//Class for operators
function Operator(input) {
this.operator = input;
if (!input) {
XCalc.log("Operator has no input.");
}
this.solve = function(segment1, segment2, x) {
var v1 = segment1.coefficient;
if (segment1.type=="variable") {
v1 = x;
}
var v2 = segment2.coefficient;
if (segment2.type=="variable") {
v2 = x;
}
if (this.operator=="+") {
return new Segment(v1 + v2);
} else if (this.operator=="-") {
return new Segment(v1 - v2);
} else if (this.operator=="*") {
return new Segment(v1 * v2);
} else if (this.operator=="/") {
return new Segment(v1 / v2);
} else if (this.operator=="^") {
return new Segment(Math.pow(v1, v2));
}
};
}
//Class for special functions
function MathFunction(input) {
this.f=input;
if (!input) {
XCalc.log("Math function has no input.");
}
this.solve = function(segment) {
var v = segment.coefficient;
if (this.f=="sin") {
return new Segment(Math.sin(v));
} else if (this.f=="cos") {
return new Segment(Math.cos(v));
} else if (this.f=="tan") {
return new Segment(Math.tan(v));
} else if (this.f=="asin") {
return new Segment(Math.asin(v));
} else if (this.f=="acos") {
return new Segment(Math.acos(v));
} else if (this.f=="atan") {
return new Segment(Math.atan(v));
} else if (this.f=="abs") {
return new Segment(Math.abs(v));
} else if (this.f=="log") {
return new Segment(Math.log(v)/Math.log(10));
} else if (this.f=="ln") {
return new Segment(Math.log(v));
}
};
}
//Class for a segment of math (a container)
function Segment(input) {
this.sections = [];
this.type="section";
this.operator=0;
this.coefficient=0;
this.mathFunction=0;
this.variable="";
var removeBrackets = function(value) {
if (!value) return "";
//While there are brackets around the string
while (value.substr(0, 1)=="(" && value.substr(value.length-1, 1)==")") {
var openBrackets=1;
//See if the end bracket closes the opening bracket or not
for (var i=1; i<value.length&&openBrackets>0; i++) {
if (value.substr(i, 1)=="(") openBrackets++;
if (value.substr(i, 1)==")") openBrackets--;
}
i-=1;
//If it corresponds to different brackets, do nothing
if (openBrackets!==0 || i!=value.length-1) {
break;
//Otherwise, remove the brackets, continue loop to see if there are more
} else {
value=value.substring(1, value.length-1);
}
}
return value;
};
var findLast = function(operator, value) {
//Keep searching for the next last sign if the one found is within brackets
var inBrackets=true;
var index=-1;
if (operator!="^") {
index=value.lastIndexOf(operator);
} else {
index=value.indexOf(operator); //Look for the first instead of last if it's an exponent
}
var operators="+-/*^";
while (inBrackets) {
var openBrackets=0;
//Find how many brackets are opened or closed at a given point in the string
for (var i=0; i<value.length; i++) {
if (value.substr(i, 1)=="(") {
openBrackets++;
} else if (value.substr(i, 1)==")") {
openBrackets--;
}
if (i==index) {
//If no brackets are open (and if the operator is actually - and not just a minus sign), break the loop.
if ((openBrackets===0 && (operator!="-" || (i>0 && operators.indexOf(value.substr(i-1, 1))==-1) || i===0)) || (openBrackets==1 && operator=="(")) {
inBrackets=false;
break;
//Otherwise, find the next operator, and loop through again to see if that one is in brackets
} else {
if (operator!="^") {
index = value.substring(0, index).lastIndexOf(operator);
} else {
var nextOperator = value.substring(index+1).indexOf(operator);
if (nextOperator==-1) {
index=-1;
} else {
index = (index+1+value.substring(index+1).indexOf(operator));
}
}
}
}
}
//If no more operators are found, break the loop
if (index==-1) {
inBrackets=false;
}
}
return index;
};
var findLastTrig = function(trig, value) {
var matches=0;
var index=-1;
var r=0;
if (trig=="sin") {
r=/(a)?sin/g;
} else if (trig=="cos") {
r=/(a)?cos/g;
} else if (trig=="tan") {
r=/(a)?tan/g;
} else {
return -1;
}
for (matches=r.exec(value); matches; matches=r.exec(value)) if (RegExp.$1 != "a") index=matches.index;
var inBrackets=true;
while (inBrackets && index!=-1) {
var openBrackets=0;
//Find how many brackets are opened or closed at a given point in the string
for (var i=0; i<value.length; i++) {
if (value.substr(i, 1)=="(") {
openBrackets++;
} else if (value.substr(i, 1)==")") {
openBrackets--;
}
if (i==index) {
//If no brackets are open (and if the operator is actually - and not just a minus sign), break the loop.
if (openBrackets===0) {
inBrackets=false;
break;
//Otherwise, find the next operator, and loop through again to see if that one is in brackets
} else {
var sub = value.substring(0, index);
index=-1;
for (matches=r.exec(sub); matches; matches=r.exec(sub)) if (RegExp.$1 != "a") index=matches.index;
}
}
}
//If no more operators are found, break the loop
if (index==-1) {
inBrackets=false;
}
}
return index;
};
//Specifically for finding brackets that can be used for multiplication
var findMultiplicationBrackets = function(value) {
//Keep searching for the next last sign if the one found is within brackets
var inBracketsOpen=true;
var inBracketsClosed=true;
var indexOpen=-1;
var indexClosed=-1;
var operators="+-/*^sincostanabsloglnsqrt";
indexOpen=value.lastIndexOf("(");
indexClosed=value.lastIndexOf(")");
while (inBracketsOpen || inBracketsClosed) {
var openBrackets=0;
//Find how many brackets are opened or closed at a given point in the string
for (var i=0; i<value.length; i++) {
if (value.substr(i, 1)=="(") {
openBrackets++;
} else if (value.substr(i, 1)==")") {
openBrackets--;
}
if (i==indexOpen && inBracketsOpen) {
if (openBrackets==1 && i!==0 && operators.indexOf(value.substr(i-1, 1))==-1) {
inBracketsOpen=false;
//Otherwise, find the next operator, and loop through again to see if that one is in brackets
} else {
indexOpen = value.substring(0, indexOpen).lastIndexOf("(");
}
}
if (i==indexClosed && inBracketsClosed) {
if (openBrackets===0 && i<value.length-1 && operators.indexOf(value.substr(i+1, 1))==-1) {
inBracketsClosed=false;
//Otherwise, find the next operator, and loop through again to see if that one is in brackets
} else {
indexClosed = value.substring(0, indexClosed).lastIndexOf(")");
}
}
}
//If no more operators are found, break the loop
if (indexOpen==-1) {
inBracketsOpen=false;
}
if (indexClosed==-1) {
inBracketsClosed=false;
}
}
if (indexClosed>indexOpen && indexClosed!=-1) {
return indexClosed;
} else {
return indexOpen;
}
};
this.containsX = function() {
if (this.type=="variable") {
return true;
} else if (this.type=="value") {
return false;
} else {
if (this.sections.length==1) {
return this.sections[0].containsX();
} else if (this.sections.length==2) {
return this.sections[0].containsX() || this.sections[1].containsX();
}
}
};
this.equals = function(expression) {
if (this.type != expression.type) {
return false;
} else {
if (this.type=="function") {
return (this.mathFunction.f==expression.mathFunction.f && this.sections[0].equals(expression.sections[0]));
} else if (this.type=="variable") {
return (this.variable==expression.variable && this.coefficient==expression.coefficient);
} else if (this.type=="value") {
return this.coefficient==expression.coefficient;
} else if (this.type=="section") {
if (this.operator.operator=="*" || this.operator.operator=="+") {
return (this.operator.operator==expression.operator.operator && ((this.sections[0].equals(expression.sections[0]) && this.sections[1].equals(expression.sections[1])) || (this.sections[0].equals(expression.sections[1]) && this.sections[1].equals(expression.sections[0]))));
} else {
return (this.operator.operator==expression.operator.operator && this.sections[0].equals(expression.sections[0]) && this.sections[1].equals(expression.sections[1]));
}
}
}
};
//Recursively solve children
this.solve = function(x) {
if (!x) x=0;
if (this.type=="value") {
return this;
} else if (this.type=="variable") {
return new Segment(x);
} else if (this.type=="function") {
return this.mathFunction.solve(this.sections[0].solve(x));
} else {
if (this.sections.length==1) {
return this.sections[0].solve(x);
} else if (this.sections.length==2) {
return this.operator.solve(this.sections[0].solve(x), this.sections[1].solve(x), x);
}
}
};
//Outputs the final answer
this.result = function(x) {
return this.solve(x).coefficient;
};
this.simplify = function() {
var expression = new Segment(this);
var final;
//If the segment is a variable, leave it as is.
