Цветная кнопка

Небольшой компонент ColorBtn дает возможность создавать цветные кнопки. 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.

unit ColorBtn;
interface

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

type
  TColorBtn = class(TButton)
  private
    IsFocused: boolean;
    FCanvas: TCanvas;
    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);
  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;
  if IsDown then OffsetRect(RC, 1, 1);
  FCanvas.Font := Self.Font;
  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.

Примечание
Кнопку по-прежнему рисует Windows, а раскрашивает ее компонент ColorBtn.