From 5df5daf78e135e0c8371012ffe56df5cae357755 Mon Sep 17 00:00:00 2001
From: Albrecht Schlosser <albrechts.fltk@online.de>
Date: Wed, 20 Dec 2023 16:56:29 +0100
Subject: Make the 'Forms' compatibility library 'fltk_forms' optional

This library is no longer needed in FLTK itself. There is only one
demo program (test/forms.cxx) that uses it if it is built. The demo
program displays a message if fltk_forms is not available.

The default is 'enabled' for backwards compatibility but this may
be changed to 'disabled' in a future version.
---
 test/CMakeLists.txt | 10 +++++++++-
 test/forms.cxx      | 23 ++++++++++++++++++++---
 2 files changed, 29 insertions(+), 4 deletions(-)

(limited to 'test')

diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index be40319ce..7fea98adc 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -75,6 +75,14 @@ else ()
   set (GLDEMO_SHARED fltk_SHARED)
   endif ()
 
+# Similar approach for the 'forms' demo (shared lib not supported)
+
+if (FLTK_BUILD_FORMS)
+  set (FORMS_LIBS fltk_forms) # implies 'fltk' as well
+else ()
+  set (FORMS_LIBS fltk)
+endif ()
+
 #######################################################################
 
 CREATE_EXAMPLE (adjuster adjuster.cxx fltk)
@@ -106,7 +114,7 @@ CREATE_EXAMPLE (flex_demo flex_demo.cxx fltk)
 CREATE_EXAMPLE (flex_login flex_login.cxx fltk)
 CREATE_EXAMPLE (fltk-versions fltk-versions.cxx fltk)
 CREATE_EXAMPLE (fonts fonts.cxx fltk)
-CREATE_EXAMPLE (forms forms.cxx "fltk_forms;fltk")
+CREATE_EXAMPLE (forms forms.cxx "${FORMS_LIBS}")
 CREATE_EXAMPLE (fullscreen fullscreen.cxx "${GLDEMO_LIBS}")
 CREATE_EXAMPLE (grid_alignment grid_alignment.cxx fltk)
 CREATE_EXAMPLE (grid_buttons grid_buttons.cxx fltk)
diff --git a/test/forms.cxx b/test/forms.cxx
index 84f623649..e19fade77 100644
--- a/test/forms.cxx
+++ b/test/forms.cxx
@@ -19,10 +19,13 @@
 //     https://www.fltk.org/bugs.php
 //
 
-#include <FL/forms.H> // changed for FLTK
+#include <FL/Fl.H>      // FLTK: includes <FL/fl_config.h>
+#ifdef FLTK_HAVE_FORMS  // FLTK: defined in <FL/fl_config.h> since FLTK 1.4.0
 
-static int border = 1; // changed from FL_TRANSIENT for FLTK
-// (this is so the close box and Esc work to close the window)
+#include <FL/forms.H>   // changed for FLTK
+
+static int border = 1;  // changed from FL_TRANSIENT for FLTK
+                        // (this is so the close box and Esc work to close the window)
 
 typedef struct { Fl_Boxtype val; const char *name; } VN_struct;
 
@@ -173,4 +176,18 @@ int main(int argc, char *argv[]) {
     ;
 
   return 0;
+
+}
+
+#else // (!FLTK_HAVE_FORMS)
+
+#include <FL/fl_ask.H>
+
+int main(int argc, char **argv) {
+  fl_message_title("This program needs the Forms compatibility library");
+  fl_message(
+    "Please configure FLTK with Forms enabled (--enable-forms)\n"
+    "or the CMake option FLTK_BUILD_FORMS=ON.");
+  return 0;
 }
+#endif // (FLTK_HAVE_FORMS)
-- 
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