[Lazarus] Raw TBitmap objects vs LCL TBitmap properties inconsistencies

[Giuliano Colla]

Hi Lazarus experts,

I have noticed a number of apparent inconsistencies which make life a 
bit complicate if you need to play with visual properties of LCL components.

If you need a different canvas brush, you need to change a button glyph, 
or to dynamically change a TImage (just to make a few examples), you 
create your TBitmap, and with a simple assignment instruction you pass 
it to the component. It works and it's Ok.

But then you're faced with a problem: what to do with the TBimap object 
you have created?

Coming from Delphi I had assumed that a TBitmap is not copied on another 
one, but just the pointer to the underlying Handle is copied. This means 
that you should never free a TBitmap after copying.

But if you use heaptrc you discover that a number of your TBitmaps are 
still there after closing all the forms.

On the other hand, in some cases if you FreeAndNil a TBitmap which has 
just been copied to an LCL component you get a crash with an AV.

Up to now my solution has been to enable heap trace, let heaptrc tell me 
what I need to free, and do it just for those bitmaps.

Is there a better way? i.e. what is the logic behind some LCL components 
just taking the pointer of a TBitmap and some to create their own 
internal bitmap leaving the original TBitmap untouched?

Giuliano

-- 
Do not do to others as you would have them do to you.They might have different tastes.