You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
275 lines
8.6 KiB
275 lines
8.6 KiB
/**
|
|
* @constructor DataStep
|
|
* The class DataStep is an iterator for data for the lineGraph. You provide a start data point and an
|
|
* end data point. The class itself determines the best scale (step size) based on the
|
|
* provided start Date, end Date, and minimumStep.
|
|
*
|
|
* If minimumStep is provided, the step size is chosen as close as possible
|
|
* to the minimumStep but larger than minimumStep. If minimumStep is not
|
|
* provided, the scale is set to 1 DAY.
|
|
* The minimumStep should correspond with the onscreen size of about 6 characters
|
|
*
|
|
* Alternatively, you can set a scale by hand.
|
|
* After creation, you can initialize the class by executing first(). Then you
|
|
* can iterate from the start date to the end date via next(). You can check if
|
|
* the end date is reached with the function hasNext(). After each step, you can
|
|
* retrieve the current date via getCurrent().
|
|
* The DataStep has scales ranging from milliseconds, seconds, minutes, hours,
|
|
* days, to years.
|
|
*
|
|
* Version: 1.2
|
|
*
|
|
* @param {Date} [start] The start date, for example new Date(2010, 9, 21)
|
|
* or new Date(2010, 9, 21, 23, 45, 00)
|
|
* @param {Date} [end] The end date
|
|
* @param {Number} [minimumStep] Optional. Minimum step size in milliseconds
|
|
*/
|
|
function DataStep(start, end, minimumStep, containerHeight, customRange, alignZeros) {
|
|
// variables
|
|
this.current = 0;
|
|
|
|
this.autoScale = true;
|
|
this.stepIndex = 0;
|
|
this.step = 1;
|
|
this.scale = 1;
|
|
|
|
this.marginStart;
|
|
this.marginEnd;
|
|
this.deadSpace = 0;
|
|
|
|
this.majorSteps = [1, 2, 5, 10];
|
|
this.minorSteps = [0.25, 0.5, 1, 2];
|
|
|
|
this.alignZeros = alignZeros;
|
|
|
|
this.setRange(start, end, minimumStep, containerHeight, customRange);
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
* Set a new range
|
|
* If minimumStep is provided, the step size is chosen as close as possible
|
|
* to the minimumStep but larger than minimumStep. If minimumStep is not
|
|
* provided, the scale is set to 1 DAY.
|
|
* The minimumStep should correspond with the onscreen size of about 6 characters
|
|
* @param {Number} [start] The start date and time.
|
|
* @param {Number} [end] The end date and time.
|
|
* @param {Number} [minimumStep] Optional. Minimum step size in milliseconds
|
|
*/
|
|
DataStep.prototype.setRange = function(start, end, minimumStep, containerHeight, customRange) {
|
|
this._start = customRange.min === undefined ? start : customRange.min;
|
|
this._end = customRange.max === undefined ? end : customRange.max;
|
|
|
|
if (this._start == this._end) {
|
|
this._start -= 0.75;
|
|
this._end += 1;
|
|
}
|
|
|
|
if (this.autoScale == true) {
|
|
this.setMinimumStep(minimumStep, containerHeight);
|
|
}
|
|
|
|
this.setFirst(customRange);
|
|
};
|
|
|
|
/**
|
|
* Automatically determine the scale that bests fits the provided minimum step
|
|
* @param {Number} [minimumStep] The minimum step size in milliseconds
|
|
*/
|
|
DataStep.prototype.setMinimumStep = function(minimumStep, containerHeight) {
|
|
// round to floor
|
|
var size = this._end - this._start;
|
|
var safeSize = size * 1.2;
|
|
var minimumStepValue = minimumStep * (safeSize / containerHeight);
|
|
var orderOfMagnitude = Math.round(Math.log(safeSize)/Math.LN10);
|
|
|
|
var minorStepIdx = -1;
|
|
var magnitudefactor = Math.pow(10,orderOfMagnitude);
|
|
|
|
var start = 0;
|
|
if (orderOfMagnitude < 0) {
|
|
start = orderOfMagnitude;
|
|
}
|
|
|
|
var solutionFound = false;
|
|
for (var i = start; Math.abs(i) <= Math.abs(orderOfMagnitude); i++) {
|
|
magnitudefactor = Math.pow(10,i);
|
|
for (var j = 0; j < this.minorSteps.length; j++) {
|
|
var stepSize = magnitudefactor * this.minorSteps[j];
|
|
if (stepSize >= minimumStepValue) {
|
|
solutionFound = true;
|
|
minorStepIdx = j;
|
|
break;
|
|
}
|
|
}
|
|
if (solutionFound == true) {
|
|
break;
|
|
}
|
|
}
|
|
this.stepIndex = minorStepIdx;
|
|
this.scale = magnitudefactor;
|
|
this.step = magnitudefactor * this.minorSteps[minorStepIdx];
|
|
};
|
|
|
|
|
|
|
|
/**
|
|
* Round the current date to the first minor date value
|
|
* This must be executed once when the current date is set to start Date
|
|
*/
|
|
DataStep.prototype.setFirst = function(customRange) {
|
|
if (customRange === undefined) {
|
|
customRange = {};
|
|
}
|
|
|
|
var niceStart = customRange.min === undefined ? this._start - (this.scale * 2 * this.minorSteps[this.stepIndex]) : customRange.min;
|
|
var niceEnd = customRange.max === undefined ? this._end + (this.scale * this.minorSteps[this.stepIndex]) : customRange.max;
|
|
|
|
this.marginEnd = customRange.max === undefined ? this.roundToMinor(niceEnd) : customRange.max;
|
|
this.marginStart = customRange.min === undefined ? this.roundToMinor(niceStart) : customRange.min;
|
|
|
|
// if we need to align the zero's we need to make sure that there is a zero to use.
