I wrote:
>> So I've incorporated the fl_draw() call in an old example that I
>> posted several years ago. Basically I want something simple like:
>>
>> char buffer[32];
>> sprintf(buffer, "%d", value);
>> fl_draw(buffer, x() + 30, y() + 30);
Greg replied:
> Don't forget to set the font ;) eg. fl_font().
> FLTK will crash if the font isn't set before the fl_draw() call.
Doh! I *knew* it would be something simple. I didn't think about
calling fl_font() first because I already had text on the screen
inside button widgets, etc. so assumed it would use the same font.
I worked around it yesterday by adding a group above a similar
colour bar and using Fl_Box widgets and their labels to show the
min/max values. Anyway, I include the updated example below for
those who are interested.
Oh, and I'm still interested to know whether there are "standard"
ways of calculating such a colour/temperature spectrum.
Cheers
D.
/*
While trying to find a stupid error (Doh! max uchar is 255 and not 256!)
I've written a simple fl_color demo that someone might find useful.
*/
// Just compile using 'fltk-config --compile filename.cxx'
#include <FL/Fl.H>
#include <FL/Fl_Box.H>
#include <FL/Fl_Window.H>
#include <FL/fl_draw.H>
#include <cmath>
#include <cstdio>
#include <cstring>
void
setGrey (double ratio)
{
uchar grey = (uchar) (255 * ratio);
fl_color (grey);
}
void
setBlueToCyan (double ratio)
{
uchar red = 0;
uchar green = (uchar) (255 * ratio);
uchar blue = 255;
fl_color (red, green, blue);
}
void
setCyanToGreen (double ratio)
{
uchar red = 0;
uchar green = 255;
uchar blue = (uchar) (255 * (1.0 - ratio));
fl_color (red, green, blue);
}
void
setGreenToYellow (double ratio)
{
uchar red = (uchar) (255 * ratio);
uchar green = 255;
uchar blue = 0;
fl_color (red, green, blue);
}
void
setYellowToRed (double ratio)
{
uchar red = 255;
uchar green = (uchar) (255 * (1.0 - ratio));
uchar blue = 0;
fl_color (red, green, blue);
}
void
setColor (double min, double max, double value)
{
double range = max - min;
double delta = value - min;
double ratio = delta / range;
if (ratio <= 0.0) {
setGrey (0.3);
}
else if (ratio < 0.25) {
setBlueToCyan (4.0 * (ratio - 0.00));
}
else if (ratio < 0.50) {
setCyanToGreen (4.0 * (ratio - 0.25));
}
else if (ratio < 0.75) {
setGreenToYellow (4.0 * (ratio - 0.50));
}
else if (ratio < 1.00) {
setYellowToRed (4.0 * (ratio - 0.75));
}
else {
setGrey (0.7);
}
}
void
drawCircle (int x, int y, int r)
{
fl_pie (x - r, y - r, 2 * r, 2 * r, 0.0, 360.0);
fl_color (FL_BLACK);
fl_arc (x - r, y - r, 2 * r, 2 * r, 0.0, 360.0);
}
class Box:public Fl_Box
{
public:
Box (int x, int y, int w, int h, const char *t = 0):Fl_Box (x, y, w, h, t)
{
}
~Box ()
{
}
void draw ()
{
int xc = x () + w () / 2;
int yc = y () + h () / 2;
int rc = (w () < h ())? w () / 3 : h () / 3;
drawCircle (xc, yc, rc);
for (double angle = 0.0; angle < 360.0; angle += 10.0) {
int xx = (int) (xc + rc * sin (angle * M_PI / 180.0));
int yy = (int) (yc - rc * cos (angle * M_PI / 180.0));
setColor (0.0, 360.0, angle);
drawCircle (xx, yy, rc / 10);
}
for (int i = 0; i < w (); ++i) {
setColor (0, w (), i);
fl_line (x () + i, y (), x () + i, y () + 20);
}
fl_font(FL_HELVETICA, 12);
int tw, th;
char buffer[32];
setColor(0, w(), 1);
sprintf(buffer, "%d", 1);
fl_measure(buffer, tw, th);
fl_draw(buffer, x(), y()+20+th);
setColor(0, w(), w()-1);
sprintf(buffer, "%d", w()-1);
fl_measure(buffer, tw, th);
fl_draw(buffer, x()+w()-tw, y()+20+th);
}
};
int
main (int argc, char *argv[])
{
Fl_Window *w = new Fl_Window (300, 300);
Box *b = new Box (5, 5, 290, 290);
w->end ();
w->show (argc, argv);
Fl::run ();
return (0);
}
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