請教一下如何開發出具 Color SpeedButton.......

發表時間：2005-09-14 10:04:55

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請教一下如何開發出具 Color 變化 SpeedButton...... ... 是繼承TSpeedButton的vcl元件哦!!! .... 以下是具Color變化Button的vcl元件程式碼.... ...其中有幾處並不是很明瞭... ColorButton.h ====================================================================== private: TColor ColorLo_; TColor ColorHi_; std::auto_ptr Canvas_;---->?????此段用意為何?? bool draw_as_default_; TColor __fastcall GetColor(); void __fastcall SetColor(TColor Value); void __fastcall SetColorLo(TColor Value); void __fastcall SetColorHi(TColor Value); ///以下是事件的觸發ㄇㄚ??? MESSAGE void __fastcall CNDrawItem(TMessage& Msg); MESSAGE void __fastcall WMLButtonDblClk(TMessage& Msg); MESSAGE void __fastcall CMFontChanged(TMessage& Msg); MESSAGE void __fastcall CMEnabledChanged(TMessage& Msg); protected: // inherited member functions virtual void __fastcall CreateParams(TCreateParams& Params); virtual void __fastcall SetButtonStyle(bool ADefault); // introduced member functions virtual void __fastcall DoDrawButtonFace(const TOwnerDrawState& state); virtual void __fastcall DoDrawButtonText(const TOwnerDrawState& state); public: BEGIN_MESSAGE_MAP MESSAGE_HANDLER(CN_DRAWITEM, TMessage, CNDrawItem) MESSAGE_HANDLER(WM_LBUTTONDBLCLK, TMessage, WMLButtonDblClk) MESSAGE_HANDLER(CM_FONTCHANGED, TMessage, CMFontChanged) MESSAGE_HANDLER(CM_ENABLEDCHANGED, TMessage, CMEnabledChanged) END_MESSAGE_MAP(TButton) __fastcall TColorButton(TComponent* Owner); __published: __property TColor Color = {read = GetColor, write = SetColor}; __property TColor ColorLo = {read = ColorLo_, write = SetColorLo,default = clBtnShadow}; __property TColor ColorHi = {read = ColorHi_, write = SetColorHi,default = clBtnHighlight}; ====================================================================== ColorButton.c ====================================================================== static inline void ValidCtrCheck(TColorButton *) { new TColorButton(NULL); } //--------------------------------------------------------------------------- __fastcall TColorButton::TColorButton(TComponent* Owner) : TButton(Owner), ColorLo_(clBtnShadow), ColorHi_(clBtnHighlight), Canvas_(new TCanvas()),draw_as_default_(false) { } // end the declaration //--------------------------------------------------------------------------- namespace Colorbutton { void __fastcall PACKAGE Register() { TComponentClass classes[1] = {__classid(TColorButton)}; RegisterComponents("Standard", classes, 0); } } //--------------------------------------------------------------------------- void __fastcall TColorButton::CreateParams(TCreateParams& Params) { TButton::CreateParams(Params); Params.Style |= BS_OWNERDRAW; } //--------------------------------------------------------------------------- void __fastcall TColorButton::SetButtonStyle(bool ADefault) { if (draw_as_default_ != ADefault) { draw_as_default_ = ADefault; InvalidateRect(Handle, NULL, FALSE); } } //--------------------------------------------------------------------------- void __fastcall TColorButton::CNDrawItem(TMessage& Msg) { // grab pointer to the DRAWITEMSTRUCT const DRAWITEMSTRUCT* pDrawItem = reinterpret_cast (Msg.LParam); // store the current state of // the target DC SaveDC(pDrawItem->hDC); // bind Canvas_ to the target DC Canvas_->Handle = pDrawItem->hDC; try { // extract the state flags... TOwnerDrawState state; // if the button has keyboard focus if (pDrawItem->itemState & ODS_FOCUS) { state = state << odFocused; } // if the button is pushed if (pDrawItem->itemState & ODS_SELECTED) { state = state << odSelected; } // if the button is disabled if (pDrawItem->itemState & ODS_DISABLED) { state = state << odDisabled; } // draw the button's face DoDrawButtonFace(state); // draw the button's text DoDrawButtonText(state); } catch (...) { // clean up Canvas_->Handle = NULL; RestoreDC(pDrawItem->hDC, -1); } // clean up Canvas_->Handle = NULL; RestoreDC(pDrawItem->hDC, -1); // reply TRUE Msg.Result = TRUE; } //--------------------------------------------------------------------------- void __fastcall TColorButton::DoDrawButtonFace(const TOwnerDrawState& state) { // draw a colored button... Canvas_->Brush = Brush; TRect RClient = ClientRect; // if the button is the default button // or has keyboard focus... if (draw_as_default_ || state.Contains(odFocused)) { Canvas_->Pen->Color = clWindowFrame; Canvas_->Rectangle( RClient.Left, RClient.Top, RClient.Right, RClient.Bottom ); InflateRect( reinterpret_cast

