소스가 있어야 확인이 가능하겠군요.

소스를 올려주세요.

---

곽효승 wrote:

> 화면 캡쳐할 때

>

> bitblt를 사용하면 처음에는 에러가 발생하지 않는데...

>

> 한 procedure에서 두번이상 사용하면

>

> Project Server2.exe raised exception class EAccessViolation with

> message 'Acces violation at address 00000000. Read of address

> 00000000'. Process stopped. Use Step or Run to continue.

>

> 라는 에러가 발생합니다.

>

> 이것을 해결하는 방법이 있을까요..

>

> 참고로 화면 캡쳐를 while문을 사용하여 계속하고 있습니다.

> 그래서 그 캡쳐한 것을 JPEG file로 저장하는데 잘 되지 않습니다.

>

> 많은 고수님들의 도움을 요청합니다...

procedure TClientThread.Execute;

var

JpegImage: TJpegImage;

Bmp: TBitmap;

DC: HDC;

JpgStream: TMemoryStream;

Length: integer;

FileLocation: String;

begin

while Sendable do

begin

try

FileLocation := ExtractFilePath(Application.ExeName);

DeleteFile(FileLocation + Form1.ServerAddr + '.JPG');



Bmp := TBitmap.Create;

Bmp.Width := Screen.Width;

Bmp.Height := Screen.Height;

DC := GetDC(0);



BitBlt(Bmp.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height,

DC, 0, 0, SRCCOPY);



JpegImage := TJpegImage.Create;

JpegImage.CompressionQuality := 45;

JpegImage.Assign(Bmp);

JpgStream := TMemoryStream.Create;



JpegImage.SaveToStream(JpgStream);

JpegImage.SaveToFile(FileLocation + Form1.ServerAddr + '.JPG');



Length := JpgStream.Size;



JpgStream.Position := 0;

finally

Bmp.Free;

ReleaseDC(0, DC);



JpegImage.Free;

JpgStream.Free;

end;

end;

end;

제가 시험한 결과 아무 문제없이 실행이 됩니다.

다만 while 문에서 Application.ProcessMessages; 라는 문장을 넣어주어야 합니다.

에러가 발생한다면 스레드 처리에서 동기화 문제가 발생하는것 같습니다.

스레드 처리부분이 포함되어 있는 full 소스를 올려 주시면 스레드 처리부분을 확인해

드리도록 하겠습니다.



---



곽효승 wrote:

> procedure TClientThread.Execute;

> var

> JpegImage: TJpegImage;

> Bmp: TBitmap;

> DC: HDC;

> JpgStream: TMemoryStream;

> Length: integer;

> FileLocation: String;

> begin

> while Sendable do

> begin

> try

> FileLocation := ExtractFilePath(Application.ExeName);

> DeleteFile(FileLocation + Form1.ServerAddr + '.JPG');

>

> Bmp := TBitmap.Create;

> Bmp.Width := Screen.Width;

> Bmp.Height := Screen.Height;

> DC := GetDC(0);

>

> BitBlt(Bmp.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height,

> DC, 0, 0, SRCCOPY);

>

> JpegImage := TJpegImage.Create;

> JpegImage.CompressionQuality := 45;

> JpegImage.Assign(Bmp);

> JpgStream := TMemoryStream.Create;

>

> JpegImage.SaveToStream(JpgStream);

> JpegImage.SaveToFile(FileLocation + Form1.ServerAddr + '.JPG');

>

> Length := JpgStream.Size;

>

> JpgStream.Position := 0;

> finally

> Bmp.Free;

> ReleaseDC(0, DC);

>

> JpegImage.Free;

> JpgStream.Free;

> end;

> end;

> end;

한번 확인해 보시고 답변 부탁 드립니다.



unit Unit1;



interface



uses

Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs, jpeg,

StdCtrls;



const

wm_RefreshClients = wm_User;



type

TForm1 = class(TForm)

Button1: TButton;

procedure FormCreate(Sender: TObject);

procedure Button1Click(Sender: TObject);

private

public

procedure RefreshClients (var Msg: TMessage);

message wm_RefreshClients;

end;



TClientthread = class(TThread)

protected

procedure Execute; override;

end;



var

Form1: TForm1;

Sendable : boolean;

ClientThread : TClientThread;





implementation



{$R *.DFM}



procedure TForm1.RefreshClients;

begin

end;



{TClientThread=================================================================}



procedure TClientThread.Execute;

var

JpegImage: TJpegImage;

Bmp: TBitmap;

DC: HDC;

JpgStream: TMemoryStream;

Length: integer;

FileLocation: String;

begin

while Sendable do

begin

try

Bmp := TBitmap.Create;

Bmp.Width := Screen.Width;

Bmp.Height := Screen.Height;

DC := GetDC(0);



BitBlt(Bmp.Canvas.Handle, 0, 0, Bmp.Width, Bmp.Height,

DC, 0, 0, SRCCOPY);



Application.ProcessMessages;



JpegImage := TJpegImage.Create;

JpegImage.CompressionQuality := 45;

JpegImage.Assign(Bmp);

JpgStream := TMemoryStream.Create;



JpegImage.SaveToStream(JpgStream);

JpegImage.SaveToFile('Test.JPG');



Length := JpgStream.Size;



JpgStream.Position := 0;

finally

Bmp.Free;

ReleaseDC(0, DC);



JpegImage.Free;

JpgStream.Free;

end;

end;



Terminate;

end;



procedure TForm1.FormCreate(Sender: TObject);

begin

Sendable := False;

end;



procedure TForm1.Button1Click(Sender: TObject);

begin

if Sendable then

begin

Sendable := False;

Button1.Caption := 'Capture';

end else

begin

Sendable := True;

Button1.Caption := 'Not Capture';

ClientThread := TClientThread.Create(True);

ClientThread.FreeOnTerminate := True;

ClientThread.Resume;

end;

end;



end.



꼭~ 답변을 주시기를 간절히 바라겠습니다...