//If it contains a variable in its subsections, simplify subsections
if (expression.containsX() && expression.type!="variable") {
for (var i=0; i<expression.sections.length; i++) {
expression.sections[i] = expression.sections[i].simplify();
}
if (expression.type=="section") {
if (expression.operator.operator == "+") {
if (expression.sections[0].type=="value" && expression.sections[0].coefficient===0) {
expression=expression.sections[1];
} else if (expression.sections[1].type=="value" && expression.sections[1].coefficient===0) {
expression=expression.sections[0];
}
} else if (expression.operator.operator == "-") {
if (expression.sections[1].type=="value" && expression.sections[1].coefficient===0) {
expression=expression.sections[1];
}
} else if (expression.operator.operator == "*") {
if (expression.sections[0].type=="value" && expression.sections[0].coefficient==1) {
expression = new Segment(expression.sections[1]);
} else if (expression.sections[1].type=="value" && expression.sections[1].coefficient==1) {
expression = new Segment(expression.sections[0]);
} else if ((expression.sections[0].type=="value" && expression.sections[0].coefficient===0) || (expression.sections[1].type=="value" && expression.sections[1].coefficient===0)) {
expression = new Segment(0);
} else if (expression.sections[1].type=="section" && expression.sections[1].operator.operator=="/" && expression.sections[1].sections[0].type=="value" && expression.sections[1].sections[0].coefficient==1) {
expression.operator = new Operator("/");
expression.sections[1]=expression.sections[1].sections[1];
} else if (expression.sections[0].type=="section" && expression.sections[0].operator.operator=="/" && expression.sections[0].sections[0].type=="value" && expression.sections[0].sections[0].coefficient==1) {
expression.operator = new Operator("/");
var num = expression.sections[1];
expression.sections[1] = expression.sections[0].sections[1];
expression.sections[0] = num;
} else if (expression.sections[0].type=="section" && expression.sections[0].operator.operator=="^" && expression.sections[1].type=="section" && expression.sections[1].operator.operator=="^" && expression.sections[0].sections[0].equals(expression.sections[1].sections[0])) {
var exponent = new Segment(0);
exponent.type="section";
exponent.sections.push(expression.sections[0].sections[1]);
exponent.sections.push(expression.sections[1].sections[1]);
exponent.operator = new Operator("+");
expression.sections[0]=expression.sections[0].sections[0];
expression.sections[1]=exponent;
expression.operator = new Operator("^");
} else if (expression.sections[0].type=="section" && expression.sections[0].operator.operator=="*") {
final = new Segment(0);
final.operator = new Operator("*");
final.type="section";
if (!expression.sections[0].sections[1].containsX()) {
if (expression.sections[0].sections[0].containsX()) {
final.sections.push(expression.sections[0].sections[0]);
final.sections.push(expression.sections[1]);
expression.sections[0]=expression.sections[0].sections[1];
expression.sections[1]=final;
} else {
final.sections.push(expression.sections[0].sections[1]);
final.sections.push(expression.sections[1]);
expression.sections[0]=expression.sections[0].sections[0];
expression.sections[1]=final;
}
} else if (!expression.sections[0].sections[0].containsX()) {
if (expression.sections[0].sections[1].containsX()) {
final.sections.push(expression.sections[0].sections[1]);
final.sections.push(expression.sections[1]);
expression.sections[0]=expression.sections[0].sections[0];
expression.sections[1]=final;
} else {
final.sections.push(expression.sections[0].sections[0]);
final.sections.push(expression.sections[1]);
expression.sections[0]=expression.sections[0].sections[1];
expression.sections[1]=final;
}
}
} else if (expression.sections[1].type=="section" && expression.sections[1].operator.operator=="*") {
final = new Segment(0);
final.operator = new Operator("*");
final.type="section";
if (!expression.sections[1].sections[1].containsX()) {
if (expression.sections[1].sections[0].containsX()) {
final.sections.push(expression.sections[1].sections[0]);
final.sections.push(expression.sections[0]);
expression.sections[1]=expression.sections[1].sections[1];
expression.sections[0] = final;
} else {
final.sections.push(expression.sections[1].sections[1]);
final.sections.push(expression.sections[0]);
expression.sections[1]=expression.sections[1].sections[0];
expression.sections[0] = final;
}
} else if (!expression.sections[1].sections[0].containsX()) {
if (expression.sections[1].sections[1].containsX()) {
final.sections.push(expression.sections[1].sections[1]);
final.sections.push(expression.sections[0]);
expression.sections[1]=(expression.sections[1].sections[0]);
expression.sections[0] = final;
} else {
final.sections.push(expression.sections[1].sections[0]);
final.sections.push(expression.sections[0]);
expression.sections[1]=(expression.sections[1].sections[1]);
expression.sections[0] = final;
}
}
}
} else if (expression.operator.operator == "/") {
if (expression.sections[1].type=="value" && expression.sections[1].coefficient==1) {
expression = expression.sections[0];
} else if (expression.sections[0].equals(expression.sections[1])) {
expression = new Segment(1);
} else if (expression.sections[0].type=="section" && expression.sections[0].operator.operator=="^" && expression.sections[1].type=="section" && expression.sections[1].operator.operator=="^" && expression.sections[0].sections[0].equals(expression.sections[1].sections[0])) {
var exponent2 = new Segment(0);
exponent2.type="section";
exponent2.sections.push(expression.sections[0].sections[1]);
exponent2.sections.push(expression.sections[1].sections[1]);
exponent2.operator = new Operator("-");
expression.sections[0]=expression.sections[0].sections[0];
expression.sections[1]=exponent2;
expression.operator = new Operator("^");
}
} else if (expression.operator.operator == "^") {
if (expression.sections[1].type=="value" && expression.sections[1].coefficient==1) {
expression = expression.sections[0];
