Identifier not found
lazarus / 5-Lazarus Extra Components

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Nusya · 2008-09-12 11:46

There is code allows to change color at the button.
The code has been written under Delphi 7.
Lazarus swears on TWMDrawItem and writes " Error: Identifier not found
"TWMDrawItem"
". And not only.
Help.

Code: [Select]unit ColorBtn;

{$MODE Delphi}

interface

uses
  LCLIntf, Messages, SysUtils, Classes, Graphics, Controls, Forms,
Dialogs,
  StdCtrls;

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('Standard', [TColorBtn]);
end;

end.

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Leledumbo · 2008-09-15 04:07

Have you read Code Conversion Guide? There's a note regarding windows
messages there.