DELPHI FAQ: Изменить цвет TButton

Изменить цвет TButton

{
  You cannot change the color of a standard TButton,
  since the windows button control always paints itself with the
  button color defined in the control panel.
  But you can derive derive a new component from TButton and handle
  the and drawing behaviour there.
}

unit ColorButton;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Buttons, ExtCtrls;

type
  TDrawButtonEvent = procedure(Control: TWinControl;
    Rect: TRect; State: TOwnerDrawState) of object;

  TColorButton = class(TButton)
  private
    FCanvas: TCanvas;
    IsFocused: Boolean;
    FOnDrawButton: TDrawButtonEvent;
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    procedure SetButtonStyle(ADefault: Boolean); override;
    procedure CMEnabledChanged(var Message: TMessage); message CM_ENABLEDCHANGED;
    procedure CMFontChanged(var Message: TMessage); message CM_FONTCHANGED;
    procedure CNMeasureItem(var Message: TWMMeasureItem); message CN_MEASUREITEM;
    procedure CNDrawItem(var Message: TWMDrawItem); message CN_DRAWITEM;
    procedure WMLButtonDblClk(var Message: TWMLButtonDblClk); message WM_LBUTTONDBLCLK;
    procedure DrawButton(Rect: TRect; State: UINT);
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
    property Canvas: TCanvas read FCanvas;
  published
    property OnDrawButton: TDrawButtonEvent read FOnDrawButton write FOnDrawButton;
    property Color;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Samples', [TColorButton]);
end;

constructor TColorButton.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  FCanvas := TCanvas.Create;
end;

destructor TColorButton.Destroy;
begin
  inherited Destroy;
  FCanvas.Free;
end;

procedure TColorButton.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  with Params do Style := Style or BS_OWNERDRAW;
end;

procedure TColorButton.SetButtonStyle(ADefault: Boolean);
begin
  if ADefault <> IsFocused then
  begin
    IsFocused := ADefault;
    Refresh;
  end;
end;

procedure TColorButton.CNMeasureItem(var Message: TWMMeasureItem);
begin
  with Message.MeasureItemStruct^ do
  begin
    itemWidth  := Width;
    itemHeight := Height;
  end;
end;

procedure TColorButton.CNDrawItem(var Message: TWMDrawItem);
var
  SaveIndex: Integer;
begin
  with Message.DrawItemStruct^ do
  begin
    SaveIndex := SaveDC(hDC);
    FCanvas.Lock;
    try
      FCanvas.Handle := hDC;
      FCanvas.Font := Font;
      FCanvas.Brush := Brush;
      DrawButton(rcItem, itemState);
    finally
      FCanvas.Handle := 0;
      FCanvas.Unlock;
      RestoreDC(hDC, SaveIndex);
    end;
  end;
  Message.Result := 1;
end;

procedure TColorButton.CMEnabledChanged(var Message: TMessage);
begin
  inherited;
  Invalidate;
end;

procedure TColorButton.CMFontChanged(var Message: TMessage);
begin
  inherited;
  Invalidate;
end;

procedure TColorButton.WMLButtonDblClk(var Message: TWMLButtonDblClk);
begin
  Perform(WM_LBUTTONDOWN, Message.Keys, Longint(Message.Pos));
end;

procedure TColorButton.DrawButton(Rect: TRect; State: UINT);
var
  Flags, OldMode: Longint;
  IsDown, IsDefault, IsDisabled: Boolean;
  OldColor: TColor;
  OrgRect: TRect;
begin
  OrgRect := Rect;
  Flags := DFCS_BUTTONPUSH or DFCS_ADJUSTRECT;
  IsDown := State and ODS_SELECTED <> 0;
  IsDefault := State and ODS_FOCUS <> 0;
  IsDisabled := State and ODS_DISABLED <> 0;

  if IsDown then Flags := Flags or DFCS_PUSHED;
  if IsDisabled then Flags := Flags or DFCS_INACTIVE;

  if IsFocused or IsDefault then
  begin
    FCanvas.Pen.Color := clWindowFrame;
    FCanvas.Pen.Width := 1;
    FCanvas.Brush.Style := bsClear;
    FCanvas.Rectangle(Rect.Left, Rect.Top, Rect.Right, Rect.Bottom);
    InflateRect(Rect, - 1, - 1);
  end;

  if IsDown then
  begin
    FCanvas.Pen.Color := clBtnShadow;
    FCanvas.Pen.Width := 1;
    FCanvas.Brush.Color := clBtnFace;
    FCanvas.Rectangle(Rect.Left, Rect.Top, Rect.Right, Rect.Bottom);
    InflateRect(Rect, - 1, - 1);
  end
  else
    DrawFrameControl(FCanvas.Handle, Rect, DFC_BUTTON, Flags);

  if IsDown then OffsetRect(Rect, 1, 1);

  OldColor := FCanvas.Brush.Color;
  FCanvas.Brush.Color := Color;
  FCanvas.FillRect(Rect);
  FCanvas.Brush.Color := OldColor;
  OldMode := SetBkMode(FCanvas.Handle, TRANSPARENT);
  FCanvas.Font.Color := clBtnText;
  if IsDisabled then
    DrawState(FCanvas.Handle, FCanvas.Brush.Handle, nil, Integer(Caption), 0,
    ((Rect.Right - Rect.Left) - FCanvas.TextWidth(Caption)) div 2,
    ((Rect.Bottom - Rect.Top) - FCanvas.TextHeight(Caption)) div 2,
      0, 0, DST_TEXT or DSS_DISABLED)
  else
    DrawText(FCanvas.Handle, PChar(Caption), - 1, Rect,
      DT_SINGLELINE or DT_CENTER or DT_VCENTER);
  SetBkMode(FCanvas.Handle, OldMode);

  if Assigned(FOnDrawButton) then
    FOnDrawButton(Self, Rect, TOwnerDrawState(LongRec(State).Lo));

  if IsFocused and IsDefault then
  begin
    Rect := OrgRect;
    InflateRect(Rect, - 4, - 4);
    FCanvas.Pen.Color := clWindowFrame;
    FCanvas.Brush.Color := clBtnFace;
    DrawFocusRect(FCanvas.Handle, Rect);
  end;
end;
end.

В книгах Калверта, Свана и других авторов можно найти похожий текст. Смысл текста – "Изменить цвет кнопок Button, BitBtn нельзя, т.к. их рисует WINDOWS". Если нельзя, но ОЧЕНЬ НУЖНО, то можно.

Небольшой компонент ColorBtn, дает возможность использовать в кнопках цвет. Кроме того, представлено новое свойство - Frame3D, позволяющее получить более реалистичный вид нажатой кнопки. В отличие от API, при изменении значения свойства Frame3D, не требуется переоткрытие компонента.

Примечание. Кнопку по-прежнему рисует WINDOWS, а раскрашивает ее ColorBtn. Код компонента на 90% повторяет код BitBtn, ничего необычного здесь нет. Чаще заглядывайте в VCL - можно найти много интересного. На рисунке представлены ColorButton и ColorBitBtn.

unit colorbtn;

interface

uses

  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Buttons;

type

  TColorBtn = class(TButton)
  private
    FCanvas: TCanvas;
    IsFocused: Boolean;
    F3DFrame: boolean;
    FButtonColor: TColor;
    procedure Set3DFrame(Value: boolean);
    procedure SetButtonColor(Value: TColor);
    procedure CNDrawItem(var Message: TWMDrawItem); message CN_DRAWITEM;
    procedure WMLButtonDblClk(var Message: TWMLButtonDblClk); message
      WM_LBUTTONDBLCLK;
    procedure DrawButtonText(const Caption: string; TRC: TRect; State:
      TButtonState; BiDiFlags: Longint);
    procedure CalcuateTextPosition(const Caption: string; var TRC: TRect;
      BiDiFlags: Longint);
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    procedure SetButtonStyle(ADefault: Boolean); override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  published
    property ButtonColor: TColor read FButtonColor write SetButtonColor default
      clBtnFace;
    property Frame3D: boolean read F3DFrame write Set3DFrame default False;
  end;

procedure Register;

implementation

{ TColorBtn }

constructor TColorBtn.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Height := 21;
  FCanvas := TCanvas.Create;
  FButtonColor := clBtnFace;
  F3DFrame := False;
end;

destructor TColorBtn.Destroy;
begin
  FCanvas.Free;
  inherited Destroy;
end;

procedure TColorBtn.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  with Params do
    Style := Style or BS_OWNERDRAW;
end;

procedure TColorBtn.Set3DFrame(Value: boolean);
begin
  if F3DFrame <> Value then
    F3DFrame := Value;
end;

procedure TColorBtn.SetButtonColor(Value: TColor);
begin
  if FButtonColor <> Value then
  begin
    FButtonColor := Value;
    Invalidate;
  end;
end;

procedure TColorBtn.WMLButtonDblClk(var Message: TWMLButtonDblClk);
begin
  Perform(WM_LBUTTONDOWN, Message.Keys, Longint(Message.Pos));
end;

procedure TColorBtn.SetButtonStyle(ADefault: Boolean);
begin
  if IsFocused <> ADefault then
    IsFocused := ADefault;
end;

