From d7b88a3bcc7e76f38ee5799be7722fd5a10781ef Mon Sep 17 00:00:00 2001 From: Michael R Sweet Date: Wed, 13 Jan 1999 19:28:54 +0000 Subject: Updated all links so they work between files. Revision 1. git-svn-id: file:///fltk/svn/fltk/trunk@219 ea41ed52-d2ee-0310-a9c1-e6b18d33e121 --- documentation/editor.html | 686 +++++++++++++++++++++------------------------- 1 file changed, 320 insertions(+), 366 deletions(-) (limited to 'documentation/editor.html') diff --git a/documentation/editor.html b/documentation/editor.html index 12c7edb12..d55616a83 100644 --- a/documentation/editor.html +++ b/documentation/editor.html @@ -1,41 +1,35 @@ - - - -

4 - Designing a Simple Text Editor

- -This chapter takes you through the design of a simple FLTK-based text editor. - + +

4 - Designing a Simple Text Editor

+ This chapter takes you through the design of a simple FLTK-based text +editor.

Determining the Goals of the Text Editor

- -Since this will be the first big project you'll be doing with FLTK, lets define -what we want our text editor to do: - -

Menu_Bar/menus for all functions. -
Edit a single text file. -
Load from a file. -
Save to a file. -
Cut/copy/delete/paste functions. -
Search and replace functions. -
Keep track of when the file has been changed. -

- + Since this will be the first big project you'll be doing with FLTK, +lets define what we want our text editor to do: +

Menu_Bar/menus for all functions.
Edit a single text file.
Load from a file.
Save to a file.
Cut/copy/delete/paste functions.
Search and replace functions.
Keep track of when the file has been changed.

Designing the Main Window

- -Now that we've outlined the goals for our editor, we can begin with the design -of our GUI. Obviously the first thing that we need is a window: - -

+ Now that we've outlined the goals for our editor, we can begin with 
+the design of our GUI.  Obviously the first thing that we need is a 
+window: 
+
+ Fl_Window *window;
 
-window = new Fl_Window(640, 480, "Text Editor");
-
-
+window = new Fl_Window(640, 480, "Text Editor");
+

Variables

- -Our text editor will need some global variables to keep track of things: - -

+ Our text editor will need some global variables to keep track of 
+things: 
+
+ Fl_Window          *window;
 Fl_Menu_Bar         *menubar;
 Fl_Multiline_Input *input;
@@ -47,187 +41,173 @@ Fl_Return_Button   *replace_next;
 Fl_Button          *replace_cancel;
 
 int                changed = 0;
-char               filename[1024] = "";
-char               search[256] = "";
-
-
-The window variable is our top-level window described previously.
-We'll cover the other variables as we build the application.
-
+char               filename[1024] = "";
+char               search[256] = "";
+

+ The window variable is our top-level window described +previously. We'll cover the other variables as we build the +application.

Menu_Bars and Menus

- -The first goal requires us to use a menubar and menus that define -each function the editor needs to perform. The -Fl_Menu_Item structure is used to -define the menus and items in a menubar: - -

+ The first goal requires us to use a menubar and menus that define each 
+function the editor needs to perform.  The 
+Fl_Menu_Item structure is used to define the menus and 
+items in a menubar: 
+
+ Fl_Menu_Item menuitems[] = {
-  { "&File", 0, 0, 0, FL_SUBMENU },
-    { "&New",        FL_ALT + 'n', new_cb },
-    { "&Open...",    FL_ALT + 'o', open_cb, 0, FL_MENU_DIVIDER },
-    { "&Save",       FL_ALT + 's', save_cb },
-    { "Save &As...", FL_ALT + FL_SHIFT + 's', saveas_cb, 0, FL_MENU_DIVIDER },
-    { "&Quit", FL_ALT + 'q', quit_cb },
+  { "&File", 0, 0, 0, FL_SUBMENU },
+    { "&New",        FL_ALT + 'n', new_cb },
+    { "&Open...",    FL_ALT + 'o', open_cb, 0, FL_MENU_DIVIDER },
+    { "&Save",       FL_ALT + 's', save_cb },
+    { "Save &As...", FL_ALT + FL_SHIFT + 's', saveas_cb, 0, FL_MENU_DIVIDER },
+    { "&Quit", FL_ALT + 'q', quit_cb },
     { 0 },
 
