    "    size(500, 500);\n",
    "    img = new PImage(500, 500, RGB);\n",
    "}\n",
    "\n",
    "void draw() {\n",
    "    myrect(10, 20, 200, 200, color(255, 0, 0));\n",
    "    mycircle(300, 300, 75, color(0, 255, 0));\n",
    "    image(img, 0, 0);\n",
    "    noLoop();\n",
    "}\n",
    "\n",
    "void myrect(int x, int y, int w, int h, color c) {\n",
    "    // what would go here?\n",
    "    img.loadPixels();\n",
    "    for (int i=x; i < x + w; i++) {\n",
    "        for (int j=y; j < y + h; j++) {\n",
    "            img.pixels[i + j * img.width] = c;\n",
    "        }\n",
    "    }\n",
    "    img.updatePixels();\n",
    "}\n",
    "\n",
    "void mycircle(int x, int y, int radius, color c) {\n",
    "    // what would go here?\n",
    "    img.loadPixels();\n",
    "    for (int i=x-radius; i < x + radius; i++) {\n",
    "        for (int j=y-radius; j < y + radius; j++) {\n",
    "            img.pixels[i + j * img.width] = c;\n",
    "        }\n",
    "    }\n",
    "    img.updatePixels();\n",
    "}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**BONUS PROBLEM 1:**\n",
    "\n",
    "Write the code that draws a green circle rather than a green square."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## 1.2 Image Flipping"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 1.2.1 Horizontal Mirror"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "For this demonstration, I'll use this picture of a student:\n",
    "\n",
    "<img src=\"IMG_4688.jpeg\"/>\n",
    "\n",
    "You can download it, and upload it yourself, or use:\n",
    "\n",
    "```\n",
    "%download https://athena.brynmawr.edu/jupyter/hub/dblank/public/CS110%20Intro%20to%20Computing/2015-Fall/Notes/IMG_4688.jpeg\n",
    "```"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "First, let's just test it and display it:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "application/javascript": [
       "\n",
       "        var component = document.getElementById(\"sketch_16\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"state_16\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"controls_div_16\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "            // FIXME: Stop all previously running versions (?)\n",
       "            var processingInstance = Processing.getInstanceById(\"canvas_16\");\n",
       "            if (processingInstance != undefined && processingInstance.isRunning())\n",
       "                processingInstance.noLoop();\n",
       "        });\n",
       "\n",
       "\n",
       "        var output_area = this;\n",
       "        // find my cell element\n",
       "        var cell_element = output_area.element.parents('.cell');\n",
       "        // which cell is it?\n",
       "        var cell_idx = Jupyter.notebook.get_cell_elements().index(cell_element);\n",
       "        // get the cell object\n",
       "        var cell = Jupyter.notebook.get_cell(cell_idx);\n",
       "\n",
       "        function jyp_print(cell, newline) {\n",
       "            return function(message) {\n",
       "                cell.get_callbacks().iopub.output({header: {\"msg_type\": \"stream\"},\n",
       "                                                   content: {text: message + newline,\n",
       "                                                             name: \"stdout\"}});\n",
       "            }\n",
       "        }\n",
       "        window.jyp_println = jyp_print(cell, \"\\n\");\n",
       "        window.jyp_print = jyp_print(cell, \"\");\n",
       "\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "           Processing.logger.println = jyp_print(cell, \"\\n\");\n",
       "           Processing.logger.print = jyp_print(cell, \"\");\n",
       "        });\n",
       "\n",
       "\n",
       "        "
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "text/html": [
       "\n",
       "<div id=\"canvas_div_16\">\n",
       "  <b>Sketch #16:</b><br/>\n",
       "  <canvas id=\"canvas_16\"></canvas><br/>\n",
       "</div>\n",
       "<div id=\"controls_div_16\">\n",
       "  <button id=\"run_button_16\" onclick=\"startSketch('16');\">\n",
       "    <i class=\"fa fa-play-circle-o\" style=\"size: 2em;\"></i>\n",
       "        Run\n",
       "  </button>\n",
       "  <button id=\"pause_button_16\" onclick=\"pauseSketch('16');\">\n",
       "    <i class=\"fa fa-pause\" style=\"size: 2em;\"></i>\n",
       "        Pause\n",
       "  </button>\n",
       "  <button id=\"setup_button_16\" onclick=\"setupSketch('16');\">\n",
