Update test/input_choice demo (#978)

- add Fl_Choice widget for layout comparison
- rewrite button callbacks
- improve layout and other details

This is a follow-up to issue #978, "merging" the existing input_choice
demo with "choicetest_v3" as mentioned.

test/input_choice.cxx

@@ -1,7 +1,7 @@
 //
-// Test program for Fl_Input_Choice
+// Test program for Fl_Input_Choice and Fl_Choice
 //
-// Copyright 1998-2010 by Bill Spitzak and others.
+// Copyright 1998-2024 by Bill Spitzak and others.
 //
 // This library is free software. Distribution and use rights are outlined in
 // the file "COPYING" which should have been included with this file.  If this
@@ -14,54 +14,84 @@
 //     https://www.fltk.org/bugs.php
 //
 
-#include <stdio.h>
-#include <FL/Fl_Button.H>
 #include <FL/Fl_Double_Window.H>
 #include <FL/Fl_Input_Choice.H>
+#include <FL/Fl_Choice.H>
 #include <FL/Fl_Scheme_Choice.H>
+#include <FL/Fl_Check_Button.H>
 #include <FL/Fl_Terminal.H>
 
-#define TERMINAL_HEIGHT 120
+#define TERMINAL_HEIGHT 150
 
 // Globals
 Fl_Terminal *G_tty = 0;
 
-void buttcb(Fl_Widget*,void*data) {
-    Fl_Input_Choice *in=(Fl_Input_Choice *)data;
-    static int flag = 1;
-    flag ^= 1;
-    if ( flag ) in->activate();
-    else        in->deactivate();
-    if (in->changed()) {
-        G_tty->printf("Callback: changed() is set\n");
-        in->clear_changed();
-    }
+void active_cb(Fl_Widget *w, void *data) {
+  Fl_Check_Button *b = (Fl_Check_Button *)w;
+  Fl_Group *g = (Fl_Group *)data;
+  if (b->value()) {
+    g->activate();
+    G_tty->printf("activate group\n");
+  } else {
+    g->deactivate();
+    G_tty->printf("deactivate group\n");
+  }
+  g->redraw();
+  if (b->changed()) {
+    G_tty->printf("Callback: changed() is set\n");
+    b->clear_changed();
+  }
 }
 
-void input_choice_cb(Fl_Widget*,void*data) {
-    Fl_Input_Choice *in=(Fl_Input_Choice *)data;
-    G_tty->printf("Value='%s'\n", (const char*)in->value());
+void input_choice_cb(Fl_Widget *, void *data) {
+  Fl_Input_Choice *in = (Fl_Input_Choice *)data;
+  G_tty->printf("Fl_Input_Choice value='%s'\n", (const char *)in->value());
+}
+
+void choice_cb(Fl_Widget *, void *data) {
+  Fl_Choice *in = (Fl_Choice *)data;
+  G_tty->printf("Fl_Choice       value='%d'\n", in->value());
 }
 
 int main(int argc, char **argv) {
-    Fl_Double_Window win(300, 200+TERMINAL_HEIGHT);
-    G_tty = new Fl_Terminal(0,200,win.w(),TERMINAL_HEIGHT);
+  Fl_Window *win = new Fl_Double_Window(300, 200 + TERMINAL_HEIGHT);
 
-    Fl_Input_Choice in(40,40,100,28,"Test");
-    in.callback(input_choice_cb, (void*)&in);
-    in.add("one");
-    in.add("two");
-    in.add("three");
-    in.value(1);
+  G_tty = new Fl_Terminal(0, 200, win->w(), TERMINAL_HEIGHT);
 
-    // Interactive control of scheme
-    Fl_Scheme_Choice sch(100, 120, 140, 25, "Scheme");
+  // this group can be activated and deactivated:
+  Fl_Group *active_group = new Fl_Group(0, 0, 300, 120);
 
-    Fl_Button onoff(40,150,200,28,"Activate/Deactivate");
-    onoff.callback(buttcb, (void*)&in);
+  // all *_Choice widgets must be aligned for easier visual comparison:
 
-    win.end();
-    win.resizable(win);
-    win.show(argc, argv);
-    return Fl::run();
+  Fl_Input_Choice *in = new Fl_Input_Choice(180, 40, 100, 25, "Fl_Input_Choice:");
+  in->callback(input_choice_cb, (void *)in);
+  in->add("one");
+  in->add("two");
+  in->add("three");
+  in->value(0);
+
+  Fl_Choice *choice = new Fl_Choice(180, 70, 100, 25, "Fl_Choice:");
+  choice->callback(choice_cb, (void *)choice);
+  choice->add("aaa");
+  choice->add("bbb");
+  choice->add("ccc");
+  choice->value(1);
+
+  active_group->end();
+
+  // Interactive control of scheme
+  Fl_Scheme_Choice *sch = new Fl_Scheme_Choice(180, 120, 100, 25, "Choose scheme:");
+  sch->visible_focus(0);
+
+  Fl_Check_Button *active = new Fl_Check_Button(50, 160, 160, 30, "Activate/deactivate");
+  active->callback(active_cb, (void *)active_group);
+  active->value(1);
+
+  win->end();
+  win->resizable(win);
+  win->size_range(200, 160);
+  win->show(argc, argv);
+  Fl::run();
+  delete win;
+  return 0;
 }