workable solution for slider zooming log charts

[Per Franck <pe...@gmail.com>]

If anyone needs dataZoom for log charts, this is a workable solution,
unless there's a better way, i'd love some feedback.

1. create a dummy yAxis following your other 'real' axis
*options.yAxis = [*
*  {id:"logyaxis", type:"log" ... },*
*  {type:"value"}*
*]*

2. create a slider dataZoom targeting the dummy yAxis, but *not *a dataZoom
for the actual axis
*{ name: "logzoom", yAxisIndex: n, type: "slider" ... } *
(i wish this could be done with a yAxisId instead)

3. handle the datazoom event of the chart
and adjust max/min of the axis instead
*function scaleToLog(scale){*


*  // play with the f(x) parameters here  return 1e-20 * Math.pow(10,
scale/1.5)}*

*g_chart.on("datazoom",function(params){*
*  if ( params.dataZoomId == "logzoom" ){*



*    startValue = scaleToLog(params.start)    endValue =
scaleToLog(params.end)    g_chart.setOption({      yAxis:{*
*        id: "logyaxis",*




*        min: startValue,        max: endValue      }     })*
*  }*
*})*