Writing a routine to display data on a horizontal axis (using PHP gd2, but that's not the point here).
The axis starts at $min to $max and displays a diamond at $result, such an image will be around 300px wide and 30px high, like this:
(source: testwolke.de)
In the example above, $min=0, $max=3, $result=0.6.
Now, I need to calculate a scale and labels that make sense, in the above example e.g. dotted lines at 0 .25 .50 .75 1 1.25 ... up to 3, with number-labels at 0 1 2 3.
If $min=-200 and $max=600, dotted lines should be at -200 -150 -100 -50 0 50 100 ... up to 600, with number-labels at -200 -100 0 100 ... up to 600.
With $min=.02and $max=5.80, dotted lines at .02 .5 1 1.5 2 2.5 ... 5.5 5.8 and numbers at .02 1 2 3 4 5 5.8.
I tried explicitly telling the function where to put dotted lines and numbers by arrays, but hey, it's the computer who's supposed to work, not me, right?!
So, how to calculate???