{%MainUnit ../buttons.pp}

{
 *****************************************************************************
 *                                                                           *
 *  This file is part of the Lazarus Component Library (LCL)                 *
 *                                                                           *
 *  See the file COPYING.modifiedLGPL, included in this distribution,        *
 *  for details about the copyright.                                         *
 *                                                                           *
 *  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.                     *
 *                                                                           *
 *****************************************************************************
}

{------------------------------------------------------------------------------}
{       TButtonGlyph Constructor                                                    }
{------------------------------------------------------------------------------}
constructor TButtonGlyph.Create;
begin
  FImagesCache := nil;
  FOriginal := TBitmap.Create;
  FOriginal.OnChange := @GlyphChanged;
end;

{------------------------------------------------------------------------------
       TButtonGlyph destructor
------------------------------------------------------------------------------}
destructor TButtonGlyph.Destroy;
begin
  if FImagesCache <> nil then
  begin
    FImagesCache.UnregisterListener(Self);
    FImagesCache := nil; // cache can free on unregister
  end;
  FOriginal.Free;
  FOriginal := nil;
  inherited Destroy;
end;

procedure TButtonGlyph.GetImageIndexAndEffect(State: TButtonState;
  var AIndex: Integer; var AEffect: TGraphicsDrawEffect);
var
  AStoredState: TButtonState;
begin
  AStoredState := bsUp;
  AEffect := gdeNormal;
  case State of
    bsDisabled:
     begin
       if NumGlyphs > 1 then
         AStoredState := State
       else
         AEffect := gdeDisabled;
      end;
    bsDown:
      begin
        if NumGlyphs > 2 then
          AStoredState := State
        else
          AEffect := gdeShadowed;
      end;
    bsExclusive:
      if NumGlyphs > 3 then
        AStoredState := State
      else
        AEffect := gdeNormal;
    bsHot:
      if NumGlyphs > 4 then
        AStoredState := State
      else
        AEffect := gdeHighlighted;
  end;
  AIndex := FImageIndexes[AStoredState];
end;

{------------------------------------------------------------------------------
       TButtonGlyph SetGlyph
------------------------------------------------------------------------------}
procedure TButtonGlyph.SetGlyph(Value : TBitmap);
var
  GlyphCount : integer;
begin
  if FOriginal = Value then
    exit;
  if FOriginal = nil then
    FOriginal := TBitmap.Create;
  FOriginal.OnChange := nil;
  FOriginal.Assign(Value);
  FOriginal.OnChange := @GlyphChanged;
  FNumGlyphs := 1;
  if (FOriginal <> nil) and (FOriginal.Height > 0) then
  begin
    if FOriginal.Width mod FOriginal.Height = 0 then
    begin
      GlyphCount := FOriginal.Width div FOriginal.Height;
      if GlyphCount > High(TNumGlyphs) then
        GlyphCount := Low(TNumGlyphs);
      FNumGlyphs := TNumGlyphs(GlyphCount);
    end;
  end;
  GlyphChanged(FOriginal);
end;

function TButtonGlyph.GetHeight: Integer;
begin
  if FImages <> nil then
    Result := FImages.Height
  else
    Result := 0;
end;

function TButtonGlyph.GetWidth: Integer;
begin
  if FImages <> nil then
    Result := FImages.Width
  else
    Result := 0;
end;

procedure TButtonGlyph.GlyphChanged(Sender: TObject);
begin
  if FImagesCache <> nil then
  begin
    FImagesCache.UnregisterListener(Self);
    FImagesCache := nil; // cache can free on unregister
    ClearImages;
  end;

  if (FOriginal.Width > 0) and (FOriginal.Height > 0) then
  begin
    FImagesCache := GetImageListCache;
    FImagesCache.RegisterListener(Self);
    FImagesCache.RegisterBitmap(Self, FOriginal, Max(1, NumGlyphs));
  end;

  if Sender = FOriginal then
    if Assigned(FOnChange) then
      FOnChange(Self);
end;

{------------------------------------------------------------------------------
       TButtonGlyph Draw
------------------------------------------------------------------------------}
function TButtonGlyph.Draw(Canvas: TCanvas; const Client: TRect;
  const Offset: TPoint;  State: TButtonState;  Transparent: Boolean;
  BiDiFlags: Longint): TRect;
var
  ImgID: integer;
  AEffect: TGraphicsDrawEffect;
begin
  Result := Client;
  if (FOriginal = nil) then
    exit;

  if (Width = 0) or (Height = 0) or
     (Client.Left >= Client.Right) or (Client.Top >= Client.Bottom) then
    Exit;
  
  GetImageIndexAndEffect(State, ImgID, AEffect);

  FImages.Draw(Canvas, Client.Left + Offset.X, Client.Top + Offset.y, ImgID,
    AEffect);

  // ToDo: VCL returns the text rectangle
end;


{------------------------------------------------------------------------------
       TButtonGlyph SetNumGlyphs
------------------------------------------------------------------------------}
procedure TButtonGlyph.SetNumGlyphs(Value : TNumGlyphs);
begin
  if Value <> FNumGlyphs then
  begin
    FNumGlyphs := Value;
    GlyphChanged(FOriginal);
  end;
end;

procedure TButtonGlyph.ClearImages;
var
  i: TButtonState;
begin
  FImages := nil;
  for i := Low(TButtonState) to High(TButtonState) do
    FImageIndexes[i] := -1;
end;

function TButtonGlyph.QueryInterface(const iid: tguid; out obj): longint; stdcall;
begin
  if GetInterface(iid, obj) then
    Result := 0
  else
    Result := E_NOINTERFACE;
end;

function TButtonGlyph._AddRef: longint; stdcall;
begin
  Result := -1;
end;

function TButtonGlyph._Release: longint; stdcall;
begin
  Result := -1;
end;

procedure TButtonGlyph.CacheSetImageList(AImageList: TCustomImageList);
begin
  FImages := AImageList;
end;

procedure TButtonGlyph.CacheSetImageIndex(AIndex, AImageIndex: Integer);
begin
  if (AIndex >= ord(Low(TButtonState))) and (AIndex <= Ord(High(TButtonState))) then
    FImageIndexes[TButtonState(AIndex)] := AImageIndex;
end;

// included by buttons.pp