paper.js/src/core/PaperScript.js
2013-06-28 06:39:00 -07:00

370 lines
11 KiB
JavaScript

/*
* Paper.js - The Swiss Army Knife of Vector Graphics Scripting.
* http://paperjs.org/
*
* Copyright (c) 2011 - 2013, Juerg Lehni & Jonathan Puckey
* http://lehni.org/ & http://jonathanpuckey.com/
*
* Distributed under the MIT license. See LICENSE file for details.
*
* All rights reserved.
*/
/**
* @name PaperScript
* @namespace
*/
// Note that due to the use of with(), PaperScript gets compiled outside the
// main paper scope, and is added to the PaperScope class. This allows for
// better minification and the future use of strict mode once it makes sense
// in terms of performance.
paper.PaperScope.prototype.PaperScript = new function() {
var Base = paper.Base,
PaperScope = paper.PaperScope,
// Locally turn of exporst for inlined acorn / esprima.
exports = undefined;
/*#*/ if (options.parser == 'acorn') {
/*#*/ include('../../components/acorn/acorn.min.js', { exports: false });
/*#*/ } else if (options.parser == 'esprima') {
/*#*/ include('../../components/esprima/esprima.min.js', { exports: false });
/*#*/ }
// Operators to overload
var binaryOperators = {
// The hidden math functions are to be injected specifically, see below.
'+': '_add',
'-': '_subtract',
'*': '_multiply',
'/': '_divide',
'%': '_modulo',
// Use the real equals.
'==': 'equals',
'!=': 'equals'
};
var unaryOperators = {
'-': '_negate',
'+': null
};
// Add hidden math functions to Point, Size and Color.
var fields = Base.each(
'add,subtract,multiply,divide,modulo,negate'.split(','),
function(name) {
this['_' + name] = '#' + name;
},
{}
);
paper.Point.inject(fields);
paper.Size.inject(fields);
paper.Color.inject(fields);
// Use very short name for the binary operator (_$_) as well as the
// unary operator ($_), as operations will be replaced with then.
// The underscores stands for the values, and the $ for the operators.
// Binary Operator Handler
function _$_(left, operator, right) {
var handler = binaryOperators[operator];
if (left && left[handler]) {
var res = left[handler](right);
return operator === '!=' ? !res : res;
}
switch (operator) {
case '+': return left + right;
case '-': return left - right;
case '*': return left * right;
case '/': return left / right;
case '%': return left % right;
case '==': return left == right;
case '!=': return left != right;
}
}
// Unary Operator Handler
function $_(operator, value) {
var handler = unaryOperators[operator];
if (handler && value && value[handler])
return value[handler]();
switch (operator) {
case '+': return +value;
case '-': return -value;
}
}
// AST Helpers
/**
* Compiles PaperScript code into JavaScript code.
*
* @name PaperScript.compile
* @function
* @param {String} code The PaperScript code.
* @return {String} The compiled PaperScript as JavaScript code.
*/
function compile(code) {
// Use Acorn or Esprima to translate the code into an AST structure
// which is then walked and parsed for operators to overload.
// Instead of modifying the AST and converting back to code, we directly
// change the source code based on the parser's range information, so we
// can preserve line-numbers in syntax errors and remove the need for
// Escodegen.
// Tracks code insertions so we can add their differences to the
// original offsets.
var insertions = [];
// Converts an original offset to the one in the current state of the
// modified code.
function getOffset(offset) {
// Add all insertions before this location together to calculate
// the current offset
for (var i = 0, l = insertions.length; i < l; i++) {
var insertion = insertions[i];
if (insertion[0] >= offset)
break;
offset += insertion[1];
}
return offset;
}
// Returns the node's code as a string, taking insertions into account.
function getCode(node) {
return code.substring(getOffset(node.range[0]),
getOffset(node.range[1]));
}
// Replaces the node's code with a new version and keeps insertions
// information up-to-date.
function replaceCode(node, str) {
var start = getOffset(node.range[0]),
end = getOffset(node.range[1]);
var insert = 0;
// Sort insertions by their offset, so getOffest() can do its thing
for (var i = insertions.length - 1; i >= 0; i--) {
if (start > insertions[i][0]) {
insert = i + 1;
break;
}
}
insertions.splice(insert, 0, [start, str.length - end + start]);
code = code.substring(0, start) + str + code.substring(end);
}
// Recursively walks the AST and replaces the code of certain nodes
function walkAst(node) {
// array[i++] is a MemberExpression with computed = true.
// We cannot replace that with array[_$_(i, "+", 1)], as it would
// break the code, so let's bail out.
if (!node || node.type === 'MemberExpression' && node.computed)
return;
for (var key in node) {
if (key === 'range')
continue;
var value = node[key];
if (Array.isArray(value)) {
for (var i = 0, l = value.length; i < l; i++)
walkAst(value[i]);
} else if (value && typeof value === 'object') {
// We cannot use Base.isPlainObject() for these since
// Acorn.js uses its own internal prototypes now.
