WinAPI: SetTextAlign - 设置绘图环境的文本对齐方式

//声明:
SetTextAlign(
  DC: HDC;    {设备环境句柄}
  Flags: UINT {对齐选项}
): UINT;      {返回对齐选项值; 如果返回 GDI_ERROR 表示设置失败}

//Flags 参数的可选值:
TA_NOUPDATECP = 0;    {每一次文本输出后, 不更新当前位置}
TA_UPDATECP   = 1;    {每一次文本输出后, 更新当前位置}
TA_LEFT       = 0;    {起始于文本外接矩形左边}
TA_RIGHT      = 2;    {起始于文本外接矩形右边}
TA_CENTER     = 6;    {起始于文本外接矩形的水平中心}
TA_TOP        = 0;    {起始于文本外接矩形顶边}
TA_BOTTOM     = 8;    {起始于文本外接矩形底边}
TA_BASELINE   = 24;   {起始于文本基线}
TA_RTLREADING = $100; {文本顺序从右到左, 只对特殊语种}

VTA_BASELINE  = TA_BASELINE; {垂直基线}
VTA_LEFT      = TA_BOTTOM;
VTA_RIGHT     = TA_TOP;
VTA_CENTER    = TA_CENTER;   {垂直居中}
VTA_BOTTOM    = TA_RIGHT;
VTA_TOP       = TA_LEFT;


//举例:
unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    RadioGroup1: TRadioGroup;
    RadioGroup2: TRadioGroup;
    procedure FormPaint(Sender: TObject);
    procedure RadioGroup1Click(Sender: TObject);
    procedure RadioGroup2Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

var
  H: Cardinal = 0;
  V: Cardinal = 0;

procedure TForm1.FormPaint(Sender: TObject);
var
  dc: HDC;
  x,y: Integer;
const
  str = '万一的 Delphi 博客';
begin
  dc := Canvas.Handle;
  x := ClientWidth div 2;
  y := ClientHeight div 2;

  SetTextAlign(dc, H or V);
  TextOut(dc, x, y, str, Length(str));
end;

procedure TForm1.RadioGroup1Click(Sender: TObject);
begin
  case RadioGroup1.ItemIndex of
    0: H := TA_LEFT;
    1: H := TA_CENTER;
    2: H := TA_RIGHT;
  end;
  Self.Repaint;
end;

procedure TForm1.RadioGroup2Click(Sender: TObject);
begin
  case RadioGroup2.ItemIndex of
    0: V := TA_TOP;
    1: V := VTA_CENTER;
    2: V := TA_BOTTOM;
  end;
  Self.Repaint;
end;

end.



//效果图:

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