-  { "&Edit", 0, 0, 0, FL_SUBMENU },
-    { "&Undo",       FL_ALT + 'z', undo_cb, 0, FL_MENU_DIVIDER },
-    { "Cu&t",        FL_ALT + 'x', cut_cb },
-    { "&Copy",       FL_ALT + 'c', copy_cb },
-    { "&Paste",      FL_ALT + 'v', paste_cb },
-    { "&Delete",     0, delete_cb },
+  { "&Edit", 0, 0, 0, FL_SUBMENU },
+    { "&Undo",       FL_ALT + 'z', undo_cb, 0, FL_MENU_DIVIDER },
+    { "Cu&t",        FL_ALT + 'x', cut_cb },
+    { "&Copy",       FL_ALT + 'c', copy_cb },
+    { "&Paste",      FL_ALT + 'v', paste_cb },
+    { "&Delete",     0, delete_cb },
     { 0 },
 
-  { "&Search", 0, 0, 0, FL_SUBMENU },
-    { "&Find...",       FL_ALT + 'f', find_cb },
-    { "F&ind Again",    FL_ALT + 'g', find2_cb },
-    { "&Replace...",    FL_ALT + 'r', replace_cb },
-    { "Re&place Again", FL_ALT + 't', replace2_cb },
+  { "&Search", 0, 0, 0, FL_SUBMENU },
+    { "&Find...",       FL_ALT + 'f', find_cb },
+    { "F&ind Again",    FL_ALT + 'g', find2_cb },
+    { "&Replace...",    FL_ALT + 'r', replace_cb },
+    { "Re&place Again", FL_ALT + 't', replace2_cb },
     { 0 },
 
   { 0 }
 };
-
-
-Once we have the menus defined we can create the Fl_Menu_Bar widget
-and assign the menus to it with:
-
-+
+
+ Once we have the menus defined we can create the Fl_Menu_Bar
+ widget and assign the menus to it with: 
+
+ Fl_Menu_Bar *menubar = new Fl_Menu_Bar(0, 0, 640, 30);
-menubar->menu(menuitems);
-
-
-We'll define the callback functions later.
-
+menubar->menu(menuitems);
+

+ We'll define the callback functions later.

Editing the Text

- -To keep things simple our text editor will use the -Fl_Multiline_Input widget to -edit the text: - -

+ To keep things simple our text editor will use the 
+Fl_Multiline_Input widget to edit the text: 
+
+ Fl_Multiline_Input *input = new Fl_Multiline_Input(0, 30, 640, 450);
-
-
-So that we can keep track of changes to the file, we also want to add a
-"changed" callback:
-
--input->callback(changed_cb);
-input->when(FL_WHEN_CHANGED);
-
-
-Finally, we want to use a mono-spaced font like FL_COURIER:
-
--input->textfont(FL_COURIER);
-
-
+

+ So that we can keep track of changes to the file, we also want to add +a "changed" callback: +

+input->callback(changed_cb);
+input->when(FL_WHEN_CHANGED);
+

+ Finally, we want to use a mono-spaced font like FL_COURIER: +

+input->textfont(FL_COURIER);
+

The Replace Dialog

- -We can use the FLTK convenience functions for many of the editor's -dialogs, however the replace dialog needs its own custom window. To -keep things simple we will have a "find" string, a "replace" string, -and "replace all", "replace next", and "cancel" buttons. The strings -are just Fl_Input widgets, the "replace all" and "cancel" -buttons are Fl_Button widgets, and the "replace next " button -is a Fl_Return_Button widget: - -

- -

-Fl_Window *replace_dlg = new Fl_Window(300, 105, "Replace");
-Fl_Input *replace_find = new Fl_Input(70, 10, 200, 25, "Find:");
-Fl_Input *replace_with = new Fl_Input(70, 40, 200, 25, "Replace:");
-Fl_Button *replace_all = new Fl_Button(10, 70, 90, 25, "Replace All");
-Fl_Button *replace_next = new Fl_Button(105, 70, 120, 25, "Replace Next");
-Fl_Button *replace_cancel = new Fl_Button(230, 70, 60, 25, "Cancel");
-

- + We can use the FLTK convenience functions for many of the editor's +dialogs, however the replace dialog needs its own custom window. To +keep things simple we will have a "find" string, a "replace" string, +and "replace all", "replace next", and "cancel" buttons. The strings +are just Fl_Input widgets, the "replace all" and "cancel" +buttons are Fl_Button widgets, and the "replace next " button +is a Fl_Return_Button widget: +

+Fl_Window *replace_dlg = new Fl_Window(300, 105, "Replace");
+Fl_Input *replace_find = new Fl_Input(70, 10, 200, 25, "Find:");
+Fl_Input *replace_with = new Fl_Input(70, 40, 200, 25, "Replace:");
+Fl_Button *replace_all = new Fl_Button(10, 70, 90, 25, "Replace All");
+Fl_Button *replace_next = new Fl_Button(105, 70, 120, 25, "Replace Next");
+Fl_Button *replace_cancel = new Fl_Button(230, 70, 60, 25, "Cancel");
+

Callbacks

- -Now that we've defined the GUI components of our editor, we need to define -our callback functions. - + Now that we've defined the GUI components of our editor, we need to +define our callback functions.

changed_cb()

- -This function will be called whenever the user changes any text in the -input widget: - -

+ This function will be called whenever the user changes any text in the 
+input widget: 
+
+ void changed_cb(void) {
   set_changed(1);
 }
-
-
-The set_changed() function is one that we will write to set the
-changed status on the current file.  We're doing it this way because some
-of the other callbacks will set the changed status to 0, and also because
-we want to show the changed status in the window's title bar.
-
+

+ The set_changed() function is one that we will write to set +the changed status on the current file. We're doing it this way +because some of the other callbacks will set the changed status to 0, +and also because we want to show the changed status in the window's +title bar.

copy_cb()

- -This callback function will call -input->copy() to copy the currently selected text to the -clipboard: - -

+ This callback function will call 
+input->copy() to copy the currently selected text to the 
+clipboard: 
+
+ void copy_cb(void) {
-  input->copy();
+  input->copy();
 }
-
-
+

cut_cb()

- -This callback function will call -input->copy() to copy the currently selected text to the -clipboard and then input->cut() -to delete it: - -

+ This callback function will call 
+input->copy() to copy the currently selected text to the 
+clipboard and then input->cut()
+ to delete it: 
+
+ void cut_cb(void) {
-  input->copy();
-  input->cut();
+  input->copy();
+  input->cut();
 }
-
-
+

delete_cb()

- -This callback function will call -input->cut() to delete the selected text: - -

+ This callback function will call 
+input->cut() to delete the selected text: 
+
+ void delete_cb(void) {
-  input->cut();
+  input->cut();
 }
-
-
+

find_cb()

- -This callback function asks for a search string using the -fl_input() convenience function and -then calls the find2_cb() function to find the string: - -

+ This callback function asks for a search string using the 
+fl_input() convenience function and then calls the 
+find2_cb() function to find the string: 
+
+ void find_cb(void) {
   const char *val;
 
-  val = fl_input("Search String:", search);
+  val = fl_input("Search String:", search);
   if (val != NULL) {
     // User entered a string - go find it!
     strcpy(search, val);
     find2_cb();
   }
 }
-
-
+

find2_cb()

- -This function will find the next occurrence of the search string. If the -search string is blank then we want to pop up the search dialog: - -

+ This function will find the next occurrence of the search string.  If 
+the search string is blank then we want to pop up the search dialog: 
+
+ void find2_cb(void) {
   const char *val, *found;
   int pos;
@@ -238,182 +218,174 @@ void find2_cb(void) {
     return;
   }
 