       "    setup()\n",
       "  </button>\n",
       "  <button id=\"draw_button_16\" onclick=\"drawSketch('16');\">\n",
       "    draw()\n",
       "  </button>\n",
       "</div>\n",
       "<b>Sketch #16 state:</b> <span id=\"state_16\">Loading...</span><br/>\n",
       "<script>\n",
       "\n",
       "function change_button(button, disable) {\n",
       "    button.disabled = disable;\n",
       "    if (disable) {\n",
       "        button.style.color = \"grey\";\n",
       "    } else {\n",
       "        button.style.color = \"black\";\n",
       "    }\n",
       "}\n",
       "\n",
       "function startSketch(id) {\n",
       "    switchSketchState(id, true);\n",
       "}\n",
       "\n",
       "function pauseSketch(id) {\n",
       "    switchSketchState(id, false);\n",
       "}\n",
       "\n",
       "function drawSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Drawing...\";\n",
       "            try {\n",
       "                processingInstance.redraw();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Drawing... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No drawing() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function setupSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.setup != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Setting up...\";\n",
       "            try {\n",
       "                processingInstance.setup();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Setting up... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No setup() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function switchSketchState(id, on) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (on) {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Running...\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"green\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id),  true);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), true);\n",
       "        processingInstance.loop();  // call Processing loop() function\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Paused.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "        processingInstance.noLoop(); // stop animation, call noLoop()\n",
       "    }\n",
       "}\n",
       "\n",
       "require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function () {\n",
       "    var processingCode = '/* @pjs preload=\"IMG_4688.jpeg\"; */\\n\\nPImage img;\\n\\nvoid setup() {\\n    img = loadImage(\"IMG_4688.jpeg\");\\n    img.resize(int(img.width/20), int(img.height/20));\\n    size(img.width, img.height);\\n    img.loadPixels();\\n}\\n\\nvoid draw() {\\n    image(img, 0, 0);\\n    noLoop();\\n}';\n",
       "    var cc;\n",
       "    var processingInstance;\n",
       "    var has_error = false;\n",
       "\n",
       "    try {\n",
       "        cc = Processing.compile(processingCode);\n",
       "    } catch (e) {\n",
       "        console.log(e);\n",
       "        cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "        document.getElementById(\"state_16\").innerHTML = e.toString();\n",
       "        document.getElementById(\"state_16\").style.color = \"red\";\n",
       "        has_error = true;\n",
       "    }\n",
       "    if (cc != undefined) {\n",
       "        try {\n",
       "            processingInstance = new Processing(\"canvas_16\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "        } catch (e) {\n",
       "            console.log(e);\n",
       "            cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "            document.getElementById(\"state_16\").innerHTML = e.toString();\n",
       "            document.getElementById(\"state_16\").style.color = \"red\";\n",
       "            processingInstance = new Processing(\"canvas_16\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "            has_error = true;\n",
       "        }\n",
       "    }\n",
       "    if (processingInstance != undefined) {\n",
       "        setTimeout(function () {\n",
       "            // Canvas:\n",
       "            if (processingInstance.externals.context === undefined) {\n",
       "                document.getElementById(\"canvas_div_16\").style.display = \"none\";\n",
       "            }\n",
       "        }, 100);\n",
       "        // Controls:\n",
       "        if (!(processingInstance.isRunning() && processingInstance.draw != undefined)) {\n",
       "            document.getElementById(\"controls_div_16\").style.display = \"none\";\n",
