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Which is gdi32 function used to draw text on a graphic?

 
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lth
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PostPosted: Fri Oct 13, 2006 5:07 pm    Post subject: Which is gdi32 function used to draw text on a graphic? Reply with quote

Hi all!

I'm a newbie. I try to reserve a plug-in DLL that draws some texts (for example 'DEMO DEMO DEMO') on to the picture after having processed. I saw it uses gdi32 but do not know which api-s to break on. Could you give me some advice to start? Thanks.
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junai
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PostPosted: Sun Oct 15, 2006 9:45 am    Post subject: Reply with quote

TextOut might be used for that. However, removing it can perhaps also be done without having to change the code, like finding the string and replace it with spaces...
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tanatos
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PostPosted: Mon Oct 16, 2006 4:53 am    Post subject: Reply with quote

the stuff like that...text outputs on documents and stuff like that(watermarks) can usually be removed by reversing a single jump...so try to find it Very Happy
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lth
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PostPosted: Mon Oct 16, 2006 6:00 pm    Post subject: Reply with quote

Thanks for your advice.
I've tried a lot without success but when trying some simple programs I wrote in Delphi I could deal with them. So maybe there is a trick (here no gdi32.ExtTextOutA, no DEMO text).
I'll keeping trying.
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junai
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PostPosted: Wed Oct 18, 2006 3:39 pm    Post subject: Reply with quote

I have done very few of this kind, but those where very simple and used a dll to write the text, may be a coincident though... I assume you have also looked out for api calls that are not preloaded...

Also, if it's displaying a picture under the text it might be easier to find that place and single-step to find the unwanted text (or possibly image) drawing. Look for bitmap/DC apis like:

BeginPaint
CreateCompatibleDC
BitBlt
DeleteDC

Maybe some other approach will suite the target better, like actually register it "for real" not just removing the annoying text...

BTW if you solve it please tell how Wink
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lth
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PostPosted: Tue Oct 24, 2006 10:22 am    Post subject: Reply with quote

Thank you for your advice.
I've read a lot, learned much while using ollydbg and was keeping trying to reverse the DLL for days (just to try and to learn).
I wrote own delphi programs to examine gdi and now knowing this: for text-write : exttextoutA, for bitmap-copy: stretchblt can be used to make nag like that.

Back to the DLL: I've stopped trying. May be I'll try it again when I know more about reserving.

The DLL is not so important to be registered Smile.
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