A custom tick formatter has no way to know what axis it is being run on for multi-series data.

[dnschnur]

Original author: b1gg...@gmail.com (July 17, 2009 18:26:21)

Problem:
Currently a custom tick tickFormatter is passed a value and an axis object.
The axis object doe not provide any information on which axis it is. So for
example a graph could have two series, on is altitude in meters and the
other is speed in km/hr. In the custom formater there is no way to add the
correct unit to the tick.

Recommendation: The axis objects need to have a 'key' that identifies them.
I have a simple fix:

Existing code:
...
canvas = null, // the canvas for the plot itself
overlay = null, // canvas for interactive stuff on top of plot
eventHolder = null, // jQuery object that events should be bound to
ctx = null, octx = null,
target = $(target_),
-> axes = { xaxis: {}, yaxis: {}, x2axis: {}, y2axis: {} },
plotOffset = { left: 0, right: 0, top: 0, bottom: 0},
canvasWidth = 0, canvasHeight = 0,
plotWidth = 0, plotHeight = 0,
...

Proposed change:
...
canvas = null, // the canvas for the plot itself
overlay = null, // canvas for interactive stuff on top of plot
eventHolder = null, // jQuery object that events should be bound to
ctx = null, octx = null,
target = $(target_),
-> axes = {
-> xaxis: {
-> axisName: 'x',
-> axisIndex: 0},
-> yaxis: {
-> axisName: 'y',
-> axisIndex: 0},
-> x2axis: {
-> axisName: 'x',
-> axisIndex: 1},
-> y2axis: {
-> axisName: 'y',
-> axisIndex: 1}
-> },
plotOffset = { left: 0, right: 0, top: 0, bottom: 0},
canvasWidth = 0, canvasHeight = 0,
plotWidth = 0, plotHeight = 0,
...

This would allow a tickFormetter like this:

options.yaxis.tickFormatter = function(val,axis){
var unit_labels = new Array('meters','km/hr');
return (val|0) + " " + unit_labels[axis.axisIndex];
}

Original issue: http://code.google.com/p/flot/issues/detail?id=193

[dnschnur]

From olau%iol...@gtempaccount.com on October 07, 2009 15:31:56
Hm, yes, something like that.

A complication is that some people want to add more axes than just the two possible
right now. This is a bit difficult because most of the critical places in Flot are
not prepared for dealing with more than two. We need to generalize that, and fix this
problem too.