Delphi的繪圖功能[9] - TextRect

//第一種重載的聲明:
TextRect(
  Rect: TRect;       {矩形}
  X, Y: Integer;     

{相對於窗體的位置}
  const Text: string {文本}
);
{如果要輸出的文本超出指定的矩形將

不被顯示}
------------------------------------------------------------------------------

--
//第一種重載的舉例:
procedure TForm1.Button1Click(Sender: TObject);
const
  

R: TRect = (Left:0; Top:0; Right:60; Bottom:60);
  s = '萬一的 Delphi 博客';
begin
 

 Canvas.Brush.Color := clWhite;
  Canvas.FillRect(R);
  Canvas.TextRect(R, 10, 10, 

s);
end;

//效果圖:

//第二種重載的聲明:
TextRect(
  var Rect: TRect;             {矩形范圍}
 

 var Text: string;            {文本}
  TextFormat: TTextFormat = [] {選項; 集合類型, 默認

值是個空的集合}
);
{參數三是 TTextFormat 類型的集合, 它定義如下:}
TTextFormat = set 

of TTextFormats;
{TTextFormats 是個枚舉, 定義如下}
TTextFormats = (tfBottom, 

tfCalcRect, tfCenter, tfEditControl, tfEndEllipsis,
  tfPathEllipsis, tfExpandTabs, 

tfExternalLeading, tfLeft, tfModifyString,
  tfNoClip, tfNoPrefix, tfRight, tfRtlReading, 

tfSingleLine, tfTop,
  tfVerticalCenter, tfWordBreak);
{所以參數三可以是下列值之一或它

們的組合}
tfBottom          


tfCalcRect
tfCenter
tfEditControl
tfEndEllipsis
tfPathEllipsis
tfExpandTa

bs
tfExternalLeading
tfLeft
tfModifyString
tfNoClip
tfNoPrefix
tfRight


tfRtlReading
tfSingleLine
tfTop
tfVerticalCenter
tfWordBreak
//這個函數是 API 

函數 DrawTextEx 的簡化, 可以參見: DrawTextEx
-------------------------------------------

-------------------------------------
//第二種重載的舉例1:
{默認是頂對齊、左對齊; 前兩

個參數都是傳址的, 不能用常量}
procedure TForm1.FormPaint(Sender: TObject);
var
  R: 

TRect;
  S: string;
begin
  R := ClientRect;
  InflateRect(R,-10,-10); {把矩形縮

小一圈}
  S := 'Delphi';
  Canvas.Brush.Color := clWhite;
  Canvas.FillRect(R);
 

 Canvas.TextRect(R, S);
end;

//效果圖:

//第二種重載的舉例2:
{單行文本、水平居中、垂直居中}
procedure 

TForm1.FormPaint(Sender: TObject);
var
  R: TRect;
  S: string;
begin
  R := 

ClientRect;
  InflateRect(R,-10,-10); {把矩形縮小一圈}
  S := 'Delphi';
  

Canvas.Brush.Color := clWhite;
  Canvas.FillRect(R);
  Canvas.TextRect(R, S , 

[tfSingleLine, tfCenter, tfVerticalCenter]);
end;

//效果圖: