Volume 6A: Motif Programming Manual

26.2 Creating the Application

The original editor.c program needs several changes before it can work with the UIL user interface we have defined.

Like any application that uses UIL, the widget creation is now handled by Mrm. The callbacks also need a few minor

changes that are related to the use of Mrm. We have added a new callback that lets the application obtain the widget

IDs of Mrm−created widgets. The new version of the application is shown in the source code Compared to the

original version, the editor_uil.c program is about 50 lines shorter. Most of the shrinkage comes from main(), in

which the Motif widget creation calls are replaced by Mrm calls.

/* editor_uil.c −− create a full−blown Motif editor application complete

* with a menubar, facilities to read and write files, text search

* and replace, clipboard support and so forth.

*/

#include <Mrm/MrmAppl.h>

#include <Xm/Text.h>

#include <Xm/MessageB.h>

#include <stdio.h>

#include <sys/types.h>

#include <sys/stat.h>

MrmHierarchy hierarchy;

Cardinal status;

MrmType class_code;

static char buf[256];

static String uid_files[] = { "editor", "menubar", "dialogs" };

XtAppContext app_context;

Widget toplevel, text_edit, search_text, replace_text, text_output;

static MrmRegisterArg widgets_list[] = {

{ "w_text_edit", (XtPointer) &text_edit },

{ "w_search_text", (XtPointer) &search_text },

{ "w_replace_text", (XtPointer) &replace_text },

{ "w_text_output", (XtPointer) &text_output },

};

void register_widget(), file_cb(), edit_cb(), search_cb(), file_select_cb();

void popdown_cb();

/* These definitions depend on the order of the menu entries and are

also defined in the procedures.uih file with the callback decls. */

typedef enum { FILE_OPEN, FILE_SAVE, FILE_EXIT } FileOp;

typedef enum { EDIT_CUT, EDIT_COPY, EDIT_PASTE, EDIT_CLEAR } EditOp;

typedef enum { SEARCH_FIND_NEXT, SEARCH_SHOW_ALL, SEARCH_REPLACE,

SEARCH_CLEAR } SearchOp;

static MrmRegisterArg callbacks_list[] = {

{ "register_widget", (XtPointer) register_widget },

{ "file_cb", (XtPointer) file_cb },

{ "edit_cb", (XtPointer) edit_cb },

{ "search_cb", (XtPointer) search_cb },

{ "file_select_cb", (XtPointer) file_select_cb },

{ "popdown_cb", (XtPointer) popdown_cb },

};

main(argc, argv)

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int argc;

char *argv[];

{

Widget main_window;

XtSetLanguageProc (NULL, NULL, NULL);

MrmInitialize();

toplevel = XtVaAppInitialize (&app_context, "Demos", NULL, 0,

&argc, argv, NULL, NULL);

status = MrmOpenHierarchyPerDisplay (XtDisplay(toplevel),

XtNumber(uid_files), uid_files, NULL, &hierarchy);

if (status != MrmSUCCESS) {

XtAppError (app_context, "MrmOpenHierarchyPerDisplay failed");

exit (1);

}

MrmRegisterNames (widgets_list, XtNumber (widgets_list));

MrmRegisterNames (callbacks_list, XtNumber (callbacks_list));

status = MrmFetchWidget (hierarchy, "main_window", toplevel,

&main_window, &class_code);

if (status != MrmSUCCESS) {

XtAppError (app_context, "MrmFetchWidget failed");

exit (1);

}

XtManageChild (main_window);

XtRealizeWidget (toplevel);

XtAppMainLoop (app_context);

}

/* routine to display an error dialog */

void

show_error (message)

char *message;

{

static Widget dialog;

XmString s;

if (dialog == NULL) {

MrmFetchWidget (hierarchy, "error_dialog", toplevel,

&dialog, &class_code);

if (dialog == NULL || ! XmIsMessageBox (dialog)) {

XtAppError (app_context, "Creation of error dialog failed.");

exit (1);

}

}

s = XmStringCreateLocalized (message);

XtVaSetValues (dialog, XmNmessageString, s, NULL);

XmStringFree (s);

XtManageChild (dialog);

}

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/* callback routine for "OK" button in FileSelectionDialogs */

void

file_select_cb (dialog, client_data, call_data)

Widget dialog;

XtPointer client_data;

XtPointer call_data;

{

char *filename, *text;

struct stat statb;

long len;

FILE *fp;

FileOp reason = *((FileOp *) client_data);

XmFileSelectionBoxCallbackStruct *cbs =

(XmFileSelectionBoxCallbackStruct *) call_data;

XmTextSetString (text_output, NULL); /* clear the message area */

if (!XmStringGetLtoR (cbs−>value, XmFONTLIST_DEFAULT_TAG, &filename))

return; /* must have been an internal error */

if (*filename == NULL) {

XtFree (filename);

