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Merge pull request #994 from brendandahl/type4func

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Type4 PostScript Functions
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notmasteryet 2011-12-30 16:05:49 -08:00
commit c0cf081ec0
7 changed files with 792 additions and 7 deletions
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546
src/function.js
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@ -336,16 +336,550 @@ var PDFFunction = (function PDFFunctionClosure() {
};
},
constructPostScript: function pdfFunctionConstructPostScript() {
return [CONSTRUCT_POSTSCRIPT];
constructPostScript: function pdfFunctionConstructPostScript(fn, dict,
xref) {
var domain = dict.get('Domain');
var range = dict.get('Range');
if (!domain)
error('No domain.');
if (!range)
error('No range.');
var lexer = new PostScriptLexer(fn);
var parser = new PostScriptParser(lexer);
var code = parser.parse();
return [CONSTRUCT_POSTSCRIPT, domain, range, code];
},
constructPostScriptFromIR: function pdfFunctionConstructPostScriptFromIR() {
TODO('unhandled type of function');
return function constructPostScriptFromIRResult() {
return [255, 105, 180];
constructPostScriptFromIR:
function pdfFunctionConstructPostScriptFromIR(IR) {
var domain = IR[1];
var range = IR[2];
var code = IR[3];
var numOutputs = range.length / 2;
var evaluator = new PostScriptEvaluator(code);
// Cache the values for a big speed up, the cache size is limited though
// since the number of possible values can be huge from a PS function.
var cache = new FunctionCache();
return function constructPostScriptFromIRResult(args) {
var initialStack = [];
for (var i = 0, ii = (domain.length / 2); i < ii; ++i) {
initialStack.push(args[i]);
}
var key = initialStack.join('_');
if (cache.has(key))
return cache.get(key);
var stack = evaluator.execute(initialStack);
var transformed = new Array(numOutputs);
for (i = numOutputs - 1; i >= 0; --i) {
var out = stack.pop();
var rangeIndex = 2 * i;
if (out < range[rangeIndex])
out = range[rangeIndex];
else if (out > range[rangeIndex + 1])
out = range[rangeIndex + 1];
transformed[i] = out;
}
cache.set(key, transformed);
return transformed;
};
}
};
})();
var FunctionCache = (function FunctionCacheClosure() {
// Of 10 PDF's with type4 functions the maxium number of distinct values seen
// was 256. This still may need some tweaking in the future though.
var MAX_CACHE_SIZE = 1024;
function FunctionCache() {
this.cache = {};
this.total = 0;
}
FunctionCache.prototype = {
has: function has(key) {
return key in this.cache;
},
get: function get(key) {
return this.cache[key];
},
set: function set(key, value) {
if (this.total < MAX_CACHE_SIZE) {
this.cache[key] = value;
this.total++;
}
}
};
return FunctionCache;
})();
var PostScriptStack = (function PostScriptStackClosure() {
var MAX_STACK_SIZE = 100;
function PostScriptStack(initialStack) {
this.stack = initialStack || [];
}
PostScriptStack.prototype = {
push: function push(value) {
if (this.stack.length >= MAX_STACK_SIZE)
error('PostScript function stack overflow.');
this.stack.push(value);
},
pop: function pop() {
if (this.stack.length <= 0)
error('PostScript function stack underflow.');
return this.stack.pop();
},
copy: function copy(n) {
if (this.stack.length + n >= MAX_STACK_SIZE)
error('PostScript function stack overflow.');
var stack = this.stack;
for (var i = stack.length - n, j = n - 1; j >= 0; j--, i++)
stack.push(stack[i]);
},
index: function index(n) {
this.push(this.stack[this.stack.length - n - 1]);
},
// rotate the last n stack elements p times
roll: function roll(n, p) {
var stack = this.stack;
var l = stack.length - n;
var r = stack.length - 1, c = l + (p - Math.floor(p / n) * n), i, j, t;
for (i = l, j = r; i < j; i++, j--) {
t = stack[i]; stack[i] = stack[j]; stack[j] = t;
}
for (i = l, j = c - 1; i < j; i++, j--) {
t = stack[i]; stack[i] = stack[j]; stack[j] = t;
}
for (i = c, j = r; i < j; i++, j--) {
t = stack[i]; stack[i] = stack[j]; stack[j] = t;
}
}
};
return PostScriptStack;
})();
var PostScriptEvaluator = (function PostScriptEvaluatorClosure() {
function PostScriptEvaluator(operators, operands) {
this.operators = operators;
this.operands = operands;
}
PostScriptEvaluator.prototype = {
execute: function execute(initialStack) {
var stack = new PostScriptStack(initialStack);
var counter = 0;
var operators = this.operators;
var length = operators.length;
var operator, a, b;
while (counter < length) {
operator = operators[counter++];
if (typeof operator == 'number') {
// Operator is really an operand and should be pushed to the stack.