-  val   = input->value() + input->mark();
+  val   = input->value() + input->mark();
   found = strstr(val, search);
 
   if (found != NULL) {
     // Found a match; update the position and mark...
-    pos = input->mark() + found - val;
-    input->position(pos, pos + strlen(search));
+    pos = input->mark() + found - val;
+    input->position(pos, pos + strlen(search));
   }
-  else fl_alert("No occurrences of \'%s\' found!", search);
+  else fl_alert("No occurrences of \'%s\' found!", search);
 }
-
-
-If the search string cannot be found we use the 
-fl_alert() convenience function to display a message to
-that effect.
-
+

+ If the search string cannot be found we use the +fl_alert() convenience function to display a message to that +effect.

new_cb()

- -This callback function will clear the input widget and current filename. -It also calls the check_save() function to give the user the -opportunity to save the current file first as needed: - -

+ This callback function will clear the input widget and current 
+filename. It also calls the check_save() function to give the 
+user the opportunity to save the current file first as needed: 
+
+ void new_cb(void) {
   if (changed)
     if (!check_save()) return;
 
   filename[0] = '\0';
-  input->value("");
+  input->value("");
   set_changed(0);
 }
-
-
+

open_cb()

- -This callback function will ask the user for a filename and then load -the specified file into the input widget and current filename. It also -calls the check_save() function to give the user the -opportunity to save the current file first as needed: - -

+ This callback function will ask the user for a filename and then load 
+the specified file into the input widget and current filename. It also 
+calls the check_save() function to give the user the 
+opportunity to save the current file first as needed: 
+
+ void open_cb(void) {
   char *newfile;
 
   if (changed)
     if (!check_save()) return;
 
-  newfile = fl_file_chooser("Open File?", "*", filename);
+  newfile = fl_file_chooser("Open File?", "*", filename);
   if (newfile != NULL) load_file(newfile);
 }
-
-
-We call the load_file() function to actually load the file.
-
+

+ We call the load_file() function to actually load the file.

paste_cb()

- -This callback function will send a FL_PASTE message to the input -widget using the Fl::paste() method: - -

+ This callback function will send a FL_PASTE message to the input
+ widget using the Fl::paste()
+ method: 
+
+ void paste_cb(void) {
   Fl::paste(*input);
 }
-
-
+

quit_cb()

- -The quit callback will first see if the current file has been modified, -and if so give the user a chance to save it. It then hides the main window: - -

+ The quit callback will first see if the current file has been 
+modified, and if so give the user a chance to save it. It then hides 
+the main window: 
+
+ void quit_cb(void) {
   if (changed)
     if (!check_save())
       return;
 
-  window->hide();
+  window->hide();
 }
-
-
+

replace_cb()

- -The replace callback just shows the replace dialog: - -

+ The replace callback just shows the replace dialog: 
+
+ void replace_cb(void) {
-  replace_dlg->show();
+  replace_dlg->show();
 }
-
-
+

replace2_cb()

- -This callback will replace the next occurence of the replacement string. If -nothing has been entered for the replacement string, then the replace dialog -is displayed instead: - -

+ This callback will replace the next occurence of the replacement 
+string. If nothing has been entered for the replacement string, then 
+the replace dialog is displayed instead: 
+
+ void replace2_cb() {
   const char *find, *val, *found;
   int pos;
 
-  find = replace_find->value();
+  find = replace_find->value();
   if (find[0] == '\0') {
     // Search string is blank; get a new one...
-    replace_dlg->show();
+    replace_dlg->show();
     return;
   }
 
-  val   = input->value() + input->position();
+  val   = input->value() + input->position();
   found = strstr(val, find);
 
   if (found != NULL) {
     // Found a match; update the position and replace text...
-    pos = input->position() + found - val;
-    input->replace(pos, pos + strlen(find), replace_with->value());
-    input->position(pos + strlen(replace_with->value()));
+    pos = input->position() + found - val;
+    input->replace(pos, pos + strlen(find), replace_with->value());
+    input->position(pos + strlen(replace_with->value()));
   }
-  else fl_alert("No occurrences of \'%s\' found!", find);
+  else fl_alert("No occurrences of \'%s\' found!", find);
 }
-
-
+

replall_cb()

- -This callback will replace all occurences of the search string in the file: - -

+ This callback will replace all occurences of the search string in the 
+file: 
+
+ void replall_cb() {
   const char *find, *val, *found;
   int pos;
   int times;
 
-  find = replace_find->value();
+  find = replace_find->value();
   if (find[0] == '\0') {
     // Search string is blank; get a new one...
-    replace_dlg->show();
+    replace_dlg->show();
     return;
   }
 
-  input->position(0);
+  input->position(0);
   times = 0;
 
   // Loop through the whole string
   do {
-    val   = input->value() + input->position();
+    val   = input->value() + input->position();
     found = strstr(val, find);
 
     if (found != NULL) {
       // Found a match; update the position and replace text...
       times ++;
-      pos = input->position() + found - val;
-      input->replace(pos, pos + strlen(find), replace_with->value());
-      input->position(pos + strlen(replace_with->value()));
+      pos = input->position() + found - val;
+      input->replace(pos, pos + strlen(find), replace_with->value());
+      input->position(pos + strlen(replace_with->value()));
     }
   } while (found != NULL);
 
-  if (times > 0) fl_message("Replaced %d occurrences.", times);
-  else fl_alert("No occurrences of \'%s\' found!", find);
+  if (times > 0) fl_message("Replaced %d occurrences.", times);
+  else fl_alert("No occurrences of \'%s\' found!", find);
 }
-
-
+

replcan_cb()

- -This callback just hides the replace dialog: - -

+ This callback just hides the replace dialog: 
+
+ void replcan_cb() {
-  replace_dlg->hide();
+  replace_dlg->hide();
 }
-
-
+

save_cb()

- -This callback saves the current file. If the current filename is blank it -calls the "save as" callback: - -

+ This callback saves the current file.  If the current filename is 
+blank it calls the "save as" callback: 
+
+ void save_cb(void) {
   if (filename[0] == '\0') {
     // No filename - get one!
@@ -422,54 +394,47 @@ void save_cb(void) {
   }
   else save_file(filename);
 }
-
-
-The save_file() function saves the current file to the specified
-filename.
-
+

+ The save_file() function saves the current file to the +specified filename.

saveas_cb()

- -This callback asks the user for a filename and saves the current file: - -

+ This callback asks the user for a filename and saves the current file: 
+
+ void saveas_cb(void) {
   char *newfile;
 
-  newfile = fl_file_chooser("Save File As?", "*", filename);
+  newfile = fl_file_chooser("Save File As?", "*", filename);
   if (newfile != NULL) save_file(newfile);
 }
-
-
-The save_file() function saves the current file to the specified
-filename.
-
+

+ The save_file() function saves the current file to the +specified filename.

undo_cb()

- -The undo callback just calls the -undo() method: - -

+ The undo callback just calls the 
+undo() method: 
+
+ void undo_cb(void) {
-  input->undo();
+  input->undo();
 }
-
-
+

Other Functions

- -Now that we've defined the callback functions, we need our support functions -to make it all work: - + Now that we've defined the callback functions, we need our support +functions to make it all work:

check_save()

- -This function checks to see if the current file needs to be saved. If -so, it asks the user if they want to save it: - -

+ This function checks to see if the current file needs to be saved.  If 
+so, it asks the user if they want to save it: 
+
+ int check_save(void) {
   if (!changed) return 1;
 
-  if (fl_ask("The current file has not been saved.\n"
-             "Would you like to save it now?")) {
+  if (fl_ask("The current file has not been saved.\n"
+             "Would you like to save it now?")) {
     // Save the file...
     save_cb();
 
@@ -477,62 +442,59 @@ int check_save(void) {
   }
   else return (1);
 }
-
-
+

load_file()

- -This function loads the specified file into the input widget: - -

+ This function loads the specified file into the input widget: 
+
+ void load_file(char *newfile) {
   FILE *fp;
   char buffer[8192];
   int  nbytes;
   int  pos;
 
-  input->value("");
+  input->value("");
 