       "        }\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_16\").innerHTML = \"Running...\";\n",
       "                document.getElementById(\"state_16\").style.color = \"green\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_16\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_16\"), false);\n",
       "            change_button(document.getElementById(\"setup_button_16\"),  true);\n",
       "            change_button(document.getElementById(\"draw_button_16\"), true);\n",
       "        } else {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_16\").innerHTML = \"Done.\";\n",
       "                document.getElementById(\"state_16\").style.color = \"blue\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_16\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_16\"), true);\n",
       "            change_button(document.getElementById(\"setup_button_16\"),  processingInstance.setup == undefined);\n",
       "            change_button(document.getElementById(\"draw_button_16\"), true);\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"canvas_div_16\").style.display = \"none\";\n",
       "        document.getElementById(\"controls_div_16\").style.display = \"none\";\n",
       "        if (!has_error) {\n",
       "            document.getElementById(\"state_16\").innerHTML = \"Error.\";\n",
       "            document.getElementById(\"state_16\").style.color = \"red\";\n",
       "        }\n",
       "        change_button(document.getElementById(\"run_button_16\"), true);\n",
       "        change_button(document.getElementById(\"pause_button_16\"), true);\n",
       "        change_button(document.getElementById(\"setup_button_16\"),  true);\n",
       "        change_button(document.getElementById(\"draw_button_16\"), true);\n",
       "    }\n",
       "});\n",
       "\n",
       "</script>\n"
      ],
      "text/plain": [
       "<IPython.core.display.HTML object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "/* @pjs preload=\"IMG_4688.jpeg\"; */\n",
    "\n",
    "PImage img;\n",
    "\n",
    "void setup() {\n",
    "    img = loadImage(\"IMG_4688.jpeg\");\n",
    "    img.resize(int(img.width/20), int(img.height/20));\n",
    "    size(img.width, img.height);\n",
    "    img.loadPixels();\n",
    "}\n",
    "\n",
    "void draw() {\n",
    "    image(img, 0, 0);\n",
    "    noLoop();\n",
    "}"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Next, let's flip it so that everything on the right is on the left and everything on the left is on the right.\n",
    "\n",
    "To do that, we just map the pixels so that the pixels in the first column (zero) will now be in the last column (img.width - 1):"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "application/javascript": [
       "\n",
       "        var component = document.getElementById(\"sketch_5\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"state_5\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"controls_div_5\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "            // FIXME: Stop all previously running versions (?)\n",
       "            var processingInstance = Processing.getInstanceById(\"canvas_5\");\n",
       "            if (processingInstance != undefined && processingInstance.isRunning())\n",
       "                processingInstance.noLoop();\n",
       "        });\n",
       "\n",
       "\n",
       "        var output_area = this;\n",
       "        // find my cell element\n",
       "        var cell_element = output_area.element.parents('.cell');\n",
       "        // which cell is it?\n",
       "        var cell_idx = Jupyter.notebook.get_cell_elements().index(cell_element);\n",
       "        // get the cell object\n",
       "        var cell = Jupyter.notebook.get_cell(cell_idx);\n",
       "\n",
       "        function jyp_print(cell, newline) {\n",
       "            return function(message) {\n",
       "                cell.get_callbacks().iopub.output({header: {\"msg_type\": \"stream\"},\n",
       "                                                   content: {text: message + newline,\n",
       "                                                             name: \"stdout\"}});\n",
       "            }\n",
       "        }\n",
       "        window.jyp_println = jyp_print(cell, \"\\n\");\n",
       "        window.jyp_print = jyp_print(cell, \"\");\n",
       "\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "           Processing.logger.println = jyp_print(cell, \"\\n\");\n",
