LCL Unicode Support/de

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Einleitung

Mit der Version 0.9.25 unterstützt Lazarus Unicode auf allen Plattformen ausser auf Gtk 1. Dieser Seite liefert Informationen für Anwender, die Strategie der Entwickler und eine Beschreibung der Konzepte und deren Anwendungsdetails.

Instructions for users

In unicode widgetsets it's important to note that not everything is unicode. The Free Pascal Runtime Library, the Free Pascal FCL library are ansi. It's the responsibility of the developer to know what is the encoding of their strings and do the proper conversion between libraries which expect different encodings.

Usually the encoding is per-library. Each library will uniformly expect 1 kind of encoding, which will usually either be unicode (UTF-8 for Lazarus) or Ansi (which means the system encoding, and may be utf-8 or not). The RTL and the FCL of FPC 2.2.2 expect ansi strings. FPC 2.3.x currently too.

You can can convert between unicode and ansi using the UTF8ToAnsi and AnsiToUTF8 functions from the System unit or the UTF8ToSys and SysToUTF8 from the FileUtil unit. The later two are smarter but pull more code into your program.

Examples:

Say you get a string from a TEdit and you want to give it to some rtl file routine:

<delphi> var

 MyString: string; // utf-8 encoded

begin

 MyString := MyTEdit.Text;
 SomeRTLRoutine(UTF8ToAnsi(MyString));

end; </delphi>

And for the opposite direction:

<delphi> var

 MyString: string; // ansi encoded

begin

 MyString := SomeRTLRoutine;
 MyTEdit.Text := AnsiToUTF8(MyString);

end; </delphi>

Important: UTF8ToAnsi will return an empty string if the UTF8 string contains invalid characters.

Important: AnsiToUTF8 and UTF8ToAnsi require a widestring manager under Linux, BSD and Mac OS X. You can use the SysToUTF8 and UTF8ToSys functions (unit FileUtil) or add a the widetstring manager by adding cwstring as one of the first units to your program's uses section.

Dealing with directory and filenames

Lazarus controls and functions expect filenames and directory names in utf-8 encoding, but the RTL uses ansi strings for directories and filenames.

For example, consider a button, which sets the Directory property of the TFileListBox to the current directory. The RTL Function GetCurrentDir is ansi, and not unicode, so conversion is needed:

<delphi> procedure TForm1.Button1Click(Sender: TObject); begin

 FileListBox1.Directory:=SysToUTF8(GetCurrentDir);
 // or use the functions from the FileUtil unit
 FileListBox1.Directory:=GetCurrentDirUTF8;

end; </delphi>

The unit FileUtil defines common file functions with UTF-8 strings:

<Delphi> // basic functions similar to the RTL but working with UTF-8 instead of the // system encoding

// AnsiToUTF8 and UTF8ToAnsi need a widestring manager under Linux, BSD, MacOSX // but normally these OS use UTF-8 as system encoding so the widestringmanager // is not needed. function NeedRTLAnsi: boolean;// true if system encoding is not UTF-8 procedure SetNeedRTLAnsi(NewValue: boolean); function UTF8ToSys(const s: string): string;// as UTF8ToAnsi but more independent of widestringmanager function SysToUTF8(const s: string): string;// as AnsiToUTF8 but more independent of widestringmanager

