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function sliding_hist() { |
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var chartWidth = 960, // default width |
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chartHeight = 500, // default height |
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binWidth = 10, |
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stepWidth = 1, |
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fillColor = "steelblue" |
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//Need last element of array later, neater to define logic here. |
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Array.prototype.last = function() { |
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return this[this.length-1]; |
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} |
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//takes your data, bin width and how much the bin slides over each step and |
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//returns an array of objects containing the "center" of the bin and the number |
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//of elements that fell in it ("in_bin"). |
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function generate_slide_hist(data, binWidth, stepSize){ |
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var binHalf = binWidth/2; |
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//Find the range of the data so we can know which window to slide overlay |
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var data_range = d3.extent(data) |
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//generate an array of the bin centers we are going to use in our sliding interval. |
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var bin_centers = [data_range[0] ] |
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while(bin_centers.last() < data_range[1]) bin_centers.push(bin_centers.last() + stepSize) |
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//Run through the bin centers counting how many are within the bin width of the value. |
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var counts = [] |
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bin_centers.forEach(function(center){ |
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var points_in_bin = data.filter(function(val){return val > (center - binHalf) && val < (center + binHalf) }) |
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counts.push({"center": center, "in_bin": points_in_bin.length}) |
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}) |
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return counts; |
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} |
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function chart(selection) { |
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selection.each(function(data){ |
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//make into the correct form. |
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var hist_data = generate_slide_hist(data,binWidth,stepWidth); |
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var margin = {top: 20, right: 20, bottom: 30, left: 50}, |
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width = chartWidth - margin.left - margin.right, |
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height = chartHeight - margin.top - margin.bottom; |
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var dataRange = d3.extent(data) |
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var x = d3.scaleLinear() |
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.range([0, width]) |
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.domain(dataRange); |
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var y = d3.scaleLinear() |
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.range([height, 0]) |
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.domain([0,d3.max(hist_data, function(d) { return d.in_bin; })]); |
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var line = d3.line() |
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.x(function(d) { return x(d.center); }) |
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.y(function(d) { return y(d.in_bin); }); |
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//shade under the line like a proper histogram. |
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var area = d3.area() |
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.x(function(d) { return x(d.center); }) |
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.y0(height) |
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.y1(function(d) { return y(d.in_bin); }); |
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var svg = d3.select(this).append("svg") |
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.attr("width", width + margin.left + margin.right) |
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.attr("height", height + margin.top + margin.bottom) |
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.append("g") |
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.attr("transform", "translate(" + margin.left + "," + margin.top + ")"); |
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//shade under the line. |
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svg.append("path") |
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.datum(hist_data) |
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.attr("class", "area") |
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.style("fill", fillColor) |
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.style("fill-opacity", 0.5) |
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.attr("d", area); |
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svg.append("path") |
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.datum(hist_data) |
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.attr("class", "line") |
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.attr("d", line); |
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svg.append("g") |
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.attr("class", "axis axis--x") |
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.attr("transform", "translate(0," + height + ")") |
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.call(d3.axisBottom(x)); |
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svg.append("g") |
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.attr("class", "axis axis--y") |
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.call(d3.axisLeft(y)) |
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.append("text") |
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.attr("class", "axis-title") |
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.attr("transform", "rotate(-90)") |
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.attr("y", 6) |
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.attr("dy", ".71em") |
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.style("text-anchor", "end") |
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.text("# in x +- binwidth/2"); |
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var focus = svg.append("g") |
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.attr("class", "focus") |
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.style("display", "none"); |
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focus.append("circle") |
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.attr("r", 4.5) |
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.style("fill", "none") |
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.style("stroke", "black"); |
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var drop_line = focus.append("line") |
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.attr("x1", 0) |
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.attr("y1", 0) |
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.attr("x2", 0) |
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.attr("y2", 0) |
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.attr("stroke","black"); |
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//how many pixles the interval takes up on the screen. |
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var interval_width = x(dataRange[0] + binWidth/2); |
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var interval_line = svg.append("g") |
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.attr("class", "interval_line") |
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//where the interval legend sits on plot when not being used for mouseover. |
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var interval_rest = "translate(" + (width - interval_width - 20) + "," + (height/7) + ")" |
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//place the interval line as a legend when not being interacted with. |
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interval_line.attr("transform", interval_rest); |
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var interval_legend_text = svg.append("text") |
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.text("Bin Width: " + binWidth) |
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.attr("text-anchor", "middle") |
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.attr("font-size", "0.9em") |
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.attr("y", -14) |
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.attr("transform", interval_rest); |
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interval_line.append("line") |
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.attr("class", "wide_line") |
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.attr("x1", interval_width) |
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.attr("y1", -10) |
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.attr("x2", -interval_width) |
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.attr("y2", -10) |
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.attr("stroke","black") |
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.attr("stroke-width","1px"); |
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interval_line.append("line") |
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.attr("class", "left_line") |
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.attr("x1", -interval_width) |
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.attr("y1", 0) |
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.attr("x2", -interval_width) |
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.attr("y2", -10) |
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.attr("stroke","black") |
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.attr("stroke-width","1px"); |
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interval_line.append("line") |
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.attr("class", "right_line") |
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.attr("x1", interval_width) |
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.attr("y1", 0) |
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.attr("x2", interval_width) |
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.attr("y2", -10) |
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.attr("stroke","black") |
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.attr("stroke-width","1px"); |
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focus.append("text") |
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.attr("x", 9) |
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.attr("dy", ".35em"); |
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svg.append("rect") |
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.attr("class", "overlay") |
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.attr("width", width) |
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.attr("height", height) |
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.style("fill","none") |
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.style("pointer-events", "all") |
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.on("mouseover", function() { |
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focus.style("display", null); }) |
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.on("mouseout", function() { |
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interval_line.transition().duration(200).attr("transform", interval_rest); |
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focus.style("display", "none"); }) |
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.on("mousemove", mousemove); |
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var bisectX = d3.bisector(function(d) { return d.center; }).left; |
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function mousemove() { |
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var x0 = x.invert(d3.mouse(this)[0]), |
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i = bisectX(hist_data, x0, 1), |
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d0 = hist_data[i - 1], |
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d1 = hist_data[i], |
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d = x0 - d0.center > d1.center - x0 ? d1 : d0; |
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focus.attr("transform", "translate(" + x(d.center) + "," + y(d.in_bin) + ")"); |
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drop_line |
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.attr("y1", 4.5) |
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.attr("y2", (height - y(d.in_bin) -10)); |
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interval_line |
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.transition() |
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.duration(20) |
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.attr("transform", "translate(" + x(d.center) + "," + (height ) + ")"); |
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focus.select("text").text(d.in_bin); |
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} |
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}) |
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} |
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chart.binWidth = function(value) { |
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if (!arguments.length) return binWidth; |
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binWidth = value; |
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return chart; |
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}; |
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chart.stepWidth = function(value) { |
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if (!arguments.length) return stepWidth; |
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stepWidth = value; |
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return chart; |
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}; |
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chart.height = function(value) { |
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if (!arguments.length) return chartHeight; |
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chartHeight = value; |
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return chart; |
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}; |
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chart.width = function(value) { |
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if (!arguments.length) return chartWidth; |
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chartWidth = value; |
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return chart; |
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}; |
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chart.fillColor = function(value) { |
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if (!arguments.length) return fillColor; |
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fillColor = value; |
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return chart; |
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}; |
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return chart; |
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} |