       "           Processing.logger.print = jyp_print(cell, \"\");\n",
       "        });\n",
       "\n",
       "\n",
       "        "
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "text/html": [
       "\n",
       "<div id=\"canvas_div_5\">\n",
       "  <b>Sketch #5:</b><br/>\n",
       "  <canvas id=\"canvas_5\"></canvas><br/>\n",
       "</div>\n",
       "<div id=\"controls_div_5\">\n",
       "  <button id=\"run_button_5\" onclick=\"startSketch('5');\">\n",
       "    <i class=\"fa fa-play-circle-o\" style=\"size: 2em;\"></i>\n",
       "        Run\n",
       "  </button>\n",
       "  <button id=\"pause_button_5\" onclick=\"pauseSketch('5');\">\n",
       "    <i class=\"fa fa-pause\" style=\"size: 2em;\"></i>\n",
       "        Pause\n",
       "  </button>\n",
       "  <button id=\"setup_button_5\" onclick=\"setupSketch('5');\">\n",
       "    setup()\n",
       "  </button>\n",
       "  <button id=\"draw_button_5\" onclick=\"drawSketch('5');\">\n",
       "    draw()\n",
       "  </button>\n",
       "</div>\n",
       "<b>Sketch #5 state:</b> <span id=\"state_5\">Loading...</span><br/>\n",
       "<script>\n",
       "\n",
       "function change_button(button, disable) {\n",
       "    button.disabled = disable;\n",
       "    if (disable) {\n",
       "        button.style.color = \"grey\";\n",
       "    } else {\n",
       "        button.style.color = \"black\";\n",
       "    }\n",
       "}\n",
       "\n",
       "function startSketch(id) {\n",
       "    switchSketchState(id, true);\n",
       "}\n",
       "\n",
       "function pauseSketch(id) {\n",
       "    switchSketchState(id, false);\n",
       "}\n",
       "\n",
       "function drawSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Drawing...\";\n",
       "            try {\n",
       "                processingInstance.redraw();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Drawing... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No drawing() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function setupSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.setup != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Setting up...\";\n",
       "            try {\n",
       "                processingInstance.setup();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Setting up... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No setup() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function switchSketchState(id, on) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (on) {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Running...\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"green\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id),  true);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), true);\n",
       "        processingInstance.loop();  // call Processing loop() function\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Paused.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "        processingInstance.noLoop(); // stop animation, call noLoop()\n",
       "    }\n",
       "}\n",
       "\n",
       "require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function () {\n",
       "    var processingCode = '/* @pjs preload=\"IMG_4688.jpeg\"; */\\n\\nPImage img;\\nPImage result;\\n\\nvoid setup() {\\n    img = loadImage(\"IMG_4688.jpeg\");\\n    img.resize(int(img.width/5), int(img.height/5));\\n    size(img.width, img.height);\\n    img.loadPixels();    \\n    // Create a result from img:\\n    result = new PImage(img.width, img.height);\\n    result.loadPixels();\\n    for (int y=0; y < img.height; y++) {\\n        for (int x=0; x < img.width; x++) {\\n            color c = img.pixels[x + y * img.width];\\n            result.pixels[img.width - 1 - x + (y * img.width)] = c;\\n        }\\n    }    \\n    result.updatePixels();\\n}\\n\\nvoid draw() {\\n    image(result, 0, 0);\\n    noLoop();\\n}\\n';\n",
       "    var cc;\n",
       "    var processingInstance;\n",
       "    var has_error = false;\n",
       "\n",
       "    try {\n",
       "        cc = Processing.compile(processingCode);\n",
       "    } catch (e) {\n",
       "        console.log(e);\n",
       "        cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "        document.getElementById(\"state_5\").innerHTML = e.toString();\n",
       "        document.getElementById(\"state_5\").style.color = \"red\";\n",
       "        has_error = true;\n",
       "    }\n",
       "    if (cc != undefined) {\n",
