Delphi - scroll group of components on block overflow

Question

I looked through such components like GroupBox, Panel, ScrollBox, ListBox, but nothing of them is what i am looking for.

What i want is a component that will have a fixed size, no visible borders, preferaly non-color background and will allow to hide contained components if they overflow this component.

Here is an example of what i want to implement in my Delphi project: http://jsfiddle.net/jgems3Ls/1/

Delphi hierarchy idea:

 #non-visible component
 #non-visible component
+---------------------+
|  visible component  |
|  visible component  |  //TOverflowBox(?) borders
|  visible component  |
+---------------------+
 #non-visible component

Unfortunately, googling didnt give me a single hint on how can i do that

Answer 1

Found a solution with using TPanel.

There are two things to start with:

1. My form has custom image as background
2. Panel settings and child components are set at run-time

Since TPanel doesn't has transparency property, i needed to find a way to keep form image instead of grey panel background. The solution was quite obvious: put form image in panel as new component with required left and top offset in order to make it look good. Example code would be:

P := Panel1;
P.Width := 300;
P.Height := 200;
P.Left := 100;
P.Top := 50;

//panel background
I := Image1;  //its width and height equal to forms ClientWidth and ClientHeight
I.Left := -100;
I.Top := -50;

Next problem was panel border, which can easily be removed by P.BevelOuter := bvNone.

To make panel components scroll, i used form MouseWheel event.

procedure TForm1.FormMouseWheel(Sender: TObject; Shift: TShiftState;
  WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
var P: TPanel;
    B: boolean;
begin
  B := true;
  case global_navigation(location, sub_location) of //returns current visible panel
    0: B := false;  //no visible panels
    1: P := Form1.Panel1;           
    ...
  end;

  //now we need to check if cursor is in panel area
  if B then
    if (PtInRect(P.ClientRect, P.ScreenToClient(Mouse.CursorPos))) then
      if WheelDelta > 0 then                     //if we scroll up
        for i := (P.ControlCount - 1) downto 1 do
          P.Controls[i].Top := P.Controls[i].Top + 10
     else                                        //if we scroll down
        for i := (P.ControlCount - 1) downto 1 do
          P.Controls[i].Top := P.Controls[i].Top - 10;
end;

Looping through panel components is done downto 1, not downto 0 because the very first component that panel contains is image used as background, which i dont want to move.