WinAPI: DrawText - 将文本绘制到指定的矩形中

//声明:

DrawText(

  hDC: HDC;          {设备句柄}

  lpString: PChar;   {文本}

  nCount: Integer;   {要绘制的字符个数; -1 表示全部}

  var lpRect: TRect; {矩形结构}

  uFormat: UINT      {选项}

): Integer;          {返回文本高度}



//uFormat 参数的可选值:

DT_TOP             = 0;         {顶对齐, 须 or DT_SINGLELINE}

DT_LEFT            = 0;         {左对齐}

DT_CENTER          = 1;         {水平居中}

DT_RIGHT           = 2;         {右对齐}

DT_VCENTER         = 4;         {垂直居中, 须 or DT_SINGLELINE}

DT_BOTTOM          = 8;         {底对齐, 须 or DT_SINGLELINE}

DT_WORDBREAK       = $10;       {给超出边界的单词换行; 如果 SetTextAlign 函数设置了 TA_UPDATECP, 这里的设置无效}

DT_SINGLELINE      = $20;       {单行文本}

DT_EXPANDTABS      = $40;       {扩展制表符, 默认制表跨 8 个字符}

DT_TABSTOP         = $80;       {TAB 后添加的字符数}

DT_NOCLIP          = $100;      {使文本不限制在指定的矩形内}

DT_EXTERNALLEADING = $200;      {返回的高度包括字体的外部行距}

DT_CALCRECT        = $400;      {自动检测容纳文本的矩形的高度和宽度, 并返回高度, 但文本不被绘制}

DT_NOPREFIX        = $800;      {不处理前缀字符(&); 默认时, & 后的字符会被添加下划线}

DT_INTERNAL        = $1000;     {用系统字体来计算文本高度}

DT_HIDEPREFIX      = $00100000; {隐藏下划线}

DT_PREFIXONLY      = $00200000; {将 & 解释为前缀}


 
   




//举例:

procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;

  Shift: TShiftState; X, Y: Integer);

var

  MyRect: TRect;

const

  str = '万一的 Delphi 博客';

begin

  MyRect.Left   := X;

  MyRect.Top    := Y;

  MyRect.Right  := X + 100;

  MyRect.Bottom := Y + 100;



  DrawText(Canvas.Handle, str, -1, MyRect, DT_LEFT);

end;


 
   




//效果图:

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