{
    fpGUI  -  Free Pascal GUI Toolkit

    Copyright (C) 2006 - 2008 See the file AUTHORS.txt, included in this
    distribution, for details of the copyright.

    See the file COPYING.modifiedLGPL, included in this distribution,
    for details about redistributing fpGUI.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

    Description:
      Defines a CheckBox control. Also known as a Check Button control.
}

unit fpg_checkbox;

{$mode objfpc}{$H+}

interface

uses
  Classes,
  SysUtils,
  fpg_base,
  fpg_main,
  fpg_widget;
  
type

  TfpgCheckBox = class(TfpgWidget)
  private
    FChecked: boolean;
    FOnChange: TNotifyEvent;
    FText: string;
    FFont: TfpgFont;
    FBoxSize: integer;
    FIsPressed: boolean;
    function    GetFontDesc: string;
    procedure   SetChecked(const AValue: boolean);
    procedure   SetFontDesc(const AValue: string);
    procedure   SetText(const AValue: string);
  protected
    procedure   HandlePaint; override;
    procedure   HandleLMouseDown(x, y: integer; shiftstate: TShiftState); override;
    procedure   HandleLMouseUp(x, y: integer; shiftstate: TShiftState); override;
    procedure   HandleKeyRelease(var keycode: word; var shiftstate: TShiftState; var consumed: boolean); override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor  Destroy; override;
    property    Font: TfpgFont read FFont;
  published
    property    BackgroundColor;
    property    Checked: boolean read FChecked write SetChecked default False;
    property    FontDesc: string read GetFontDesc write SetFontDesc;
    property    ParentShowHint;
    property    ShowHint;
    property    TabOrder;
    property    Text: string read FText write SetText;
    property    TextColor;
    property    OnChange: TNotifyEvent read FOnChange write FOnChange;
    property    OnEnter;
    property    OnExit;
  end;


function CreateCheckBox(AOwner: TComponent; x, y: TfpgCoord; AText: string): TfpgCheckBox;

implementation

function CreateCheckBox(AOwner: TComponent; x, y: TfpgCoord; AText: string): TfpgCheckBox;
begin
  Result := TfpgCheckBox.Create(AOwner);
  Result.Top    := y;
  Result.Left   := x;
  Result.Text   := AText;
  Result.Width  := Result.Font.TextWidth(Result.Text) + 24;
end;

{ TfpgCheckBox }

procedure TfpgCheckBox.SetChecked(const AValue: boolean);
begin
  if FChecked = AValue then
    Exit; //==>
  FChecked := AValue;
  RePaint;
end;

function TfpgCheckBox.GetFontDesc: string;
begin
  Result := FFont.FontDesc;
end;

procedure TfpgCheckBox.SetFontDesc(const AValue: string);
begin
  FFont.Free;
  FFont := fpgGetFont(AValue);
  RePaint;
end;

procedure TfpgCheckBox.SetText(const AValue: string);
begin
  if FText = AValue then
    Exit; //==>
  FText := AValue;
  RePaint;
end;

procedure TfpgCheckBox.HandlePaint;
var
  r: TfpgRect;
  ty: integer;
  tx: integer;
  ix: integer;
  img: TfpgImage;
begin
  inherited HandlePaint;
  
  Canvas.SetColor(FBackgroundColor);
  Canvas.FillRectangle(0, 0, Width, Height);
  Canvas.SetFont(Font);

  if FFocused then
  begin
    Canvas.SetColor(clText1);
    Canvas.SetLineStyle(1, lsDot);
    Canvas.DrawRectangle(1, 1, Width-2, Height-2);
  end;
  Canvas.SetLineStyle(1, lsSolid);

  r.SetRect(2, (Height div 2) - (FBoxSize div 2), FBoxSize, FBoxSize);
  if r.top < 0 then
    r.top := 0;

  // calculate which image to paint.
  if Enabled then
  begin
    ix := Ord(FChecked);
    if FIsPressed then
      Inc(ix, 2);
  end
  else
    ix := (2 + (Ord(FChecked) * 2)) - Ord(FChecked);

  // paint the check (in this case a X)
  tx := r.right + 8;
  inc(r.left, 2);
  inc(r.top, 1);
  img := fpgImages.GetImage('sys.checkboxes');    // Do NOT localize
  Canvas.DrawImagePart(r.Left, r.Top, img, ix*13, 0, 13, 13);

  ty := (Height div 2) - (Font.Height div 2);
  if ty < 0 then
    ty := 0;
  Canvas.SetTextColor(FTextColor);
  fpgStyle.DrawString(Canvas, tx, ty, FText, Enabled);
end;

procedure TfpgCheckBox.HandleLMouseDown(x, y: integer; shiftstate: TShiftState);
begin
  inherited HandleLMouseDown(x, y, shiftstate);
  FIsPressed := True;
  Repaint;
end;

procedure TfpgCheckBox.HandleLMouseUp(x, y: integer; shiftstate: TShiftState);
begin
  inherited HandleLMouseUp(x, y, shiftstate);
  FIsPressed := False;
  Checked := not FChecked;
  if Assigned(FOnChange) then
    FOnChange(self);
end;

procedure TfpgCheckBox.HandleKeyRelease(var keycode: word;
  var shiftstate: TShiftState; var consumed: boolean);
begin
  if (keycode = keySpace) or (keycode = keyReturn) or (keycode = keyPEnter) then
  begin
    consumed := True;
    Checked := not FChecked;
    if Assigned(FOnChange) then
      FOnChange(self);
  end;

  if consumed then
    Exit; //==>

  inherited HandleKeyRelease(keycode, shiftstate, consumed);
end;

constructor TfpgCheckBox.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FText       := 'CheckBox';
  FFont       := fpgGetFont('#Label1');
  FHeight     := FFont.Height + 4;
  FWidth      := 120;
  FTextColor  := Parent.TextColor;
  FBackgroundColor := Parent.BackgroundColor;
  FFocusable  := True;
  FBoxSize    := 14;
  FChecked    := False;
  FIsPressed  := False;
  FOnChange   := nil;
end;

destructor TfpgCheckBox.Destroy;
begin
  FFont.Free;
  inherited Destroy;
end;

end.