• The Toolkit Intrinsics Library available with Release 6 of the X Window System (libXt)

• The libraries available with Version 1.2 of OSF/Motif (libXm)

• Features provided as DECwindows Extensions to the OSF/Motif Toolkit (libDXm)

• The X Library available with Release 6 of the X Window System (libX11)

This chapter assumes that you are already familiar with these components. For more complete information on them, refer to the following documents:

• X Window System

• X Window System Toolkit

• OSF/Motif Programmer's Guide

• DECwindows Motif Guide to Application Programming

  This guide includes a chapter that specifically addresses internationalization concerns of programmers writing Motif applications.

• DECwindows Extensions to Motif

This chapter does not discuss internationalization features specific to the Common Desktop Environment. Refer to the Common Desktop Environment: Internationalization Programmer's Guide for information about using these features.

XtSetLanguageProc(NULL,NULL,NULL);

• XtInitialize()

• XtAppInitialize()

• XtOpenDisplay()

• XtNFontSet (the resource name)

• XtCFontSet (the resource class)

• XtRFontSet (the resource representation type)

• Search the font list for an entry that is a font set and has the font list element tag XmFONTLIST_DEFAULT_TAG

• Search the font list for an entry that specifies a font set and use the first one found

• Use the first font in the font list

Items in the preceding list are in precedence order from highest to lowest; the widgets stop the search when an item higher on the list determines a font set.

#include <stdio.h>
#include <X11/Xlocale.h>
#include <X11/Xlib.h>

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#define DEFAULT_LOCALE          "zh_TW.dechanyu"   (1)

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main(argc, argv)
int     argc;
char    *argv[];
{

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     immodifier[0]           = '\0';
     for(i=1; i<argc; i++) {
             if(!strcmp(argv[i], "-Root")) {
                      best_style = XIMPreeditNothing;
                     }

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             else if (!strcmp(argv[i], "-locale"))   (2)
                     locale = argv[++i];
             else if (!strcmp(argv[i], "-immodifier")) {
                     strcpy(immodifier, "@im=");
                     strcat(immodifier, argv[++i]);
                  }
             }

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     if(locale == NULL)
             locale = DEFAULT_LOCALE;   (3)
     if(setlocale(LC_CTYPE, locale) == NULL) {
             fprintf(stderr, "Error : setlocale() !\n");
             exit(0);
             }
     if (!XSupportsLocale()) {
        fprintf(stderr, "X does not support this locale");
        exit(1);
     }
     if (XSetLocaleModifiers(immodifier) == NULL) {
        (void) fprintf(stderr, "%s: Warning : cannot set locale \
modifiers. \n", argv[0]);
     }

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1. Defines a constant to contain the setting for the default locale.

   In this example, the constant's value is explicitly set to zh_TW.dechanyu.

2. Determines if a locale was specified on the application command line.

   The user can override the default locale by using the -locale option on the command line that runs this application.

3. Sets locale to the value of the DEFAULT_LOCALE constant if the locale was not specified on the application command line.

   If this constant had been set to NULL rather than zh_TW.dechanyu, the default locale would be determined by the setting of the LANG environment variable for the process in which the application is run.

A font set is bound to the locale with which it was created. The functions that draw and measure text interpret the text according to the locale of the font set and therefore map characters to their font glyphs correctly.

Digital's implementation of functions that draw and measure text allow you to use fonts with different encodings to display native-language text.

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#define DEFAULT_FONT_NAME     "-*-SCREEN-*-*-R-Normal--*-*, -*"  (1)

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        char                  *base_font_name = NULL;

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        XFontSet              font_set;

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        char                  **missing_list;
        int                   missing_count;
        char                  *def_string;

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        if (base_font_name == NULL)
                base_font_name = DEFAULT_FONT_NAME;   (2)
        font_set = XCreateFontSet(display, base_font_name, &missing_list,
                               &missing_count, &def_string);

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        /*
         * if there are charsets for which no fonts can be found,
         * print a warning message.
         */
        if (missing_count > 0) {
                fprintf(stderr, "The following charsets are \
missing: \n");
                for (i=0; i<missing_count; i++)
                    fprintf(stderr, "%s \n", missing_list[i]);
                XFreeStringList(missing_list);
        }

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1. Defines the constant, DEFAULT_FONT_NAME, to contain the value of the the default base font name list.

   In this example, the default base font name list is set to -*-SCREEN-*-*-R-Normal--*-*, -*. For a default base font name list, you should specify a generic name (using wildcard fields as shown in the example) rather than a fully specified list of fonts. A fully specified font list works only for a particular locale, whereas a generic name can be the default for multiple locales.