       "        try {\n",
       "            processingInstance = new Processing(\"canvas_5\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "        } catch (e) {\n",
       "            console.log(e);\n",
       "            cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "            document.getElementById(\"state_5\").innerHTML = e.toString();\n",
       "            document.getElementById(\"state_5\").style.color = \"red\";\n",
       "            processingInstance = new Processing(\"canvas_5\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "            has_error = true;\n",
       "        }\n",
       "    }\n",
       "    if (processingInstance != undefined) {\n",
       "        setTimeout(function () {\n",
       "            // Canvas:\n",
       "            if (processingInstance.externals.context === undefined) {\n",
       "                document.getElementById(\"canvas_div_5\").style.display = \"none\";\n",
       "            }\n",
       "        }, 100);\n",
       "        // Controls:\n",
       "        if (!(processingInstance.isRunning() && processingInstance.draw != undefined)) {\n",
       "            document.getElementById(\"controls_div_5\").style.display = \"none\";\n",
       "        }\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_5\").innerHTML = \"Running...\";\n",
       "                document.getElementById(\"state_5\").style.color = \"green\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_5\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_5\"), false);\n",
       "            change_button(document.getElementById(\"setup_button_5\"),  true);\n",
       "            change_button(document.getElementById(\"draw_button_5\"), true);\n",
       "        } else {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_5\").innerHTML = \"Done.\";\n",
       "                document.getElementById(\"state_5\").style.color = \"blue\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_5\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_5\"), true);\n",
       "            change_button(document.getElementById(\"setup_button_5\"),  processingInstance.setup == undefined);\n",
       "            change_button(document.getElementById(\"draw_button_5\"), true);\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"canvas_div_5\").style.display = \"none\";\n",
       "        document.getElementById(\"controls_div_5\").style.display = \"none\";\n",
       "        if (!has_error) {\n",
       "            document.getElementById(\"state_5\").innerHTML = \"Error.\";\n",
       "            document.getElementById(\"state_5\").style.color = \"red\";\n",
       "        }\n",
       "        change_button(document.getElementById(\"run_button_5\"), true);\n",
       "        change_button(document.getElementById(\"pause_button_5\"), true);\n",
       "        change_button(document.getElementById(\"setup_button_5\"),  true);\n",
       "        change_button(document.getElementById(\"draw_button_5\"), true);\n",
       "    }\n",
       "});\n",
       "\n",
       "</script>\n"
      ],
      "text/plain": [
       "<IPython.core.display.HTML object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    }
   ],
   "source": [
    "/* @pjs preload=\"IMG_4688.jpeg\"; */\n",
    "\n",
    "PImage img;\n",
    "PImage result;\n",
    "\n",
    "void setup() {\n",
    "    img = loadImage(\"IMG_4688.jpeg\");\n",
    "    img.resize(int(img.width/5), int(img.height/5));\n",
    "    size(img.width, img.height);\n",
    "    img.loadPixels();    \n",
    "    // Create a result from img:\n",
    "    result = new PImage(img.width, img.height);\n",
    "    result.loadPixels();\n",
    "    for (int y=0; y < img.height; y++) {\n",
    "        for (int x=0; x < img.width; x++) {\n",
    "            color c = img.pixels[x + y * img.width];\n",
    "            result.pixels[img.width - 1 - x + (y * img.width)] = c;\n",
    "        }\n",
    "    }    \n",
    "    result.updatePixels();\n",
    "}\n",
    "\n",
    "void draw() {\n",
    "    image(result, 0, 0);\n",
    "    noLoop();\n",
    "}\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "collapsed": true
   },
   "source": [
    "**BONUS PROBLEM 2:**\n",
    "\n",
    "Flip student upside down. "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "data": {
      "application/javascript": [
       "\n",
