将 LTR 转换为 RTL？

Question

你知道很多 ui 组件和开发工具不支持 rtl ，我们可以称之为 flipping text ，因为结果是相同的例子：

LTR

سلام salam متن راهنما word

RTL

word متن راهنما salam  سلام

无论如何要将此 LTR 转换为 RTL，我没有任何想法，语言无关紧要

实际上，我正在寻找一种解决方案来在 RAD Studio Firemonkey Application 中完成这项工作，因为您可能知道 firemonkey 应用程序不支持 rtl，它在 rad studio 的路线图中但尚未实施

Answer 1

如果您使用MFC，这里是如何设置翻正方向和对齐方式。假设您的 CEdit 控件名为 m_TextEdit：

void MyDialog::SetLangDirection(bool RTL)
{
    DWORD w_dwStyle;

    w_dwStyle = GetWindowLong(m_TextEdit.GetSafeHwnd(), GWL_EXSTYLE);

    if (RTL)
    {
        w_dwStyle -= WS_EX_LEFT | WS_EX_LTRREADING;
        w_dwStyle |= WS_EX_RIGHT | WS_EX_RTLREADING;
    }
    else
    {
        w_dwStyle -= WS_EX_RIGHT | WS_EX_RTLREADING;
        w_dwStyle |= WS_EX_LEFT | WS_EX_LTRREADING;
    }

    SetWindowLong(m_TextEdit.GetSafeHwnd(), GWL_EXSTYLE, w_dwStyle);
}

见my tip。

Answer 2

在 Windows 下，您可以通过 UniScribe API 来实现。

我已经使用它来将 Unicode 文本转换为一组字形，用于我们的 Open Source PDF writer。

您有SynPdf.pas 单元中的源代码示例。见TPdfWrite.AddUnicodeHexTextUniScribe方法：

function TPdfWrite.AddUnicodeHexTextUniScribe(PW: PWideChar;
  WinAnsiTTF: TPdfFontTrueType; NextLine: boolean; Canvas: TPdfCanvas): boolean;
var L, i,j: integer;
    res: HRESULT;
    max, count, numSp: integer;
    Sp: PScriptPropertiesArray;
    W: PWideChar;
    items: array of TScriptItem;
    level: array of byte;
    VisualToLogical: array of integer;
    psc: pointer; // opaque Uniscribe font metric cache
    complex,R2L: boolean;
    complexs: array of byte;
    glyphs: array of TScriptVisAttr;
    glyphsCount: integer;
    OutGlyphs, LogClust: array of word;
procedure Append(i: Integer);
// local procedure used to add glyphs from items[i] to the PDF content stream
var L: integer;
    W: PWideChar;
procedure DefaultAppend;
var tmpU: array of WideChar;
begin
  SetLength(tmpU,L+1); // we need the text to be ending with #0
  move(W^,tmpU[0],L*2);
  AddUnicodeHexTextNoUniScribe(pointer(tmpU),WinAnsiTTF,false,Canvas);
end;
begin
  L := items[i+1].iCharPos-items[i].iCharPos; // length of this shapeable item
  if L=0 then
    exit; // nothing to append
  W := PW+items[i].iCharPos;
  if not GetBit(complexs[0],i) then begin
    // not complex items are rendered as fast as possible
    DefaultAppend;
    exit;
  end;
  res := ScriptShape(0,psc,W,L,max,@items[i].a,
    pointer(OutGlyphs),pointer(LogClust),pointer(glyphs),glyphsCount);
  case res of
    E_OUTOFMEMORY: begin // max was not big enough (should never happen)
      DefaultAppend;
      exit;
    end;
    E_PENDING, USP_E_SCRIPT_NOT_IN_FONT: begin // need HDC and a selected font object
      res := ScriptShape(Canvas.FDoc.GetDCWithFont(WinAnsiTTF),
        psc,W,L,max,@items[i].a,
        pointer(OutGlyphs),pointer(LogClust),pointer(glyphs),glyphsCount);
      if res<>0 then begin // we won't change font if necessary, sorry
        // we shall implement the complex technic as stated by
        // http://msdn.microsoft.com/en-us/library/dd374105(v=VS.85).aspx
        DefaultAppend;
        exit;
      end;
    end;
    0: ; // success -> will add glyphs just below
    else exit;
  end;
  // add glyphs to the PDF content
  // (NextLine has already been handled: not needed here)
  AddGlyphs(pointer(OutGlyphs),glyphsCount,Canvas);
end;
begin
  result := false; // on UniScribe error, handle as Unicode
  // 1. Breaks a Unicode string into individually shapeable items
  L := StrLenW(PW)+1; // include last #0
  max := L+2; // should be big enough
  SetLength(items,max);
  count := 0;
  if ScriptItemize(PW,L,max,nil,nil,pointer(items),count)<>0 then
    exit; // error trying processing Glyph Shaping -> fast return
  // 2. guess if requiring glyph shaping or layout
  SetLength(complexs,(count shr 3)+1);
  ScriptGetProperties(sP,numSp);
  complex := false;
  R2L := false;
  for i := 0 to Count-2 do // don't need Count-1 = Terminator
    if fComplex in sP^[items[i].a.eScript and (1 shl 10-1)]^.fFlags then begin
      complex := true;
      SetBit(complexs[0],i);
    end else
      if fRTL in items[i].a.fFlags then
        R2L := true;
  if not complex then begin
    // no glyph shaping -> fast append as normal Unicode Text
    if R2L then begin
      // handle Right To Left but not Complex text
      W := pointer(items); // there is enough temp space in items[]
      W[L] := #0;
      dec(L);
      for i := 0 to L do
        W[i] := PW[L-i];
      AddUnicodeHexTextNoUniScribe(W,WinAnsiTTF,NextLine,Canvas);
      result := true; // mark handled here
    end;
    exit;
  end;
  // 3. get Visual Order, i.e. how to render the content from left to right
  SetLength(level,count);
  for i := 0 to Count-1 do
    level[i] := items[i].a.s.uBidiLevel;
  SetLength(VisualToLogical,count);
  if ScriptLayout(Count,pointer(level),pointer(VisualToLogical),nil)<>0 then
    exit;
  // 4. now we have enough information to start drawing
  result := true;
  if NextLine then
    Canvas.MoveToNextLine; // manual NextLine handling
  // 5. add glyphs for all shapeable items
  max := (L*3)shr 1+32; // should be big enough - allocate only once
  SetLength(glyphs,max);
  SetLength(OutGlyphs,max);
  SetLength(LogClust,max);
  psc := nil; // cached for the same character style used
  if Canvas.RightToLeftText then
    // append from right to left visual order
    for j := Count-2 downto 0 do // Count-2: ignore last ending item
      Append(VisualToLogical[j]) else
    // append from left to right visual order
    for j := 0 to Count-2 do // Count-2: ignore last ending item
      Append(VisualToLogical[j]);
end;

当然，这仅适用于 Windows。所以它不能在 Mac OS X 上运行。你必须在 Mac OS X 下使用另一个库...

Answer 3

这很复杂。如果你想正确地做到这一点，你必须使用International Components for Unicode中的Bidi Library。