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What it is

CurvedLines is a plugin for flot, which displays lines in a smooth curved way. This is achieved by adding additional points in between the "real" data points. See the test files for examples. Feel free to add additional features and correct errors.

Regards Michael

Hermite Splines v1.x.y

With the new version 1.x.y the original curve computation ('s code) has been replaced by a new algorithm which computes hermite splines. In general the result should be closer to the data however the old implementation is still accessible through the legacyOverride option.

The approximation with local third-degree polynoms solves some existing issues. The problematic parameters curvePointFactor and fitPointDist are not longer needed and I hope that the new nrSplinePoints parameter needs less manual adjustment (basically only if you use zooming or large segments) and is easier to understand.

The old fit option has been replaced with monotonicFit, which if set, enforces the use of the Fritsch-Carlson method (anti wiggle no overshooting / undershooting).

Hands on

examples: <- random data example <- nrSplinePoints parameter <- fit parameters <- advanced usage <- legacy example

how to use it:


CurvedLines assumes xi < xi+1 that is x values must be ordered from smallest to largest and must be unique.

  ... lines: { show: true},
     curvedLines: {
                      apply: true,
                   } ...


parameter type effect
active bool true => plugin can be used
apply bool true => series will be drawn as curved line
monotonicFit bool true => uses monotone cubic interpolation (preserve monotonicity)
tension double [0,1] defines the tension parameter of the hermite spline interpolation (only if monotonicFit = false)
nrSplinePoints int defines the number of sample points (of the spline) in between two consecutive points
Versioning and Linking

CurvedLines is listed at Releases are marked in GitHub

The following snippet uses RawGit as CDN to include CurvedLines and loads a local copy as fallback. Before copy pasting this please check the terms and conditions at RawGit!

<script src=""></script>

  $.plot.plugins.find(function(element){return == "curvedLines"}) || 
  document.write('<script src="[server_local_copy]"><\/script>');

deprecated pre 1.0.0 plotting

legacy options:

to use the old curve computation algorithm with default parameters simply set legacyOverride to true

parameter type effect
legacyOverride bool true => use old default

or to get more control set a parameter object with the old parameters as members

parameter type effect
fit bool true => forces the max,mins of the curve to be on the datapoints
curvePointFactor int defines how many "virtual" points are used per "real" data point to emulate the curvedLines (points total = real points * curvePointFactor)
fitPointDist double defines the x axis distance of the additional two points that are used to enforce the min max condition.
 ... lines: { show: true},
     curvedLines: {
                   apply: true,
                   legacyOverride: {
                                    fit: true
                   } ...


CurvedLines is a plugin for flot, which displays lines in a smooth curved way. This is achieved by adding additional points in between the "real" data points.






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