paper.js/src/core/PaperScript.js

597 lines
26 KiB
JavaScript

/*
* Paper.js - The Swiss Army Knife of Vector Graphics Scripting.
* http://paperjs.org/
*
* Copyright (c) 2011 - 2016, Juerg Lehni & Jonathan Puckey
* http://scratchdisk.com/ & http://jonathanpuckey.com/
*
* Distributed under the MIT license. See LICENSE file for details.
*
* All rights reserved.
*/
/**
* @name PaperScript
* @namespace
*/
Base.exports.PaperScript = function() {
// Locally turn of exports and define for inlined acorn.
// Just declaring the local vars is enough, as they will be undefined.
var exports, define,
// The scope into which the library is loaded.
scope = this;
/*#*/ include('../../node_modules/acorn/acorn.min.js', { exports: false });
// Operators to overload
var binaryOperators = {
// The hidden math methods are to be injected specifically, see below.
'+': '__add',
'-': '__subtract',
'*': '__multiply',
'/': '__divide',
'%': '__modulo',
'==': '__equals',
'!=': '__equals'
};
var unaryOperators = {
'-': '__negate',
'+': null
};
// Inject underscored math methods as aliases to Point, Size and Color.
var fields = Base.each(
['add', 'subtract', 'multiply', 'divide', 'modulo', 'equals', 'negate'],
function(name) {
// Create an alias for each math method to be injected into the
// classes using Straps.js' #inject()
this['__' + name] = '#' + name;
},
{}
);
Point.inject(fields);
Size.inject(fields);
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
function parse(code, options) {
return scope.acorn.parse(code, options);
}
/**
* Compiles PaperScript code into JavaScript code.
*
* @name PaperScript.compile
* @function
*
* @option options.url {String} the url of the source, for source-map
* generation
* @option options.source {String} the source to be used for the source-
* mapping, in case the code that's passed in has already been mingled.
*
* @param {String} code the PaperScript code
* @param {Object} [option] the compilation options
* @return {Object} an object holding the compiled PaperScript translated
* into JavaScript code along with source-maps and other information.
*/
function compile(code, options) {
if (!code)
return '';
options = options || {};
// 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 translating it back to code, we directly change
// the source code based on the parser's range information, to preserve
// line-numbers in syntax errors and remove the need for Escodegen.
// Track code insertions so their differences can be added 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]));
}
// Returns the code between two nodes, e.g. an operator and white-space.
function getBetween(left, right) {
return code.substring(getOffset(left.range[1]),
getOffset(right.range[0]));
}
// 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]),
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, parent) {
if (!node)
return;
// The easiest way to walk through the whole AST is to simply loop
// over each property of the node and filter out fields we don't
// need to consider...
for (var key in node) {
if (key === 'range' || key === 'loc')
continue;
var value = node[key];
if (Array.isArray(value)) {
for (var i = 0, l = value.length; i < l; i++)
walkAST(value[i], node);
} else if (value && typeof value === 'object') {
// We cannot use Base.isPlainObject() for these since
// Acorn.js uses its own internal prototypes now.
walkAST(value, node);
}
}
switch (node.type) {
case 'UnaryExpression': // -a
if (node.operator in unaryOperators
&& node.argument.type !== 'Literal') {
var arg = getCode(node.argument);
replaceCode(node, '$__("' + node.operator + '", '
+ arg + ')');
}
break;
case 'BinaryExpression': // a + b, a - b, a / b, a * b, a == b, ...
if (node.operator in binaryOperators
&& node.left.type !== 'Literal') {
var left = getCode(node.left),
right = getCode(node.right),
between = getBetween(node.left, node.right),
operator = node.operator;
replaceCode(node, '__$__(' + left + ','
// To preserve line-breaks, get the code in between
// left & right, and replace the occurrence of the
// operator with its string counterpart:
+ between.replace(new RegExp('\\' + operator),
'"' + operator + '"')
+ ', ' + right + ')');
}
break;
case 'UpdateExpression': // a++, a--, ++a, --a
case 'AssignmentExpression': /// a += b, a -= b
var parentType = parent && parent.type;
if (!(
// Filter out for statements to allow loop increments
// to perform well
parentType === 'ForStatement'
// We need to filter out parents that are comparison
// operators, e.g. for situations like `if (++i < 1)`,
// as we can't replace that with
// `if (__$__(i, "+", 1) < 1)`
// Match any operator beginning with =, !, < and >.