       "        var component = document.getElementById(\"sketch_14\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"state_14\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        component = document.getElementById(\"controls_div_14\");\n",
       "        if (component != undefined)\n",
       "            component.remove();\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "            // FIXME: Stop all previously running versions (?)\n",
       "            var processingInstance = Processing.getInstanceById(\"canvas_14\");\n",
       "            if (processingInstance != undefined && processingInstance.isRunning())\n",
       "                processingInstance.noLoop();\n",
       "        });\n",
       "\n",
       "\n",
       "        var output_area = this;\n",
       "        // find my cell element\n",
       "        var cell_element = output_area.element.parents('.cell');\n",
       "        // which cell is it?\n",
       "        var cell_idx = Jupyter.notebook.get_cell_elements().index(cell_element);\n",
       "        // get the cell object\n",
       "        var cell = Jupyter.notebook.get_cell(cell_idx);\n",
       "\n",
       "        function jyp_print(cell, newline) {\n",
       "            return function(message) {\n",
       "                cell.get_callbacks().iopub.output({header: {\"msg_type\": \"stream\"},\n",
       "                                                   content: {text: message + newline,\n",
       "                                                             name: \"stdout\"}});\n",
       "            }\n",
       "        }\n",
       "        window.jyp_println = jyp_print(cell, \"\\n\");\n",
       "        window.jyp_print = jyp_print(cell, \"\");\n",
       "\n",
       "        require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function() {\n",
       "           Processing.logger.println = jyp_print(cell, \"\\n\");\n",
       "           Processing.logger.print = jyp_print(cell, \"\");\n",
       "        });\n",
       "\n",
       "\n",
       "        "
      ],
      "text/plain": [
       "<IPython.core.display.Javascript object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "data": {
      "text/html": [
       "\n",
       "<div id=\"canvas_div_14\">\n",
       "  <b>Sketch #14:</b><br/>\n",
       "  <canvas id=\"canvas_14\"></canvas><br/>\n",
       "</div>\n",
       "<div id=\"controls_div_14\">\n",
       "  <button id=\"run_button_14\" onclick=\"startSketch('14');\">\n",
       "    <i class=\"fa fa-play-circle-o\" style=\"size: 2em;\"></i>\n",
       "        Run\n",
       "  </button>\n",
       "  <button id=\"pause_button_14\" onclick=\"pauseSketch('14');\">\n",
       "    <i class=\"fa fa-pause\" style=\"size: 2em;\"></i>\n",
       "        Pause\n",
       "  </button>\n",
       "  <button id=\"setup_button_14\" onclick=\"setupSketch('14');\">\n",
       "    setup()\n",
       "  </button>\n",
       "  <button id=\"draw_button_14\" onclick=\"drawSketch('14');\">\n",
       "    draw()\n",
       "  </button>\n",
       "</div>\n",
       "<b>Sketch #14 state:</b> <span id=\"state_14\">Loading...</span><br/>\n",
       "<script>\n",
       "\n",
       "function change_button(button, disable) {\n",
       "    button.disabled = disable;\n",
       "    if (disable) {\n",
       "        button.style.color = \"grey\";\n",
       "    } else {\n",
       "        button.style.color = \"black\";\n",
       "    }\n",
       "}\n",
       "\n",
       "function startSketch(id) {\n",
       "    switchSketchState(id, true);\n",
       "}\n",
       "\n",
       "function pauseSketch(id) {\n",
       "    switchSketchState(id, false);\n",
       "}\n",
       "\n",
       "function drawSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Drawing...\";\n",
       "            try {\n",
       "                processingInstance.redraw();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Drawing... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No drawing() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function setupSketch(id) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (processingInstance != undefined) {\n",
       "        if (processingInstance.setup != undefined) {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"Setting up...\";\n",
       "            try {\n",
       "                processingInstance.setup();\n",
       "                document.getElementById(\"state_\" + id).innerHTML = \"Setting up... done! Paused.\";\n",
       "                document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "            } catch (e) {\n",