} else if (expression.sections[1].type=="value" && expression.sections[1].coefficient===0) {
expression = new Segment(0);
} else if (expression.sections[0].type=="value" && expression.sections[0].coefficient==1) {
expression = new Segment(1);
} else if (expression.sections[0].type=="section" && (expression.sections[0].operator.operator=="/" || expression.sections[0].operator.operator=="/")) {
var num2 = new Segment(0);
num2.type="section";
num2.operator = new Operator("^");
num2.sections.push(expression.sections[0].sections[0]);
num2.sections.push(expression.sections[1]);
var denom = new Segment(0);
denom.type="section";
denom.operator = new Operator("^");
denom.sections.push(expression.sections[0].sections[1]);
denom.sections.push(expression.sections[1]);
expression.operator = expression.sections[0].operator;
expression.sections[0] = num2;
expression.sections[1] = denom;
}
}
}
//If it can be simplified to a value, simplify
} else if (expression.type!="variable") {
expression.coefficient = expression.result();
expression.type="value";
}
//Keep simplifying until it's the same
if (this.equals(expression)) {
return this;
} else {
return expression.simplify();
}
};
this.derivative = function() {
var expression = new Segment(this);
var deriv = new Segment(0);
var s1, s2, s3, s4;
if (expression.type=="variable") {
deriv.coefficient = 1;
} else if (expression.type == "value" || !expression.containsX()) {
deriv.coefficient = 0;
} else if (expression.type=="section" && expression.operator.operator!="^") {
//+/- rules
if (expression.operator.operator == "+") {
deriv.type = "section";
deriv.sections.push(expression.sections[0].derivative());
deriv.sections.push(expression.sections[1].derivative());
deriv.operator = new Operator("+");
} else if (expression.operator.operator == "-") {
deriv.type = "section";
deriv.sections.push(expression.sections[0].derivative());
deriv.sections.push(expression.sections[1].derivative());
deriv.operator = new Operator("-");
//Product rule
} else if (expression.operator.operator == "*") {
s1 = new Segment(0);
s1.type = "section";
s1.sections.push(expression.sections[0].derivative());
s1.sections.push(expression.sections[1]);
s1.operator = new Operator("*");
s2 = new Segment(0);
s2.type = "section";
s2.sections.push(expression.sections[0]);
s2.sections.push(expression.sections[1].derivative());
s2.operator = new Operator("*");
deriv.type = "section";
deriv.sections.push(s1);
deriv.sections.push(s2);
deriv.operator = new Operator("+");
//Quotient rule
} else if (expression.operator.operator == "/") {
s1 = new Segment(0);
s1.type = "section";
s1.sections.push(expression.sections[0].derivative());
s1.sections.push(expression.sections[1]);
s1.operator = new Operator("*");
s2 = new Segment(0);
s2.type = "section";
s2.sections.push(expression.sections[1].derivative());
s2.sections.push(expression.sections[0]);
s2.operator = new Operator("*");
var num = new Segment(0);
num.type = "section";
num.sections.push(s1);
num.sections.push(s2);
num.operator = new Operator("-");
var denom = new Segment(0);
denom.type = "section";
denom.sections.push(expression.sections[1]);
denom.sections.push(new Segment(2));
denom.operator = new Operator("^");
deriv.type = "section";
deriv.sections.push(num);
deriv.sections.push(denom);
deriv.operator = new Operator("/");
}
//functions
} else {
var uprime;
s1 = new Segment(0);
s1.type = "section";
//Exponents
if (expression.type == "section" && expression.operator.operator=="^") {
//Implicitly derive ln(y)
if (expression.sections[1].containsX() && expression.sections[0].containsX()) {
s1 = expression;
s2 = new Segment(0);
s2.type = "function";
s2.sections.push(expression.sections[0]);
s2.mathFunction = new MathFunction("ln");
s3 = new Segment(0);
s3.type="section";
s3.sections.push(expression.sections[1]);
s3.sections.push(s2);
s3.operator = new Operator("*");
uprime = s3.derivative();
//Power rule
} else if (expression.sections[1].containsX()) {
s2 = new Segment(0);
s2.type = "function";
s2.sections.push(expression.sections[0]);
s2.mathFunction = new MathFunction("ln");
s1.sections.push(expression);
s1.sections.push(s2);
s1.operator = new Operator("*");
uprime = expression.sections[1].derivative();
//Polynomial rule
} else {
var exp = new Segment(0);
exp.type = "section";
exp.sections.push(expression.sections[1]);
exp.sections.push(new Segment(1));
exp.operator = new Operator("-");
s2 = new Segment(0);
s2.type = "section";
s2.sections.push(expression.sections[0]);
s2.sections.push(exp);
s2.operator = new Operator("^");
s1.sections.push(expression.sections[1]);
s1.sections.push(s2);
s1.operator = new Operator("*");
uprime = expression.sections[0].derivative();
}
} else {
uprime = expression.sections[0].derivative();
if (expression.mathFunction.f=="ln") {
s1.sections.push(new Segment(1));
s1.sections.push(expression.sections[0]);
s1.operator = new Operator("/");
} else if (expression.mathFunction.f=="log") {
s2 = new Segment(0);
s2.mathFunction = new MathFunction("ln");
s2.type="function";
s2.sections.push(new Segment(10));
s3 = new Segment(0);
s3.type="section";
s3.sections.push(expression.sections[0]);
s3.sections.push(s2);
s3.operator = new Operator("*");
s1.sections.push(new Segment(1));
s1.sections.push(s3);
s1.operator = new Operator("/");
} else if (expression.mathFunction.f=="sin") {
s1.mathFunction = new MathFunction("cos");
s1.type="function";
s1.sections.push(expression.sections[0]);
} else if (expression.mathFunction.f=="cos") {
s2 = new Segment(0);
s2.mathFunction = new MathFunction("sin");
s2.type="function";
s2.sections.push(expression.sections[0]);
s1.sections.push(new Segment(0));
s1.sections.push(s2);
s1.operator = new Operator("-");
} else if (expression.mathFunction.f=="tan") {
s2 = new Segment(0);
s2.mathFunction = new MathFunction("cos");
s2.type="function";
s2.sections.push(expression.sections[0]);
s3 = new Segment(0);
s3.type="section";
s3.sections.push(s2);
s3.sections.push(new Segment(2));
s3.operator = new Operator("^");
s1.sections.push(new Segment(1));
s1.sections.push(s3);
s1.operator = new Operator("/");
