Sorry, I was unclear. Let me try again...
I would like to keep dynamic axis range, so that it can expand and contract around the points, but I'd like to be able to set a minimum difference between minimum and maximum, so that it doesn't automatically zoom in too far.
Something like this in pseudo code...
Code:min = dataArray[0];
max = dataArray[0];
minimumDifference = 10;
// get min and max from data series
for each point in dataArray
{
if( point < min )
min = point;
if( point > max )
max = point;
}
// pad the axis so that the range isn't too small
diff = max - min;
if( diff < minimumDifference )
{
min -= ( ( minimumDiffence - diff ) / 2 )
max += ( ( minimumDiffence - diff ) / 2 )
}
// set value in graph
axis.min = min;
axis.max = max;