Last active
August 29, 2015 14:05
-
-
Save erohinaelena/882e7cadc2fd687cf2b3 to your computer and use it in GitHub Desktop.
Farthest feasible point filter
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <link href="main.css" rel="stylesheet"> | |
| </head> | |
| <body> | |
| <script src="http://d3js.org/d3.v3.min.js"></script> | |
| <script src="main.js"></script> | |
| </body> | |
| </html> |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| .axis path, | |
| .axis line { | |
| fill: none; | |
| stroke: #ccc; | |
| shape-rendering: crispEdges; | |
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| var margin = {top: 50, right: 20, bottom: 50, left: 40}, | |
| width = 960 - margin.left - margin.right, | |
| height = 300 - margin.top - margin.bottom | |
| var pointsNumber = 45 | |
| var Δ = 0.1 | |
| var x = d3.scale.linear() | |
| .domain([0, pointsNumber]) | |
| .range([0, width]) | |
| var y = d3.scale.linear() | |
| .domain([0, 1]) | |
| .range([height, 0]) | |
| var yAxis = d3.svg.axis() | |
| .scale(y) | |
| .orient("left") | |
| var svg = d3.select("body").append("svg") | |
| .attr("width", width + margin.left + margin.right) | |
| .attr("height", height + margin.top + margin.bottom) | |
| var area = svg | |
| .append("g") | |
| .attr("transform", "translate(" + margin.left + "," + margin.top + ")") | |
| area.append("g") | |
| .attr("class", "axis") | |
| .call(yAxis) | |
| var areaGroup = area.append('g') | |
| var ffpGroup = area.append('g') | |
| var ε = 1e-6 | |
| function filterData(d, Δ) { | |
| d = d.slice() | |
| var start = 0, | |
| result = [], | |
| trendBoundaries = [Infinity, -Infinity], | |
| currentPointBoundaries = [], | |
| currentPointTrend, | |
| farthestFeasible = 0, | |
| lower = 0, | |
| upper = 1, | |
| pushPoint = function () { result.push({ x: farthestFeasible, y: d[farthestFeasible] }) } | |
| pushPoint() | |
| while (farthestFeasible < d.length - 1) { | |
| for (var i = start; i < d.length; i++) { | |
| currentPointBoundaries = [ | |
| (d[i] - d[start] + Δ) / (i - start), | |
| (d[i] - d[start] - Δ) / (i - start) | |
| ] | |
| if (trendBoundaries[upper] < currentPointBoundaries[upper] + ε) { | |
| trendBoundaries[upper] = currentPointBoundaries[upper] | |
| } | |
| if (currentPointBoundaries[lower] < trendBoundaries[lower] + ε) { | |
| trendBoundaries[lower] = currentPointBoundaries[lower] | |
| } | |
| currentPointTrend = (d[i] - d[start]) / (i - start) | |
| if (trendBoundaries[upper] < currentPointTrend + ε && currentPointTrend < trendBoundaries[lower] + ε) { | |
| farthestFeasible = i | |
| } else if (trendBoundaries[lower] < trendBoundaries[upper] + ε) { | |
| trendBoundaries = [Infinity, -Infinity] | |
| i = start = farthestFeasible | |
| pushPoint() | |
| } | |
| } | |
| trendBoundaries = [Infinity, -Infinity] | |
| start = farthestFeasible | |
| pushPoint() | |
| } | |
| return result | |
| } | |
| var i = 0 | |
| var currentValue = Math.random() | |
| var values = [] | |
| var limit = d3.scale.linear().clamp(true) | |
| setInterval(function() { | |
| if (i < pointsNumber) { | |
| currentValue = limit(currentValue + .3 * Math.random() - .15 + .01 * Math.cos(i * 5)) | |
| values.push(currentValue) | |
| var circles = areaGroup.selectAll('circle') | |
| .data(values) | |
| circles.exit().remove() | |
| circles | |
| .enter().append('circle') | |
| .attr('cx', function(d, i) { return x(i) }) | |
| .attr('cy', function(d) { return y(d) }) | |
| .attr('r', 0) | |
| .attr('fill', '#aaa') | |
| .transition() | |
| .attr('r', 1.5) | |
| var data = filterData(values, Δ) | |
| var filteredDots = ffpGroup.selectAll('circle') | |
| .data(data, function (d) { return d.x + " " + d.y }) | |
| filteredDots.exit().remove() | |
| filteredDots | |
| .enter().append('circle') | |
| .attr('cx', function(d) { return x(d.x) }) | |
| .attr('cy', function(d) { return y(d.y) }) | |
| .attr('fill', '#000') | |
| .attr('r', 0) | |
| .transition() | |
| .attr('r', 1.5) | |
| var boundaries = [] | |
| function offsetLine (line, offset) { | |
| return [{x: line[0].x, y: line[0].y + offset}, {x: line[1].x, y: line[1].y + offset}] | |
| } | |
| d3.pairs(data).forEach(function(d) { | |
| boundaries.push(d) | |
| boundaries.push(offsetLine(d, Δ)) | |
| boundaries.push(offsetLine(d, -Δ)) | |
| }) | |
| var lines = areaGroup.selectAll('line') | |
| .data(boundaries, function (d) { return d[0].x + " " + d[0].y + " " + d[1].x + " " + d[1].y }) | |
| lines.exit().remove() | |
| lines.enter().append('line') | |
| .attr('stroke', '#ccc') | |
| .attr('x1', function(d) { return x(d[0].x) }) | |
| .attr('y1', function(d) { return y(d[0].y) }) | |
| .attr('x2', function(d) { return x(d[1].x) }) | |
| .attr('y2', function(d) { return y(d[1].y) }) | |
| i++ | |
| } | |
| }, 500) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment