How to determine the right height for container controls (TPanel)? - inno-setup

Question

Here is my custom page definition so far:
var
{ Backup Settings Page & Controls }
pageAutoBackup: TWizardPage;
btnSelectBackupFolder: TNewButton;
textBackupFolder: TNewEdit;
lblWhereToBackup: TLabel;
lblPromptMode: TLabel;
comboPromptMode: TNewComboBox;
lblReminder: TLabel;
radioBackupModeManual: TNewRadioButton;
radioBackupModeAuto: TNewRadioButton;
lblHowToBackup: TLabel;
radioBackupHowEssential: TNewRadioButton;
radioBackupHowComplete: TNewRadioButton;
radioBackupHowNone: TNewRadioButton;
lblWhatToBackup: TLabel;
panelWhatToPackup: TPanel;
panelHowToPackup: TPanel;
function pageAutoBackup_CreatePage(PreviousPageId: Integer): Integer;
begin
pageAutoBackup := CreateCustomPage(PreviousPageId, 'Automatic Backup', 'Configure automatic backup settings.');
{ panelWhatToPackup (TPanel) }
panelWhatToPackup := TPanel.Create(pageAutoBackup);
panelWhatToPackup.Caption := '';
panelWhatToPackup.BevelOuter := bvNone;
panelWhatToPackup.BevelInner := bvNone; { default }
panelWhatToPackup.BevelKind := bkNone;
panelWhatToPackup.Parent := pageAutoBackup.Surface;
panelWhatToPackup.Enabled := True;
panelWhatToPackup.Visible := True;
panelWhatToPackup.Left := ScaleX(0);
panelWhatToPackup.Top := ScaleY(0);
panelWhatToPackup.Width := pageAutoBackup.Surface.Width;
panelWhatToPackup.Height := ScaleY(90);
panelWhatToPackup.Anchors := [akLeft, akRight];
{ lblWhatToBackup (TLabel) }
lblWhatToBackup := TLabel.Create(pageAutoBackup);
lblWhatToBackup.Parent := panelWhatToPackup;
lblWhatToBackup.Enabled := True;
lblWhatToBackup.Visible := True;
lblWhatToBackup.Width := panelWhatToPackup.Width;
lblWhatToBackup.Font.Color := $000000;
lblWhatToBackup.Color := $F0F0F0;
lblWhatToBackup.Caption := 'What to backup:';
{ radioBackupHowNone (TNewRadioButton) }
radioBackupHowNone := TNewRadioButton.Create(pageAutoBackup);
radioBackupHowNone.Parent := panelWhatToPackup;
radioBackupHowNone.Enabled := True;
radioBackupHowNone.Visible := True;
radioBackupHowNone.Top := lblWhatToBackup.Top + lblWhatToBackup.Height + ScaleY(2);
radioBackupHowNone.Width := panelWhatToPackup.Width;
radioBackupHowNone.Checked := False;
radioBackupHowNone.Font.Color := $000000;
radioBackupHowNone.Color := $F0F0F0;
radioBackupHowNone.Caption := 'Don''t perform any backup when the program shuts down';
{ radioBackupHowComplete (TNewRadioButton) }
radioBackupHowComplete := TNewRadioButton.Create(pageAutoBackup);
radioBackupHowComplete.Parent := panelWhatToPackup;
radioBackupHowComplete.Enabled := True;
radioBackupHowComplete.Visible := True;
radioBackupHowComplete.Top := radioBackupHowNone.Top + radioBackupHowNone.Height + ScaleY(2);
radioBackupHowComplete.Width := panelWhatToPackup.Width;
radioBackupHowComplete.Checked := False;
radioBackupHowComplete.Font.Color := $000000;
radioBackupHowComplete.Color := $F0F0F0;
radioBackupHowComplete.Caption := 'Make a complete backup when the program shuts down';
{ radioBackupHowEssential (TNewRadioButton) }
radioBackupHowEssential := TNewRadioButton.Create(pageAutoBackup);
radioBackupHowEssential.Parent := panelWhatToPackup;
radioBackupHowEssential.Enabled := True;
radioBackupHowEssential.Visible := True;
