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我在 Windows 7 64 位下运行 Delphi XE。

我加载了这些第三方组件： Virtual Trees 版本 4.8.7 TZip 版本 1.5 JVCL 3.45 Graphics32 1.9 Final GExperts 1.33 DWS DCP Crypt 版本 2.0 TeeChart Pro v2011

当鼠标悬停在 TListBox Item 上时，我想创建 PDF 的弹出“预览”图像。我想我会在我的窗口的 F​​ormCreate 中创建一个 TForm，然后隐藏它，直到我的 TfrmMain.ListBoxMouseMove 例程上的 (ListBox.ItemIndex > -1)。

现在，我只是想掌握使用 JPEG 图像，而不是 PDF。
我注意到使用 TImage 和 OnMouseOver 相当慢。 有没有更快的方法来做到这一点？也许使用 JEDI 组件？

unit MainUnit;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, PicUnit, jpeg, GraphUtil;

type
  TfrmMain = class(TForm)
    lst: TListBox;
    procedure FormCreate(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure lstClick(Sender: TObject);
    procedure lstMouseMove(Sender: TObject; Shift: TShiftState; 
      X, Y: Integer);
    procedure lstMouseLeave(Sender: TObject);
    public
      popPic: TfrmPic;
      ImagePaths: TStringList;
      LastHoover: Integer;
      procedure LoadImages(Item: Integer);
  end;

var
  frmMain: TfrmMain;

Implementation

{$R *.dfm}

procedure TfrmMain.FormCreate(Sender: TObject);
begin
  popPic := TfrmPic.Create(nil);
  ImagePaths := TStringList.Create;
  LastHoover := -1;
end;

procedure TfrmMain.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  popPic.Free;
  ImagePaths.Free;
end;

procedure TfrmMain.lstClick(Sender: TObject);
begin
  if (lst.ItemIndex > -1) then
  begin
    popPic.Show;
  end { ItemIndex > -1 }
  else
    popPic.Hide;
end;

procedure TfrmMain.lstMouseLeave(Sender: TObject);
begin
  frmPic.Hide;
end;

procedure TfrmMain.lstMouseMove(Sender: TObject; Shift: TShiftState;
  X, Y: Integer);
var
  HooverItem : Integer;
begin
  { Returns -1 if the mouse is NOT over a item on the list }
  HooverItem := lst.ItemAtPos (Point (X, Y), True);

  if (HooverItem > -1) and (HooverItem <> LastHoover) then
  begin
    { Match the image onto the screen }
    frmPic.Left := frmMain.ClientToScreen(Point(X, Y)).X;
    frmPic.Top := frmMain.ClientToScreen(Point(X, Y)).Y;

    LoadImages(HooverItem);
    LastHoover := HooverItem;

    if (ImagePaths.Count > 0) then
    begin
      { TImage Method }
      frmPic.imgStd.Stretch := True;
      frmPic.imgStd.Picture.LoadFromFile (ImagePaths [0]);
      frmPic.Show;
      frmMain.SetFocus;
    end
    else
      frmPic.Hide;
  end
  else
  if (HooverItem = -1) then
    frmPic.Hide;
end;

procedure TfrmMain.LoadImages(Item: Integer);
begin
  { Clear off the existing list }
  ImagePaths.Clear;

  if (Item = 0) then
  begin
    ImagePaths.Add ('C:\Floating Image Demo\0.jpeg');
    ImagePaths.Add ('C:\Floating Image Demo\1.jpeg');
  end
  else
  if (Item = 1) then
  begin
    ImagePaths.Add ('C:\Floating Image Demo\1.jpeg');
    ImagePaths.Add ('C:\Floating Image Demo\0.jpeg');
  end;
end;

end.
4

1 回答 1

1

嗯...我发现 Adob​​e 的 Acrobat Control 组件正是我所需要的。它有点慢，但比 TImage 方法快得多。这是我修改后的解决方案：

Unit MainUnit;

Interface

Uses
  Windows,
  Messages,
  SysUtils,
  Variants,
  Classes,
  Graphics,
  Controls,
  Forms,
  Dialogs,
  StdCtrls,
  OleCtrls,
  AcroPDFLib_TLB;


Type
  TfrmMain = Class (TForm)
    lst : TListBox;


