Inno Setup: Enlarge component page only with previ

Question

I need help from you to merge two scripts found here to have preview image on a maximized components windows:

• Add image into the components list - component description
• Long descriptions on Inno Setup components

---

Edit: Thanks to Martin Prikryl. With his patience and his help, I successfully merge these two scripts.

Your preview image should have a resolution of 208x165 in .bmp

[Files]

...
Source: "1.bmp"; Flags: dontcopy
Source: "2.bmp"; Flags: dontcopy
Source: "3.bmp"; Flags: dontcopy
Source: "InnoCallback.dll"; Flags: dontcopy

[Code]

    var
  LastMouse: TPoint;

type
  TTimerProc = procedure(H: LongWord; Msg: LongWord; IdEvent: LongWord; Time: LongWord);

function GetCursorPos(var lpPoint: TPoint): BOOL; external '[e-mail] stdcall';
function SetTimer(hWnd: longword; nIDEvent, uElapse: LongWord; lpTimerFunc: LongWord): LongWord; external '[e-mail] stdcall';
function ScreenToClient(hWnd: HWND; var lpPoint: TPoint): BOOL; external '[e-mail] stdcall';
function ClientToScreen(hWnd: HWND; var lpPoint: TPoint): BOOL; external '[e-mail] stdcall';
function ListBox_GetItemRect(const hWnd: HWND; const Msg: Integer; Index: LongInt; var Rect: TRect): LongInt; external '[e-mail] stdcall';  

const
  LB_GETITEMRECT = $0198;
  LB_GETTOPINDEX = $018E;

function WrapTimerProc(Callback: TTimerProc; ParamCount: Integer): LongWord; external 'wrapcallback@files:InnoCallback.dll stdcall';

function FindControl(Parent: TWinControl; P: TPoint): TControl;
var
  Control: TControl;
  WinControl: TWinControl;
  I: Integer;
  P2: TPoint;
begin
  for I := 0 to Parent.ControlCount - 1 do
  begin
    Control := Parent.Controls[I];
    if Control.Visible and
       (Control.Left <= P.X) and (P.X < Control.Left + Control.Width) and
       (Control.Top <= P.Y) and (P.Y < Control.Top + Control.Height) then
    begin
      if Control is TWinControl then
      begin
        P2 := P;
        ClientToScreen(Parent.Handle, P2);
        WinControl := TWinControl(Control);
        ScreenToClient(WinControl.Handle, P2);
        Result := FindControl(WinControl, P2);
        if Result <> nil then Exit;
      end;

      Result := Control;
      Exit;
    end;
  end;

  Result := nil;
end;

function PointInRect(const Rect: TRect; const Point: TPoint): Boolean;
begin
  Result := (Point.X >= Rect.Left) and (Point.X <= Rect.Right) and
    (Point.Y >= Rect.Top) and (Point.Y <= Rect.Bottom);
end;

function ListBoxItemAtPos(ListBox: TCustomListBox; Pos: TPoint): Integer;
var
  Count: Integer;
  ItemRect: TRect;
begin
  Result := SendMessage(ListBox.Handle, LB_GETTOPINDEX, 0, 0);
  Count := ListBox.Items.Count;
  while Result < Count do
  begin
    ListBox_GetItemRect(ListBox.Handle, LB_GETITEMRECT, Result, ItemRect);
    if PointInRect(ItemRect, Pos) then Exit;
    Inc(Result);
  end;
  Result := -1;
end;

var
  CompLabel: TLabel;
  CompImage: TBitmapImage;
  LoadingImage: Boolean;

procedure HoverComponentChanged(Index: Integer);
var 
  Description: string;
  Image: string;
  ImagePath: string;
begin
  case Index of
    0: begin Description := 'Component 1'; Image := '1.bmp'; end;
    1: begin Description := 'Component 2'; Image := '2.bmp'; end;
    2: begin Description := 'Component 3'; Image := '3.bmp'; end;

  else
    Description := 'Move your mouse over a component to see its description.';
  end;
  CompLabel.Caption := Description;

  if Image <> '' then
  begin
    // The ExtractTemporaryFile pumps the message queue, prevent recursion
    if not LoadingImage then
    begin
      LoadingImage := True;
      try
        ImagePath := ExpandConstant('{tmp}\' + Image);
        if not FileExists(ImagePath) then
        begin
          ExtractTemporaryFile(Image);
        end;
        CompImage.Bitmap.LoadFromFile(ImagePath);
      finally
        LoadingImage := False;
      end;
    end;
    CompImage.Visible := True;
  end
    else
  begin
    CompImage.Visible := False;
  end;
end;

procedure HoverTimerProc(H: LongWord; Msg: LongWord; IdEvent: LongWord; Time: LongWord);
var
  P: TPoint;
  Control: TControl; 
  Index: Integer;
begin
  GetCursorPos(P);
  if P <> LastMouse then // just optimization
  begin
    LastMouse := P;
    ScreenToClient(WizardForm.Handle, P);

    if (P.X < 0) or (P.Y < 0) or
       (P.X > WizardForm.ClientWidth) or (P.Y > WizardForm.ClientHeight) then
    begin
      Control := nil;
    end
      else
    begin
      Control := FindControl(WizardForm, P);
    end;