radioBackupHowEssential.Top := radioBackupHowComplete.Top + radioBackupHowComplete.Height + ScaleY(2);
radioBackupHowEssential.Width := panelWhatToPackup.Width;
radioBackupHowEssential.Checked := False;
radioBackupHowEssential.Font.Color := $000000;
radioBackupHowEssential.Color := $F0F0F0;
radioBackupHowEssential.Caption := 'Only make an essential backup when the program shuts down';
{ panelHowToPackup (TPanel) }
panelHowToPackup := TPanel.Create(pageAutoBackup);
panelHowToPackup.Caption := '';
panelHowToPackup.BevelOuter := bvNone;
panelHowToPackup.BevelInner := bvNone; { default }
panelHowToPackup.BevelKind := bkNone;
panelHowToPackup.Parent := pageAutoBackup.Surface;
panelHowToPackup.Enabled := True;
panelHowToPackup.Visible := True;
panelHowToPackup.Top := panelWhatToPackup.Top + panelWhatToPackup.Height + ScaleY(2);
panelHowToPackup.Width := pageAutoBackup.Surface.Width;
panelHowToPackup.Height := ScaleY(100);
panelHowToPackup.Anchors := [akLeft, akRight];
{ lblHowToBackup (TLabel) }
lblHowToBackup := TLabel.Create(pageAutoBackup);
lblHowToBackup.Parent := panelHowToPackup;
lblHowToBackup.Enabled := True;
lblHowToBackup.Visible := True;
lblHowToBackup.Width := panelHowToPackup.Width;
lblHowToBackup.Font.Color := $000000;
lblHowToBackup.Color := $F0F0F0;
lblHowToBackup.Caption := 'How to backup:';
{ radioBackupModeAuto (TNewRadioButton) }
radioBackupModeAuto := TNewRadioButton.Create(pageAutoBackup);
radioBackupModeAuto.Parent := panelHowToPackup;
radioBackupModeAuto.Enabled := True;
radioBackupModeAuto.Visible := True;
radioBackupModeAuto.Left := ScaleX(0);
radioBackupModeAuto.Top := lblHowToBackup.Top + lblHowToBackup.Height + ScaleY(2);
radioBackupModeAuto.Width := panelHowToPackup.Width;
radioBackupModeAuto.Checked := False;
radioBackupModeAuto.Font.Color := $000000;
radioBackupModeAuto.Color := $F0F0F0;
radioBackupModeAuto.Caption := 'Perform automatically when the program is shut down';
{ radioBackupModeManual (TNewRadioButton) }
radioBackupModeManual := TNewRadioButton.Create(pageAutoBackup);
radioBackupModeManual.Parent := panelHowToPackup;
radioBackupModeManual.Enabled := True;
radioBackupModeManual.Visible := True;
radioBackupModeManual.Top := radioBackupModeAuto.Top + radioBackupModeAuto.Height + ScaleY(2);
radioBackupModeManual.Width := panelHowToPackup.Width;
radioBackupModeManual.Checked := False;
radioBackupModeManual.Font.Color := $000000;
radioBackupModeManual.Color := $F0F0F0;
radioBackupModeManual.Caption := 'Prompt the user when the program is shut down';
{ lblPromptMode (TLabel) }
lblPromptMode := TLabel.Create(pageAutoBackup);
lblPromptMode.Parent := panelHowToPackup;
lblPromptMode.Enabled := True;
lblPromptMode.Visible := True;
lblPromptMode.Top := radioBackupModeManual.Top + radioBackupModeManual.Height + ScaleY(2);
lblPromptMode.Width := panelHowToPackup.Width;
lblPromptMode.Font.Color := $000000;
lblPromptMode.Color := $F0F0F0;
lblPromptMode.Caption := 'Also prompt to backup at the following intervals while the application is running:';
{ comboPromptMode (TNewComboBox) }
comboPromptMode := TNewComboBox.Create(pageAutoBackup);
comboPromptMode.Parent := panelHowToPackup;
comboPromptMode.Style := csDropDownList;
comboPromptMode.Enabled := True;