2. Determines whether the default base font name list was supplied on the command line.

   The user can override the default base font name list by using the -fs option on the application command line.

GC      Jxgc_on, Jxgc_off;
int     Jxcx, Jxcy;
int     Jxcx_offset=2, Jxcy_offset=2;
int     Jxsfont_w, Jxwfont_w, Jxfont_height;
XRectangle      *Jxfont_rect;
int     Jxw_width, Jxw_height;
#define Jxmax_line      10
int     Jxsize[Jxmax_line];
char    Jxbuff[Jxmax_line][128];
int     Jxline_no;
int     Jxline_height;

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static int
JxWriteText(display, client, font_set, len, string)
     Display *display;
     Window     client;
     XFontSet   font_set;
     int        len;
     char       *string;
     {
     int   fy;
     XFillRectangle(display, client, Jxgc_off, Jxcx, Jxcy,
                    Jxsfont_w, Jxfont_height);                (1)
     if(len == 1 &&
         (string[0] == LF || string[0] == TAB
          || string[0] == CR)) {
         _JxNextLine();
         XFillRectangle(display, client, Jxgc_off, 0, Jxcy,
                        Jxw_width, Jxfont_height);
         }
     else {
         if(Jxcx >= (Jxw_width - Jxwfont_w)
         || (Jxsize[Jxline_no] + len) >=  256) {
             _JxNextLine();
             XFillRectangle(display, client, Jxgc_off, 0, Jxcy,
                            Jxw_width, Jxfont_height);
         }
         strncpy(&Jxbuff[Jxline_no][Jxsize[Jxline_no]], string,
                 len);
         Jxsize[Jxline_no] += len;
         fy   = -Jxfont_rect->y + Jxcy;
         XmbDrawImageString(display, client, font_set,
                            Jxgc_on, Jxcx, fy, string, len); (2)
         Jxcx += XmbTextEscapement(font_set, string, len);   (3)
         if(Jxcx >= Jxw_width) {
             _JxNextLine();
             XFillRectangle(display, client, Jxgc_off, 0, Jxcy, \
                            Jxw_width, Jxfont_height);
             }
         }
     XFillRectangle(display, client, Jxgc_on, Jxcx, Jxcy, \
                    Jxsfont_w, Jxfont_height);
     }

To draw locale-dependent text, the application needs to know which fonts are required for that text, how the text can be separated into its components, and which font is required for each of those components. Version 6 of the X library therefore incorporates the following objects to address this problem:

• X Output Method (XOM)

  XOM is an opaque data structure that the application can use to communicate with an output method.

• X Output Context (XOC)

  XOC is compatible with XFontSet in terms of its program interface but is a more generalized abstraction.

The following table summarizes the X library functions related to XOM and XOC. For more information on these functions, refer to their reference pages.

• More than one encoding for a character set may be in common use.

  For example, character sets for Japanese (JIS X0208), Chinese (GB 2312), and Korean (KS C 5601) are available in GL or GR encoding.

• More than one character set may be supported in a particular country.

• Different vendors have adopted different font encoding schemes in their products.

Font-encoding divergence from one system to another causes problems for applications that you run on different kinds of systems. Therefore, Digital's implementation of the functions for text drawing and measurement incorporates a mechanism to convert between different font encodings. For conversion to take place, you must design your application so that it can determine the base font name list appropriate for the run-time environment. The application can obtain the base font name list from a resource file or through an option the user specifies on the command line. For example, in the command line to run the ximdemo application, the user can include the -fs option to specify a base font name list.

The conversion mechanism for font encoding is available only when your application uses the internationalized text drawing functions in the X Library. The conversion mechanism is not available with the primitive text drawing functions, such as XDrawText() and XDrawString().

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        if (!strcmp(locale,"zh_TW.dechanyu")) {
                strcpy(title, "XIM F|n/");
        } else if (!strcmp(locale, "zh_CN.dechanzi")) {
                strcpy(title, "XIM J>76");
        } else if (!strncmp(locale, "ja_JP", 5)) {
                strcpy(title, "XIM %G%b");
        } else if (!strcmp(locale, "ko_KR.deckorean")) {
                strcpy(title, "XIM 5%8p");
        } else if (!strcmp(locale, "th_TH.TACTIS")) {
                strcpy(title, "XIM !RCJR8T5");
        } else {
            strcpy(title, "XIM Demo")   (1)
        }
        XmbSetWMProperties(display, window, title, title, NULL, \
                           0, NULL, NULL, NULL);   (2)

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• The server for the specified input method is not running.

