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With the new version 1.x.y the original curve computation (nergal.dev's code) has been replaced by a new algorithm which computes hermite splines.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

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examples:

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http://jsfiddle.net/p55d7bk8/2/ <- random data example
http://jsfiddle.net/yqsb8mdc/2/ <- nrSplinePoints parameter
http://jsfiddle.net/jd9q53fw/2/ <- fit parameters
https://jsfiddle.net/L0kgfytv/ <- advanced usage
http://jsfiddle.net/n0600qo4/2/ <- legacy example

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how to use it:

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Data:

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

Config:

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

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options:

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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 bower.io. 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="https://cdn.rawgit.com/MichaelZinsmaier/CurvedLines/1.1.1/curvedLines.js"></script>

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

deprecated pre 1.0.0 plotting

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legacy options:

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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
                                    }
                   } ...