截取屏幕,並保存為JPEG文件格式
procedure TForm1.ScreenCap(LeftPos,TopPos,RightPos,BottomPos:integer);
var
RectWidth,RectHeight:integer;
SourceDC,DestDC,Bhandle:integer;
Bitmap:TBitmap;
MyJpeg: TJpegImage;
Stream:TMemoryStream;
begin
MyJpeg:= TJpegImage.Create;
RectWidth:=RightPos-LeftPos;
RectHeight:=BottomPos-TopPos;
SourceDC:=CreateDC('DISPLAY','','',nil);
DestDC:=CreateCompatibleDC(SourceDC);
Bhandle:=CreateCompatibleBitmap(SourceDC,
RectWidth,RectHeight);
SelectObject(DestDC,Bhandle);
BitBlt(DestDC,0,0,RectWidth,RectHeight,SourceDC,
LeftPos,TopPos,SRCCOPY);
Bitmap:=TBitmap.Create;
Bitmap.Handle:=BHandle;
Stream := TMemoryStream.Create;
Bitmap.SaveToStream(Stream);
Stream.Free;
try
MyJpeg.Assign(Bitmap);
MyJpeg.CompressionQuality:=70;
MyJpeg.Compress;
MyJpeg.SaveToFile('C:MyJPEGImage.JPG');
finally
MyJpeg.Free;
Bitmap.Free;
DeleteDC(DestDC);
ReleaseDC(Bhandle,SourceDC);
end;
end;