} else if (expression.mathFunction.f=="asin") {
s2 = new Segment(0);
s2.type="section";
s2.sections.push(expression.sections[0]);
s2.sections.push(new Segment(2));
s2.operator=new Operator("^");
s3 = new Segment(0);
s3.type="section";
s3.sections.push(new Segment(1));
s3.sections.push(s2);
s3.operator = new Operator("-");
s4 = new Segment(0);
s4.type="section";
s4.sections.push(s3);
s4.sections.push(new Segment(0.5));
s4.operator = new Operator("^");
s1.sections.push(new Segment(1));
s1.sections.push(s4);
s1.operator = new Operator("/");
} else if (expression.mathFunction.f=="acos") {
s2 = new Segment(0);
s2.type="section";
s2.sections.push(expression.sections[0]);
s2.sections.push(new Segment(2));
s2.operator=new Operator("^");
s3 = new Segment(0);
s3.type="section";
s3.sections.push(new Segment(1));
s3.sections.push(s2);
s3.operator = new Operator("-");
s4 = new Segment(0);
s4.type="section";
s4.sections.push(new Segment(0));
s4.sections.push(new Segment(1));
s4.operator = new Operator("-");
var s5 = new Segment(0);
s5.type="section";
s5.sections.push(s3);
s5.sections.push(new Segment(0.5));
s5.operator = new Operator("^");
s1.sections.push(s4);
s1.sections.push(s5);
s1.operator = new Operator("/");
} else if (expression.mathFunction.f=="atan") {
s2 = new Segment(0);
s2.type="section";
s2.sections.push(expression.sections[0]);
s2.sections.push(new Segment(2));
s2.operator=new Operator("^");
s3 = new Segment(0);
s3.type="section";
s3.sections.push(s2);
s3.sections.push(new Segment(1));
s3.operator = new Operator("+");
s1.sections.push(new Segment(1));
s1.sections.push(s3);
s1.operator = new Operator("/");
}
}
//Chain rule
deriv.type = "section";
deriv.sections.push(s1);
deriv.sections.push(uprime);
deriv.operator = new Operator("*");
}
return deriv;
};
//Returns a string with the formula of the function
this.formula = function() {
var str = "";
if (this.type=="value") {
str += this.coefficient;
} else if (this.type=="variable") {
str += "x";
} else if (this.type=="function") {
str += this.mathFunction.f + "(" + this.sections[0].formula() + ")";
} else if (this.type=="section") {
if (this.sections[0].type=="section") {
str+= "(" + this.sections[0].formula() + ")";
} else {
str+= this.sections[0].formula();
}
str += this.operator.operator;
if (this.sections[1].type=="section") {
str+= "(" + this.sections[1].formula() + ")";
} else {
str+= this.sections[1].formula();
}
}
return str;
};
this.derive = function() {
return this.simplify().derivative().simplify();
};
//Returns formula in divs for CSS
this.prettyFormula = function() {
var str="<div class='group " + this.type + ((this.type=="section" && this.operator.operator=="/")?" division":"") + "'>";
if (this.type=="value") {
str += this.coefficient;
} else if (this.type=="variable") {
str += "x";
} else if (this.type=="function") {
str += this.mathFunction.f + "(" + this.sections[0].prettyFormula() + ")";
} else if (this.type=="section") {
if (this.sections[0].type=="section" && this.sections[0].operator.operator!="/") {
str+= "(" + this.sections[0].prettyFormula() + ")";
} else {
str+= this.sections[0].prettyFormula();
}
if (this.operator.operator=="*") {
str += "<span class='operator'>×</span>";
} else if (this.operator.operator!="^" && this.operator.operator!="/") {
str += "<span class='operator'>" + this.operator.operator + "</span>";
}
if (this.operator.operator=="^") {
str += "<div class='group exponent'>" + this.sections[1].prettyFormula() + "</div>";
} else if (this.operator.operator == "/") {
str += "<div class='group denom'>" + this.sections[1].prettyFormula() + "</div>";
} else {
if (this.sections[1].type=="section" && this.sections[0].operator.operator!="/") {
str+= "(" + this.sections[1].prettyFormula() + ")";
} else {
str+= this.sections[1].prettyFormula();
}
}
}
str+="</div>";
return str;
};
//constructor: parse the string
if (input!==undefined) {
if (typeof(input)=="string") {
//Remove excess whitespace
input = input.replace(/\s/g, "");
//get rid of unnecessary brackets surrounding the section
input = removeBrackets(input);
//Find the last instance of each operator in the string
var addition = findLast("+", input);
var subtraction = findLast("-", input);
var division = findLast("/", input);
var exponent = findLast("^", input); //Find the first exponent, since those work in reverse
var bracket1 = findLast("(", input);
var sin = findLastTrig("sin", input);
var cos = findLastTrig("cos", input);
var tan = findLastTrig("tan", input);
var asin = findLast("asin", input);
var acos = findLast("acos", input);
var atan = findLast("atan", input);
var abs = findLast("abs", input);
var log = findLast("log", input);
var ln = findLast("ln", input);
var sqrt = findLast("sqrt", input);
var multiplication = findLast("*", input);
var multiplication2 = findMultiplicationBrackets(input); //Find brackets that are the same as multiplication
var xMultiplication = findLast("x", input);
var xMultiplication2 = findLast("X", input);
if (xMultiplication2>xMultiplication) xMultiplication = xMultiplication2;
var functionMultiplication = -1;
var operators="+-/*^sincostanabsloglnsqrt";
if (sin>multiplication && (sin===0 || operators.indexOf(input.substr(sin-1, 1))==-1)) functionMultiplication=sin;
if (cos>multiplication && (cos===0 || operators.indexOf(input.substr(cos-1, 1))==-1)) functionMultiplication=cos;
if (tan>multiplication && (tan===0 || operators.indexOf(input.substr(tan-1, 1))==-1)) functionMultiplication=tan;
if (asin>multiplication && (asin===0 || operators.indexOf(input.substr(asin-1, 1))==-1)) functionMultiplication=asin;
if (acos>multiplication && (acos===0 || operators.indexOf(input.substr(acos-1, 1))==-1)) functionMultiplication=acos;
if (atan>multiplication && (atan===0 || operators.indexOf(input.substr(atan-1, 1))==-1)) functionMultiplication=atan;
if (abs>multiplication && (abs===0 || operators.indexOf(input.substr(abs-1, 1))==-1)) functionMultiplication=abs;
if (log>multiplication && (log===0 || operators.indexOf(input.substr(log-1, 1))==-1)) functionMultiplication=log;
