Mega Code Archive
How to change a TButtons Color
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Title: How to change a TButtons Color
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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