我想让panel半透明并且让panel可以在边上时自动隐藏，高手请指点。

tianwailiuxingy 2009-12-11 04:37:35

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yjkn 2011-08-17

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帮顶的

SAMLLY 2011-08-10

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Ding

king_shadow 2010-01-13

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看不到内容？

yymao2005 2010-01-09

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[Quote=引用 2 楼 delphi_freeman 的回复:]
panel 放在form里，让form隐藏不就ok了。
[/Quote]

如果form 透明是用CustomForm实现的，那么隐藏form，上面的panel是不会一同隐藏的。

hjkto 2009-12-11

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哎，没看明白怎么用呀？

mdejtod 2009-12-11

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继承tcustompanel控件重写一个，覆盖paint 事件
再作处理
var FAlphaValue : byte; //0-255

procedure Paint(); override;
procedure TTransParentPanel.Paint;
var FRect : windows.TRect;
Buf : TBitmap;
uDrawTextFlag : Integer;
begin
Buf := TBitmap.Create();
Buf.Width := Width;
Buf.Height := Height;
Buf.Canvas.Brush.Color := Color;
buf.Canvas.FillRect(Buf.Canvas.ClipRect);
DoTrans(Buf.Canvas,Self);//获取背景图
DrawAlpha(Buf); //将背景图与控件颜色用FAlphaValue进行混合透明
Buf.Canvas.Brush.Style := bsClear;

if Trim(Caption) <> '' then
begin
Buf.Canvas.Font := Font;

if (FCaptionPosX <> -1) and (FCaptionPosY <> -1) then
begin
Buf.Canvas.TextOut(FCaptionPosX, FCaptionPosY, Caption);
FLastDrawCaptionRect := Classes.Rect(
FCaptionPosX,
FCaptionPosY,
FCaptionPosX + Buf.Canvas.TextWidth(Caption),
FCaptionPosY + Buf.Canvas.TextWidth(Caption)
);
end
else
begin
FRect := ClientRect;
uDrawTextFlag := DT_CENTER;
if Alignment = taRightJustify then
uDrawTextFlag := DT_RIGHT
else if Alignment = taLeftJustify then
uDrawTextFlag := DT_LEFT;
DrawText(Buf.Canvas.Handle, PChar(Caption), -1, FRect, uDrawTextFlag or DT_SINGLELINE or DT_VCENTER);
FLastDrawCaptionRect := FRect;
end;
end;
BitBlt(Canvas.Handle, 0, 0, Width, Height, Buf.Canvas.Handle, 0, 0, SRCCOPY);
Buf.Free();
end;
procedure TTransParentPanel.DoTrans(FCanvas: TCanvas;FContorl : TWincontrol);
var DC : Hdc;SaveIndex :HDC; Position : Tpoint;
begin
if FContorl.Parent <> nil then
begin
{$R-}
Dc := FCanvas.Handle;
SaveIndex := SaveDc(Dc);
GetViewPortOrgEx(Dc,Position);
SetViewPortOrgEx(Dc,Position.X - FContorl.Left,Position.Y - FContorl.Top,nil);
IntersectClipRect(Dc,0,0,FContorl.parent.clientwidth,FContorl.parent.clientheight);
FContorl.Parent.perform(WM_ERASEBKGND,Dc,0);
FContorl.Parent.Perform(WM_PAINT,DC,0);
RestoreDC(Dc,SaveIndex);
{$R+}
end;
end;

procedure TTransParentPanel.DrawAlpha(var dBmp : TBitmap);
var i,j ,FCurX,aW,aH: Integer;
PD : PByteArray;
R,G,B : Byte;
begin
dBmp.Canvas.Lock;
R := GetRValue(DWORD(Color));//控件颜色
G := GetGValue(DWORD(Color));
B := GetBValue(DWORD(Color));
aH := dBmp.Height;
aW := dBmp.Width;
for i := 0 to aH - 1 do
begin
PD := dBmp.ScanLine[i];
for j := 0 to aW - 1 do
begin
try
FCurX := j *3;
PD[FCurX] := (PD[FCurX] * ( 255 - FAlphaValue) + B * FAlphaValue) shr 8;
PD[FCurX + 1] := (PD[FCurX + 1] * ( 255 - FAlphaValue) + G * FAlphaValue) shr 8;
PD[FCurX + 2] := (PD[FCurX + 2] * ( 255 - FAlphaValue) + R * FAlphaValue) shr 8;
except
Continue;
end;
end;
end;
dBmp.Canvas.Unlock;
end;
自动隐藏只要判断控件的位置是否在一个设定的范围内就隐藏掉就可以了

hjkto 2009-12-11

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mark

无条件为你 2009-12-11

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顶一下。

yumenyoudian 2009-12-11

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半透明可以重载Panel的WM_Paint消息：
procedure TPanel.WMPaint(var: TMessage); message WM_Paint;
procedure AlphaBlendTabControl;
var
MemBitmap, OldBitmap: HBITMAP;
BF: BLENDFUNCTION;
MemDC, DC: HDC;
begin
if (Parent = nil) or not Parent.HandleAllocated then
Exit;
DC := GetDC(0);
MemBitmap := CreateCompatibleBitmap(DC, Parent.Width, Parent.Height);
ReleaseDC(0, DC);
MemDC := CreateCompatibleDC(0);
OldBitmap := SelectObject(MemDC, MemBitmap);
try
Parent.Perform(WM_ERASEBKGND, MemDC, MemDC);
Parent.Perform(WM_PAINT, MemDC, 0);

BF.SourceConstantAlpha := 100;
BF.AlphaFormat := 0;
BF.BlendOp := AC_SRC_OVER;
BF.BlendFlags := 0;
Windows.AlphaBlend(Canvas.Handle, 0, 0, Width, Height, MemDC, Left, Top, Width, Height, BF);
finally
SelectObject(MemDC, OldBitmap);
DeleteDC(MemDC);
DeleteObject(MemBitmap);
end;
end;
begin
inherited;
AlphaBlendTabControl;
end;
至于自动应藏可以在WM_WINDOWPOSCHANGED消息里面处理