comboPromptMode.Visible := True;
comboPromptMode.Top := lblPromptMode.Top + lblPromptMode.Height + ScaleY(2);
comboPromptMode.Width := panelHowToPackup.Width;
comboPromptMode.Font.Color := $000000;
comboPromptMode.ItemIndex := 0;
comboPromptMode.Color := $FFFFFF;
comboPromptMode.Items.Add('Never prompt to backup');
comboPromptMode.Items.Add('Prompt to backup everyday');
comboPromptMode.Items.Add('Prompt to backup once a week');
comboPromptMode.Items.Add('Prompt to backup once a month');
comboPromptMode.Anchors := [akLeft, akRight];
{ lblWhereToBackup (TLabel) }
lblWhereToBackup := TLabel.Create(pageAutoBackup);
lblWhereToBackup.Parent := pageAutoBackup.Surface;
lblWhereToBackup.Enabled := True;
lblWhereToBackup.Visible := True;
lblWhereToBackup.Top := panelHowToPackup.Top + panelHowToPackup.Height + ScaleY(2);
lblWhereToBackup.Width := panelHowToPackup.Width;
lblWhereToBackup.Font.Color := $000000;
lblWhereToBackup.Color := $F0F0F0;
lblWhereToBackup.Caption := 'Where to backup:';
lblWhereToBackup.Anchors := [akLeft, akRight, akBottom];
{ textBackupFolder (TNewEdit) }
textBackupFolder := TNewEdit.Create(pageAutoBackup);
textBackupFolder.Parent := pageAutoBackup.Surface;
textBackupFolder.Enabled := True;
textBackupFolder.Visible := True;
textBackupFolder.Top := lblWhereToBackup.Top + lblWhereToBackup.Height + ScaleY(2);
textBackupFolder.Width := ScaleX(335);
textBackupFolder.Font.Color := $000000;
textBackupFolder.Color := $F0F0F0;
textBackupFolder.Anchors := [akLeft, akRight, akBottom];
{ btnSelectBackupFolder (TNewButton) }
btnSelectBackupFolder := TNewButton.Create(pageAutoBackup);
btnSelectBackupFolder.Parent := pageAutoBackup.Surface;
btnSelectBackupFolder.Enabled := True;
btnSelectBackupFolder.Visible := True;
btnSelectBackupFolder.Left := ScaleX(340);
btnSelectBackupFolder.Top := textBackupFolder.Top;
btnSelectBackupFolder.Width := ScaleX(75);
btnSelectBackupFolder.Caption := 'Browse ...';
btnSelectBackupFolder.Anchors := [akRight, akBottom];
btnSelectBackupFolder.OnClick := #btnSelectBackupFolder_Click;
Result := pageAutoBackup.ID;
end;
This is what it looks like at smallest size possible:
Due to limited space I decided to remove one of the static labels as it was not really needed.
This is what it looks like when resized:
It is looking good. My queries relate to some specific sizes of controls:
I had to manually come up with figures for the heights of the TPanels or have I got that logic wrong? I now realise that the "Where to Backup" controls are just part of the second panel. Should I be added a third? I just didn't know how to work out the height needed for a panel to cover the controls on it.

Answer 1

You already correctly place the controls relatively to the previous controls.
So use the same logic to size the panels. Once you place the last control, query its position (bottom edge), add some margin, and use that for the panel height.
panelWhatToPackup.ClientHeight :=
radioBackupHowEssential.Top + radioBackupHowEssential.Height + ScaleY(8);
There's a caveat: Checkboxes and radio buttons created on run-time in Inno Setup do not scale automatically. You have to correct their height programmatically:
Scale radio button list with font size