|
|
if (this.alignZeros == true && (this.marginEnd - this.marginStart) % this.step != 0) {
|
|
this.marginEnd += this.marginEnd % this.step;
|
|
}
|
|
|
|
this.deadSpace = this.roundToMinor(niceEnd) - niceEnd + this.roundToMinor(niceStart) - niceStart;
|
|
this.marginRange = this.marginEnd - this.marginStart;
|
|
|
|
|
|
this.current = this.marginEnd;
|
|
};
|
|
|
|
DataStep.prototype.roundToMinor = function(value) {
|
|
var rounded = value - (value % (this.scale * this.minorSteps[this.stepIndex]));
|
|
if (value % (this.scale * this.minorSteps[this.stepIndex]) > 0.5 * (this.scale * this.minorSteps[this.stepIndex])) {
|
|
return rounded + (this.scale * this.minorSteps[this.stepIndex]);
|
|
}
|
|
else {
|
|
return rounded;
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* Check if the there is a next step
|
|
* @return {boolean} true if the current date has not passed the end date
|
|
*/
|
|
DataStep.prototype.hasNext = function () {
|
|
return (this.current >= this.marginStart);
|
|
};
|
|
|
|
/**
|
|
* Do the next step
|
|
*/
|
|
DataStep.prototype.next = function() {
|
|
var prev = this.current;
|
|
this.current -= this.step;
|
|
|
|
// safety mechanism: if current time is still unchanged, move to the end
|
|
if (this.current == prev) {
|
|
this.current = this._end;
|
|
}
|
|
};
|
|
|
|
/**
|
|
* Do the next step
|
|
*/
|
|
DataStep.prototype.previous = function() {
|
|
this.current += this.step;
|
|
this.marginEnd += this.step;
|
|
this.marginRange = this.marginEnd - this.marginStart;
|
|
};
|
|
|
|
|
|
|
|
/**
|
|
* Get the current datetime
|
|
* @return {String} current The current date
|
|
*/
|
|
DataStep.prototype.getCurrent = function(decimals) {
|
|
// prevent round-off errors when close to zero
|
|
var current = (Math.abs(this.current) < this.step / 2) ? 0 : this.current;
|
|
var toPrecision = '' + Number(current).toPrecision(5);
|
|
|
|
// If decimals is specified, then limit or extend the string as required
|
|
if(decimals !== undefined && !isNaN(Number(decimals))) {
|
|
// If string includes exponent, then we need to add it to the end
|
|
var exp = "";
|
|
var index = toPrecision.indexOf("e");
|
|
if(index != -1) {
|
|
// Get the exponent
|
|
exp = toPrecision.slice(index);
|
|
// Remove the exponent in case we need to zero-extend
|
|
toPrecision = toPrecision.slice(0, index);
|
|
}
|
|
index = Math.max(toPrecision.indexOf(","), toPrecision.indexOf("."));
|
|
if(index === -1) {
|
|
// No decimal found - if we want decimals, then we need to add it
|
|
if(decimals !== 0) {
|
|
toPrecision += '.';
|
|
}
|
|
// Calculate how long the string should be
|
|
index = toPrecision.length + decimals;
|
|
}
|
|
else if(decimals !== 0) {
|
|
// Calculate how long the string should be - accounting for the decimal place
|
|
index += decimals + 1;
|
|
}
|
|
if(index > toPrecision.length) {
|
|
// We need to add zeros!
|
|
for(var cnt = index - toPrecision.length; cnt > 0; cnt--) {
|
|
toPrecision += '0';
|
|
}
|
|
}
|
|
else {
|
|
// we need to remove characters
|
|
toPrecision = toPrecision.slice(0, index);
|
|
}
|
|
// Add the exponent if there is one
|
|
toPrecision += exp;
|
|
}
|
|
else {
|
|
if (toPrecision.indexOf(",") != -1 || toPrecision.indexOf(".") != -1) {
|
|
// If no decimal is specified, and there are decimal places, remove trailing zeros
|
|
for (var i = toPrecision.length - 1; i > 0; i--) {
|
|
if (toPrecision[i] == "0") {
|
|
toPrecision = toPrecision.slice(0, i);
|
|
}
|
|
else if (toPrecision[i] == "." || toPrecision[i] == ",") {
|
|
toPrecision = toPrecision.slice(0, i);
|
|
break;
|
|
}
|
|
else {
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return toPrecision;
|
|
};
|
|
|
|
|
|
|
|
/**
|
|
* Snap a date to a rounded value.
|
|
* The snap intervals are dependent on the current scale and step.
|
|
* @param {Date} date the date to be snapped.
|
|
* @return {Date} snappedDate
|
|
*/
|
|
DataStep.prototype.snap = function(date) {
|
|
|
|
};
|
|
|
|
/**
|
|
* Check if the current value is a major value (for example when the step
|
|
* is DAY, a major value is each first day of the MONTH)
|
|
* @return {boolean} true if current date is major, else false.
|
|
*/
|
|
DataStep.prototype.isMajor = function() {
|
|
return (this.current % (this.scale * this.majorSteps[this.stepIndex]) == 0);
|
|
};
|
|
|
|
module.exports = DataStep;
|