-  fp = fopen(newfile, "r");
+  fp = fopen(newfile, "r");
   if (fp != NULL) {
     // Was able to open file; let's read from it...
     strcpy(filename, newfile);
     pos = 0;
 
-    while ((nbytes = fread(buffer, 1, sizeof(buffer), fp)) > 0) {
-      input->replace(pos, pos, buffer, nbytes);
+    while ((nbytes = fread(buffer, 1, sizeof(buffer), fp)) > 0) {
+      input->replace(pos, pos, buffer, nbytes);
       pos += nbytes;
     }
 
     fclose(fp);
-    input->position(0);
+    input->position(0);
     set_changed(0);
   } else {
     // Couldn't open file - say so...
-    fl_alert("Unable to open \'%s\' for reading!");
+    fl_alert("Unable to open \'%s\' for reading!");
   }
 }
-
-
-When loading the file we use the 
-input->replace() method to "replace" the text at the end of
-the buffer.  The pos variable keeps track of the end of the
-buffer.
-
+

+ When loading the file we use the +input->replace() method to "replace" the text at the end +of the buffer. The pos variable keeps track of the end of the +buffer.

save_file()

- -This function saves the current buffer to the specified file: - -

+ This function saves the current buffer to the specified file: 
+
+ void save_file(char *newfile) {
   FILE *fp;
 
-  fp = fopen(newfile, "w");
+  fp = fopen(newfile, "w");
   if (fp != NULL) {
     // Was able to create file; let's write to it...
     strcpy(filename, newfile);
 
-    if (fwrite(input->value(), 1, input->size(), fp) < 1) {
-      fl_alert("Unable to write file!");
+    if (fwrite(input->value(), 1, input->size(), fp) < 1) {
+      fl_alert("Unable to write file!");
       fclose(fp);
       return;
     }
@@ -541,17 +503,16 @@ void save_file(char *newfile) {
     set_changed(0);
   } else {
     // Couldn't open file - say so...
-    fl_alert("Unable to create \'%s\' for writing!");
+    fl_alert("Unable to create \'%s\' for writing!");
   }
 }
-
-
+

set_changed()

- -This function sets the changed variable and updates the window label -accordingly: - -

+ This function sets the changed variable and updates the 
+window label accordingly: 
+
+ void set_changed(int c) {
   if (c != changed) {
     char title[1024];
@@ -559,7 +520,7 @@ void set_changed(int c) {
 
     changed = c;
 
-    if (filename[0] == '\0') strcpy(title, "Untitled");
+    if (filename[0] == '\0') strcpy(title, "Untitled");
     else {
       slash = strrchr(filename, '/');
       if (slash == NULL) slash = strrchr(filename, '\\');
@@ -568,36 +529,29 @@ void set_changed(int c) {
       else strcpy(title, filename);
     }
 
-    if (changed) strcat(title, " (modified)");
+    if (changed) strcat(title, " (modified)");
 
-    window->label(title);
+    window->label(title);
   }
 }
-
-
+

Compiling the Editor

- -The complete source for our text editor can be found in the -test/editor.cxx source file. Both the Makefile and Visual C++ -workspace include the necessary rules to build the editor. You can -also compile it using a standard compiler with: - -

+ The complete source for our text editor can be found in the +test/editor.cxx source file. Both the Makefile and Visual C++ +workspace include the necessary rules to build the editor. You can +also compile it using a standard compiler with: +

 CC -o editor editor.cxx -lfltk -lXext -lX11 -lm
-

- -As noted in Chapter 1, you may need to include -compiler and linker options to tell them where to find the FLTK library. -Also, the CC command may also be called gcc or -c++ on your system. - -

Congratulations, you've just built your own text editor! - +

+ As noted in Chapter 1, you may need to +include compiler and linker options to tell them where to find the FLTK +library. Also, the CC command may also be called gcc + or c++ on your system. +

Congratulations, you've just built your own text editor!

The Final Product

- -The final editor window should look like the image below: - -

- - - + The final editor window should look like the image below: +

+ \ No newline at end of file -- cgit v1.2.3