Mega Code Archive
Change a TButtons Color
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Title: change a TButton's Color ?
{
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.
Die Farbe eines Standard TButtons kann nicht ver ndert werden, sie
ist abh ngig von den Systemeinstellungen.
Durch Ableiten des TButtons kann der Button aber Farbe annehmen.
}
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.
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