Create Floating Image Popup Window in Delphi XE (Windows 7) - image

Question

I'm running Delphi XE, under Windows 7 64 bit.
I have these third party components loaded:
Virtual Trees Version 4.8.7
TZip Version 1.5
JVCL 3.45
Graphics32 1.9 Final
GExperts 1.33
DWS
DCP Crypt Version 2.0
TeeChart Pro v2011
I want to create a popup "preview" image of a PDF when the mouse is hoovering over a TListBox Item. I'd figure I would create a TForm within my my window's FormCreate, and hide it, until (ListBox.ItemIndex > -1) on my TfrmMain.ListBoxMouseMove routine.
For now, I'm just trying to master using a JPEG image, instead of a PDF.
I noticed that using the TImage and OnMouseOver is rather SLOW. Is there a faster way of doing this? Maybe using a JEDI component?
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.

Answer 1

Well...I found that the Adobe's Acrobat Control component to be just what I needed. It's a little slow, but it's MUCH faster than the TImage method.
Here's my revised solution:
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.