• The im modifier is specified incorrectly.

• The specified input method does not support the current locale.

main(argc, argv)
int     argc;
char    *argv[];
        {
        Display                 *display;

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        XIM                     im;

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        char                    *res_file = NULL;

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        XrmDatabase             rdb = NULL;

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        preedcb_cd.win = client;
        if(res_file) {
                printf("Set Database : file name = %s\n", res_file);
                rdb = XrmGetFileDatabase(res_file);   (1)
                }
        if((im = XOpenIM(display, rdb, NULL, NULL)) == NULL) {
                printf("Error : XOpenIM() !\n");    (2)
                exit(0);
                }

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        XCloseIM(im);   (3)

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main(argc, argv)
int     argc;
char    *argv[];
        {
        Display                 *display;

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        int                     i, n;

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        XIMStyles               *im_styles;
        XIMStyle                xim_mode=0;
        XIMStyle                best_style = XIMPreeditCallbacks;
        XIM                     im;

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        XIMStyle                app_supported_styles;

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        for(i=1; i<argc; i++) {
                if(!strcmp(argv[i], "-Root")) {
                        best_style = XIMPreeditNothing;
                        }
                else if (!strcmp(argv[i], "-Cb")) {
                        best_style = XIMPreeditCallbacks;    (1)
                        }

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        /* set flags for the styles our application can support */
        app_supported_styles = XIMPreeditNone | XIMPreeditNothing |
XIMPreeditCallbacks;    (2)
        app_supported_styles |= XIMStatusNone | XIMStatusNothing;
        XGetIMValues(im, XNQueryInputStyle, &im_styles, NULL);
        n = 1;    (3)
        if(im_styles != (XIMStyles *)NULL) {
                for(i=0; i<im_styles->count_styles; i++) {
                        xim_mode = im_styles->supported_styles[i];
                        if((xim_mode & app_supported_styles) ==
xim_mode) { /* if we can handle it */
                                n = 0;
                               if (xim_mode & best_style) /* pick user
selected style */
                                   break;   (4)
                        }
                }
        }
        if(n) {
                printf("warning : Unsupport InputStyle. or No
IMserver.\n");
                exit (0);
                }

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• The interaction style for the input context

• The font set with which preediting and status text is drawn

• The callbacks for handling on-the-spot preediting

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        Display                 *display;

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        Window                  root, window, client;

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        XIMStyle                xim_mode=0;

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        XIM                     im;
        XIC                     ic;

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        XVaNestedList           preedit_attr, status_attr;
        XIMCallback             ximapicb[10];
        char                    immodifier[100];
        preedcb_data            preedcb_cd;

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        window = XCreateSimpleWindow(display, root, 0, 0,
                                W_WIDTH, W_HEIGHT, 2, bpixel, fpixel);

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        client = JxCreateTextWindow(display, window, 0, 0,
                                W_WIDTH-2, W_HEIGHT-2, 1, bpixel, fpixel,
                                font_set, &font_height);

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        if (xim_mode & XIMPreeditCallbacks) {
                ximapicb[0].client_data = (XPointer)NULL;
                ximapicb[0].callback = (XIMProc)api_preedit_start_cb;
                ximapicb[1].client_data = (XPointer)(&preedcb_cd);
                ximapicb[1].callback = (XIMProc)api_preedit_done_cb;
                ximapicb[2].client_data = (XPointer)(&preedcb_cd);
                ximapicb[2].callback = (XIMProc)api_preedit_draw_cb;
                ximapicb[3].client_data = (XPointer)NULL;
                ximapicb[3].callback = (XIMProc)api_preedit_caret_cb;
                nestlist = XVaCreateNestedList(10,
                                XNPreeditStartCallback, &ximapicb[0],
                                XNPreeditDoneCallback, &ximapicb[1],
                                XNPreeditDrawCallback, &ximapicb[2],
                                XNPreeditCaretCallback, &ximapicb[3],
                                NULL);    (1)
        }
        if (xim_mode & XIMPreeditCallbacks) {    (2)
                        ic = XCreateIC(im,
                        XNInputStyle, xim_mode,
                        XNClientWindow, window,
                        XNFocusWindow, client,
                        XNPreeditAttributes, nestlist,
                        NULL);    (3)
        } else {        /* preedit nothing */
                        ic = XCreateIC(im,
                                XNInputStyle, xim_mode,
                                XNClientWindow, window,
                                XNFocusWindow, client,
                                NULL );   (4)
        }
        if(ic == NULL) {     (5)
                printf("Error : XCreateIC() !\n");
                XCloseIM(im);
                exit(0);
                }

