unit TFlatCheckListBoxUnit;

interface

{$I DFS.inc}

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, ExtCtrls, FlatUtilitys;

type
  TFlatCheckListBox = class(TCustomControl)
  private
    FSelected: Integer;
    FTransparent: TTransparentMode;
    FOnClickCheck: TNotifyEvent;
    cWheelMessage: Cardinal;
    scrollType: TScrollType;
    firstItem: Integer;
    maxItems: Integer;
    FSorted: Boolean;
    FItems: TStringList;
    FItemsRect: TList;
    FItemsHeight: Integer;
    FChecked: set of Byte;
    FScrollBars: Boolean;
    FUseAdvColors: Boolean;
    FAdvColorBorder: TAdvColors;
    FArrowColor: TColor;
    FCheckColor: TColor;
    FBorderColor: TColor;
    FItemsRectColor: TColor;
    FItemsSelectColor: TColor;
    procedure SetColors (Index: Integer; Value: TColor);
    procedure SetAdvColors (Index: Integer; Value: TAdvColors);
    procedure SetUseAdvColors (Value: Boolean);
    procedure SetSorted (Value: Boolean);
    procedure SetItems (Value: TStringList);
    procedure SetItemsRect;
    procedure SetItemsHeight (Value: Integer);
    function GetChecked (Index: Integer): Boolean;
    procedure SetChecked (Index: Integer; Value: Boolean);
    function GetSelCount: Integer;
    procedure SetScrollBars (Value: Boolean);
    function GetItemIndex: Integer;
    procedure SetItemIndex (Value: Integer);
    procedure WMSize (var Message: TWMSize); message WM_SIZE;
    procedure WMMove (var Message: TWMMove); message WM_MOVE;
    procedure CMEnabledChanged (var Message: TMessage); message CM_ENABLEDCHANGED;
    procedure CMSysColorChange (var Message: TMessage); message CM_SYSCOLORCHANGE;
    procedure CMParentColorChanged (var Message: TWMNoParams); message CM_PARENTCOLORCHANGED;
    procedure ScrollTimerHandler (Sender: TObject);
    procedure ItemsChanged (Sender: TObject);
    procedure WMSetFocus (var Message: TWMSetFocus); message WM_SETFOCUS;
    procedure WMKillFocus (var Message: TWMKillFocus); message WM_KILLFOCUS;
    procedure CNKeyDown (var Message: TWMKeyDown); message CN_KEYDOWN;
    procedure WMMouseWheel (var Message: TMessage); message WM_MOUSEWHEEL;
    procedure SetTransparent (const Value: TTransparentMode);
  protected
    procedure CalcAdvColors;
    procedure DrawCheckRect (canvas: TCanvas; start: TPoint; checked: Boolean);
    procedure DrawScrollBar (canvas: TCanvas);
    procedure Paint; override;
    procedure Loaded; override;
    procedure MouseDown (Button: TMouseButton; Shift: TShiftState; X, Y: Integer); override;
    procedure MouseUp (Button: TMouseButton; Shift: TShiftState; X, Y: Integer); override;
    procedure WndProc (var Message: TMessage); override;
   {$IFDEF DFS_COMPILER_4_UP}
    procedure SetBiDiMode(Value: TBiDiMode); override;
   {$ENDIF}
  public
    constructor Create (AOwner: TComponent); override;
    destructor Destroy; override;
    property Checked [Index: Integer]: Boolean read GetChecked write SetChecked;
    property SelCount: Integer read GetSelCount;
    procedure Clear;
    property ItemIndex: Integer read GetItemIndex write SetItemIndex;
  published
    property Items: TStringList read FItems write SetItems;
    property ItemHeight: Integer read FItemsHeight write SetItemsHeight default 17;
    property ScrollBars: Boolean read FScrollBars write SetScrollBars default false;
    property Color default $00E1EAEB;
    property ColorArrow: TColor index 0 read FArrowColor write SetColors default clBlack;
    property ColorBorder: TColor index 1 read FBorderColor write SetColors default $008396A0;
    property ColorItemsRect: TColor index 2 read FItemsRectColor write SetColors default clWhite;
    property ColorItemsSelect: TColor index 3 read FItemsSelectColor write SetColors default $009CDEF7;
    property ColorCheck: TColor index 4 read FCheckColor write SetColors default clBlack;
    property AdvColorBorder: TAdvColors index 0 read FAdvColorBorder write SetAdvColors default 40;
    property UseAdvColors: Boolean read FUseAdvColors write SetUseAdvColors default false;
    property Sorted: Boolean read FSorted write SetSorted default false;
    property TransparentMode: TTransparentMode read FTransparent write SetTransparent default tmNone;
    property Align;
    property Font;
    property ParentFont;
    property ParentColor;
    property ParentShowHint;
    property Enabled;
    property Visible;
    property PopupMenu;
    property ShowHint;