XBell (XtDisplay (text_edit), 50);

XmTextSetString (text_output, "Choose a file.");

return; /* nothing typed */

}

if (reason == FILE_SAVE) {

long bytes_written;

if (!(fp = fopen (filename, "w"))) {

perror (filename);

sprintf (buf, "Can't save to %s.", filename);

show_error (buf);

XtFree (filename);

return;

}

/* saving −− get text from Text widget... */

text = XmTextGetString (text_edit);

len = XmTextGetLastPosition (text_edit);

/* write it to file (check for error) */

bytes_written = fwrite (text, sizeof (char), len, fp);

if (bytes_written != len) {

strcpy (buf, "Warning: did not write entire file!");

show_error (buf);

}

else {

/* make sure a newline terminates file */

if (text[len−1] != '0)

fputc ('0, fp);

sprintf (buf, "Saved %ld bytes to %s.", len, filename);

XmTextSetString (text_output, buf);

}

}

else { /* reason == FILE_OPEN */

/* make sure the file is a regular text file and open it */

if (stat (filename, &statb) == −1 ||

(statb.st_mode & S_IFMT) != S_IFREG ||

!(fp = fopen (filename, "r"))) {

perror (filename);

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sprintf (buf, "Can't read %s.", filename);

show_error (buf);

XtFree (filename);

return;

}

/* put the contents of the file in the Text widget by

* allocating enough space for the entire file, reading the

* file into the space, and using XmTextSetString() to show

* the file.

*/

len = statb.st_size;

if (!(text = XtMalloc ((unsigned)(len+1)))) { /* +1 for NULL */

sprintf (buf, "%s: XtMalloc(%ld) failed.", len, filename);

show_error (buf);

}

else {

long bytes_read = fread (text, sizeof(char), len, fp);

if (bytes_read != len) {

sprintf (buf, "Did not read entire file!");

show_error (buf);

}

sprintf (buf, "Loaded %ld bytes from %s.", bytes_read, filename);

XmTextSetString (text_output, buf);

text[len] = 0; /* NULL−terminate */

XmTextSetString (text_edit, text);

}

}

/* free all allocated space. */

XtFree (text);

XtFree (filename);

fclose (fp);

XtUnmanageChild (dialog);

}

/* a menu item from the "File" pulldown menu was selected */

void

file_cb (w, client_data, call_data)

Widget w;

XtPointer client_data;

XtPointer call_data;

{

static Widget open_dialog, save_dialog;

FileOp reason = *((FileOp *) client_data);

if (reason == FILE_EXIT) {

MrmCloseHierarchy (hierarchy);

exit (0);

}

XmTextSetString (text_output, NULL); /* clear the message area */

if (reason == FILE_OPEN) {

if (open_dialog == NULL)

MrmFetchWidget (hierarchy, "open_dialog", toplevel,

&open_dialog, &class_code);

if (open_dialog)

XtManageChild (open_dialog);

else

show_error ("Creation of the open dialog failed.");

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}

else { /* reason == FILE_SAVE */

if (save_dialog == NULL)

MrmFetchWidget (hierarchy, "save_dialog", toplevel,

&save_dialog, &class_code);

if (save_dialog)

XtManageChild (save_dialog);

else

show_error ("Creation of the save dialog failed.");

}

}

/* a menu item from the "Search" pulldown menu was selected */

void

search_cb (w, client_data, call_data)

Widget w;

XtPointer client_data;

XtPointer call_data;

{

char *search_pat, *p, *string, *new_pat;

XmTextPosition pos = 0;

int len, nfound = 0;

int search_len, pattern_len;

SearchOp reason = *((SearchOp *) client_data);

Boolean found = False;

XmTextSetString (text_output, NULL); /* clear the message area */

if (reason == SEARCH_CLEAR) {

pos = XmTextGetLastPosition (text_edit);

XmTextSetHighlight (text_edit, 0, pos, XmHIGHLIGHT_NORMAL);

return;

}

if (!(string = XmTextGetString (text_edit)) || !*string) {

show_error ("No text to search.");

return;

}

if (!(search_pat = XmTextGetString (search_text)) || !*search_pat) {

XmTextSetString (text_output, "Specify a search pattern.");

XtFree (string);

return;

}

new_pat = XmTextGetString (replace_text);

search_len = strlen (search_pat);

pattern_len = strlen (new_pat);

if (reason == SEARCH_FIND_NEXT) {

pos = XmTextGetCursorPosition (text_edit) + 1;

found = XmTextFindString (text_edit, pos, search_pat,

XmTEXT_FORWARD, &pos);

if (!found)

found = XmTextFindString (text_edit, 0, search_pat,

XmTEXT_FORWARD, &pos);

if (found)

nfound++;

}

else { /* reason == SHOW_ALL || reason == SEARCH_REPLACE */

do {

found = XmTextFindString (text_edit, pos, search_pat,

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