TFlowPanel alike in D5

Question

I am looking for an implementation of TFlowPanel (or similar) that will work with D5.
Basically I need the TFlowPanel to work inside a TScrollBox (with Vertical scroll bar), so the controls will wrap based on the Width of that TScrollBox.

The images basically show what I need:

After resizing the controls are automatically repositioned:

With Vertical scroll bar:

Answer 1

Just a concept. No various FlowTypes, and no possibility to change the order of the controls. You could still move them around by changing the order in the DFM, I think, or by resetting the parent.

The panel sizes vertically to fit all controls. This means, that when you put it inside a scrollbox it will automatically work.

unit uAlignPanel;

interface

uses
  Windows, SysUtils, Classes, Controls, ExtCtrls;

type
  TAlignPanel = class(TPanel)
  protected
    procedure SetChildOrder(Child: TComponent; Order: Integer); overload; override;
    procedure SetZOrder(TopMost: Boolean); override;
  public
    procedure AlignControls(AControl: TControl; var Rect: TRect); override;
    procedure Insert(AControl: TControl);
    procedure Append(AControl: TControl);
    function GetChildOrder(Child: TControl): Integer;
    procedure SetChildOrder(Child: TControl; Order: Integer); reintroduce; overload; virtual;
    procedure MoveChildBefore(Child: TControl; Sibling: TControl); virtual;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('StackOverflow', [TAlignPanel]);
end;

{ TAlignPanel }

procedure TAlignPanel.AlignControls(AControl: TControl; var Rect: TRect);
var
  i: Integer;
  x, y: Integer;
  LineHeight: Integer;
begin
  x := 0; y := 0;
  LineHeight := 0;
  for i := 0 to ControlCount - 1 do
  begin
    if x + Controls[i].Width > ClientWidth then
    begin
      x := 0;
      y := y + LineHeight;
      LineHeight := 0;
    end;
    Controls[i].Top := y;
    Controls[i].Left := x;
    x := x + Controls[i].Width;
    if Controls[i].Height > LineHeight then
      LineHeight := Controls[i].Height;
  end;

  // Height + 1. Not only looks nices, but also prevents a small redrawing
  // problem of the bottom line of the panel when adding controls.
  ClientHeight := y + LineHeight + 1;

end;

procedure TAlignPanel.Append(AControl: TControl);
begin
  AControl.Parent := Self;
  AControl.BringToFront;
  Realign;
end;

function TAlignPanel.GetChildOrder(Child: TControl): Integer;
begin
  for Result := 0 to ControlCount - 1 do
    if Controls[Result] = Child then
      Exit;
  Result := -1;
end;

procedure TAlignPanel.Insert(AControl: TControl);
begin
  AControl.Parent := Self;
  AControl.SendToBack;
  Realign;
end;

procedure TAlignPanel.MoveChildBefore(Child, Sibling: TControl);
var
  CurrentIndex: Integer;
  NewIndex: Integer;
begin
  if Child = Sibling then
    raise Exception.Create('Child and sibling cannot be the same');

  CurrentIndex := GetChildOrder(Child);
  if CurrentIndex = -1 then
    raise Exception.CreateFmt( 'Control ''%s'' is not a child of panel ''%s''',
                               [Sibling.Name, Name]);

  if Sibling <> nil then
  begin
    NewIndex := GetChildOrder(Sibling);
    if NewIndex = -1 then
      raise Exception.CreateFmt( 'Sibling ''%s'' is not a child of panel ''%s''',
                                 [Sibling.Name, Name]);
    if CurrentIndex < NewIndex then
      Dec(NewIndex);
  end
  else
    NewIndex := ControlCount;

  SetChildOrder(Child, NewIndex);
end;

procedure TAlignPanel.SetChildOrder(Child: TComponent; Order: Integer);
begin
  inherited;
  Realign;
end;

procedure TAlignPanel.SetChildOrder(Child: TControl; Order: Integer);
begin
  SetChildOrder(TComponent(Child), Order);
end;

procedure TAlignPanel.SetZOrder(TopMost: Boolean);
begin
  inherited;
  Realign;
end;

end.