AMCAF Fonts Bug?

[Mikket]

Hi.

Have you noticed this kind of bug in Amcaf?

Text bank change seems to eat all the memory . First fast, then chip.

I have hud, where I like to use different sizes of fonts, so I change
the bank in main loop.

This problem does not exist, in some winuae configurations.
But in real Amiga 1200 + 4mb (and Winuae, with similar config) it happends.

How can it be avoided?


Here's code to test:

Screen Open 0,320,256,2,Lowres
Curs Off : Colour 1,$FFF
Make Bank Font 7
Change Font "ruby.font",8
Make Bank Font 8

Repeat
Change Bank Font 7
Text 10,10,"Chip:"+Str$(Chip Free)+" "
Change Bank Font 8
Text 10,20,"Fast:"+Str$(Fast Free)+" "
Until Mouse Click

[adrazar]

Hey, it's leaking my memory too!

Like you I am using Change Bank Font frequently in the project I'm currently working on, so this problem is relevant for me as well.
Incredible find @Mikket

[Retro1234]

No idea but what is you Erase 7 etc or Erase All etc does it make a difference?

[adrazar]

Lucky me! I found a way to plug the leak

Originally Posted by Retro1234

No idea but what is you Erase 7 etc or Erase All etc does it make a difference?

No, not this (it increased the chip ram, but fast ram did not come back)

I went over to the SetFont docs, and found in the BUGS section that this function is known to have a memory leak problem, starting from kickstart V36 (which according to wikipedia means starting with the A500+ model). It further suggests using StripFont to solve the problem, and this appears to work.

The following instructions will call StripFont with the required arguments:

Areg(0)=Leek(Scrn Rastport+52) : RESULT=Gfxcall(-822)

I found that it works to insert this code right after each call to Change Bank Font.

[Retro1234]

[Mikket]

Great, that you found this fix adrazar. I had to transfer one font to icons, but now i can change back to amcaf font bank. Thanks.

[adrazar]

Originally Posted by adrazar

I found that it works to insert this code right after each call to Change Bank Font.

After (finally) testing this for real, in the real application, I'm doubting this is the right way to do it... It frees the memory all right, but it apparently also makes the font unusable. So I have a new prevailing theory, which is that the right time to call StripFont must be, not just after, but just before calling Change Bank Font.

Another thing I found while testing is that if the same bank font is used in two different screens at the same time, then StripFont can restore the memory for only one of them. So to avoid memory leak, one must see to it that two screens never share the same bank font. Achieving this turns out to be a bit tricky, but I've nevertheless managed to concoct a strategy which I'm reasonably satisfied with: First, for simplicity I try to invariantly make it so that at all times at most one screen has a bank font assigned to it (this was already more or less the case in my program). Second, to return to the default amos font I created this procedure:

AMOSFONT=Leek(Scrn Rastport+52)
Global AMOSFONT

Procedure RESETFONT
   ' Avoid calling StripFont on the default font
   If Leek(Scrn Rastport+52)=AMOSFONT Then Pop Proc

   ' Call StripFont
   Areg(0)=Leek(Scrn Rastport+52)
   RESULT=Gfxcall(-822)

   ' Restore the default font
   Loke Scrn Rastport+52,AMOSFONT
   Doke Scrn Rastport+62,6 : Rem <- value returned by Text Base
End Proc

The last part, which restores the default font, could be expanded to assign further font-related rastport values, but so far these two values has proven to be sufficient.