stack.push(operator);
continue;
}
switch (operator) {
// non standard ps operators
case 'jz': // jump if false
b = stack.pop();
a = stack.pop();
if (!a)
counter = b;
break;
case 'j': // jump
a = stack.pop();
counter = a;
break;
// all ps operators in alphabetical order (excluding if/ifelse)
case 'abs':
a = stack.pop();
stack.push(Math.abs(a));
break;
case 'add':
b = stack.pop();
a = stack.pop();
stack.push(a + b);
break;
case 'and':
b = stack.pop();
a = stack.pop();
if (isBool(a) && isBool(b))
stack.push(a && b);
else
stack.push(a & b);
break;
case 'atan':
a = stack.pop();
stack.push(Math.atan(a));
break;
case 'bitshift':
b = stack.pop();
a = stack.pop();
if (a > 0)
stack.push(a << b);
else
stack.push(a >> b);
break;
case 'ceiling':
a = stack.pop();
stack.push(Math.ceil(a));
break;
case 'copy':
a = stack.pop();
stack.copy(a);
break;
case 'cos':
a = stack.pop();
stack.push(Math.cos(a));
break;
case 'cvi':
a = stack.pop() | 0;
stack.push(a);
break;
case 'cvr':
// noop
break;
case 'div':
b = stack.pop();
a = stack.pop();
stack.push(a / b);
break;
case 'dup':
stack.copy(1);
break;
case 'eq':
b = stack.pop();
a = stack.pop();
stack.push(a == b);
break;
case 'exch':
stack.roll(2, 1);
break;
case 'exp':
b = stack.pop();
a = stack.pop();
stack.push(Math.pow(a, b));
break;
case 'false':
stack.push(false);
break;
case 'floor':
a = stack.pop();
stack.push(Math.floor(a));
break;
case 'ge':
b = stack.pop();
a = stack.pop();
stack.push(a >= b);
break;
case 'gt':
b = stack.pop();
a = stack.pop();
stack.push(a > b);
break;
case 'idiv':
b = stack.pop();
a = stack.pop();
stack.push((a / b) | 0);
break;
case 'index':
a = stack.pop();
stack.index(a);
break;
case 'le':
b = stack.pop();
a = stack.pop();
stack.push(a <= b);
break;
case 'ln':
a = stack.pop();
stack.push(Math.log(a));
break;
case 'log':
a = stack.pop();
stack.push(Math.log(a) / Math.LN10);
break;
case 'lt':
b = stack.pop();
a = stack.pop();
stack.push(a < b);
break;
case 'mod':
b = stack.pop();
a = stack.pop();
stack.push(a % b);
break;
case 'mul':
b = stack.pop();
a = stack.pop();
stack.push(a * b);
break;
case 'ne':
b = stack.pop();
a = stack.pop();
stack.push(a != b);
break;
case 'neg':
a = stack.pop();
stack.push(-b);
break;
case 'not':
a = stack.pop();
if (isBool(a) && isBool(b))
stack.push(a && b);
else
stack.push(a & b);
break;
case 'or':
b = stack.pop();
a = stack.pop();
if (isBool(a) && isBool(b))
stack.push(a || b);
else
stack.push(a | b);
break;
case 'pop':
stack.pop();
break;
case 'roll':
b = stack.pop();
a = stack.pop();
stack.roll(a, b);
break;
case 'round':
a = stack.pop();
stack.push(Math.round(a));
break;
case 'sin':
a = stack.pop();
stack.push(Math.sin(a));
break;
case 'sqrt':
a = stack.pop();
stack.push(Math.sqrt(a));
break;
case 'sub':
b = stack.pop();
a = stack.pop();
stack.push(a - b);
break;
case 'true':
stack.push(true);
break;
case 'truncate':
a = stack.pop();
a = a < 0 ? Math.ceil(a) : Math.floor(a);
stack.push(a);
break;
case 'xor':
b = stack.pop();
a = stack.pop();
if (isBool(a) && isBool(b))
stack.push(a != b);
else
stack.push(a ^ b);
break;
default:
error('Unknown operator ' + operator);
break;
}
}
return stack.stack;
}
};
return PostScriptEvaluator;
})();
var PostScriptParser = (function PostScriptParserClosure() {
function PostScriptParser(lexer) {
this.lexer = lexer;
this.operators = [];
this.token;
this.prev;
}
PostScriptParser.prototype = {
nextToken: function nextToken() {
this.prev = this.token;
this.token = this.lexer.getToken();
},
accept: function accept(type) {
if (this.token.type == type) {
this.nextToken();
return true;
}
return false;
},
expect: function expect(type) {
if (this.accept(type))
return true;
error('Unexpected symbol: found ' + this.token.type + ' expected ' +
type + '.');
},
parse: function parse() {
this.nextToken();
this.expect(PostScriptTokenTypes.LBRACE);
this.parseBlock();
this.expect(PostScriptTokenTypes.RBRACE);
return this.operators;
},
parseBlock: function parseBlock() {
while (true) {
if (this.accept(PostScriptTokenTypes.NUMBER)) {
this.operators.push(this.prev.value);
} else if (this.accept(PostScriptTokenTypes.OPERATOR)) {
this.operators.push(this.prev.value);
} else if (this.accept(PostScriptTokenTypes.LBRACE)) {
this.parseCondition();
} else {
return;
}
}
},
parseCondition: function parseCondition() {
// Add two place holders that will be updated later
var conditionLocation = this.operators.length;
this.operators.push(null, null);
this.parseBlock();
this.expect(PostScriptTokenTypes.RBRACE);
if (this.accept(PostScriptTokenTypes.IF)) {
// The true block is right after the 'if' so it just falls through on
// true else it jumps and skips the true block.
