透明Panel：
unit TranPanel;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ExtCtrls;
type
TGlassStyle = (
gsBlackness, gsDstInvert, gsMergeCopy, gsMergePaint, gsNotSrcCopy,
gsNotSrcErase, gsPatCopy, gsPatInvert, gsPatPaint, gsSrcAnd,
gsSrcCopy, gsSrcErase, gsSrcInvert, gsSrcPaint, gsWhiteness);
TGlass = class(TCustomControl)
private
FColor: TColor;
FStyle: TGlassStyle;
FOnPaint: TNotifyEvent;
procedure SetColor(Value: TColor);
procedure SetStyle(Value: TGlassStyle);
procedure CMCtl3DChanged(var Message: TMessage);
message CM_CTL3DCHANGED;
procedure WMEraseBkgnd(var Message: TMessage);
message WM_ERASEBKGND;
procedure WMWindowPosChanging(var Message: TWMWindowPosChanging);
message WM_WINDOWPOSCHANGING;
protected
Buffer: TBitmap;
procedure CreateParams(var Params: TCreateParams);
override;
procedure Paint;
override;
procedure Resize;
override;
public
constructor Create(AOwner: TComponent);
override;
destructor Destroy;
override;
property Canvas;
published
property Align;
property Anchors;
property AutoSize;
property BiDiMode;
property BorderWidth;
property Color: TColor read FColor write SetColor;
property Ctl3D;
property Enabled;
property Style: TGlassStyle read FStyle write SetStyle default gsSrcAnd;
property Visible;
property OnClick;
property OnDblClick;
property OnEnter;
property OnExit;
property OnMouseDown;
property OnMouseMove;
property OnMouseUp;
property OnResize;
property OnPaint: TNotifyEvent read FOnPaint write FOnPaint;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('Samples', [TGlass]);
end;
function GlassStyleToInt(gs: TGlassStyle): LongInt;
begin
case gs of
gsBlackness : Result := cmBlackness;
gsDstInvert : Result := cmDstInvert;
gsMergeCopy : Result := cmMergeCopy;
gsMergePaint : Result := cmMergePaint;
gsNotSrcCopy : Result := cmNotSrcCopy;
gsNotSrcErase: Result := cmNotSrcErase;
gsPatCopy : Result := cmPatCopy;
gsPatInvert : Result := cmPatInvert;
gsPatPaint : Result := cmPatPaint;
gsSrcAnd : Result := cmSrcAnd;
gsSrcCopy : Result := cmSrcCopy;
gsSrcErase : Result := cmSrcErase;
gsSrcInvert : Result := cmSrcInvert;
gsSrcPaint : Result := cmSrcPaint;
gsWhiteness : Result := cmWhiteness;
else
Assert(True, 'Error parameter in function GlassStyleToInt');
end;
end;
constructor TGlass.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
Buffer := TBitmap.Create;
ControlStyle := [csAcceptsControls, csCaptureMouse, csClickEvents,
csDoubleClicks, csReplicatable];
Width := 100;
Height := 100;
FStyle := gsSrcAnd;
ParentCtl3d := False;
Ctl3D := False;
ParentColor := False;
FColor := clWhite;
end;
destructor TGlass.Destroy;
begin
Buffer.Free;
inherited Destroy;
end;
procedure TGlass.Paint;
var
R: TRect;
rop: LongInt;
begin
R := Rect(0, 0, Width, Height);
Buffer.Width := Width;
Buffer.Height := Height;
Buffer.Canvas.Brush.Style := bsSolid;
Buffer.Canvas.Brush.Color := FColor;
Buffer.Canvas.FillRect(Rect(0, 0, Width, Height));
rop := GlassStyleToInt(FStyle);
StretchBlt(Buffer.Canvas.Handle, 0, 0, Width, Height,
Canvas.Handle, 0, 0, Width, Height, rop);
if Ctl3D then
DrawEdge(Buffer.Canvas.Handle, R, BDR_RAISEDINNER, BF_RECT);
Buffer.Canvas.Pen.Mode := pmCopy;
Buffer.Canvas.Pen.Style := psSolid;
Canvas.Draw(0, 0, Buffer);
if Assigned(FOnPaint) then
FOnPaint(Self);
end;
procedure TGlass.SetColor(Value: TColor);
begin
if Value <> FColor then
begin
FColor := Value;
RecreateWnd;
end;
end;
procedure TGlass.CreateParams(var Params: TCreateParams);
begin
inherited CreateParams(Params);
Params.ExStyle := Params.ExStyle + WS_EX_TRANSPARENT;
end;
procedure TGlass.WMWindowPosChanging(var Message: TWMWindowPosChanging);
begin
Invalidate;
inherited;
end;
procedure TGlass.WMEraseBkgnd(var Message: TMessage);
begin
Message.Result := 0;
end;
procedure TGlass.Resize;
begin
Invalidate;
inherited;
end;
procedure TGlass.CMCtl3DChanged(var Message: TMessage);
begin
inherited;
RecreateWnd;
end;
procedure TGlass.SetStyle(Value: TGlassStyle);
begin
if Value <> FStyle then
begin
FStyle := Value;
RecreateWnd;
end;
end;
end.