if (ln>multiplication && (ln===0 || operators.indexOf(input.substr(ln-1, 1))==-1)) functionMultiplication=ln;
if (sqrt>multiplication && (sqrt===0 || operators.indexOf(input.substr(sqrt-1, 1))==-1)) functionMultiplication=sqrt;
if (xMultiplication>multiplication && (xMultiplication===0 || operators.indexOf(input.substr(xMultiplication-1, 1))==-1)) functionMultiplication=xMultiplication;
//Push back each half of the equation into a section, in reverse order of operations
if (addition != -1 && addition>subtraction) {
this.sections.push(new Segment(input.substring(0, addition)));
this.sections.push(new Segment(input.substring(addition+1)));
this.operator = new Operator("+");
} else if (subtraction != -1) {
if (subtraction>0) {
this.sections.push(new Segment(input.substring(0, subtraction)));
} else {
this.sections.push(new Segment(0));
}
this.sections.push(new Segment(input.substring(subtraction+1)));
this.operator = new Operator("-");
} else if (functionMultiplication > 0 && Math.max(functionMultiplication, multiplication, multiplication2, division)==functionMultiplication) {
this.sections.push(new Segment(input.substring(0, functionMultiplication)));
this.sections.push(new Segment(input.substring(functionMultiplication)));
this.operator = new Operator("*");
} else if (multiplication2 != -1 && Math.max(multiplication2, multiplication, division)==multiplication2) {
this.sections.push(new Segment(input.substring(0, multiplication2)));
this.sections.push(new Segment(input.substring(multiplication2)));
this.operator = new Operator("*");
} else if (multiplication != -1 && multiplication>division) {
this.sections.push(new Segment(input.substring(0, multiplication)));
this.sections.push(new Segment(input.substring(multiplication+1)));
this.operator = new Operator("*");
} else if (division != -1) {
this.sections.push(new Segment(input.substring(0, division)));
this.sections.push(new Segment(input.substring(division+1)));
this.operator = new Operator("/");
} else if (exponent != -1) {
this.sections.push(new Segment(input.substring(0, exponent)));
this.sections.push(new Segment(input.substring(exponent+1)));
this.operator = new Operator("^");
} else if (sin != -1 && Math.max(sin, cos, tan, asin, acos, atan, abs, log, ln, sqrt)==sin) {
this.sections.push(new Segment(input.substring(sin+3)));
this.mathFunction = new MathFunction("sin");
this.type = "function";
} else if (cos != -1 && Math.max(cos, tan, asin, acos, atan, abs, log, ln, sqrt)==cos) {
this.sections.push(new Segment(input.substring(cos+3)));
this.mathFunction = new MathFunction("cos");
this.type = "function";
} else if (tan != -1 && Math.max(tan, asin, acos, atan, abs, log, ln, sqrt)==tan) {
this.sections.push(new Segment(input.substring(tan+3)));
this.mathFunction = new MathFunction("tan");
this.type = "function";
} else if (asin != -1 && Math.max(asin, acos, atan, abs, log, ln, sqrt)==asin) {
this.sections.push(new Segment(input.substring(asin+4)));
this.mathFunction = new MathFunction("asin");
this.type = "function";
} else if (acos != -1 && Math.max(acos, atan, abs, log, ln, sqrt)==acos) {
this.sections.push(new Segment(input.substring(acos+4)));
this.mathFunction = new MathFunction("acos");
this.type = "function";
} else if (atan != -1 && Math.max(atan, abs, log, ln, sqrt)==atan) {
this.sections.push(new Segment(input.substring(atan+4)));
this.mathFunction = new MathFunction("atan");
this.type = "function";
} else if (abs != -1 && Math.max(abs, log, ln, sqrt)==abs) {
this.sections.push(new Segment(input.substring(abs+3)));
this.mathFunction = new MathFunction("abs");
this.type = "function";
} else if (log != -1 && Math.max(log, ln, sqrt)==log) {
this.sections.push(new Segment(input.substring(log+3)));
this.mathFunction = new MathFunction("log");
this.type = "function";
} else if (ln != -1 && Math.max(ln, sqrt)==ln) {
this.sections.push(new Segment(input.substring(ln+2)));
this.mathFunction = new MathFunction("ln");
this.type = "function";
} else if (sqrt != -1) {
this.sections.push(new Segment(input.substring(sqrt+4)));
this.sections.push(new Segment("0.5"));
this.operator = new Operator("^");
} else if (bracket1 != -1) {
var openBrackets=1;
for (var i=bracket1+1; i<input.length&&openBrackets>0; i++) {
if (input.substr(i, 1)=="(") openBrackets++;
if (input.substr(i, 1)==")") openBrackets--;
}
if (openBrackets===0) {
var bracket2=i-1;
if (bracket1>0) this.sections.push(new Segment(input.substring(0, bracket1)));
if (bracket2-bracket1!=1) this.sections.push(new Segment(input.substring(bracket1+1, bracket2)));
if (bracket2!=input.length-1) this.sections.push(new Segment(input.substring(bracket2+1)));
this.operator = new Operator("*");
} else {
XCalc.log("Brackets nesting error: " + input);
}
//If there are no operators, just push the input itself
} else {
var xLocation=input.toLowerCase().indexOf("x");
if (xLocation!=-1) {
if (xLocation>0) {
this.sections.push(new Segment(input.substring(0, xLocation)));
this.sections.push(new Segment("x"));
this.operator=new Operator("*");
} else {
this.variable="x";
this.type="variable";
}
} else {
this.coefficient = parseFloat(input);
this.type = "value";
}
}
} else if (typeof(input)=="number") {
this.coefficient = input;
this.type = "value";
} else if (input.simplify) {
this.coefficient = input.coefficient;
this.operator = input.operator;
this.mathFunction = input.mathFunction;
this.variable = input.variable;
this.type=input.type;
this.sections=[];
for (var j=0; j<input.sections.length; j++) {
this.sections.push(new Segment(input.sections[j]));
}
}
} else {
XCalc.log("Segment has no input.");
}
}
//One point on a graph
function Point(x, y) {
this.x = x;
this.y = y;
}
//MathFunction to create graphs
function Graph(value, width, height, startx1, startx2, starty1, starty2) {
var autoRange=(starty1===undefined || starty1=="auto");
//Properties
if (typeof(value)=="string") {
this.expression = new Segment(value);
} else {
this.expression = value;
}
var points = [];
var canvas = document.createElement("canvas");
canvas.width=width || 400;
canvas.height=height || 400;
var graphCanvas = document.createElement("canvas");