|| parentType === 'BinaryExpression'
&& /^[=!<>]/.test(parent.operator)
// array[i++] is a MemberExpression with computed = true
// We can't replace that with array[__$__(i, "+", 1)].
|| parentType === 'MemberExpression' && parent.computed
)) {
if (node.type === 'UpdateExpression') {
var arg = getCode(node.argument),
exp = '__$__(' + arg + ', "' + node.operator[0]
+ '", 1)',
str = arg + ' = ' + exp;
// If this is not a prefixed update expression
// (++a, --a), assign the old value before updating it.
if (!node.prefix
&& (parentType === 'AssignmentExpression'
|| parentType === 'VariableDeclarator')) {
// Handle special issue #691 where the old value is
// assigned to itself, and the expression is just
// executed after, e.g.: `var x = ***; x = x++;`
if (getCode(parent.left || parent.id) === arg)
str = exp;
str = arg + '; ' + str;
}
replaceCode(node, str);
} else { // AssignmentExpression
if (/^.=$/.test(node.operator)
&& node.left.type !== 'Literal') {
var left = getCode(node.left),
right = getCode(node.right),
exp = left + ' = __$__(' + left + ', "'
+ node.operator[0] + '", ' + right + ')';
// If the original expression is wrapped in
// parenthesis, do the same with the replacement:
replaceCode(node, /^\(.*\)$/.test(getCode(node))
? '(' + exp + ')' : exp);
}
}
}
break;
}
}
// Source-map support:
// Encodes a Variable Length Quantity as a Base64 string.
// See: http://www.html5rocks.com/en/tutorials/developertools/sourcemaps
function encodeVLQ(value) {
var res = '',
base64 = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
value = (Math.abs(value) << 1) + (value < 0 ? 1 : 0);
while (value || !res) {
var next = value & (32 - 1);
value >>= 5;
if (value)
next |= 32;
res += base64[next];
}
return res;
}
var url = options.url || '',
agent = paper.agent,
version = agent.versionNumber,
offsetCode = false,
sourceMaps = options.sourceMaps,
// Include the original code in the sourceMap if there is no linked
// source file so the debugger can still display it correctly.
source = options.source || code,
lineBreaks = /\r\n|\n|\r/mg,
offset = options.offset || 0,
map;
// TODO: Verify these browser versions for source map support, and check
// other browsers.
if (sourceMaps && (agent.chrome && version >= 30
|| agent.webkit && version >= 537.76 // >= Safari 7.0.4
|| agent.firefox && version >= 23
|| agent.node)) {
if (agent.node) {
// -2 required to remove function header:
// https://code.google.com/p/chromium/issues/detail?id=331655
offset -= 2;
} else if (window && url && !window.location.href.indexOf(url)) {
// If the code stems from the actual html page, determine the
// offset of inlined code.
var html = document.getElementsByTagName('html')[0].innerHTML;
// Count the amount of line breaks in the html before this code
// to determine the offset.
offset = html.substr(0, html.indexOf(code) + 1).match(
lineBreaks).length + 1;
}
// A hack required by older versions of browsers to align inlined
// code: Instead of starting the mappings at the given offset, we
// have to shift the actual code down to the place in the original
// file, as source-map support seems incomplete in these browsers.
offsetCode = offset > 0 && !(
agent.chrome && version >= 36 ||
agent.safari && version >= 600 ||
agent.firefox && version >= 40 ||
agent.node);
var mappings = ['AA' + encodeVLQ(offsetCode ? 0 : offset) + 'A'];
// Create empty entries by the amount of lines + 1, so join can be
// used below to produce the actual instructions that many times.
mappings.length = (code.match(lineBreaks) || []).length + 1
+ (offsetCode ? offset : 0);
map = {
version: 3,
file: url,
names:[],
// Since PaperScript doesn't actually change the offsets between
// the lines of the original code, all that is required is a
// mappings string that increments by one between each line.
// AACA is the instruction to increment the line by one.
