Re: How many float values in range 0f - 1f inclusive?

In article <CygFj.65$z51.55@[EMAIL PROTECTED]
>,
 "Jeff Higgins" <oohiggins@[EMAIL PROTECTED]
> wrote:
[...]
> This all came about because I am using a JSlider control to pick
> values for an java.awt.Color, where the arguments to the Color
> constructor are values between 0f - 1f.  Because JSlider only
> operates with integer values I was using a range of 0 - 10000
> and then multiplying by .0001 to get my float value.  I was trying
> to find a better range of integers to use for my JSlider range
> so that when I display the value I've picked with the slider
> I don't get ugly .50168 or some such for .5.  I guess I'll probably
> be better off dealing with that on the display end using printf or
> decimalFormat or such.

Indeed, you should keep the model (rational approximation of a floating 
point number) separate from the view (meaningful decimal format).

It's also useful to recall that a slider models an analog device: it 
re****ts the ratio of two screen coordinates with a resolution no greater 
than that provided by the mouse, roughly one pixel. Given a slider 1000 
pixels long, the accuracy can never be more than one part in 10^3, 
corresponding to an accuracy of three significant digits (sd). The 
accuracy is pro****tionally less for a shorter slider: Math.floor 
(Math.log10 (length)).

You can "pin" the slider's value to a particular tick size using an 
expression such as Math.rint (value / tickSize) * tickSize. You can 
adjust the tick size according to the slider's longest dimension: say 
0.01 for a 100 to 1000 pixels, and 0.001 for > 1000 pixels.

Would a custom color chooser provide a better abstraction?

<http://java.sun.com/docs/books/tutorial/uiswing/components/colorchooser.
html>

John
-- 
John B. Matthews
trashgod at gmail dot com
home dot woh dot rr dot com slash jbmatthews