graphCanvas.width = canvas.width;
graphCanvas.height = canvas.height;
var min;
var max;
var x1 = (startx1===undefined)?-10:startx1;
var x2 = (startx2===undefined)?10:startx2;
var y1 = (starty1===undefined)?-10:starty1;
var y2 = (starty2===undefined)?10:starty2;
var startMouse = new Point(0, 0);
var mousePos = new Point(0, 0);
var stage=0;
var graphStage=0;
var img=0;
var timer=0;
var distX=0;
var distY=0;
//Gets minimum y value in the set of points
this.getMin = function() {
if (min===undefined) {
if (points.length>0) {
var i=0;
while (isNaN(points[i].y) || points[i].y === undefined || Math.abs(points[i].y) == Infinity) i++;
var _min = points[i].y;
for (i++; i<points.length; i++) {
if (points[i].y<_min) _min = points[i].y;
}
min=_min;
return min;
} else {
return 0;
}
} else {
return min;
}
};
//Gets maximum y value in the set of points
this.getMax = function() {
if (max===undefined) {
if (points.length>0) {
var i=0;
while (isNaN(points[i].y) || points[i].y === undefined || Math.abs(points[i].y) == Infinity) i++;
var _max = points[i].y;
for (i++; i<points.length; i++) {
if (points[i].y>_max) _max = points[i].y;
}
max=_max;
return max;
} else {
return 0;
}
} else {
return max;
}
};
//Updates the points and graph
this.update = function() {
var accuracy = (x2-x1)/canvas.width;
points = [];
for (var i=x1; i<=x2; i+=accuracy) {
points.push(new Point(i, this.expression.result(i)));
if ((points[points.length-1].y!==0 && !points[points.length-1].y) || Math.abs(points[points.length-1].y)>10000) {
points[points.length-1].y=undefined;
}
}
max=undefined;
min=undefined;
if (autoRange) {
if (this.getMax()-this.getMin()>100000) {
y1=-100;
y2=100;
} else {
y1=this.getMin()-5;
y2=this.getMax()+5;
}
autoRange = false;
}
this.redraw();
};
var drawAxes = function(_x1, _x2, _y1, _y2) {
stage.strokeStyle="#bdc3c7";
stage.fillStyle="#bdc3c7";
var limit=0;
var i=0;
//Draw the y axis if it is in the view
if (0>=_x1-30 && 0<=_x2+30) {
stage.lineWidth=2;
stage.beginPath();
stage.moveTo(canvas.width/2-(((_x2+_x1)/2)/(_x2-_x1))*canvas.width, 0);
stage.lineTo(canvas.width/2-(((_x2+_x1)/2)/(_x2-_x1))*canvas.width, canvas.height);
stage.closePath();
stage.stroke();
stage.textAlign = "right";
stage.textBaseline="middle";
//Draw ticks and numbers on x axis
stage.lineWidth=1;
limit = (Math.abs(_y2)>Math.abs(_y1))?Math.abs(_y2):Math.abs(_y1);
for (i=0; i<=limit; i+=Math.pow(10, Math.floor(Math.log(_y2-_y1) / Math.LN10))/2) {
if (i===0) continue;
if (i<=_y2+50) {
stage.beginPath();
stage.moveTo(canvas.width/2-(((_x2+_x1)/2)/(_x2-_x1))*canvas.width-5, canvas.height-((i-_y1)/(_y2-_y1))*canvas.height);
stage.lineTo(canvas.width/2-(((_x2+_x1)/2)/(_x2-_x1))*canvas.width+5, canvas.height-((i-_y1)/(_y2-_y1))*canvas.height);
stage.closePath();
stage.stroke();
stage.fillText(""+(Math.round(i*100)/100), canvas.width/2-(((_x2+_x1)/2)/(_x2-_x1))*canvas.width-8, canvas.height-((i-_y1)/(_y2-_y1))*canvas.height);
}
if (i>=_y1-50) {
stage.beginPath();
stage.moveTo(canvas.width/2-(((_x2+_x1)/2)/(_x2-_x1))*canvas.width-5, canvas.height-((-i-_y1)/(_y2-_y1))*canvas.height);
stage.lineTo(canvas.width/2-(((_x2+_x1)/2)/(_x2-_x1))*canvas.width+5, canvas.height-((-i-_y1)/(_y2-_y1))*canvas.height);
stage.closePath();
stage.stroke();
stage.fillText(""+(Math.round(-i*100)/100), canvas.width/2-(((_x2+_x1)/2)/(_x2-_x1))*canvas.width-8, canvas.height-((-i-_y1)/(_y2-_y1))*canvas.height);
}
}
}
//Draw the x axis if it is in the view
if (0>=_y1-50 && 0<=_y2+50) {
stage.lineWidth=2;
stage.beginPath();
stage.moveTo(0, canvas.height/2+(((_y2+_y1)/2)/(_y2-_y1))*canvas.height);
stage.lineTo(canvas.width, canvas.height/2+(((_y2+_y1)/2)/(_y2-_y1))*canvas.height);
stage.closePath();
stage.stroke();
stage.textAlign = "center";
stage.textBaseline="top";
//Draw ticks and numbers on y axis
stage.lineWidth=1;
limit = (Math.abs(_x2)>Math.abs(_x1))?Math.abs(_x2):Math.abs(_x1);
for (i=0; i<=limit; i+=Math.pow(10, Math.floor(Math.log(_x2-_x1) / Math.LN10))/2) {
if (i===0) continue;
if (i<=_x2+50) {
stage.beginPath();
stage.moveTo(((i-_x1)/(_x2-_x1))*canvas.width, canvas.height/2+(((_y2+_y1)/2)/(_y2-_y1))*canvas.height-5);
stage.lineTo(((i-_x1)/(_x2-_x1))*canvas.width, canvas.height/2+(((_y2+_y1)/2)/(_y2-_y1))*canvas.height+5);
stage.closePath();
stage.stroke();
stage.fillText(""+(Math.round(i*100)/100), ((i-_x1)/(_x2-_x1))*canvas.width, canvas.height/2+(((_y2+_y1)/2)/(_y2-_y1))*canvas.height+8);
}
if (i>=_x1-50) {
stage.beginPath();
stage.moveTo(((-i-_x1)/(_x2-_x1))*canvas.width, canvas.height/2+(((_y2+_y1)/2)/(_y2-_y1))*canvas.height-5);
stage.lineTo(((-i-_x1)/(_x2-_x1))*canvas.width, canvas.height/2+(((_y2+_y1)/2)/(_y2-_y1))*canvas.height+5);
stage.closePath();
stage.stroke();
stage.fillText(""+(Math.round(-i*100)/100), ((-i-_x1)/(_x2-_x1))*canvas.width, canvas.height/2+(((_y2+_y1)/2)/(_y2-_y1))*canvas.height+8);
}
}
}
}.bind(this);
//Updates the canvas
this.redraw = function() {
if (points.length>1) {
stage.fillStyle = "#FFFFFF";
stage.fillRect(0, 0, canvas.width, canvas.height);
graphStage.clearRect(0, 0, canvas.width, canvas.height);
graphStage.lineCap="round";
var offsetY = -y1;
drawAxes(x1, x2, y1, y2);
//Draw all the points
graphStage.strokeStyle="#2980b9";
graphStage.lineWidth=1;
graphStage.beginPath();
//Find the first point that exists
var i=0;
while (isNaN(points[i].y) || points[i].y === undefined || Math.abs(points[i].y) == Infinity) i++;
graphStage.moveTo((i/points.length)*canvas.width, canvas.height-((points[i].y+offsetY)/(y2-y1))*canvas.height);
for (i++; i<points.length; i++) {
if (Math.abs((canvas.height-((points[i].y+offsetY)/(y2-y1))*canvas.height)-(canvas.height-((points[i-1].y+offsetY)/(y2-y1))*canvas.height))<=canvas.height && points[i].y !== undefined && Math.abs(points[i].y) != Infinity && !isNaN(points[i].y)) {
graphStage.lineTo((i/(points.length-1))*canvas.width, canvas.height-((points[i].y+offsetY)/(y2-y1))*canvas.height);
}
if (points[i].y !== undefined && Math.abs(points[i].y) != Infinity && !isNaN(points[i].y)) {
graphStage.moveTo((i/(points.length-1))*canvas.width, canvas.height-((points[i].y+offsetY)/(y2-y1))*canvas.height);