// file operations function FileExistsUTF8(const Filename: string): boolean; function FileAgeUTF8(const FileName: string): Longint; function DirectoryExistsUTF8(const Directory: string): Boolean; function ExpandFileNameUTF8(const FileName: string): string; function ExpandUNCFileNameUTF8(const FileName: string): string; {$IFNDEF VER2_2_0} function ExtractShortPathNameUTF8(Const FileName : String) : String; {$ENDIF} function FindFirstUTF8(const Path: string; Attr: Longint; out Rslt: TSearchRec): Longint; function FindNextUTF8(var Rslt: TSearchRec): Longint; procedure FindCloseUTF8(var F: TSearchrec); function FileSetDateUTF8(const FileName: String; Age: Longint): Longint; function FileGetAttrUTF8(const FileName: String): Longint; function FileSetAttrUTF8(const Filename: String; Attr: longint): Longint; function DeleteFileUTF8(const FileName: String): Boolean; function RenameFileUTF8(const OldName, NewName: String): Boolean; function FileSearchUTF8(const Name, DirList : String): String; function FileIsReadOnlyUTF8(const FileName: String): Boolean; function GetCurrentDirUTF8: String; function SetCurrentDirUTF8(const NewDir: String): Boolean; function CreateDirUTF8(const NewDir: String): Boolean; function RemoveDirUTF8(const Dir: String): Boolean; function ForceDirectoriesUTF8(const Dir: string): Boolean;

// environment function ParamStrUTF8(Param: Integer): string; function GetEnvironmentStringUTF8(Index : Integer): String; function GetEnvironmentVariableUTF8(const EnvVar: String): String; function GetAppConfigDirUTF8(Global: Boolean): string; </Delphi>

Mac OS X

The file functions of the FileUtil unit also take care of a Mac OS X special: OS X normalizes filenames. For example the filename 'ä.txt' can be encoded in unicode with two different sequences (#$C3#$A4 and 'a'#$CC#$88). Under Linux and BSD you can create a filename with both encodings. OS X automatically converts the a umlaut to the three byte sequence. This means:

<Delphi> if Filename1=Filename2 then ... // is not sufficient under OS X if AnsiCompareFileName(Filename1,Filename2)=0 then ... // not sufficient under fpc 2.2.2, even not with cwstring if CompareFilenames(Filename1,Filename2)=0 then ... // this always works (unit FileUtil or FileProcs) </Delphi>

East Asian languages on Windows

The default font (Tahoma) for user interface controls under Windows XP is capable of displaying correctly several languages, including arabic, russian and western languages, but not east asian languages, like chinese, japanese and korean. By going to the Control Panel, choosing Regional Settings, clicking on the Languages Tab and installing the East Asia Language Pack, the standard user interface font will simply start showing those languages correctly. Obviously Windows XP versions localized for those languages will already contain this language pack installed. Extended instructions here.

Implementierungsrichtlinien

Voraussetzungen

Die Vision von Lazarus ist: "Write once, compile everywhere." Das bedeutet im Idealfall, eine Applikation, die Unicode eingeschaltet hat, hat nur einen Source-Code, der für alle Plattformen gültig ist, ohne irgendwelche konditionalen Definitionen.

Der "Interface" Teil der LCL sollte Unicode für die Zielplattform bereitstellen, die Zielplattform sollte Unicode selber unterstützen, ohne den Anwendungsprogrammierer mit Details zu belästigen.

Was Lazarus betrifft ist die interne String-Kommunikation an den Schnittstellen "Anwendungscode <--> LCL" und "LCL <--> Widgetsets". Beide basieren nämlich auf den klassischen byte-orientierten Strings. Logisch sollten diese String konvertiert werden zu dem Code UTF-8.

Migration to Unicode

Most existing Lazarus use Ansi encodings, because that´s the default for Gtk1 and win32 interfaces today. This will change in the future and all widgetsets will support UTF-8, so all applications that pass strings directly to the interface (be written on code or on the object inspector) will need to be converted to utf-8.

When people develop software for non-fully working widgetsets like Gtk 2, Qt, WinCE (and futurely Win32U), they use the IDE compiled for more stable widgetsets, like Gtk and win32. To avoid inconsistencies (like passing iso characters for a utf-8 widgetset), it´s necessary to use an IDE working on the same encoding as the target widgetset. This means that we will need stable UTF-8 IDE before completing the migration to Unicode.

Currently we have various groups of widgetsets, according to the encoding:

• Interfaces that use ANSI encoding: win32 and gtk (1) interfaces.

