Taking a screenshot of the screen
lazarus / 39-Graphics

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fabienwang · 2010-08-18 11:59

Hello

I have followed the:
http://wiki.lazarus.freepascal.org/Developing_with_Graphics
example to take a screenshot but i have an error:

Code: [Select]procedure TForm1.Button1Click(Sender: TObject);
var
  MyBitmap: TBitmap;
  ScreenDC: HDC;
begin
  MyBitmap := TBitmap.Create;
  ScreenDC := GetDC(0);
  MyBitmap.LoadFromDevice(ScreenDC);
  ReleaseDC(ScreenDC);
end;
I have the following errors while i have the uses LCLIntf and LCLType:

Quoteunit1.pas(88,23) Error: Unknown record field identifier "CREATE"
unit1.pas(90,12) Error: Unknown record field identifier
"LOADFROMDEVICE"
unit1.pas(91,21) Error: Wrong number of parameters specified for call
to "ReleaseDC"
What did i do wrong?

My version of lazarus is:

Lazarus 0.9.28.2 r22279 FPC 2.2.4 i386-win32-win32/win64
on Windows XP SP3 v5512
CPU: Intel Core 2 Duo

Thanks for your help

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felipemdc · 2010-08-18 12:07

Please read here:
http://wiki.lazarus.freepascal.org/Lazarus_Faq#What_is_the_correct_way
_to_ask_questions_in_the_forum_.3F

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fabienwang · 2010-08-18 12:19

Thanks felipemdc i didn't know.

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felipemdc · 2010-08-18 12:56

No problem =)

Your application has the unit "Windows" in the uses clause, so it is
catching Windows.TBitmap, try like this:

var
  MyBitmap: Graphics.TBitmap;
  ScreenDC: LCLType.HDC;
begin
  MyBitmap := Graphics.TBitmap.Create;
  ScreenDC := LCLIntf.GetDC(0);
  MyBitmap.LoadFromDevice(ScreenDC);
  LCLIntf.ReleaseDC(ScreenDC);
end;

This code doesn't require the Windows unit, so if you aren't using it
for anything else you can remove it and then the extra information as
from which unit you are catching each type will no longer be
necessary.

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fabienwang · 2010-08-18 13:10

ohh i got it.

Actually i'm using it with shellapi to start the browser i'll be happy
with the next openURL()

thanks it's working great now.

Except that the wiki suggest:
ReleaseDC(ScreenDC);
while it is:
ReleaseDC(0 , ScreenDC);

Thanks
Best Regards,
Fabien Wang aka Dr4x