} else {
graphStage.moveTo((i/(points.length-1))*canvas.width, canvas.height-((0+offsetY)/(y2-y1))*canvas.height);
}
}
graphStage.closePath();
graphStage.stroke();
img = graphStage.getImageData(0, 0, canvas.width, canvas.height);
stage.drawImage(graphCanvas, 0, 0);
} else {
XCalc.log("Not enough points to graph.");
}
};
//Updates the view of the graph
this.setRange = function(_x1, _x2, _y1, _y2) {
x1=_x1;
x2=_x2;
y1=_y1;
y2=_y2;
if (_y1=="auto" || _y1===undefined) autoRange=true;
this.update();
};
//Gets x and y of the mouse relative to the top left of the canvas
var getMousePos = function(evt) {
var rect = canvas.getBoundingClientRect();
var root = document.documentElement;
// return relative mouse position
var mouseX = evt.clientX - rect.left - root.scrollLeft;
var mouseY = evt.clientY - rect.top - root.scrollTop;
return new Point(mouseX, mouseY);
}.bind(this);
//Starts panning
var startDrag = function(event) {
document.addEventListener("mousemove", dragMouse, false);
document.addEventListener("mouseup", endDrag, false);
document.documentElement.style["-moz-user-select"] = "none";
document.documentElement.style["-webkit-user-select"] = "none";
document.documentElement.style["-khtml-user-select"] = "none";
document.documentElement.style["user-select"] = "none";
canvas.removeEventListener("mouseover", startMouseOver, false);
canvas.removeEventListener("mousemove", moveMouse, false);
startMouse = getMousePos(event);
}.bind(this);
//Recalculate and redraws the view based on the mouse position
var redrawLine = function() {
var offsetX = ((mousePos.x-startMouse.x)/canvas.width)*(x2-x1);
var offsetY = ((mousePos.y-startMouse.y)/canvas.height)*(y2-y1);
this.setRange(x1-offsetX, x2-offsetX, y1+offsetY, y2+offsetY);
startMouse = mousePos;
}.bind(this);
var dragMouse = function(event) {
stage.fillStyle = "#FFFFFF";
stage.fillRect(0, 0, canvas.width, canvas.height);
mousePos = getMousePos(event);
var newx1 = x1-((mousePos.x-startMouse.x)/canvas.width)*(x2-x1);
var newx2 = x2-((mousePos.x-startMouse.x)/canvas.width)*(x2-x1);
var newy1 = y1+((mousePos.y-startMouse.y)/canvas.height)*(y2-y1);
var newy2 = y2+((mousePos.y-startMouse.y)/canvas.height)*(y2-y1);
//If it's been dragged far enough, recalculate the line
if (Math.abs(mousePos.x-startMouse.x)>canvas.width*0.2 || Math.abs(mousePos.y-startMouse.y)>canvas.height*0.2) {
redrawLine();
//Otherwise, move around the drawing we already have
} else {
drawAxes(newx1, newx2, newy1, newy2);
stage.drawImage(graphCanvas, mousePos.x-startMouse.x, mousePos.y-startMouse.y);
}
if (event.preventDefault) event.preventDefault();
return false;
}.bind(this);
//Stops dragging, resets listeners
var endDrag = function(event) {
document.removeEventListener("mousemove", dragMouse, false);
document.removeEventListener("mouseup", endDrag, false);
document.documentElement.style["-moz-user-select"] = "auto";
document.documentElement.style["-webkit-user-select"] = "auto";
document.documentElement.style["-khtml-user-select"] = "auto";
document.documentElement.style["user-select"] = "auto";
canvas.addEventListener("mouseover", startMouseOver, false);
canvas.addEventListener("mousemove", moveMouse, false);
mousePos = getMousePos(event);
var offsetX = ((mousePos.x-startMouse.x)/canvas.width)*(x2-x1);
var offsetY = ((mousePos.y-startMouse.y)/canvas.height)*(y2-y1);
this.setRange(x1-offsetX, x2-offsetX, y1+offsetY, y2+offsetY);
}.bind(this);
var startMouseOver = function(event) {
canvas.addEventListener("mousemove", moveMouse, false);
canvas.addEventListener("mouseout", endMouseOver, false);
}.bind(this);
//Draws coordinates over point
var moveMouse = function(event) {
if (distX===0 && distY===0) {
stage.fillStyle = "#FFFFFF";
stage.fillRect(0, 0, canvas.width, canvas.height);
drawAxes(x1, x2, y1, y2);
stage.drawImage(graphCanvas, 0, 0);
mousePos = getMousePos(event);
if (mousePos.x<0) mousePos.x=0;
if (mousePos.y<0) mousePos.y=0;
var offsetY = -y1;
//Check if the function exists at that x value
if (points[Math.round(mousePos.x/canvas.width*points.length)].y===0 || points[Math.round(mousePos.x/canvas.width*points.length)].y) {
//Draw the coordinate
stage.fillStyle="#2980b9";
stage.beginPath();
stage.arc(mousePos.x, canvas.height-((points[Math.round(mousePos.x/canvas.width*points.length)].y+offsetY)/(y2-y1))*canvas.height, 4, 0, 2*Math.PI);
stage.closePath();
stage.fill();
stage.fillStyle="#000";
stage.strokeStyle="#FFF";
stage.lineWidth=4;
stage.textBaseline="alphabetic";
var txt="(" + (Math.round(points[Math.round(mousePos.x/canvas.width*points.length)].x*100)/100).toFixed(2) + ", " + (Math.round(points[Math.round(mousePos.x/canvas.width*points.length)].y*100)/100).toFixed(2) + ")";
if (mousePos.x<stage.measureText(txt).width/2+2) {
stage.textAlign = "left";
} else if (mousePos.x>canvas.width-stage.measureText(txt).width/2-2) {
stage.textAlign = "right";
} else {
stage.textAlign = "center";
}
stage.strokeText(txt, mousePos.x, -10+canvas.height-((points[Math.round(mousePos.x/canvas.width*points.length)].y+offsetY)/(y2-y1))*canvas.height);
stage.fillText(txt, mousePos.x, -10+canvas.height-((points[Math.round(mousePos.x/canvas.width*points.length)].y+offsetY)/(y2-y1))*canvas.height);
}
}
}.bind(this);
var endMouseOver = function(event) {
canvas.removeEventListener("mousemove", moveMouse, false);
canvas.removeEventListener("mouseout", endMouseOver, false);
stage.fillStyle = "#FFFFFF";
stage.fillRect(0, 0, canvas.width, canvas.height);
drawAxes(x1, x2, y1, y2);
stage.drawImage(graphCanvas, 0, 0);
}.bind(this);
//Zooms based on scroll wheel
var scrollZoom = function(event) {
var delta = Math.max(-1, Math.min(1, (event.wheelDelta || -event.detail)));
distX += delta*(x2-2*distX-x1)/25;
distY += delta*(y2-2*distY-y1)/25;
stage.fillStyle = "#FFFFFF";
stage.fillRect(0, 0, canvas.width, canvas.height);
drawAxes(x1 + distX, x2 - distX, y1 + distY, y2 - distY);
stage.drawImage(graphCanvas, canvas.width*(1-((x2-x1)/(x2-2*distX-x1)))/2, canvas.height*(1-((y2-y1)/(y2-2*distY-y1)))/2, canvas.width*((x2-x1)/(x2-2*distX-x1)), canvas.height*((y2-y1)/(y2-2*distY-y1)));