• Interfaces that use UTF-8 encoding: gtk (1), gtk2, qt, fpGUI, carbon

• Interfaces that currently use ANSI encoding, but need migration to UTF-8: win32, wince

Notice that gtk 1 is on both ANSI and UTF-8 groups. That´s because the encoding is controlled by an environment variable on Gtk 1.

As Lazarus is today, existing software will work, if recompiled for win32, wince or gtk interfaces, but will face encoding issues compiling for other widgetset. And new software, using UTF-8 will work when recompiled for any of the widgetsets on the Unicode group.

One very important note is that you must use the IDE compiled for the same group you are targeting. This is because the IDE uses the encoding of the widgetset it was compiled to, and not the one of the target widgetset to write LFM and LRS files.

Roadmap

Now that we have guidelines, it´s time to create a roadmap and put it into practice. For this, the following realistic plan was created. Our plan splits tasks in 2 groups. One for Primary tasks and another for Secondary tasks.

All primary tasks must be fully implemented before we can say Lazarus is Unicode enabled, and as such will be the main attention of our effort.

Secondary tasks are desirable, but won´t be implemented unless someone volunteers for them, or posts a bounty for them.

Primäre Aufgaben

Make Win32 Widgetset support UTF-8

Anmerkungen: On this step we will target all 32-bits Windows versions at the same time. All code produced on this effort will be isolated from the current win32 interface by IFDEFs, to avoid introducing bugs on this primary interface. After the transition time, the IFDEFs will be removed and only the Unicode code will remain.

Status: teilweise implementiert

Aktualisieren der GTK2 Tastaturfunktionen, damit sie mit UTF-8 funktionieren

Anmerkungen:

Status: fast vollendet. Some pre-editing features of the gtk2 are not yet supported in custom controls. I don't know, which language needs them.

Make sure the Lazarus IDE runs correctly with Win32 Unicode widgetset and supports UTF-8

Anmerkungen:

Status: vollendet. Except for the character map, which still shows only 255 characters. But all modern OS provide nice unicode character maps anyway.

Make sure the Lazarus IDE runs correctly with Gtk 2 widgetset and supports UTF-8

Anmerkungen:

Status: vollendet. Es gibt noch GTK2 intf bugs, aber diese haben nichts mit UTF-8 zu tun.

Sekundäre Aufgaben

Update Windows CE widgetset so it uses UTF-8

Anmerkungen: String conversion routines are concentrated on the winceproc.pp file. Many tests are needed.

Status: nicht implementiert

Aktualisieren der GTK1 Tastaturfunktionen, damit sie mit UTF-8 funktionieren

Anmerkungen:

Status: nicht implementiert

Complete RTL in synedit

Anmerkungen: RTL meint von rechts nach links (right to left) wie es z.B. im Arabischen verwendet wird

Status: nicht implementiert.

Unicode essentials

Unicode standard maps integers from 0 to 10FFFF(h) to characters. Each such mapping is called a code point. In other words, Unicode characters are in principle defined for code points from U+000000 to U+10FFFF (0 to 1 114 111).

There are three schemes for representing Unicode code points as unique byte sequences. These schemes are called Unicode transformation formats: UTF-8, UTF-16 and UTF-32. The conversions between all of them are possible. Here are their basic properties:

                           UTF-8 UTF-16 UTF-32
Smallest code point [hex] 000000 000000 000000
Largest code point  [hex] 10FFFF 10FFFF 10FFFF
Code unit size [bits]          8     16     32
Minimal bytes/character        1      2      4
Maximal bytes/character        4      4      4

UTF-8 has several important and useful properties: It is interpreted as a sequence of bytes, so that the concept of lo- and hi-order byte does not exist. Unicode characters U+0000 to U+007F (ASCII) are encoded simply as bytes 00h to 7Fh (ASCII compatibility). This means that files and strings which contain only 7-bit ASCII characters have the same encoding under both ASCII and UTF-8. All characters >U+007F are encoded as a sequence of several bytes, each of which has the two most significant bits set. No byte sequence of one character is contained within a longer byte sequence of another character. This allows easy search for substrings. The first byte of a multibyte sequence that represents a non-ASCII character is always in the range C0h to FDh and it indicates how many bytes follow for this character. All further bytes in a multibyte sequence are in the range 80h to BFh. This allows easy resynchronization and robustness.