       "                processingInstance.println(e.toString());\n",
       "                document.getElementById(\"state_\" + id).innerHTML = e.toString();\n",
       "                document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "            }\n",
       "        } else {\n",
       "            document.getElementById(\"state_\" + id).innerHTML = \"No setup() function. Paused.\";\n",
       "            document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Error.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"red\";\n",
       "    }\n",
       "    change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "    change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "    change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "    change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "}\n",
       "\n",
       "function switchSketchState(id, on) {\n",
       "    var processingInstance = Processing.getInstanceById(\"canvas_\" + id);\n",
       "    if (on) {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Running...\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"green\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id),  true);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), true);\n",
       "        processingInstance.loop();  // call Processing loop() function\n",
       "    } else {\n",
       "        document.getElementById(\"state_\" + id).innerHTML = \"Paused.\";\n",
       "        document.getElementById(\"state_\" + id).style.color = \"blue\";\n",
       "        change_button(document.getElementById(\"run_button_\" + id), processingInstance.draw == undefined);\n",
       "        change_button(document.getElementById(\"pause_button_\" + id), true);\n",
       "        change_button(document.getElementById(\"setup_button_\" + id), processingInstance.setup == undefined);\n",
       "        change_button(document.getElementById(\"draw_button_\" + id), processingInstance.draw == undefined);\n",
       "        processingInstance.noLoop(); // stop animation, call noLoop()\n",
       "    }\n",
       "}\n",
       "\n",
       "require([window.location.protocol + \"//calysto.github.io/javascripts/processing/processing.js\"], function () {\n",
       "    var processingCode = '/* @pjs preload=\"IMG_4688.jpeg\"; */\\n\\nPImage img;\\n\\nvoid setup() {\\n    img = loadImage(\"IMG_4688.jpeg\");\\n    img.resize(int(img.width/5), int(img.height/5));\\n    size(img.width, img.height);\\n    img.loadPixels();\\n    for (int y=0; y < img.height; y++) {\\n        for (int x=0; x < img.width; x++) {\\n            color c = img.pixels[x + y * img.width];\\n            float r = red(c);\\n            float g = green(c);\\n            float b = blue(c);\\n            // 201, 59, 98\\n            if (190 < r && r < 250 &&\\n               55 < g && g < 90 &&\\n               90 < b && b < 150) {\\n                img.pixels[x + (y * img.width)] = color(0, 255, 0);\\n            }\\n        }\\n    }    \\n    img.updatePixels();    \\n}\\n\\nvoid mousePressed() {\\n    color c = img.get(mouseX, mouseY);\\n    float r = red(c);\\n    float g = green(c);\\n    float b = blue(c);\\n    println(\"RGB: \" + r + \", \" + g + \", \" + b);\\n}\\n\\nvoid draw() {\\n    image(img, 0, 0);\\n    noLoop();\\n}';\n",
       "    var cc;\n",
       "    var processingInstance;\n",
       "    var has_error = false;\n",
       "\n",
       "    try {\n",
       "        cc = Processing.compile(processingCode);\n",
       "    } catch (e) {\n",
       "        console.log(e);\n",
       "        cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "        document.getElementById(\"state_14\").innerHTML = e.toString();\n",
       "        document.getElementById(\"state_14\").style.color = \"red\";\n",
       "        has_error = true;\n",
       "    }\n",
       "    if (cc != undefined) {\n",
       "        try {\n",
       "            processingInstance = new Processing(\"canvas_14\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "        } catch (e) {\n",
       "            console.log(e);\n",
       "            cc = Processing.compile(\"println('\" + e.toString() + \"');\");\n",
       "            document.getElementById(\"state_14\").innerHTML = e.toString();\n",
       "            document.getElementById(\"state_14\").style.color = \"red\";\n",
       "            processingInstance = new Processing(\"canvas_14\", cc);\n",
       "            processingInstance.println = window.jyp_println\n",
