Weird TAdvSpinEdit bug

[Tony_Bryer]

I've just finished changing my apps (Rad Studio 10, 32-bit Windows) to use themes, a point size rather than font height in dialogs with scaled= true (was false). Apps ran fine on all my machines except one - Windows 8 full HD 13" laptop. On calling up one dialog I got this (MadExcept extract): 

exception class : EIntOverflow

exception message : Integer overflow.

main thread ($cbc):
00729cca sb7.exe AdvSpin TAdvSpinEdit.UpdateLabelPos
00729b97 sb7.exe AdvSpin TAdvSpinEdit.UpdateLabel
007275b5 sb7.exe AdvSpin TAdvSpinEdit.SetBounds

I tracked it down to this line in TAdvSpinEdit.UpdateLabelPos:

flabel.top := Top + ((Height - flabel.Height) shr 1);

On my dialog, when Windows scaled the form it was returning a Height of 36 and fLabel.Height of 38, thus the last part of the expression above becomes -2 shr 1. Somehow it appears that the calculation is using unsigned integers, so -2 shr 1 becomes 2147483647, triggering the error.

Changing the code above (and making it more readable IMO) to

flabel.top := Top + ((Height - flabel.Height) div 2);

seems to fix things.

Have posted this in case it helps someone else out down the line.

Tony Bryer

Greentram Software, Melbourne, Australia www.greentram.com

[brunofierens]

We'll apply this improvement in our code. It is indeed safer this way. Next update will have the improvement.

[Tony_Bryer]

Thanks Bruno. Sorry about the fonts in the original post - not sure what happened there.