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exit:
        XDestroyIC(ic);    (6)

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int     Jxsize[Jxmax_line];
char    Jxbuff[Jxmax_line][128];
int     Jxline_no;
int     Jxline_height;
int     sav_cx, sav_cy;
int     sav_w_width, w_height;
int     sav_size[Jxmax_line];
int     sav_line_no;
char    preedit_buffer[12];
void
save_value()
{
    int i;
    sav_cx = Jxcx;
    sav_cy = Jxcy;
    sav_line_no = Jxline_no;
    for (i=0; i< Jxmax_line; i++)
        sav_size[i] = Jxsize[i];
}
void
restore_value()
{
    int i;
    Jxcx = sav_cx;
    Jxcy = sav_cy;
    Jxline_no = sav_line_no;
    for (i=0; i< Jxmax_line; i++)
        Jxsize[i] = sav_size[i];
}
int
api_preedit_start_cb(ic, clientdata, calldata)
XIC ic;
XPointer clientdata;
XPointer calldata;
{
    int len;
    len = 12;
/* save up the values */
    save_value();   (1)
    return(len);    (2)
}
void
api_preedit_done_cb(ic, clientdata, calldata)
XIC ic;
XPointer clientdata;
XPointer calldata;
{
    preedcb_data *cd = (preedcb_data *)clientdata;
/* restore up the values */
    restore_value();    (3)
/* convenient handling */
    JxRedisplayText(cd->dpy, cd->win, cd->fset);
    return;
}
void
api_preedit_draw_cb( ic, clientdata, calldata)
XIC ic;
XPointer clientdata;
XIMPreeditDrawCallbackStruct *calldata;
{
    preedcb_data *cd = (preedcb_data *)clientdata;
    int count;
    char *reset_str;
    if (calldata->text) {
        if (calldata->text->encoding_is_wchar)    (4)
        {
        } else {
          count =  strlen(calldata->text->string.multi_byte);
          if (count > 12) {
/* preedit string > max preedit buffer */
             reset_str = XmbResetIC(ic);    (5)
             XFillRectangle(cd->dpy, cd->win, Jxgc_off, Jxcx, Jxcy,
Jxw_width*13, Jxfont_height);       /* clear the preedit area */
             restore_value();
             if (reset_str)
                XFree(reset_str);
             return;
          }
          if (!calldata->chg_length) {  /* insert character */
             if (!calldata->chg_first)  { /* insert in first character
in preedit buffer */
strncpy(&preedit_buffer[0],calldata->text->string.multi_byte, count);
                restore_value();
             } else {
                /* Not Yet Implemented */
             }
          } else {                      /* replace character */
             if (!calldata->chg_first)  { /* replace from first
character in pre-edit buffer */
strncpy(&preedit_buffer[0],calldata->text->string.multi_byte, count);
                restore_value();
             } else {
                /* Not Yet Implemented */
             }
          }
          XFillRectangle(cd->dpy, cd->win, Jxgc_off, Jxcx, Jxcy,
Jxw_width*13, Jxfont_height); /* clear the preedit area */
          JxWriteText(cd->dpy, cd->win, cd->fset, count, preedit_buffer);
        }
    } else {    /* should delete preedit buffer */
        /* Not yet implemented */
    }
    return;
}
void
api_preedit_caret_cb(ic, clientdata, calldata)
XIC ic;
XPointer clientdata;
XIMPreeditCaretCallbackStruct *calldata;
{
    /* Not yet implemented */
    return;
}

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       long                    im_event_mask;

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       XGetICValues(ic, XNFilterEvents, &im_event_mask, NULL);
       mask = StructureNotifyMask | FocusChangeMask | ExposureMask;
       XSelectInput(display, window, mask);
       mask = ExposureMask | KeyPressMask | FocusChangeMask |
              im_event_mask;
       XSelectInput(display, client, mask);

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        for(;;) {
                XNextEvent(display, &event);
                if(XFilterEvent(&event, NULL) == True)
                        continue;   (1)
                switch(event.type ) {
                /* dispatch event */

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                }
       }

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static void icDestroyCallback(ic, client_data, call_data)
XIC ic;
XPointer client_data;
XPointer call_data;