    Procedure FormCreate    (     Sender: TObject     );
    Procedure FormClose     (     Sender: TObject;
                              Var Action: TCloseAction);
    Procedure lstClick      (     Sender: TObject     );
    Procedure lstMouseMove  (     Sender: TObject;
                                   Shift: TShiftState;
                                       X,
                                       Y: Integer     );
    Procedure lstMouseLeave (     Sender: TObject     );


    Public
      frmPic     : TForm;
      Pdf        : TAcroPDF;
      ImagePaths : TStringList;
      LastHoover : Integer;


      Procedure LoadImages  (       Item: Integer     );

  End;

Var
  frmMain: TfrmMain;

Implementation

{$R *.dfm}




Procedure TfrmMain.FormCreate      (             Sender: TObject              );
Begin

  frmPic     := TForm.Create (Nil);
  ImagePaths := TStringList.Create;
  LastHoover := -1;

  { Create the "popup" form, and the PDF viewer object }
  frmPic.Height      := 160;
  frmPic.Width       := 200;
  frmPic.BorderStyle := bsNone;
  Pdf                := TAcroPDF.Create (frmPic);
  Pdf.Parent         := frmPic;
  Pdf.Name           := 'AcroPDF';
  Pdf.Align          := alClient;
  Pdf.setShowToolbar (False);

End;


Procedure TfrmMain.FormClose       (             Sender: TObject;
                                             Var Action: TCloseAction         );
Begin

  { Free the objects }
  Try
    FreeAndNil (Pdf);
    frmPic.Free;
    ImagePaths.Free;

  Finally
    { Stop ALL threads-If this is removed some fonts within the drawings cause Adobe a screw up and keep running, thus causing an AV }
    Application.Terminate;
  End;

End;


Procedure TfrmMain.lstClick        (             Sender: TObject              );
Var
  CurrentPos : TPoint;

Begin

  If (lst.ItemIndex > -1) Then Begin

    { Match the image onto the screen }
    Windows.GetCursorPos (CurrentPos);
    frmPic.Left := CurrentPos.X + 20;
    frmPic.Top  := CurrentPos.Y + 20;

    { Load the PDFs }
    LoadImages (lst.ItemIndex);


    If (ImagePaths.Count > 0) Then Begin
      { Adobe Acrobat Control ActiveX Component }
      PDF.LoadFile (WideString (ImagePaths [0]));
      PDF.setShowToolbar (False);
      PDF.gotoFirstPage;


      frmPic.Show;
      frmPic.SetFocus;
    End;

  End { ItemIndex > -1 }
  Else
    frmPic.Hide;

End;


Procedure TfrmMain.lstMouseLeave   (   Sender: TObject   );
Begin

  frmPic.Hide;

End;

Procedure TfrmMain.lstMouseMove (Sender: TObject; Shift: TShiftState; X, Y: Integer);
Var
  HooverItem : Integer;

Begin

  { Returns -1 if the mouse is NOT over a item on the list }
  HooverItem := lst.ItemAtPos (Point (X, Y), True);

  If (HooverItem > -1) Then Begin

    { Match the image onto the screen }
    frmPic.Left := frmMain.ClientToScreen (Point (X, Y)).X + 20;
    frmPic.Top  := frmMain.ClientToScreen (Point (X, Y)).Y + 20;

  End;

End;
{ ---------------------------------------------------------------------------- }








{ ---------------------------------------------------------------------------- }
{ --------------------------- PRIVATE METHODS -------------------------------- }
{ ---------------------------------------------------------------------------- }

Procedure TfrmMain.LoadImages                    (        Item: Integer       );
Begin

  { Clear off the existing list }
  ImagePaths.Clear;

  If (Item = 0) Then Begin
    ImagePaths.Add ('C:\Project_Files\SVN\Local\EXAMPLES, TEMPLATES, MISC\Floating Image Demo\0.pdf');
    ImagePaths.Add ('C:\Project_Files\SVN\Local\EXAMPLES, TEMPLATES, MISC\Floating Image Demo\1.pdf');
  End
  Else if (Item = 1) Then Begin
    ImagePaths.Add ('C:\Project_Files\SVN\Local\EXAMPLES, TEMPLATES, MISC\Floating Image Demo\1.pdf');
    ImagePaths.Add ('C:\Project_Files\SVN\Local\EXAMPLES, TEMPLATES, MISC\Floating Image Demo\0.pdf');
  End;

End; { LoadImages Procedure }
{ ---------------------------------------------------------------------------- }

End.
于 2012-04-26T15:27:03.463 回答