(&RClient),
       -1, -1
       );
  }      // if the button is pushed...
  if (state.Contains(odSelected))
  {
    Canvas_->Pen->Color = ColorLo_;
    Canvas_->Rectangle(
       RClient.Left, RClient.Top,
       RClient.Right, RClient.Bottom
       );
  }      // if the button isn't pushed...
  else
  {
    Canvas_->FillRect(RClient);
    Frame3D(
      Canvas_.get(), RClient,
      ColorHi_, clWindowFrame, 1
      );        POINT P[] = {
      {1, RClient.Bottom - 1},
      {RClient.Right - 1,
       RClient.Bottom - 1},
      {RClient.Right - 1,
       RClient.Top - 1}
      };
    Canvas_->Pen->Color = ColorLo_;
    Canvas_->Polyline(
       reinterpret_cast(P), 2
       );
  }
}
//---------------------------------------------------------------------------
void __fastcall TColorButton::DoDrawButtonText(const TOwnerDrawState& state)
{
  if (Caption.Length() == 0) return;      RECT RText = {0, 0, Width, Height};
  Canvas_->Font = Font;
  Canvas_->Brush = Brush;
  SetBkMode(
    Canvas_->Handle, TRANSPARENT
    );      // if the button is pushed...
  if (state.Contains(odSelected))
  {
     // offset the caption
     OffsetRect(&RText, 1, 1);
  }
  // if the button is disabled...
  if (!Enabled ||
      state.Contains(odDisabled))
  {        // render the caption
    // in a disabled fashion
    OffsetRect(&RText, 1, 1);
    Canvas_->Font->Color = ColorHi_;
    DrawText(
      Canvas_->Handle, Caption.c_str(),
      -1, &RText, DT_CENTER |
      DT_VCENTER | DT_SINGLELINE
      );
    OffsetRect(&RText, -1, -1);
    Canvas_->Font->Color = ColorLo_;
  }      // render the caption
  DrawText(
    Canvas_->Handle, Caption.c_str(), -1,
    &RText, DT_CENTER | DT_VCENTER |
    DT_SINGLELINE
    );      // if the button has keyboard focus...
  if (state.Contains(odFocused))
  {
    // render the selection rectangle
    TRect RFocus = ClientRect;
    InflateRect(
      reinterpret_cast(&RFocus),
      -4, -4
      );
    Canvas_->DrawFocusRect(RFocus);
  }
}
//---------------------------------------------------------------------------
TColor __fastcall TColorButton::GetColor()
{
  return Brush->Color;
}
//---------------------------------------------------------------------------
void __fastcall TColorButton::SetColor(TColor Value)
{
  if (Brush->Color != Value)
  {
    Brush->Color = Value;
    InvalidateRect(Handle, NULL, TRUE);
  }
}
//---------------------------------------------------------------------------
void __fastcall TColorButton::SetColorLo(TColor Value)
{
  if (ColorLo_ != Value)
  {
    ColorLo_ = Value;
    InvalidateRect(Handle, NULL, TRUE);
  }
}
//---------------------------------------------------------------------------
void __fastcall TColorButton::SetColorHi(TColor Value)
{
  if (ColorHi_ != Value)
  {
    ColorHi_ = Value;
    InvalidateRect(Handle, NULL, TRUE);
  }
}
//---------------------------------------------------------------------------
void __fastcall TColorButton::CMFontChanged(TMessage& Msg)
{
  TButton::Dispatch(&Msg);
  InvalidateRect(Handle, NULL, TRUE);
}
//---------------------------------------------------------------------------
void __fastcall TColorButton::CMEnabledChanged(TMessage& Msg)
{
  TButton::Dispatch(&Msg);
  InvalidateRect(Handle, NULL, TRUE);
}
//---------------------------------------------------------------------------
void __fastcall TColorButton::WMLButtonDblClk(TMessage& Msg)
{
  SNDMSG(
    Handle, WM_LBUTTONDOWN,
    Msg.WParam, Msg.LParam
    );
}
======================================================================