this.operators[conditionLocation] = this.operators.length;
this.operators[conditionLocation + 1] = 'jz';
} else if (this.accept(PostScriptTokenTypes.LBRACE)) {
var jumpLocation = this.operators.length;
this.operators.push(null, null);
var endOfTrue = this.operators.length;
this.parseBlock();
this.expect(PostScriptTokenTypes.RBRACE);
this.expect(PostScriptTokenTypes.IFELSE);
// The jump is added at the end of the true block to skip the false
// block.
this.operators[jumpLocation] = this.operators.length;
this.operators[jumpLocation + 1] = 'j';
this.operators[conditionLocation] = endOfTrue;
this.operators[conditionLocation + 1] = 'jz';
} else {
error('PS Function: error parsing conditional.');
}
}
};
return PostScriptParser;
})();
var PostScriptTokenTypes = {
LBRACE: 0,
RBRACE: 1,
NUMBER: 2,
OPERATOR: 3,
IF: 4,
IFELSE: 5
};
var PostScriptToken = (function PostScriptTokenClosure() {
function PostScriptToken(type, value) {
this.type = type;
this.value = value;
}
var opCache = {};
PostScriptToken.getOperator = function getOperator(op) {
var opValue = opCache[op];
if (opValue)
return opValue;
return opCache[op] = new PostScriptToken(PostScriptTokenTypes.OPERATOR, op);
};
PostScriptToken.LBRACE = new PostScriptToken(PostScriptTokenTypes.LBRACE,
'{');
PostScriptToken.RBRACE = new PostScriptToken(PostScriptTokenTypes.RBRACE,
'}');
PostScriptToken.IF = new PostScriptToken(PostScriptTokenTypes.IF, 'IF');
PostScriptToken.IFELSE = new PostScriptToken(PostScriptTokenTypes.IFELSE,
'IFELSE');
return PostScriptToken;
})();
var PostScriptLexer = (function PostScriptLexerClosure() {
function PostScriptLexer(stream) {
this.stream = stream;
}
PostScriptLexer.prototype = {
getToken: function getToken() {
var s = '';
var ch;
var comment = false;
var stream = this.stream;
// skip comments
while (true) {
if (!(ch = stream.getChar()))
return EOF;
if (comment) {
if (ch == '\x0a' || ch == '\x0d')
comment = false;
} else if (ch == '%') {
comment = true;
} else if (!Lexer.isSpace(ch)) {
break;
}
}
switch (ch) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
case '+': case '-': case '.':
return new PostScriptToken(PostScriptTokenTypes.NUMBER,
this.getNumber(ch));
case '{':
return PostScriptToken.LBRACE;
case '}':
return PostScriptToken.RBRACE;
}
// operator
var str = ch.toLowerCase();
while (true) {
ch = stream.lookChar().toLowerCase();
if (ch >= 'a' && ch <= 'z')
str += ch;
else
break;
stream.skip();
}
switch (str) {
case 'if':
return PostScriptToken.IF;
case 'ifelse':
return PostScriptToken.IFELSE;
default:
return PostScriptToken.getOperator(str);
}
},
getNumber: function getNumber(ch) {
var str = ch;
var stream = this.stream;
while (true) {
ch = stream.lookChar();
if ((ch >= '0' && ch <= '9') || ch == '-' || ch == '.')
str += ch;
else
break;
stream.skip();
}
var value = parseFloat(str);
if (isNaN(value))
error('Invalid floating point number: ' + value);
return value;
}
};
return PostScriptLexer;
})();