问题
I have developed programs in Khan Academy's Computer Programming lessons that I would like to run outside of Khan Academy. How can that be done?
回答1:
Khan Academy uses Processing.js, a JavaScript library for interacting with <canvas> elements. Although Processing is actually a language in its own right, Khan Academy uses JavaScript-only Processing.js code.
So you need to set up a web page that imports Processing.js, sets up a <canvas>, and builds a Processing.js instance on the canvas. Finally you need to make sure your Khan Academy code has all the members of the Processing.js instance in scope (I do this with with), plus some equivalent of Khan Academy's small modifications to Processing.js, like mouseIsPressed and getImage.
Here is some boilerplate that has been working for me. Probably further development will be required to get it working for more complicated examples; please post comments when you find examples that don't work.
<!DOCTYPE html>
<html>
<head>
<title>JavaScript</title>
<script src="http://cdnjs.cloudflare.com/ajax/libs/processing.js/1.4.8/processing.min.js"></script>
</head>
<body>
<canvas id="canvas"></canvas>
<script>
var canvas = document.getElementById("canvas");
var processing = new Processing(canvas, function(processing) {
processing.size(400, 400);
processing.background(0xFFF);
var mouseIsPressed = false;
processing.mousePressed = function () { mouseIsPressed = true; };
processing.mouseReleased = function () { mouseIsPressed = false; };
var keyIsPressed = false;
processing.keyPressed = function () { keyIsPressed = true; };
processing.keyReleased = function () { keyIsPressed = false; };
function getImage(s) {
var url = "https://www.kasandbox.org/programming-images/" + s + ".png";
processing.externals.sketch.imageCache.add(url);
return processing.loadImage(url);
}
// use degrees rather than radians in rotate function
var rotateFn = processing.rotate;
processing.rotate = function (angle) {
rotateFn(processing.radians(angle));
};
with (processing) {
// INSERT YOUR KHAN ACADEMY PROGRAM HERE
}
if (typeof draw !== 'undefined') processing.draw = draw;
});
</script>
</body>
</html>
回答2:
ADDON to the answer of Robert:
Processing.js uses radians as default for angle values, Khan Academy JS uses degrees. If you add following lines to Robert's code above (before the with statement), then you can use the rotate commands as they come from KA.
var rotateFn = processing.rotate;
processing.rotate = function(angle) {
rotateFn(processing.radians(angle));
}
回答3:
Yeah, sorry I'm kind-of late to this question. But I have figured it out on my own...
You can clone this repository or follow the instructions down below:
Or you can set things up like this: In your index.html put source to all 3 of these files:
Processing.js:
https://raw.githubusercontent.com/Khan/processing-js/66bec3a3ae88262fcb8e420f7fa581b46f91a052/processing.js
loadKa.js:
This is production code to load multiple separate files together:
!(function(window, JSON, localStorage)
{
function createProcessing()
{
var args = Array.prototype.slice.call(arguments);
args.push({ beginCode: "with(processing)\n{", endCode: "}"});
var any = combine.apply(this, args);
this.cache = window.cache = {};
this.cache.loadedImages = window.cache.loadedImages = {};
this.cache.imageNames = window.cache.imageNames = [
"avatars/aqualine-sapling",
"avatars/aqualine-seed",
"avatars/aqualine-seedling",
"avatars/aqualine-tree",
"avatars/aqualine-ultimate",
"avatars/avatar-team",
"avatars/duskpin-sapling",
"avatars/duskpin-seed",
"avatars/duskpin-tree",
"avatars/duskpin-ultimate",
"avatars/leaf-blue",
"avatars/leaf-green",
"avatars/leaf-grey",
"avatars/leaf-orange",
"avatars/leaf-red",
"avatars/leaf-yellow",
"avatars/leafers-sapling",
"avatars/leafers-seed",
"avatars/leafers-seedling",
