我希望在Canvas上Draw光暈效果文字(Halo Text, 見附圖), 請問該如何繪製呢.

Halo 效果說明:
在文字筆畫的邊上套上一個像素寬度的白邊.
也即每一個文字像素點(黑色)的周圍有八個像素點, 如果不屬於文字像素點, 則要作爲光暈點而繪爲白色. (不知道描述明白沒有, 也許看樣圖更明白

------
------------------------
博采眾家之長,奉獻綿薄之力
------------------------

附加檔案：471f5def420d1_HaloText.PNG

[code delphi]

procedure TForm1.FormCreate(Sender: TObject);
begin
Color := clNavy;
end;

procedure TForm1.FormPaint(Sender: TObject);
const
S = '泰安產物保險公司';
var
I, TW, TH: Integer;
R: TRect;
begin
Canvas.Font.Name := '標楷體';
Canvas.Font.Height := 36;
Canvas.Font.Color := clWhite;
Canvas.Font.Style := [];
Canvas.Brush.Color := clWhite;
Canvas.Brush.Style := bsClear;
TW := Canvas.TextWidth(S);
TH := Canvas.TextHeight(S);
R := Rect(0, 0, TW, TH);
OffsetRect(R, 10, 10);
for I := 0 to 8 do
begin
case I of
0: OffsetRect(R, -1, -1);
1: OffsetRect(R, 1, 0);
2: OffsetRect(R, 1, 0);
3: OffsetRect(R, 0, 1);
4: OffsetRect(R, 0, 1);
5: OffsetRect(R, -1, 0);
6: OffsetRect(R, -1, 0);
7: OffsetRect(R, 0, -1);
8:begin
Canvas.Font.Color := clRed;
OffsetRect(R, 1, 0);
end;
end;
DrawText(Canvas.Handle, S, Length(S), R, DT_CENTER or DT_SINGLELINE);
end;

end;
[/code]

編輯記錄

借用JOW前輩的程式改成BCB版

[code cpp]
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
Color = clNavy;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::FormPaint(TObject *Sender)
{
const String S = "泰安產物保險公司";
int I, TW, TH;
TRect R;
Canvas->Font->Name = "標楷體";
Canvas->Font->Height = 36;
Canvas->Font->Color = clWhite;
Canvas->Brush->Color = clWhite;
Canvas->Brush->Style = bsClear;
TW = Canvas->TextWidth(S);
TH = Canvas->TextHeight(S);
R = Rect(0, 0, TW, TH);
OffsetRect(R, 10, 10);
for (I=0; I<=8; I )
{
switch (I)
{
case 0: OffsetRect(R, -1, -1); break;
case 1: OffsetRect(R, 1, 0); break;
case 2: OffsetRect(R, 1, 0); break;
case 3: OffsetRect(R, 0, 1); break;
case 4: OffsetRect(R, 0, 1); break;
case 5: OffsetRect(R, -1, 0); break;
case 6: OffsetRect(R, -1, 0); break;
case 7: OffsetRect(R, 0, -1); break;
case 8:
{
Canvas->Font->Color = clRed;
OffsetRect(R, 1, 0);
}
}
DrawText(Canvas->Handle, S.c_str(), S.Length(), &R , DT_CENTER | DT_SINGLELINE);
}
}
[/code]