fltk/src/Fl_Valuator.cxx

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//
// "$Id$"
//
// Valuator widget for the Fast Light Tool Kit (FLTK).
//
// Copyright 1998-2005 by Bill Spitzak and others.
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
// USA.
//
// Please report all bugs and problems on the following page:
//
// http://www.fltk.org/str.php
//
/** \fn int Fl_Valuator::changed() const
This value is true if the user has moved the slider. It is
turned off by value(x) and just before doing a callback
(the callback can turn it back on if desired).
*/
// Base class for sliders and all other one-value "knobs"
#include <FL/Fl.H>
#include <FL/Fl_Valuator.H>
#include <FL/math.h>
#include <stdio.h>
#include "flstring.h"
Fl_Valuator::Fl_Valuator(int X, int Y, int W, int H, const char* L)
/**
Creates a new Fl_Valuator widget using the given position,
size, and label string. The default boxtype is FL_NO_BOX.
*/
: Fl_Widget(X,Y,W,H,L) {
align(FL_ALIGN_BOTTOM);
when(FL_WHEN_CHANGED);
value_ = 0;
previous_value_ = 1;
min = 0;
max = 1;
A = 0.0;
B = 1;
}
const double epsilon = 4.66e-10;
/** See double Fl_Valuator::step() const */
void Fl_Valuator::step(double s) {
if (s < 0) s = -s;
A = rint(s);
B = 1;
while (fabs(s-A/B) > epsilon && B<=(0x7fffffff/10)) {B *= 10; A = rint(s*B);}
}
/** Sets the step value to 1/10<SUP>digits.*/
void Fl_Valuator::precision(int p) {
A = 1.0;
for (B = 1; p--;) B *= 10;
}
/** Asks for partial redraw */
void Fl_Valuator::value_damage() {damage(FL_DAMAGE_EXPOSE);} // by default do partial-redraw
/** See double Fl_Valuator::value() const */
int Fl_Valuator::value(double v) {
clear_changed();
if (v == value_) return 0;
value_ = v;
value_damage();
return 1;
}
double Fl_Valuator::softclamp(double v) {
int which = (min<=max);
double p = previous_value_;
if ((v<min)==which && p!=min && (p<min)!=which) return min;
else if ((v>max)==which && p!=max && (p>max)!=which) return max;
else return v;
}
// inline void Fl_Valuator::handle_push() {previous_value_ = value_;}
void Fl_Valuator::handle_drag(double v) {
if (v != value_) {
value_ = v;
value_damage();
set_changed();
if (when() & FL_WHEN_CHANGED) do_callback();
}
}
void Fl_Valuator::handle_release() {
if (when()&FL_WHEN_RELEASE) {
// insure changed() is off even if no callback is done. It may have
// been turned on by the drag, and then the slider returned to it's
// initial position:
clear_changed();
// now do the callback only if slider in new position or always is on:
if (value_ != previous_value_ || when() & FL_WHEN_NOT_CHANGED) {
do_callback();
}
}
}
/**
Round the passed value to the nearest step increment. Does
nothing if step is zero.
*/
double Fl_Valuator::round(double v) {
if (A) return rint(v*B/A)*A/B;
else return v;
}
/** Clamps the passed value to the valuator range.*/
double Fl_Valuator::clamp(double v) {
if ((v<min)==(min<=max)) return min;
else if ((v>max)==(min<=max)) return max;
else return v;
}
/**
Adds n times the step value to the passed value. If
step was set to zero it uses fabs(maximum() - minimum()) /
100.
*/
double Fl_Valuator::increment(double v, int n) {
if (!A) return v+n*(max-min)/100;
if (min > max) n = -n;
return (rint(v*B/A)+n)*A/B;
}
/**
Uses internal rules to format the fields numerical value into
the character array pointed to by the passed parameter.</P>
<P>The actual format used depends on the current step value. If
the step value has been set to zero then a %g format is used.
If the step value is non-zero, then a %.*f format is used,
where the precision is calculated to show sufficient digits
for the current step value. An integer step value, such as 1
or 1.0, gives a precision of 0, so the formatted value will
appear as an integer.</P>
<P>This method is used by the Fl_Value_... group of widgets to
format the current value into a text string.
The return value is the length of the formatted text.
The formatted value is written into in <i>buffer</i>.
<i>buffer</i> should have space for at least 128 bytes.</P>
<P>You may override this function to create your own text formatting.
*/
int Fl_Valuator::format(char* buffer) {
double v = value();
// MRS: THIS IS A HACK - RECOMMEND ADDING BUFFER SIZE ARGUMENT
if (!A || !B) return snprintf(buffer, 128, "%g", v);
// Figure out how many digits are required to correctly format the
// value.
int i, c = 0;
char temp[32];
// output a number with many digits after the decimal point. This
// seems to be needed to get high precission
snprintf(temp, sizeof(temp), "%.12f", A/B);
// strip all trailing 0's
for (i=strlen(temp)-1; i>0; i--) {
if (temp[i]!='0') break;
}
// count digits until we find the decimal point (or comma or whatever
// letter is set in the current locale)
for (; i>0; i--, c++) {
if (!isdigit(temp[i])) break;
}
// MRS: THIS IS A HACK - RECOMMEND ADDING BUFFER SIZE ARGUMENT
return snprintf(buffer, 128, "%.*f", c, v);
}
//
// End of "$Id$".
//