用TImage动态加载过图片的请进

Question

我动态加载一个图片，这个图片可能很多大约十几M源码如下：
  Stream:=TMemoryStream.Create;
  Stream.LoadFromFile(PicName);
     Jpg:=TJPEGImage.Create;
     try       Jpg.LoadFromStream(stream);
       Image1.Stretch:=false;
       //image1.Left:=0;
       //image1.Top:=0;
       Image1.Height:=jpg.Height;
       Image1.Width:=jpg.Width;
       Image1.Picture.Assign(jpg);
       Image1.BringToFront;
       Image1.Visible:=true;
     finally
         Jpg.Free;
     end;这样如果图片很大的话加载很慢，有没有办法能让图片加载快点。请给个思路或者给段代码

Answer 1

先导入到内存再显示
放个进度条
var
BufBit                 :array [0..255]of Byte;
F                      :File;
Stream                 :TMemoryStream;
NumRead                :Integer;
begin
AssignFile(F,PICPath);
Seek(F,0);Progress.Max:=FileSize(F); //进度条初始化
Progress.Position:=0;Stream:=TMemoryStream.Create; //MemoryStream初始化
Stream.SetSize(FileSize(F));
Stream.Seek(0,soFromBeginning);repeat  //读入内存
   BlockRead(F,BufBit,sizeof(BufBit),NumRead);
   Stream.Write(BufBit,sizeof(BufBit));
   Progress.Position:=FilePos(F);
until NumRead = 0;Stream.Position:=0;JPEGImage := TJPEGImage.Create;
JPEGImage.LoadFromStream(Stream);Stream.Clear;
Stream.Free;
CloseFile(F);
end;

Answer 2

不好意思,没做测试
重写了一个
uses JPEG  //引用JPEG单元
ProgressBar1: TProgressBar; //进度条
OpenDialog1: TOpenDialog; //打开文件对话框
Button1: TButton;  //按钮
///////////////////////////////////////////////////////////////////////
procedure TForm1.Button1Click(Sender: TObject);
var
BufBit   :array [0..255]of Byte;
F        :File;
Stream   :TMemoryStream;
NumRead  :Integer;
JPEGImage:TJPEGImage;
begin
if not OpenDialog1.Execute then exit;
AssignFile(F,OpenDialog1.FileName);  //打开JPG文件
Reset(F,1);
Seek(F,0);ProgressBar1.Max:=FileSize(F); //进度条初始化
ProgressBar1.Position:=0;Stream:=TMemoryStream.Create; //MemoryStream初始化
Stream.SetSize(FileSize(F));
Stream.Seek(0,soFromBeginning);repeat  //读入到内存
   BlockRead(F,BufBit,sizeof(BufBit),NumRead);
   Stream.Write(BufBit,sizeof(BufBit));
   ProgressBar1.Position:=FilePos(F);
until NumRead = 0;
CloseFile(F);Stream.Position:=0;JPEGImage := TJPEGImage.Create;    //建立JPEG对象
JPEGImage.LoadFromStream(Stream);  //复制内存到JPEG对象Stream.Clear;
Stream.Free;   //清理内存self.Canvas.StretchDraw(self.Canvas.ClipRect,JPEGImage); //显示在Form布景上
JPEGImage.Free; //释放JPEG对象
end;