Is BiDiMode detected when a right to left language is used?

[Windsurfer]

I am learning how to use multiple languages in a small application, using the DefaultTranslations unit (thanks #wp) and have now reached BidiMode.

Is bidiMode automatically detected when the default language is changed, or must the programmer find a way to test for it?

If the latter case, I guess the obvious place is to include the information in the .po file header.

[Avishai]

Welcome to my world

This is what I use.  I hope it helps.

Code: [Select]

const
  AR_XX: LongWord = $0401;  //Arabic
  FA_XX: LongWord = $0429;  //Farsi
  HE_IL: LongWord = $040D;  //Hebrew
  UR_XX: LongWord = $0420;  //Urdu

function R2Llang(Lang: Integer): Boolean;
begin
  Result:= False;
  if (Lang=AR_XX)or(Lang=FA_XX)or(Lang=HE_IL)or(Lang=UR_XX) then
    Result:= True;
end;

I know there are other R2L languages but I don't know which ones.  Hopefully someone can add to the list.

Someplace in Lazarus code there is a routine to test for R2L but I don't use it and can't find it right now.  If I do find it, I'll let you know.

Edit: I just found it.  Look for 'function TApplication.IsRTLLang(ALang: String): Boolean;' in Application.inc

[Avishai]

Windsurfer, I think I should warn you about BiDiMode with Lazarus.  On MSWindows platform Lazarus does not truly support RightToLeft.  What *should* happen is that TForm would be Mirrored so that the 'Close/Restore/Minimize' buttons are on the Left and the Icon/Caption are on the Right.  Also the TForm.Canvas *should* be mirrored so that painting is from RightToLeft. 

Also, most controls can not draw themselves RightToLeft.  There's more to RightToLeft than just the Text.  TPageControl is a good example.

[Windsurfer]

Thanks Avishai,

My application has some stringgrids and a bitmap that plots a seres of GPS points. It will be interesting to see what happens.

[Avishai]

It sounds like you may be in luck.  TStringGrid is one of the few Lazarus components that does a very good job with BiDiMode.  There's a tiny problem with the cell editor but it isn't so bad that you can't use it.

[Windsurfer]

It also has a few statements like:

StringGrid1.Cells[1, I] := Formatdatetime('yyyy/mm/dd hh:mm:ss', aySpeed[I - 1].Datetime);

I have not created resource strings for the formatting string, to ensure the data is handled properly.

Do I need to change the order of the date display?

[Avishai]

Yes there are a few things with Dates.  You may need some of this code, maybe not.  But this is ONLY for MSWindows.  I'm afraid I can't help you with any other OS.

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procedure FixHebShortDayNames; 
// This is only good for Hebrew
var
  HebShortDayNames: TWeekNameArray = ('א','ב','ג','ד','ה','ו','ש');
begin
  if SysLocale.DefaultLCID = HE_IL then
    ShortDayNames:= HebShortDayNames;
end;

function GetLongMonthNames(I: Integer): String;
begin
  Result:= AnsiToUTF8(FormatSettings.LongMonthNames[I]);
end;

function GetShortMonthNames(I: Integer): String;
begin
  Result:= AnsiToUTF8(FormatSettings.ShortMonthNames[I]);
end;

function GetLongDayNames(I: Integer): String;
begin
  Result:= AnsiToUTF8(FormatSettings.LongDayNames[I]);
end;

function GetShortDayNames(I: Integer): String;
begin
  Result:= AnsiToUTF8(FormatSettings.ShortDayNames[I]);
end;

function GetCurrencyString: String;
begin
  Result:= AnsiToUTF8(CurrencyString);
end;

function GetHebLongDate(ADate: TDate): String;
begin
  Result:= IntToStr(DayOf(ADate))+AnsiToUTF8(' ב')+
    AnsiToUTF8(FormatDateTime('MMMM, YYYY',ADate));
end;

Edit:  Oops.  I just noticed that GetHebLongDate is only for Hebrew as well.

[wp]

No need to hard-code formatstrings. You can use the LCID to find the correct formatsettings:

Code: [Select]

  GetLocaleFormatSettings(LCID_code, DefaultFormatSettings);

No idea, though, how to do this in Linux. There is another problem even in Windows that I don't know how to relate the LCID with the language code as used by Lazarus ('de', 'en', etc.).

Therefore, I modified the DefaultTranslator unit to build up a language list for getting access to all the necessary information. Essentially, you just add this unit to your uses list and call the procedure "SetLanguage" to set the language according to your wishes; it also sets the DefaultFormatSettings as needed. SetLanguage can also be used in code writing to a configuration file to store the selected language. The "opposite" of Setlanguage is GetLanguage to be called when reading the config file.

Additionally, you can use "PopulateLanguageStrings" to populate a stringlist for a combobox, listbox etc. with all the translations available.  Use "GetLangIDOfListIndex" to convert the ItemIndex of the combobox to the language abbrevation of the selected language, or "GetListIndexOfLang" to find the index of a given language for selecting it in the combo-/listbox.

I hope that everything works out; the unit is used in a larger project of mine, and I am not sure if it works separately. Also be warned - my description may not be correct here and there. So: no warranty...

One thing that you may have to change is the last (optional) parameter of "RegisterLanguage" as it is called by "CreateLanguages": this is the index to an image list containing the flag images for each language. Free icons can be found at http://www.famfamfam.com/lab/icons/flags/.

[Avishai]

This is another MSWindows ONLY routine you might need for setting the Keyboard Language.

Code: [Select]

function GetKBD: Word;
begin
  Result:= GetKeyboardLayout(0);
End;

function SetKBD(LangID: HKL): Word;
begin
  if not(ActivateKeyboardLayout(LangID, $1)) then
    LoadKeyboardLayoutA(PChar(IntToHex(LangID,$1)),KLF_ACTIVATE);
  Result:= GetKBD;
end;


[Windsurfer]

Thanks for the help. It will keep me quiet for a while, as I absorb it.

wp I submitted the attachment into the Bugtracker today, for inclusion as an example. It does not include BidiMode. I removed an arabic translation because it was unreliable.

I also found this ISO standard for language identifiers. I guess that it should be the guide for all software producers. http://www.iso.org/iso/home/standards/language_codes.htm I looked for it because I realised that many countries speak arabic, so country codes were too restrictive.

[Avishai]

If you look in ..\FPC\2.6.2\source\rtl\win\wininc\defines.inc near Line# 4135 you should find where the languages are defined for MSWindows.

[Avishai]

Windsurfer, I've given this a little thought and this code may be what you are looking for.

Code: [Select]

procedure TForm1.FormCreate(Sender: TObject);
begin
  if SysLocale.MiddleEast then begin
    Self.BiDiMode:= bdRightToLeft;
    Self.FlipChildren(True);
  end;
end;


[Windsurfer]

Thanks Avishai,

I'll try it.

[Avishai]

There is another function just below TApplication.IsRTLLang

Code: [Select]

function TApplication.Direction(ALang: String): TBiDiMode;
const
  BidiModeMap: array[Boolean] of TBiDiMode = (bdLeftToRight, bdRightToLeft);
begin
  Result := BidiModeMap[IsRTLLang(ALang)];
end;


So you can have:

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Application.BiDiMode:= Application.Direction('he');