    Index := -1;
    if Control = WizardForm.ComponentsList then
    begin
      P := LastMouse;
      ScreenToClient(WizardForm.ComponentsList.Handle, P);
      Index := ListBoxItemAtPos(WizardForm.ComponentsList, P);
    end;

    HoverComponentChanged(Index);
  end;
end;

type
  TPositionStorage = array of Integer;

var
  CompPageModified: Boolean;
  CompPagePositions: TPositionStorage;

procedure SaveComponentsPage(out Storage: TPositionStorage);
begin
  SetArrayLength(Storage, 10);

  Storage[0] := WizardForm.Height;
  Storage[1] := WizardForm.NextButton.Top;
  Storage[2] := WizardForm.BackButton.Top;
  Storage[3] := WizardForm.CancelButton.Top;
  Storage[4] := WizardForm.ComponentsList.Height;
  Storage[5] := WizardForm.OuterNotebook.Height;
  Storage[6] := WizardForm.InnerNotebook.Height;
  Storage[7] := WizardForm.Bevel.Top;
  Storage[8] := WizardForm.BeveledLabel.Top;
  Storage[9] := WizardForm.ComponentsDiskSpaceLabel.Top;
end;

procedure LoadComponentsPage(const Storage: TPositionStorage;
  HeightOffset: Integer);
begin
  if GetArrayLength(Storage) <> 10 then
    RaiseException('Invalid storage array length.');

  WizardForm.Height := Storage[0] + HeightOffset;
  WizardForm.NextButton.Top := Storage[1] + HeightOffset;
  WizardForm.BackButton.Top := Storage[2] + HeightOffset;
  WizardForm.CancelButton.Top := Storage[3] + HeightOffset;
  WizardForm.ComponentsList.Height := Storage[4] + ScaleY(150);
  WizardForm.OuterNotebook.Height := Storage[5] + HeightOffset;
  WizardForm.InnerNotebook.Height := Storage[6] + HeightOffset;
  WizardForm.Bevel.Top := Storage[7] + HeightOffset;
  WizardForm.BeveledLabel.Top := Storage[8] + HeightOffset;
  WizardForm.ComponentsDiskSpaceLabel.Top := Storage[9] + HeightOffset;
end;

procedure InitializeWizard1();
var
  HoverTimerCallback: LongWord;
begin
  HoverTimerCallback := WrapTimerProc(@HoverTimerProc, 4);

  SetTimer(0, 0, 50, HoverTimerCallback);

  CompLabel := TLabel.Create(WizardForm);
  CompLabel.Parent := WizardForm.SelectComponentsPage;
  CompLabel.Left := WizardForm.ComponentsList.Left;
  CompLabel.Width := WizardForm.ComponentsList.Width div 2;
  CompLabel.Height := ScaleY(64);
  CompLabel.Top := WizardForm.ComponentsList.Top + WizardForm.ComponentsList.Height - CompLabel.Height + ScaleY(150);
  CompLabel.AutoSize := false;
  CompLabel.WordWrap := True;

  CompImage := TBitmapImage.Create(WizardForm);
  CompImage.Parent := WizardForm.SelectComponentsPage;
  CompImage.Top := CompLabel.Top;
  CompImage.Width := CompImage.Width + ScaleX(128);
  CompImage.Height := CompLabel.Height + ScaleX(128);
  CompImage.Left := WizardForm.ComponentsList.Left + WizardForm.ComponentsList.Width - CompLabel.Width;

  WizardForm.ComponentsList.Height := WizardForm.ComponentsList.Height - CompLabel.Height - ScaleY(8);
end;

procedure InitializeWizard2();
begin
  CompPageModified := False;
end;

procedure CurPageChanged(CurPageID: Integer);
begin
  if CurpageID = wpSelectComponents then
  begin
    SaveComponentsPage(CompPagePositions);
    LoadComponentsPage(CompPagePositions, ScaleY(250));
    CompPageModified := True;
  end
  else
  if CompPageModified then
  begin
    LoadComponentsPage(CompPagePositions, 0);
    CompPageModified := False;
  end;
end;

procedure InitializeWizard();
begin 
  InitializeWizard1();
  InitializeWizard2();
end;

Answer 1

Just copy both codes and merge the InitializeWizard implementations according to this guide:
Merging event function (InitializeWizard) implementations from different sources.

Though, actually, the InitializeWizard in the Larger “Select Components” page in Inno Setup is noop. You can skip that. And you do not need to merge anything.

The only other change you need to do, is not to enlarge the ComponentsList in the LoadComponentsPage.