laza(麻风瘦),麻烦你再来看看这个图象转换的问题

Question

写成你的代码：
  Bitmap:=TBitmap.Create;
  Bitmap.PixelFormat:=pf24Bit;
  Bitmap.Handle:=BHandle;
  //Bitmap.PixelFormat:=pf8bit;
  BitMap.SaveToStream(BmpStream);
  BmpStream.Position:=0;
  LeftSize:=BmpStream.Size;
  ....
  jpg := TJPEGImage.Create;
  Jpg.assign(bitmap);
  jpg.SaveToFile('temp.jpg');//就是jpg格式
  jpg.Free;
  Bitmap.Free;
  
2.
  image1.Picture.LoadFromFile('temp.jpg')别忘了加入jpeg单元

Answer 1

昨天晚上我自己试了一下，procedure ScreenCap(LeftPos,TopPos,
RightPos,BottomPos:integer);
var
  RectWidth,RectHeight:integer;
  SourceDC,DestDC,Bhandle:integer;
  Bitmap:TBitmap;
  jpg1,Jpg:TJpegImage;
begin
  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;  jpg:=TJpegImage.Create;
  jpg1:=TJpegImage.Create;
  jpg1.Assign(BitMap);
  jpg1.SaveToFile('c:\2211.jpg');
  jpg.LoadFromFile('c:\2211.jpg');
  jpg.SaveToStream(BmpStream);
  
  BmpStream.Position:=0;
  LeftSize:=BmpStream.Size;
  Bitmap.Free;
  Jpg.Free;
  jpg1.Free;
  DeleteDC(DestDC);
  ReleaseDC(Bhandle,SourceDC);
end;这样抓到的图象是空的，2211.jpg文件是0K

Answer 2

jpg1.SaveToFile('c:\2211.jpg');
这里存为文件的时候可以指定分辨率吗？

Answer 3

type TJPEGPixelFormat = (jf24Bit, jf8Bit);
property PixelFormat: TJPEGPixelFormat;}自己看DEMO，写的很好。Borland\delphi5\help\examples\jpeg