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.

The plugin is based on nergal.dev's work and gives you an option to display curved lines. I further extended the code with a 2nd mode, which forces the lines to have their minima/maxima on the original data points.

Feel free to add additional features and correct errors.

Regards Michael


Update
added tests/Issue18.htm with a better explanation of the curvePointFactor
and fitPointDist parameter!

   
   
   
    how to use it:
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    var d1 = [[5,5],[7,3],[9,12]];

    var options = { series: { curvedLines: {  active: true }}};

    //you might want to adjust curvePointFactor 
    $.plot($("#placeholder"), [{data = d1, lines: { show: true}, 
                                curvedLines: {apply: true}}], options);

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     options:
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     active:           bool true => plugin can be used
     apply:            bool true => series will be drawn as curved line
     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:     int  defines the x axis distance of the additional two points
                                that are used to enforce the min max condition.