       "            has_error = true;\n",
       "        }\n",
       "    }\n",
       "    if (processingInstance != undefined) {\n",
       "        setTimeout(function () {\n",
       "            // Canvas:\n",
       "            if (processingInstance.externals.context === undefined) {\n",
       "                document.getElementById(\"canvas_div_14\").style.display = \"none\";\n",
       "            }\n",
       "        }, 100);\n",
       "        // Controls:\n",
       "        if (!(processingInstance.isRunning() && processingInstance.draw != undefined)) {\n",
       "            document.getElementById(\"controls_div_14\").style.display = \"none\";\n",
       "        }\n",
       "        if (processingInstance.draw != undefined) {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_14\").innerHTML = \"Running...\";\n",
       "                document.getElementById(\"state_14\").style.color = \"green\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_14\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_14\"), false);\n",
       "            change_button(document.getElementById(\"setup_button_14\"),  true);\n",
       "            change_button(document.getElementById(\"draw_button_14\"), true);\n",
       "        } else {\n",
       "            if (!has_error) {\n",
       "                document.getElementById(\"state_14\").innerHTML = \"Done.\";\n",
       "                document.getElementById(\"state_14\").style.color = \"blue\";\n",
       "            }\n",
       "            change_button(document.getElementById(\"run_button_14\"), true);\n",
       "            change_button(document.getElementById(\"pause_button_14\"), true);\n",
       "            change_button(document.getElementById(\"setup_button_14\"),  processingInstance.setup == undefined);\n",
       "            change_button(document.getElementById(\"draw_button_14\"), true);\n",
       "        }\n",
       "    } else {\n",
       "        document.getElementById(\"canvas_div_14\").style.display = \"none\";\n",
       "        document.getElementById(\"controls_div_14\").style.display = \"none\";\n",
       "        if (!has_error) {\n",
       "            document.getElementById(\"state_14\").innerHTML = \"Error.\";\n",
       "            document.getElementById(\"state_14\").style.color = \"red\";\n",
       "        }\n",
       "        change_button(document.getElementById(\"run_button_14\"), true);\n",
       "        change_button(document.getElementById(\"pause_button_14\"), true);\n",
       "        change_button(document.getElementById(\"setup_button_14\"),  true);\n",
       "        change_button(document.getElementById(\"draw_button_14\"), true);\n",
       "    }\n",
       "});\n",
       "\n",
       "</script>\n"
      ],
      "text/plain": [
       "<IPython.core.display.HTML object>"
      ]
     },
     "metadata": {},
     "output_type": "display_data"
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "RGB: 165, 48, 74\n"
     ]
    }
   ],
   "source": [
    "/* @pjs preload=\"IMG_4688.jpeg\"; */\n",
    "\n",
    "PImage img;\n",
    "\n",
    "void setup() {\n",
    "    img = loadImage(\"IMG_4688.jpeg\");\n",
    "    img.resize(int(img.width/5), int(img.height/5));\n",
    "    size(img.width, img.height);\n",
    "    img.loadPixels();\n",
    "    for (int y=0; y < img.height; y++) {\n",
    "        for (int x=0; x < img.width; x++) {\n",
    "            color c = img.pixels[x + y * img.width];\n",
    "            float r = red(c);\n",
    "            float g = green(c);\n",
    "            float b = blue(c);\n",
    "            // 201, 59, 98\n",
    "            if (190 < r && r < 250 &&\n",
    "               55 < g && g < 90 &&\n",
    "               90 < b && b < 150) {\n",
    "                img.pixels[x + (y * img.width)] = color(0, 255, 0);\n",
    "            }\n",
    "        }\n",
    "    }    \n",
    "    img.updatePixels();    \n",
    "}\n",
    "\n",
    "void mousePressed() {\n",
    "    color c = img.get(mouseX, mouseY);\n",
    "    float r = red(c);\n",
    "    float g = green(c);\n",
    "    float b = blue(c);\n",
    "    println(\"RGB: \" + r + \", \" + g + \", \" + b);\n",
    "}\n",
    "\n",
    "void draw() {\n",
    "    image(img, 0, 0);\n",
    "    noLoop();\n",
    "}"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "collapsed": true
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   "outputs": [],
   "source": []
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