walkAst(value);
}
}
switch (node && node.type) {
case 'BinaryExpression':
if (node.operator in binaryOperators
&& node.left.type !== 'Literal') {
var left = getCode(node.left),
right = getCode(node.right);
replaceCode(node, '_$_(' + left + ', "' + node.operator
+ '", ' + right + ')');
}
break;
case 'AssignmentExpression':
if (/^.=$/.test(node.operator)
&& node.left.type !== 'Literal') {
var left = getCode(node.left),
right = getCode(node.right);
replaceCode(node, left + ' = _$_(' + left + ', "'
+ node.operator[0] + '", ' + right + ')');
}
break;
case 'UpdateExpression':
if (!node.prefix) {
var arg = getCode(node.argument);
replaceCode(node, arg + ' = _$_(' + arg + ', "'
+ node.operator[0] + '", 1)');
}
break;
case 'UnaryExpression':
if (node.operator in unaryOperators
&& node.argument.type !== 'Literal') {
var arg = getCode(node.argument);
replaceCode(node, '$_("' + node.operator + '", '
+ arg + ')');
}
break;
}
}
// Now do the parsing magic
/*#*/ if (options.parser == 'acorn') {
walkAst(acorn.parse(code, { ranges: true }));
/*#*/ } else if (options.parser == 'esprima') {
walkAst(esprima.parse(code, { range: true }));
/*#*/ }
return code;
}
/**
* Evaluates parsed PaperScript code in the passed {@link PaperScope}
* object. It also installs handlers automatically for us.
*
* @name PaperScript.evaluate
* @function
* @param {String} code The PaperScript code.
* @param {PaperScript} scope The scope in which the code is executed.
* @return {Object} The result of the code evaluation.
*/
function evaluate(code, scope) {
// Set currently active scope.
paper = scope;
var view = scope.project && scope.project.view,
res;
// Define variables for potential handlers, so eval() calls below to
// fetch their values do not require try-catch around them.
// Use with(){} in order to make the scope the current 'global' scope
// instead of window.
with (scope) {
// Within this, use a function scope, so local variables to not try
// and set themselves on the scope object.
(function() {
var onActivate, onDeactivate, onEditOptions,
onMouseDown, onMouseUp, onMouseDrag, onMouseMove,
onKeyDown, onKeyUp, onFrame, onResize;
res = eval(compile(code));
// Only look for tool handlers if something resembling their
// name is contained in the code.
if (/on(?:Key|Mouse)(?:Up|Down|Move|Drag)/.test(code)) {
Base.each(paper.Tool.prototype._events, function(key) {
var value = eval(key);
if (value) {
// Use the getTool accessor that handles auto tool
// creation for us:
scope.getTool()[key] = value;
}
});
}
if (view) {
view.setOnResize(onResize);
// Fire resize event directly, so any user
// defined resize handlers are called.
view.fire('resize', {
size: view.size,
delta: new Point()
});
view.setOnFrame(onFrame);
// Automatically draw view at the end.
view.draw();
}
}).call(scope);
}
return res;
}
/*#*/ if (options.browser) {
// Code borrowed from Coffee Script:
function request(url, scope) {
var xhr = new (window.ActiveXObject || XMLHttpRequest)(
'Microsoft.XMLHTTP');
xhr.open('GET', url, true);
if (xhr.overrideMimeType)
xhr.overrideMimeType('text/plain');
xhr.onreadystatechange = function() {
if (xhr.readyState === 4) {
return evaluate(xhr.responseText, scope);
}
};
return xhr.send(null);
}
function load() {
var scripts = document.getElementsByTagName('script');
for (var i = 0, l = scripts.length; i < l; i++) {
var script = scripts[i];
// Only load this script if it not loaded already.
// Support both text/paperscript and text/x-paperscript:
if (/^text\/(?:x-|)paperscript$/.test(script.type)
&& !script.getAttribute('data-paper-ignore')) {
// Produce a new PaperScope for this script now. Scopes are
// cheap so let's not worry about the initial one that was
// already created.
// Define an id for each PaperScript, so its scope can be
// retrieved through PaperScope.get().
// If a canvas id is provided, pass it on to the PaperScope
// so a project is created for it now.
var canvas = PaperScope.getAttribute(script, 'canvas'),
// See if there already is a scope for this canvas and reuse
// it, to support multiple scripts per canvas. Otherwise
// create a new one.
scope = PaperScope.get(canvas)
|| new PaperScope(script).setup(canvas);
if (script.src) {
// If we're loading from a source, request that first and then
// run later.
request(script.src, scope);
} else {
// We can simply get the code form the script tag.
evaluate(script.innerHTML, scope);
}
// Mark script as loaded now.
script.setAttribute('data-paper-ignore', true);
}
}
}
// Catch cases where paper.js is loaded after the browser event has already
// occurred.
if (document.readyState === 'complete') {
// Handle it asynchronously
setTimeout(load);
} else {
paper.DomEvent.add(window, { load: load });
}
return {
compile: compile,
evaluate: evaluate,
load: load
};
/*#*/ } else { // !options.browser
/*#*/ if (options.node) {
// Register the .pjs extension for automatic compilation as PaperScript
var fs = require('fs'),
path = require('path');
require.extensions['.pjs'] = function(module, uri) {
var source = compile(fs.readFileSync(uri, 'utf8')),
scope = new PaperScope();
scope.__filename = uri;
scope.__dirname = path.dirname(uri);
// Expose core methods and values
scope.require = require;
scope.console = console;
evaluate(source, scope);
module.exports = scope;
};
/*#*/ } // options.node
return {
compile: compile,
evaluate: evaluate
};
/*#*/ } // !options.browser
};