// ialpha is 0..200 where 0 is completely black
// and 200 is completely white and 100 is the same
// convert that to normal alpha 0.0 - 1.0
ialpha = wxMin(ialpha, 200);
ialpha = wxMax(ialpha, 0);
double alpha = ((double)(ialpha - 100.0))/100.0;
// ialpha is 0..200 where 0 is completely black
// and 200 is completely white and 100 is the same
// convert that to normal alpha 0.0 - 1.0
ialpha = wxMin(ialpha, 200);
ialpha = wxMax(ialpha, 0);
double alpha = ((double)(ialpha - 100.0))/100.0;