Improve 'test/fltk-versions' demo program

- add code to get the platform and backend
- display platform and backend on screen
- improve and simplify layout (using Fl_Grid)
- add version check indicator

test/fltk-versions.cxx

@@ -1,7 +1,7 @@
 //
 // Library version test program for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2017 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
@@ -14,65 +14,129 @@
 //     https://www.fltk.org/bugs.php
 //
 
+// This program is work in progress and may not be "perfect".
+
 #include <FL/Fl.H>
+#include <FL/platform.H>
 #include <FL/Fl_Window.H>
+#include <FL/Fl_Grid.H>
 #include <FL/Fl_Box.H>
 #include <FL/fl_ask.H>
-
 #include <stdio.h>
 
-static char version[8][80] = { "","","","","","","","" };
+static const int ww = 640, mw = 750;  // initial, max. window width
+static const int wh = 200, mh = 300;  // initial, max. window height
+
+// Function to determine the platform (system and backend).
+// Note: the display must have been opened before this is called.
+// Returns a string describing the system/platform and backend.
+
+static const char *get_platform() {
+#if defined(_WIN32)
+  return "Windows";
+#elif defined(FLTK_USE_X11) || defined(FLTK_USE_WAYLAND)
+# if defined(FLTK_USE_X11)
+  if (fl_x11_display())
+    return "Unix/Linux (X11)";
+# endif
+# if defined(FLTK_USE_WAYLAND)
+  if (fl_wl_display())
+    return "Unix/Linux (Wayland)";
+# endif
+  return "X11 or Wayland (backend unknown or display not opened)";
+#elif defined(__APPLE__)
+  return "macOS (native)";
+#endif
+  return "platform unknown, unsupported, or display not opened";
+}
+
+// set box attributes and optionally set a background color (debug mode)
+
+static void set_attributes(Fl_Widget *w, Fl_Color col) {
+  w->labelfont(FL_COURIER);
+  w->labelsize(16);
+  w->align(FL_ALIGN_CENTER | FL_ALIGN_INSIDE);
+#if (0) // 1 = debug: set a background color for a box (widget)
+  w->box(FL_FLAT_BOX);
+  w->color(col);
+#endif
+}
+
+static char version[9][80];
+
+// Optional: uncomment next line to disable wayland backend
+// FL_EXPORT bool fl_disable_wayland = true;
 
 int main(int argc, char **argv) {
-
   int versions = 0;
+  fl_open_display();
+  const char *platform = get_platform();
+  printf("System/platform   = %s\n", platform);
 
-  sprintf(version[versions++],"FL_VERSION        = %6.4f",FL_VERSION);
+  // Version comparison results (Unicode check marks in comments are experimental)
-  sprintf(version[versions++],"Fl::version()     = %6.4f  %s",Fl::version(),
-    (FL_VERSION == Fl::version()) ? "" : "***");
 
-#ifdef FL_API_VERSION
+  const char *YES = "OK";   // "🗹"; // "✓";
-  sprintf(version[versions++],"FL_API_VERSION    = %6d",FL_API_VERSION);
+  const char *NO  = "FAIL"; // "🗷"; // "❌";
-  sprintf(version[versions++],"Fl::api_version() = %6d  %s",Fl::api_version(),
-    (FL_API_VERSION == Fl::api_version()) ? "" : "***");
-#endif
 
-#ifdef FL_ABI_VERSION
+  sprintf(version[versions++], "FL_VERSION        = %6.4f", FL_VERSION);
-  sprintf(version[versions++],"FL_ABI_VERSION    = %6d",FL_ABI_VERSION);
+  sprintf(version[versions++], "Fl::version()     = %6.4f", Fl::version());
-  sprintf(version[versions++],"Fl::abi_version() = %6d  %s",Fl::abi_version(),
+  sprintf(version[versions++], "%s", (FL_VERSION == Fl::version()) ? YES : NO);
-    (FL_ABI_VERSION == Fl::abi_version()) ? "" : "***");
-#endif
 
-  for (int i=0; i<versions; i++) {
+  sprintf(version[versions++], "FL_API_VERSION    = %6d", FL_API_VERSION);
-    printf("%s\n",version[i]);
+  sprintf(version[versions++], "Fl::api_version() = %6d", Fl::api_version());
+  sprintf(version[versions++], "%s", (FL_API_VERSION == Fl::api_version()) ? YES : NO);
+
+  sprintf(version[versions++], "FL_ABI_VERSION    = %6d", FL_ABI_VERSION);
+  sprintf(version[versions++], "Fl::abi_version() = %6d", Fl::abi_version());
+  sprintf(version[versions++], "%s", (FL_ABI_VERSION == Fl::abi_version()) ? YES : NO);
+
+  for (int i = 0; i < versions; i++) {
+    if (i % 3 == 1)                 // 2nd line followed by check mark or text
+      printf("%s  ", version[i]);
+    else                            // 1st and 3rd line
+      printf("%s\n", version[i]);
   }
   fflush(stdout);
 
 #ifdef FL_ABI_VERSION
   if (FL_ABI_VERSION != Fl::abi_version()) {
     printf("*** FLTK ABI version mismatch: headers = %d, lib = %d ***\n",
-      FL_ABI_VERSION, Fl::abi_version());
+           FL_ABI_VERSION, Fl::abi_version());
     fflush(stdout);
     fl_message("*** FLTK ABI version mismatch: headers = %d, lib = %d ***",
-      FL_ABI_VERSION, Fl::abi_version());
+               FL_ABI_VERSION, Fl::abi_version());
-    // exit(1);
   }
 #endif
 
-  Fl_Window *window = new Fl_Window(670,300);
+  Fl_Window *window = new Fl_Window(ww, wh);
 
-  Fl_Box *box[8];
+  Fl_Grid *grid = new Fl_Grid(0, 0, ww, wh);
-  for (int i=0; i<4; i++) {
+  grid->layout(4, 3, 20, 5);
-    box[2*i]   = new Fl_Box( 10,40+40*i,320,30,version[2*i]);
+
-    box[2*i+1] = new Fl_Box(340,40+40*i,320,30,version[2*i+1]);
+  Fl_Box *title = new Fl_Box(0, 0, 0, 0, platform);
+  set_attributes(title, FL_YELLOW);
+  title->labelfont(FL_HELVETICA_BOLD);
+  grid->widget(title, 0, 0, 1, 3);
+  grid->row_height(0, 40);
+  title->labelsize(20);
+
+  Fl_Box *box[versions];
+  for (int i = 0; i < versions/3; i += 1) {
+    box[3 * i    ] = new Fl_Box(0, 0, 270, 0, version[3 * i]);
+    box[3 * i + 1] = new Fl_Box(0, 0, 270, 0, version[3 * i + 1]);
+    box[3 * i + 2] = new Fl_Box(0, 0,  40, 0, version[3 * i + 2]);
+    grid->widget(box[3 * i],     i + 1, 0);
+    grid->widget(box[3 * i + 1], i + 1, 1);
+    grid->widget(box[3 * i + 2], i + 1, 2);
+    grid->row_height(i + 1, 30);
   }
 
-  for (int i=0; i<8; i++) {
+  for (int i = 0; i < versions; i++)
-    box[i]->labelfont(FL_COURIER);
+    set_attributes(box[i], FL_GREEN);
-    box[i]->align(FL_ALIGN_LEFT | FL_ALIGN_INSIDE);
-  }
 
   window->end();
+  window->resizable(grid);
+  window->size_range(ww, wh, mw, mh);
   window->show(argc, argv);
   return Fl::run();
 }