"avatars/leafers-tree",
"avatars/leafers-ultimate",
"avatars/marcimus",
"avatars/marcimus-orange",
"avatars/marcimus-purple",
"avatars/marcimus-red",
"avatars/mr-pants",
"avatars/mr-pants-green",
"avatars/mr-pants-orange",
"avatars/mr-pants-pink",
"avatars/mr-pants-purple",
"avatars/mr-pants-with-hat",
"avatars/mr-pink",
"avatars/mr-pink-green",
"avatars/mr-pink-orange",
"avatars/old-spice-man",
"avatars/old-spice-man-blue",
"avatars/orange-juice-squid",
"avatars/piceratops-sapling",
"avatars/piceratops-seed",
"avatars/piceratops-seedling",
"avatars/piceratops-tree",
"avatars/piceratops-ultimate",
"avatars/primosaur-sapling",
"avatars/primosaur-seed",
"avatars/primosaur-seedling",
"avatars/primosaur-tree",
"avatars/primosaur-ultimate",
"avatars/purple-pi",
"avatars/purple-pi-pink",
"avatars/purple-pi-teal",
"avatars/questionmark",
"avatars/robot_female_1",
"avatars/robot_female_2",
"avatars/robot_female_3",
"avatars/robot_male_1",
"avatars/robot_male_2",
"avatars/robot_male_3",
"avatars/spunky-sam",
"avatars/spunky-sam-green",
"avatars/spunky-sam-orange",
"avatars/spunky-sam-red",
"avatars/starky-sapling",
"avatars/starky-seed",
"avatars/starky-seedling",
"avatars/starky-tree",
"avatars/starky-ultimate",
"creatures/Hopper-Happy",
"creatures/Hopper-Cool",
"creatures/Hopper-Jumping",
"creatures/OhNoes",
"creatures/OhNoes-Happy",
"creatures/OhNoes-Hmm",
"cute/Blank",
"cute/BrownBlock",
"cute/CharacterBoy",
"cute/CharacterCatGirl",
"cute/CharacterHornGirl",
"cute/CharacterPinkGirl",
"cute/CharacterPrincessGirl",
"cute/ChestClosed",
"cute/ChestLid",
"cute/ChestOpen",
"cute/DirtBlock",
"cute/DoorTallClosed",
"cute/DoorTallOpen",
"cute/EnemyBug",
"cute/GemBlue",
"cute/GemGreen",
"cute/GemOrange",
"cute/GrassBlock",
"cute/Heart",
"cute/Key",
"cute/PlainBlock",
"cute/RampEast",
"cute/RampWest",
"cute/Rock",
"cute/RoofEast",
"cute/RoofNorth",
"cute/RoofNorthEast",
"cute/RoofNorthWest",
"cute/RoofSouth",
"cute/RoofSouthEast",
"cute/RoofSouthWest",
"cute/RoofWest",
"cute/Selector",
"cute/ShadowEast",
"cute/ShadowNorth",
"cute/ShadowNorthEast",
"cute/ShadowNorthWest",
"cute/ShadowSideWest",
"cute/ShadowSouth",
"cute/ShadowSouthEast",
"cute/ShadowSouthWest",
"cute/ShadowWest",
"cute/WoodBlock",
"cute/Star",
"cute/StoneBlock",
"cute/StoneBlockTall",
"cute/TreeShort",
"cute/TreeTall",
"space/girl2",
"space/girl3",
"space/girl4",
"space/girl5",
"space/healthheart",
"space/minus",
"space/octopus",
"space/planet",
"space/plus",
"space/rocketship",
"space/star",
"space/3",
"space/4",
"space/5",
"space/6",
"space/7",
"space/8",
"space/9"
];
window.links = {
proxyUrl : "https://cors-anywhere.herokuapp.com/",
image : ["https://www.kasandbox.org/third_party/javascript-khansrc/live-editor/build/images/",
"https://github.com/Khan/live-editor/tree/master/images",
"https://www.kasandbox.org/programming-images/"],
};
var self = this;
this.setup = function()
{
function code(processing)
{
processing.size(400, 400);
processing.background(255, 255, 255);
processing.angleMode = "degrees";
processing.mousePressed = function() {};
processing.mouseReleased = function() {};
processing.mouseMoved = function() {};
processing.mouseDragged = function() {};
processing.mouseOver = function() {};
processing.mouseOut = function() {};
processing.keyPressed = function() {};
processing.keyReleased = function() {};
processing.keyTyped = function() {};
processing.getSound = function(name)
{
return "Sound";
};
processing.playSound = function(sound)
{
console.log(sound + " is not supported yet...");
};
processing.getImage = function(name)
{
return (window.cache || self.cache).loadedImages[name] || processing.get(0, 0, 1, 1);
};
var lastGet = processing.get;
processing.get = function()
{
try{
return lastGet.apply(this, arguments);
}
catch(e)
{