UTF-16 has the following most important properties: It uses a single 16-bit word to encode characters from U+0000 to U+d7ff, and a pair of 16-bit words to encode any of the remaining Unicode characters.

Finally, any Unicode character can be represented as a single 32-bit unit in UTF-32.

Für weitere Informationen siehe: Unicode FAQ - Basic questions, Unicode FAQ - UTF-8, UTF-16, UTF-32 & BOM, Wikipedia: UTF-8 [1]

Lazarus component library architecture essentials

Die LCL besteht aus zwei Teilen:

1. A target platform independent part, which implements a class hierarchy analogous to Delphi VCL;
2. "Interfaces" - a part that implements the interface to APIs of each target platform.

The communication between the two parts is done by an abstract class TWidgetset. Each widgetset is implemented by its own class derived from TWidgetset.

The GTK 1 widgetset is the oldest. In this widgetset the string encoding is determined by the LANG environment variable, which is usually a iso The ISO-8859-n group of single byte encodings. Recently (as of Mandriva 2007, for example), many distributions have being shipping Gtk 1 configured for UTF-8. Our Gtk 1 interface lacks proper support for UTF-8 on the keyboard handling routines, so this is a big problem, that increases the need for Lazarus to implement cross-platform Unicode support.

Gtk2 widgetset only works with UTF-8 encoding and supports UTF-8 completely.

The win32 interface is setup with ansi widgets and UTF-8 support is started, but not yet complete and therefore disabled by default. So it is currently not possible to use Unicode with win32.

Qt interface is prepared for UTF-8. Qt itself uses UTF-16 as native encoding, but the lazarus interface for Qt converts from UTF-8 to UTF-16.

Windows CE only support UTF-16 as character encoding, but our interface for it currently converts strings from ISO to UTF-16 before calling the Windows API. This is very easy to fix, as all conversion code is concentrated on a few routines on the winceproc.pp file.

For more, see: Internals of the LCL

Unicode-enabling the win32 interface

Compiling LCL-Win32 with Unicode

To enable unicode on LCL for Windows go to the menu "Tools" --> "Configure Build Lazarus"

Put -dWindowsUnicodeSupport on the "Options" field. Select all targets to NONE, and only LCL to Clean+Build. Select win32 as target widgetset. Click on "Build".

Now you can recompile your existing applications and they will have Unicode mode enabled. Note that at the moment only a few parts of the software will be really unicode enabled and you may find bugs on those parts.

Richtlinien

First, and most importantly, all Unicode patches for the Win32 interface must be enclosed by IFDEF WindowsUnicodeSupport, to avoid breaking the existing ANSI interface. After this stabilizes, all ifdefs will be removed and only the Unicode part will remain. At this moment all existing programs that use ANSI characters will need migration to Unicode.

Windows platforms <=Win9x are based on ISO code page standards and only partially support Unicode. Windows platforms starting with WinNT and Windows CE fully support Unicode. Win 9x and NT offer two parallel sets of API functions: the old ANSI enabled *A and the new, Unicode enabled *W. *W functions accept wide strings, i.e. UTF-16 encoded strings, as parameters. Windows CE only uses Wide API functions.