procedure TColorBtn.CNDrawItem(var Message: TWMDrawItem);
var
  RC: TRect;
  Flags: Longint;
  State: TButtonState;
  IsDown, IsDefault: Boolean;
  DrawItemStruct: TDrawItemStruct;
begin
  DrawItemStruct := Message.DrawItemStruct^;
  FCanvas.Handle := DrawItemStruct.HDC;
  RC := ClientRect;
  with DrawItemStruct do
  begin
    IsDown := ItemState and ODS_SELECTED <> 0;
    IsDefault := ItemState and ODS_FOCUS <> 0;
    if not Enabled then
      State := bsDisabled
    else if IsDown then
      State := bsDown
    else
      State := bsUp;
  end;
  Flags := DFCS_BUTTONPUSH or DFCS_ADJUSTRECT;
  if IsDown then
    Flags := Flags or DFCS_PUSHED;
  if DrawItemStruct.ItemState and ODS_DISABLED <> 0 then
    Flags := Flags or DFCS_INACTIVE;
  if IsFocused or IsDefault then
  begin
    FCanvas.Pen.Color := clWindowFrame;
    FCanvas.Pen.Width := 1;
    FCanvas.Brush.Style := bsClear;
    FCanvas.Rectangle(RC.Left, RC.Top, RC.Right, RC.Bottom);
    InflateRect(RC, -1, -1);
  end;
  if IsDown then
  begin
    FCanvas.Pen.Color := clBtnShadow;
    FCanvas.Pen.Width := 1;
    FCanvas.Rectangle(RC.Left, RC.Top, RC.Right, RC.Bottom);
    InflateRect(RC, -1, -1);
    if F3DFrame then
    begin
      FCanvas.Pen.Color := FButtonColor;
      FCanvas.Pen.Width := 1;
      DrawFrameControl(DrawItemStruct.HDC, RC, DFC_BUTTON, Flags);
    end;
  end
  else
    DrawFrameControl(DrawItemStruct.HDC, RC, DFC_BUTTON, Flags);
  FCanvas.Brush.Color := FButtonColor;
  FCanvas.FillRect(RC);
  InflateRect(RC, 1, 1);
  if IsFocused then
  begin
    RC := ClientRect;
    InflateRect(RC, -1, -1);
  end;
  FCanvas.Font := Self.Font;
  if IsDown then
    OffsetRect(RC, 1, 1);
  DrawButtonText(Caption, RC, State, 0);
  if IsFocused and IsDefault then
  begin
    RC := ClientRect;
    InflateRect(RC, -4, -4);
    FCanvas.Pen.Color := clWindowFrame;
    Windows.DrawFocusRect(FCanvas.Handle, RC);
  end;
  FCanvas.Handle := 0;
end;

procedure TColorBtn.CalcuateTextPosition(const Caption: string; var TRC: TRect;
  BiDiFlags: Integer);
var
  TB: TRect;
  TS, TP: TPoint;
begin
  with FCanvas do
  begin
    TB := Rect(0, 0, TRC.Right + TRC.Left, TRC.Top + TRC.Bottom);
    DrawText(Handle, PChar(Caption), Length(Caption), TB, DT_CALCRECT or
      BiDiFlags);
    TS := Point(TB.Right - TB.Left, TB.Bottom - TB.Top);
    TP.X := ((TRC.Right - TRC.Left) - TS.X + 1) div 2;
    TP.Y := ((TRC.Bottom - TRC.Top) - TS.Y + 1) div 2;
    OffsetRect(TB, TP.X + TRC.Left, TP.Y + TRC.Top);
    TRC := TB;
  end;
end;

procedure TColorBtn.DrawButtonText(const Caption: string; TRC: TRect; State:
  TButtonState; BiDiFlags: Integer);
begin
  with FCanvas do
  begin
    CalcuateTextPosition(Caption, TRC, BiDiFlags);
    Brush.Style := bsClear;
    if State = bsDisabled then
    begin
      OffsetRect(TRC, 1, 1);
      Font.Color := clBtnHighlight;
      DrawText(Handle, PChar(Caption), Length(Caption), TRC,
        DT_CENTER or DT_VCENTER or BiDiFlags);
      OffsetRect(TRC, -1, -1);
      Font.Color := clBtnShadow;
      DrawText(Handle, PChar(Caption), Length(Caption), TRC,
        DT_CENTER or DT_VCENTER or BiDiFlags);
    end
    else
      DrawText(Handle, PChar(Caption), Length(Caption), TRC,
        DT_CENTER or DT_VCENTER or BiDiFlags);
  end;
end;

procedure Register;
begin
  RegisterComponents('Controls', [TColorBtn]);
end;

end.

Небольшое дополнение. Кнопку по прежнему рисует WINDOWS, а раскрашивает ее ColorBtn. Код компонента на 90% повторяет код BitBtn, ничего необычного здесь нет. Хочется повторить слова Калверта – "Пользуйтесь исходным кодом". Чаще заглядывайте в VCL - можно найти много интересного.

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