if(arguments[2] !== 0 && arguments[3] !== 0)
{
console.log(e);
}else{
throw e;
}
}
};
processing.debug = function(event)
{
try{
return window.console.log.apply(this, arguments);
}
catch(e)
{
processing.println.apply(this, arguments);
}
};
processing.Program = {
restart: function()
{
window.location.reload();
},
assertEqual: function(equiv)
{
if(!equiv)
{
console.warn(equiv);
}
},
};
}
code = combine(new Function("return " + code.toString().split("\n").join(" "))(), any);
var matched = code.toString().match("this[ ]*\[[ ]*\[[ ]*(\"KAInfiniteLoopSetTimeout\")[ ]*\][ ]*\][ ]*\([ ]*\d*[ ]*\);*");
if(matched)
{
code = new Function("return " + code.toString().replace(matched[0], ""))();
}
window.canvas = document.getElementById("canvas");
window.processing = new Processing(canvas, code);
};
this.imageProcessing = new Processing(canvas, function(processing)
{
try{
processing.imageCache = JSON.parse(localStorage.getItem("imageCache"));
}
catch(e)
{
console.log(e);
}
if(!processing.imageCache)
{
processing.imageCache = {};
}
processing.getImage = function(name, callback, url)
{
if(name === undefined) { return get(0, 0, 1, 1); }
url = url || window.links.image[0] + name.split(".")[0] + ".png";
callback = callback || function() {};
if(!processing.imageCache)
{
var img = processing.loadImage(url);
callback(img, name);
return img;
}
if(processing.imageCache[name])
{
var img = processing.loadImage(processing.imageCache[name]);
callback(img, name);
return img;
}
toDataURL(window.links.proxyUrl + url, function(dataUrl)
{
processing.imageCache[name] = dataUrl;
localStorage.setItem("imageCache", JSON.stringify(processing.imageCache));
callback(processing.imageCache[name], name);
});
return processing.loadImage(processing.imageCache[url] || url);
};
window.cache.imageNames.forEach(function(element, index, array)
{
processing.getImage(element, function(img, name)
{
window.cache.loadedImages[name] = img;
if(index === array.length - 1)
{
(window.setTimeout || function(func)
{
return func.apply(this, arguments);
})
(function()
{
self.setup();
}, 50);
}
});
});
});
}
function combine(a, c)
{
var args = Array.prototype.slice.call(arguments);
var config = {};
var funcArgs = "";
var join = "";
for(var i = 0; i < args.length; i++)
{
if(typeof args[i] === "object")
{
config = args[i];
continue;
}
var to = args[i].toString();
var temp = to.substring(to.indexOf('(') + 1, to.indexOf(')'));
if(temp !== "" && temp !== " ")
{
funcArgs += temp + ",";
}
join += to.slice(to.indexOf('{') + 1, -1);
}
funcArgs = funcArgs.slice(0, -1);
return new Function("return function any(" + funcArgs + "){" + (config.beginCode || "").replace("\n", "") + join + (config.endCode || "") + "}")();
}
function toDataURL(url, callback)
{
var xhr = new XMLHttpRequest();
xhr.onload = function()
{
var reader = new FileReader();
reader.onloadend = function()
{
callback(reader.result);
}
reader.readAsDataURL(xhr.response);
};
xhr.open('GET', url);
xhr.responseType = 'blob';
xhr.send();
}
return {
createProcessing: window.createProcessing = this.createProcessing = createProcessing,
toDataURL: window.toDataURL = this.toDataURL = toDataURL,
combine: window.combine = this.combine = combine,
};
}(
(window || {}),
(JSON || { stringify: function() { return "{}"; }, parse: function() { return {}; } }),
(localStorage || { getItem: function() { return {} }, setItem: function() {}, removeItem: function() {} })
));
Index.js:
In your index.js file Usage:
function main()
{
//Your code here (Trust me it really works!)
}
createProcessing(main);
You can also add more arguments as functions to the createProcessing function. Yeah I have everything except sounds and sometimes (rarely) hyped up controls!
来源：https://stackoverflow.com/questions/25341597/how-can-khan-academy-computer-programs-be-run-offline-or-on-my-own-website