if (event.preventDefault) event.preventDefault();
clearTimeout(timer);
timer = setTimeout(updateZoom, 50);
return false;
}.bind(this);
var updateZoom = function() {
stage.fillStyle = "#FFFFFF";
stage.fillRect(0, 0, canvas.width, canvas.height);
this.setRange(x1 + distX, x2 - distX, y1 + distY, y2 - distY);
distX=0;
distY=0;
clearTimeout(timer);
}.bind(this);
//Returns the canvas element
this.getCanvas = function() {
return canvas;
};
this.getX1 = function() {
return x1;
};
this.getX2 = function() {
return x2;
};
this.getY1 = function() {
return y1;
};
this.getY2= function() {
return y2;
};
//If canvas drawing is supported
if (canvas.getContext) {
//Get the canvas context to draw onto
stage = canvas.getContext("2d");
stage.font = "12px sans-serif";
canvas.style.backgroundColor="#FFF";
graphStage = graphCanvas.getContext("2d");
//Make points
this.update();
canvas.addEventListener("mousedown", startDrag, false);
canvas.addEventListener("mouseover", startMouseOver, false);
canvas.addEventListener("mousewheel", scrollZoom, false);
canvas.addEventListener("DOMMouseScroll", scrollZoom, false);
} else {
XCalc.log("Canvas not supported in this browser.");
canvas = document.createElement("div");
canvas.innerHTML="Canvas is not supported in this browser.";
}
}
//Module for input checking and parsing
var XCalc = (function() {
var worker={};
worker.errors=[];
//logs errors
worker.log = function(message) {
this.errors.push(message);
};
worker.clearErrors = function() {
this.errors = [];
};
worker.hasErrors = function() {
return this.errors.length;
};
//creates a list of errors to be displayed
worker.displayErrors = function() {
var errorDiv = document.createElement("div");
errorDiv.className="error";
errorDiv.innerHTML = "Errors:";
var errorList = document.createElement("ul");
for (var i=0; i<this.errors.length; i++) {
var e = document.createElement("li");
e.innerHTML = this.errors[i];
errorList.appendChild(e);
}
errorDiv.appendChild(errorList);
return errorDiv;
};
//Checks to see if brackets are properly nested in a string
worker.properBrackets = function(value) {
var openBrackets=0;
for (var i=0; i<value.length; i++) {
if (value.substr(i, 1)=="(") openBrackets++;
if (value.substr(i, 1)==")") openBrackets--;
}
return openBrackets===0;
};
//Creates a new Segment for an expression
worker.createExpression = function(value) {
if (this.properBrackets(value)) {
return new Segment(value);
} else {
this.log("Improperly nested brackets.");
return 0;
}
};
//Creates a new Graph for an expression
worker.graphExpression = function(value, width, height, x1, x2, y1, y2) {
if (this.properBrackets(value)) {
return new Graph(value, width, height, x1, x2, y1, y2);
} else {
this.log("Improperly nested brackets.");
return 0;
}
};
return worker;
}());
function simplifyText(event) {
//Grabs data from input elements
var input = document.getElementById("input").value;
var x1 = (document.getElementById("x1").value==="")?undefined:parseFloat(document.getElementById("x1").value);
var x2 = (document.getElementById("x2").value==="")?undefined:parseFloat(document.getElementById("x2").value);
var y1 = document.getElementById("y1").value?(document.getElementById("y1").value.trim()=="auto")?"auto":parseFloat(document.getElementById("y1").value):undefined;
var y2 = document.getElementById("y2").value?(document.getElementById("y2").value.trim()=="auto")?"auto":parseFloat(document.getElementById("y2").value):undefined;
var derive = false;
if (input.lastIndexOf("derive")!=-1) {
derive=true;
input = input.substring(input.lastIndexOf("derive")+6);
} else if (input.lastIndexOf("derivative of")!=-1) {
derive=true;
input = input.substring(input.lastIndexOf("derivative of")+13);
} else if (input.lastIndexOf("derivative")!=-1) {
derive=true;
input = input.substring(input.lastIndexOf("derivative")+10);
} else if (input.lastIndexOf("dy/dx")!=-1) {
derive=true;
input = input.substring(input.lastIndexOf("dy/dx")+5);
} else if (input.lastIndexOf("d/dx")!=-1) {
derive=true;
input = input.substring(input.lastIndexOf("d/dx")+4);
}
//Makes the results pane close
document.getElementById("wrapper").className="";
//wait for pane to close
var timer = setTimeout(function() {
var width=500;
if (document.getElementById("wrapper").offsetWidth<550) width = document.getElementById("wrapper").offsetWidth - 50;
document.getElementById("result").innerHTML = "";
var inputFunction = XCalc.createExpression(input);
var graph;
var derivative;
var derivativeGraph;
if (derive) {
derivative = inputFunction.derive();
derivativeGraph = XCalc.graphExpression(derivative, width, Math.round(width*0.4), x1, x2, y1, y2);
graph = XCalc.graphExpression(inputFunction, width, Math.round(width*0.5), x1, x2, y1, y2);
} else {
graph = XCalc.graphExpression(inputFunction, width, Math.round(width*0.8), x1, x2, y1, y2);
}
//If there are no errors, show the graph
if (!XCalc.hasErrors()) {
if (derive) {
var derivativeFormula = document.createElement("div");
derivativeFormula.className = "formula";
derivativeFormula.innerHTML = "y' = " + derivative.prettyFormula();
document.getElementById("result").appendChild(derivativeFormula);
document.getElementById("result").appendChild(derivativeGraph.getCanvas());
}
var inputFormula = document.createElement("div");
inputFormula.className = "formula";
inputFormula.innerHTML = "y = " + inputFunction.simplify().prettyFormula();
document.getElementById("result").appendChild(inputFormula);
document.getElementById("result").appendChild(graph.getCanvas());
document.getElementById("wrapper").className="open";
//Otherwise, show the errors, then clear the error list
} else {
document.getElementById("result").appendChild(XCalc.displayErrors());
document.getElementById("wrapper").className="open";
XCalc.clearErrors();
}
}, 800);
}
function onKeyUp(event) {
if (event.keyCode==13) {
simplifyText();
}
}
window.onload = function() {
document.getElementById("graph").addEventListener("click", simplifyText);
document.getElementById("input").addEventListener("keyup", onKeyUp);
simplifyText();
};
!