// TODO: Add support for column offsets!
mappings: mappings.join(';AACA'),
sourceRoot: '',
sources: [url],
sourcesContent: [source]
};
}
// Now do the parsing magic
walkAST(parse(code, { ranges: true }));
if (map) {
if (offsetCode) {
// Adjust the line offset of the resulting code if required.
// This is part of a browser hack, see above.
code = new Array(offset + 1).join('\n') + code;
}
if (/^(inline|both)$/.test(sourceMaps)) {
code += "\n//# sourceMappingURL=data:application/json;base64,"
+ self.btoa(unescape(encodeURIComponent(
JSON.stringify(map))));
}
code += "\n//# sourceURL=" + (url || 'paperscript');
}
return {
url: url,
source: source,
code: code,
map: map
};
}
/**
* Compiles the PaperScript code into a compiled function and executes it.
* The compiled function receives all properties of the passed {@link
* PaperScope} as arguments, to emulate a global scope with unaffected
* performance. It also installs global view and tool handlers automatically
* on the respective objects.
*
* @name PaperScript.execute
* @function
*
* @option options.url {String} the url of the source, for source-map
* generation
* @option options.source {String} the source to be used for the source-
* mapping, in case the code that's passed in has already been mingled.
*
* @param {String} code the PaperScript code
* @param {PaperScope} scope the scope for which the code is executed
* @param {Object} [option] the compilation options
* @return {Object} an object holding the compiled PaperScript translated
* into JavaScript code along with source-maps and other information.
*/
function execute(code, scope, options) {
// Set currently active scope.
paper = scope;
var view = scope.getView(),
// Only create a tool if the tool object is accessed or something
// resembling a global tool handler is contained in the code, but
// no tool objects are actually created.
tool = /\btool\.\w+|\s+on(?:Key|Mouse)(?:Up|Down|Move|Drag)\b/
.test(code) && !/\bnew\s+Tool\b/.test(code)
? new Tool() : null,
toolHandlers = tool ? tool._events : [],
// Compile a list of all handlers that can be defined globally
// inside the PaperScript. These are passed on to the function as
// undefined arguments, so that their name exists, rather than
// injecting a code line that defines them as variables. They are
// exported again at the end of the function.
handlers = ['onFrame', 'onResize'].concat(toolHandlers),
// compile a list of parameter names for all variables that need to
// appear as globals inside the script. At the same time, also
// collect their values, so we can pass them on as arguments in the
// function call.
params = [],
args = [],
func,
compiled = typeof code === 'object' ? code : compile(code, options);
code = compiled.code;
function expose(scope, hidden) {
// Look through all enumerable properties on the scope and expose
// these too as pseudo-globals, but only if they seem to be in use.
for (var key in scope) {
// Next to \b well also need to match \s and \W in the beginning
// of $__, since $ is not part of \w. And that causes \b to not
// match ^ longer, so include that specifically too.
if ((hidden || !/^_/.test(key)) && new RegExp('([\\b\\s\\W]|^)'
+ key.replace(/\$/g, '\\$') + '\\b').test(code)) {
params.push(key);
args.push(scope[key]);
}
}
}
expose({ __$__: __$__, $__: $__, paper: scope, view: view, tool: tool },
true);
expose(scope);
// Finally define the handler variable names as parameters and compose
// the string describing the properties for the returned object at the
// end of the code execution, so we can retrieve their values from the
// function call.
handlers = Base.each(handlers, function(key) {
// Check for each handler explicitly and only return them if they
// seem to exist.
if (new RegExp('\\s+' + key + '\\b').test(code)) {
params.push(key);
this.push(key + ': ' + key);
}
}, []).join(', ');
// We need an additional line that returns the handlers in one object.
if (handlers)
code += '\nreturn { ' + handlers + ' };';
var agent = paper.agent;
if (document && (agent.chrome
|| agent.firefox && agent.versionNumber < 40)) {
// On older Firefox, all error numbers inside dynamically compiled
// code are relative to the line where the eval / compilation
// happened. To fix this issue, we're temporarily inserting a new
// script tag.
