Dialog base units implementation question

[mxmauro]

Hi,

I make a new topic here because i don't know if it is a bug or a "behaviour"

CreateDialog, MapDialogRect and many api uses the dialog box base units to convert from dialog units to pixels.

Seeing the implementation in wine and the results that real Windows o.s. do I think that instead of using these formulas:

pixels_x = MulDiv(dlu_x, xBaseUnit, 4);
pixels_y = MulDiv(dlu_y, yBaseUnit, ;

i get best results converting values to floating points and then rounding the result:

pixels_x = (int)(((double)dlu_x * (double)xBaseUnit / 4.0) + 0.5);
pixels_y = (int)(((double)dlu_y * (double)yBaseUnit / 8.0) + 0.5);

If anyone can confirm (or negate) this please inform me.

Best regards,
Mauro H. Leggieri

[vitamin]

i get best results converting values to floating points and then rounding the result:

Integer arithmetic is always faster then float point. And it makes no sense to convert something into float just to do 2 operations. MulDiv is specifically made for that.