Wide functions present on Windows 9x

Some Wide API functions are present on Windows 9x. Here is a list of such functions: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/mslu/winprog/other_existing_unicode_support.asp

Conversion example:

  GetTextExtentPoint32(hdcNewBitmap, LPSTR(ButtonCaption),
Length(ButtonCaption), TextSize);

Becomes:

  {$ifdef WindowsUnicodeSupport}
    GetTextExtentPoint32W(hdcNewBitmap, PWideChar(Utf8Decode(ButtonCaption)), Length(WideCaption), TextSize);
  {$else}
    GetTextExtentPoint32(hdcNewBitmap, LPSTR(ButtonCaption), Length(ButtonCaption), TextSize);
  {$endif}

Funktionen die Ansi und Wide Versionen benötigen

First Conversion example:

<delphi> function TGDIWindow.GetTitle: String; var

l: Integer;

begin

  l := Windows.GetWindowTextLength(Handle);
  SetLength(Result, l);
  Windows.GetWindowText(Handle, @Result[1], l);

end; </delphi>

Becomes:

<delphi> function TGDIWindow.GetTitle: String; var

l: Integer;
AnsiBuffer: string;
WideBuffer: WideString;

begin

{$ifdef WindowsUnicodeSupport}

if UnicodeEnabledOS then
begin
  l := Windows.GetWindowTextLengthW(Handle);
  SetLength(WideBuffer, l);
  l := Windows.GetWindowTextW(Handle, @WideBuffer[1], l);
  SetLength(WideBuffer, l);
  Result := Utf8Encode(WideBuffer);
end
else
begin
  l := Windows.GetWindowTextLength(Handle);
  SetLength(AnsiBuffer, l);
  l := Windows.GetWindowText(Handle, @AnsiBuffer[1], l);
  SetLength(AnsiBuffer, l);
  Result := AnsiToUtf8(AnsiBuffer);
end;

{$else}

  l := Windows.GetWindowTextLength(Handle);
  SetLength(Result, l);
  Windows.GetWindowText(Handle, @Result[1], l);

{$endif}

end;

</delphi>

Roadmap

Was sollte bereits mit Unicode funktionieren:

• TForm, TButton, TLabel
• die meisten Controls
• Menüs
• LCLIntf.ExtTextOut and most other text related winapis
• TStrings based controls. Examples: TComboBox, TListBox, etc
• SynEdit shows and can input UTF-8 characters correctly

Bekannte Probleme bei der Unicode Unterstützung:

• SynEdit unterstützt nicht RTL (right to left, von rechts nach links)
• MessageBox buttons don't show unicode correctly when they are translated. Tested on the IDE. Could be a problem on the IDE however.

Liste der zu prüfenden Units:

• "win32callback.inc"
• "win32def.pp"
• "win32int.pp"
• "win32lclintf.inc"
• "win32lclintfh.inc"
• "win32listsl.inc"
• "win32listslh.inc"
• "win32memostrings.inc"
• "win32object.inc"
• "win32proc.pp"
• "win32winapi.inc"
• "win32winapih.inc"
• "win32wsactnlist.pp"
• "win32wsarrow.pp"
• "win32wsbuttons.pp"
• "win32wscalendar.pp"
• "win32wschecklst.pp"
• "win32wsclistbox.pp"
• "win32wscomctrls.pp"
• "win32wscontrols.pp"
• "win32wscustomlistview.inc"
• "win32wsdbctrls.pp"
• "win32wsdbgrids.pp"
• "win32wsdialogs.pp"
• "win32wsdirsel.pp" - Felipe
• "win32wseditbtn.pp" - Felipe
• "win32wsextctrls.pp" - Felipe
• "win32wsextdlgs.pp" - Felipe
• "win32wsfilectrl.pp" - Felipe
• "win32wsforms.pp" - Felipe
• "win32wsgrids.pp" - Felipe
• "win32wsimglist.pp" - Felipe
• "win32wsmaskedit.pp" - Felipe
• "win32wsmenus.pp" - Felipe
• "win32wspairsplitter.pp" - Felipe
• "win32wsspin.pp" - Felipe
• "win32wsstdctrls.pp" - Felipe
• "win32wstoolwin.pp" - Felipe
• "winext.pas" - Felipe

Screenshots

Siehe auch

• UTF-8 - Beschreibung von UTF-8 Zeichenketten