// We also use this on Chrome to fix issues with compiled functions:
// https://code.google.com/p/chromium/issues/detail?id=331655
var script = document.createElement('script'),
head = document.head || document.getElementsByTagName('head')[0];
// Add a new-line before the code on Firefox since the error
// messages appear to be aligned to line number 0...
if (agent.firefox)
code = '\n' + code;
script.appendChild(document.createTextNode(
'paper._execute = function(' + params + ') {' + code + '\n}'
));
head.appendChild(script);
func = paper._execute;
delete paper._execute;
head.removeChild(script);
} else {
func = Function(params, code);
}
var res = func.apply(scope, args) || {};
// Now install the 'global' tool and view handlers, and we're done!
Base.each(toolHandlers, function(key) {
var value = res[key];
if (value)
tool[key] = value;
});
if (view) {
if (res.onResize)
view.setOnResize(res.onResize);
// Emit resize event directly, so any user
// defined resize handlers are called.
view.emit('resize', {
size: view.size,
delta: new Point()
});
if (res.onFrame)
view.setOnFrame(res.onFrame);
// Automatically request an update at the end. This is only needed
// if the script does not actually produce anything yet, and the
// used canvas contains previous content.
view.requestUpdate();
}
return compiled;
}
function loadScript(script) {
// Only load this script if it not loaded already.
// Support both text/paperscript and text/x-paperscript:
if (/^text\/(?:x-|)paperscript$/.test(script.type)
&& PaperScope.getAttribute(script, 'ignore') !== 'true') {
// 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 canvasId = PaperScope.getAttribute(script, 'canvas'),
canvas = document.getElementById(canvasId),
// To avoid possible duplicate browser requests for PaperScript
// files, support the data-src attribute as well as src:
// TODO: Consider switching from data-paper- to data- prefix
// in PaperScope.getAttribute() and use it here too:
src = script.src || script.getAttribute('data-src'),
async = PaperScope.hasAttribute(script, 'async'),
scopeAttribute = 'data-paper-scope';
if (!canvas)
throw new Error('Unable to find canvas with id "'
+ canvasId + '"');
// See if there already is a scope for this canvas and reuse it, to
// support multiple scripts per canvas. Otherwise create a new one.
var scope = PaperScope.get(canvas.getAttribute(scopeAttribute))
|| new PaperScope().setup(canvas);
// Link the element to this scope, so we can reuse the scope when
// compiling multiple scripts for the same element.
canvas.setAttribute(scopeAttribute, scope._id);
if (src) {
// If we're loading from a source, request the source
// synchronously to guarantee code is executed in the
// same order the script tags appear.
// If the async attribute is specified on the script element,
// request the source asynchronously and execute as soon as
// it is retrieved.
Http.request({
url: src,
async: async,
mimeType: 'text/plain',
onLoad: function(code) {
execute(code, scope, src);
}
});
} else {
// We can simply get the code form the script tag.
execute(script.innerHTML, scope, script.baseURI);
}
// Mark script as loaded now.
script.setAttribute('data-paper-ignore', 'true');
return scope;
}
}
function loadAll() {
Base.each(document && document.getElementsByTagName('script'),
loadScript);
}
/**
* Loads, compiles and executes PaperScript code in the HTML document. Note
* that this method is executed automatically for all scripts in the
* document through a window load event. You can optionally call it earlier
* (e.g. from a DOM ready event), or you can mark scripts to be ignored by
* setting the attribute `ignore="true"` or `data-paper-ignore="true"`, and
* call the `PaperScript.load(script)` method for each script separately
* when needed.
*
* @name PaperScript.load
* @function
* @param {HTMLScriptElement} [script=null] the script to load. If none is
* provided, all scripts of the HTML document are iterated over and
* loaded
* @return {PaperScope} the scope produced for the passed `script`, or
* `undefined` of multiple scripts area loaded
*/
function load(script) {
return script ? loadScript(script) : loadAll();
}
if (window) {
// Catch cases where paper.js is loaded after the browser event has
// already occurred.
if (document.readyState === 'complete') {
// Handle it asynchronously
setTimeout(loadAll);
} else {
DomEvent.add(window, { load: loadAll });
}
}
return {
compile: compile,
execute: execute,
load: load,
parse: parse
};
// Pass on `this` as the binding object, so we can reference Acorn both in
// development and in the built library.
}.call(this);