WinAPI: DrawTextEx - 多功能文本绘制

//声明:

DrawTextEx(

  DC: HDC;                  {设备句柄}

  lpchText: PChar;          {文本}

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

  var p4: TRect;            {矩形结构}

  dwDTFormat: UINT;         {选项}

  DTParams: PDrawTextParams {附加参数, 指向一个 DRAWTEXTPARAMS 结构}

): Integer;                 {返回文本高度}



//dwDTFormat 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}

DT_EDITCONTROL     = $2000;     {如果最后一行只是部分可见, 将不被绘制}

DT_PATH_ELLIPSIS   = $4000;     {文本过长时, 中间使用 ... 会尽量保留最后一个 \ 后面的字符}

DT_END_ELLIPSIS    = $8000;     {文本过长时, 尾部使用 ...}

DT_MODIFYSTRING    = $10000;    {省略显示, 只与 DT_PATH_ELLIPSIS、DT_END_ELLIPSIS 联合使用}

DT_RTLREADING      = $20000;    {从右到左绘制文本, 只用于相应语种}

DT_WORD_ELLIPSIS   = $40000;    {截短不符合矩形的正文, 并增加椭圆}



//DRAWTEXTPARAMS 结构是 tagDRAWTEXTPARAMS 的重定义:

tagDRAWTEXTPARAMS = packed record

  cbSize: UINT;          {结构大小}

  iTabLength: Integer;   {TAB 占位大小, 以字符平均宽度为单位}

  iLeftMargin: Integer;  {左边距, 以字符平均宽度为单位}

  iRightMargin: Integer; {右边距, 以字符平均宽度为单位}

  uiLengthDrawn: UINT;   {返回 DrawTextEx 函数绘制的字符个数, 包括空格}

end;


 
   




//例1:

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

  Shift: TShiftState; X, Y: Integer);

var

  MyRect: TRect;

  str: string;

begin

  MyRect.Left   := X;

  MyRect.Top    := Y;

  MyRect.Right  := X + 200;

  MyRect.Bottom := Y + 200;



  str := Application.ExeName;



  DrawTextEx(

    Canvas.Handle,

    PChar(str),

    -1,

    MyRect,

    DT_MODIFYSTRING or DT_END_ELLIPSIS,

    nil

  );

end;


 
   




//效果图:

---

//例2:

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

  Shift: TShiftState; X, Y: Integer);

var

  MyRect: TRect;

  str: string;

begin

  MyRect.Left   := X;

  MyRect.Top    := Y;

  MyRect.Right  := X + 200;

  MyRect.Bottom := Y + 200;



  str := Application.ExeName;



  DrawTextEx(

    Canvas.Handle,

    PChar(str),

    -1,

    MyRect,

    DT_MODIFYSTRING or DT_PATH_ELLIPSIS,

    nil

  );

end;


 
   




//效果图:

---