    property OnClick;
    property OnClickCheck: TNotifyEvent read FOnClickCheck write FOnClickCheck;
    property OnMouseMove;
    property OnMouseDown;
    property OnMouseUp;
   {$IFDEF DFS_COMPILER_4_UP}
    property Anchors;
    property BiDiMode write SetBidiMode;
    property Constraints;
    property DragKind;
    property ParentBiDiMode;
    property OnEndDock;
    property OnStartDock;
   {$ENDIF}
  end;

implementation

var
  ScrollTimer: TTimer = nil;

const
  FTimerInterval = 600; 
  FScrollSpeed = 100;

constructor TFlatCheckListBox.Create (AOwner: TComponent);
begin
  inherited;
  if ScrollTimer = nil then
  begin
    ScrollTimer := TTimer.Create(nil);
    ScrollTimer.Enabled := False;
    ScrollTimer.Interval := FTimerInterval;
  end;
  ControlStyle := ControlStyle + [csOpaque];
  SetBounds(Left, Top, 137, 99);
  FItems := TStringList.Create;
  FItemsRect := TList.Create;
  FItemsHeight := 17;

  TStringList(FItems).OnChange := ItemsChanged;

  FScrollBars := false;
  firstItem := 0;
  FArrowColor := clBlack;
  FBorderColor := $008396A0;
  FItemsRectColor := clWhite;
  FItemsSelectColor := $009CDEF7;
  FCheckColor := clBlack;
  ParentColor := True;
  ParentFont := True;
  Enabled := true;
  Visible := true;
  FUseAdvColors := false;
  FAdvColorBorder := 40;
  FSorted := false;
  FTransparent := tmNone;
  FSelected := -1;
  cWheelMessage:= RegisterWindowMessage(MSH_MOUSEWHEEL);
end;

destructor TFlatCheckListBox.Destroy;
var
  counter: Integer;
begin
  ScrollTimer.Free;
  ScrollTimer := nil;
  FItems.Free;
  for counter := 0 to FItemsRect.Count - 1 do
    Dispose(FItemsRect.Items[counter]);
  FItemsRect.Free;
  inherited;
end;

procedure TFlatCheckListBox.WndProc (var Message: TMessage);
begin
  if Message.Msg = cWheelMessage then
  begin
    SendMessage (Self.Handle, WM_MOUSEWHEEL, Message.wParam, Message.lParam);
  end;
  inherited;
end;

procedure TFlatCheckListBox.WMMouseWheel (var Message: TMessage);
var
  fScrollLines: Integer;
begin
  if not(csDesigning in ComponentState) then
  begin
    SystemParametersInfo(SPI_GETWHEELSCROLLLINES, 0, @fScrollLines, 0);

    if (fScrollLines = 0) then
      fScrollLines := maxItems;

    if ShortInt(Message.WParamHi) = -WHEEL_DELTA then
      if firstItem + maxItems + fScrollLines <= FItems.Count then
        Inc(firstItem, fScrollLines)
      else
        if FItems.Count - maxItems < 0 then
          firstItem := 0
        else
          firstItem := FItems.Count - maxItems
    else
      if ShortInt(Message.WParamHi) = WHEEL_DELTA then
        if firstItem - fScrollLines < 0 then
          firstItem := 0
        else
          dec(firstItem, fScrollLines);
    Invalidate;
  end;
end;

procedure TFlatCheckListBox.ItemsChanged (Sender: TObject);
begin
  if Enabled then
  begin
    FChecked := FChecked - [0..High(Byte)];
    Invalidate;
  end;
end;

procedure TFlatCheckListBox.SetColors (Index: Integer; Value: TColor);
begin
  case Index of
    0: FArrowColor := Value;
    1: FBorderColor := Value;
    2: FItemsRectColor := Value;
    3: FItemsSelectColor := Value;
    4: FCheckColor := Value;
  end;
  Invalidate;       
end;

procedure TFlatCheckListBox.CalcAdvColors;
begin
  if FUseAdvColors then
  begin
    FBorderColor := CalcAdvancedColor(Color, FBorderColor, FAdvColorBorder, darken);
  end;
end;

procedure TFlatCheckListBox.SetAdvColors (Index: Integer; Value: TAdvColors);
begin
  case Index of
    0: FAdvColorBorder := Value;
  end;
  CalcAdvColors;
  Invalidate;
end;

procedure TFlatCheckListBox.SetUseAdvColors (Value: Boolean);
begin
  if Value <> FUseAdvColors then
  begin
    FUseAdvColors := Value;
    ParentColor := Value;
    CalcAdvColors;
    Invalidate;
  end;
end;

procedure TFlatCheckListBox.SetSorted (Value: Boolean);
begin
  if Value <> FSorted then
  begin
    FSorted := Value;
    FItems.Sorted := Value;
    FChecked := FChecked - [0..High(Byte)];
    Invalidate;
  end;
end;

procedure TFlatCheckListBox.SetItems (Value: TStringList);
var
  counter: Integer;
begin
  if Value.Count - 1 > High(Byte) then
    Exit;

  // delete all spaces at left and right
  for counter := 0 to Value.Count - 1 do
    Value[counter] := Trim(Value[counter]);

  FItems.Assign(Value);

  Invalidate;
end;

procedure TFlatCheckListBox.SetItemsRect;
var
  counter: Integer;
  ItemRect: ^TRect;
  position: TPoint;
begin
  // Delete all curent Rects
  FItemsRect.Clear;

  // calculate the maximum items to draw
  if ScrollBars then
    maxItems := (Height - 24) div (FItemsHeight + 2)
  else
    maxItems := (Height - 4) div (FItemsHeight + 2);

  // set left/top position for the the first item
  if ScrollBars then
   position := Point(ClientRect.left + 3, ClientRect.top + 13)
  else
    position := Point(ClientRect.left + 3, ClientRect.top + 3);

  for counter := 0 to maxItems - 1 do
  begin
    // create a new Item-Rect
    New(ItemRect);
    // calculate the Item-Rect
    ItemRect^ := Rect(position.x, position.y, ClientRect.Right - 3, position.y + FItemsHeight);
    // set left/top position for next Item-Rect
    position := Point(position.x, position.y + FItemsHeight + 2);
    // add the Item-Rect to the Items-Rect-List
    FItemsRect.Add(ItemRect);
  end;
  Invalidate;
end;

procedure TFlatCheckListBox.SetItemsHeight (Value: Integer);
begin
  if Value < 1 then
    Value := 1;

  FItemsHeight := Value;

  if not (csLoading in ComponentState) then
    if ScrollBars then
      SetBounds(Left, Top, Width, maxItems * (FItemsHeight + 2) + 24)
    else
      SetBounds(Left, Top, Width, maxItems * (FItemsHeight + 2) + 4);
      
  SetItemsRect;
end;

function TFlatCheckListBox.GetChecked (Index: Integer): Boolean;
begin
  Result := Index in FChecked;
end;

procedure TFlatCheckListBox.SetChecked (Index: Integer; Value: Boolean);
begin
  if Value then
    Include(FChecked, Index)
  else
    Exclude(FChecked, Index);
  Invalidate;
end;

{$IFDEF DFS_COMPILER_4_UP}
procedure TFlatCheckListBox.SetBiDiMode(Value: TBiDiMode);
begin
  inherited;
  Invalidate;
end;
{$ENDIF}

function TFlatCheckListBox.GetSelCount: Integer;
var
  counter: Integer;
begin
  Result := 0;
  for counter := 0 to High(Byte) do
    if counter in FChecked then
      Inc(Result);
end;

procedure TFlatCheckListBox.SetScrollBars (Value: Boolean);
begin
  if FScrollBars <> Value then
  begin
    FScrollBars := Value;
    if not (csLoading in ComponentState) then
      if Value then
        Height := Height + 20
      else
        Height := Height - 20;
    SetItemsRect;
  end;
end;

procedure TFlatCheckListBox.DrawScrollBar (canvas: TCanvas);
var
  x, y: Integer;
begin
  // Draw the ScrollBar background
  canvas.Brush.Color := Color;
  canvas.FillRect(Rect(ClientRect.Left, ClientRect.Top, ClientRect.Right, ClientRect.Top + 11));
  canvas.FillRect(Rect(ClientRect.Left, ClientRect.Bottom - 11, ClientRect.Right, ClientRect.Bottom));

  // Draw the ScrollBar border
  canvas.Brush.Color := FBorderColor;
  canvas.FrameRect(Rect(ClientRect.Left, ClientRect.Top, ClientRect.Right, ClientRect.Top + 11));
  canvas.FrameRect(Rect(ClientRect.Left, ClientRect.Bottom - 11, ClientRect.Right, ClientRect.Bottom));

  // Draw the up arrow
  x := (ClientRect.Right - ClientRect.Left) div 2 - 6;
  y := ClientRect.Top + 4;

  if (firstItem <> 0) and Enabled then
  begin
    canvas.Brush.Color := FArrowColor;
    canvas.Pen.Color := FArrowColor;
    canvas.Polygon([Point(x + 4, y + 2), Point(x + 8, y + 2), Point(x + 6, y)]);
  end
  else
  begin
    canvas.Brush.Color := clWhite;
    canvas.Pen.Color := clWhite;
    Inc(x); Inc(y);
    canvas.Polygon([Point(x + 4, y + 2), Point(x + 8, y + 2), Point(x + 6, y)]);
    Dec(x); Dec(y);
    canvas.Brush.Color := clGray;
    canvas.Pen.Color := clGray;
    canvas.Polygon([Point(x + 4, y + 2), Point(x + 8, y + 2), Point(x + 6, y)]);
  end;