CMake: add examples folder to build (optional)

- replace misnamed option 'OPTION_BUILD_EXAMPLES' with 'FLTK_BUILD_TEST'
- add option 'FLTK_BUILD_EXAMPLES' to build apps in examples folder
- move examples/fltk-versions.cxx to test/fltk-versions.cxx
- [Travis-CI] enable option 'FLTK_BUILD_EXAMPLES' for automatic builds

2 files changed, 129 insertions, 78 deletions

diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
new file mode 100644
index 000000000..6dadb17af
--- /dev/null
+++ b/examples/CMakeLists.txt
@@ -0,0 +1,129 @@
+#
+# CMakeLists.txt used to build example apps by the CMake build system
+#
+# Copyright 2020 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
+# file is missing or damaged, see the license at:
+#
+#     https://www.fltk.org/COPYING.php
+#
+# Please see the following page on how to report bugs and issues:
+#
+#     https://www.fltk.org/bugs.php
+#
+################################################################################
+
+include (../CMake/fl_create_example.cmake)
+
+set (EXECUTABLE_OUTPUT_PATH ${CMAKE_CURRENT_BINARY_DIR}/../bin/examples)
+file (MAKE_DIRECTORY ${EXECUTABLE_OUTPUT_PATH})
+
+################################################################################
+
+# create separate lists of all source (.cxx) files
+# depending on the required FLTK and system libraries
+
+############################################################
+# simple examples w/o extra libs
+############################################################
+
+set (SIMPLE_SOURCES
+  browser-simple
+  draggable-group
+  howto-add_fd-and-popen
+  howto-browser-with-icons
+  howto-drag-and-drop
+  howto-draw-an-x
+  howto-menu-with-images
+  howto-parse-args
+  howto-remap-numpad-keyboard-keys
+  howto-text-over-image-button
+  menubar-add
+  nativefilechooser-simple-app
+  nativefilechooser-simple
+  progress-simple
+  shapedwindow
+  simple-terminal
+  table-as-container
+  table-simple
+  table-sort
+  table-spreadsheet
+  table-spreadsheet-with-keyboard-nav
+  table-with-keynav
+  table-with-right-column-stretch-fit
+  tabs-simple
+  textdisplay-with-colors
+  texteditor-simple
+  texteditor-with-dynamic-colors
+  tree-as-container
+  tree-custom-draw-items
+  tree-custom-sort
+  tree-of-tables
+  tree-simple
+  wizard-simple
+)
+
+############################################################
+# examples requiring fltk_images
+############################################################
+
+set (IMAGE_SOURCES
+  clipboard
+  howto-simple-svg
+)
+
+############################################################
+# examples requiring OpenGL + libGLEW
+############################################################
+
+set (OPENGL_SOURCES
+  OpenGL3-glut-test
+  OpenGL3test
+)
+
+############################################################
+# create simple example programs
+############################################################
+
+foreach (src ${SIMPLE_SOURCES})
+  CREATE_EXAMPLE (${src} ${src}.cxx fltk)
+endforeach (src)
+
+############################################################
+# create example programs with fltk_images library
+############################################################
+
+foreach (src ${IMAGE_SOURCES})
+  CREATE_EXAMPLE (${src} ${src}.cxx "fltk_images;fltk")
+endforeach (src)
+
+############################################################
+# create example programs with OpenGL + libGLEW
+############################################################
+
+# Note: macOS does not need libGLEW
+
+if (APPLE AND (NOT OPTION_APPLE_X11) AND (NOT OPTION_APPLE_SDL))
+  if (NOT LIB_GLEW)
+    set (LIB_GLEW TRUE)
+  endif ()
+  set (REQUIRED_LIBS fltk_gl fltk ${OPENGL_LIBRARIES})
+else ()
+  set (REQUIRED_LIBS fltk_gl fltk ${OPENGL_LIBRARIES} GLEW)
+endif ()
+
+if (OPENGL_FOUND AND LIB_GLEW)
+  foreach (src ${OPENGL_SOURCES})
+    CREATE_EXAMPLE (${src} ${src}.cxx "${REQUIRED_LIBS}")
+  endforeach (src)
+else ()
+  message (STATUS
+    "OpenGL or libGLEW not present: OpenGL example programs will not be built.")
+  fl_debug_var (OPENGL_FOUND)
+  fl_debug_var (LIB_GLEW)
+  message ("")
+endif (OPENGL_FOUND AND LIB_GLEW)
+
+unset (REQUIRED_LIBS)
diff --git a/examples/fltk-versions.cxx b/examples/fltk-versions.cxx
deleted file mode 100644
index ed80c7b1f..000000000
--- a/examples/fltk-versions.cxx
+++ /dev/null
@@ -1,78 +0,0 @@
-//
-// Library version test program for the Fast Light Tool Kit (FLTK).
-//
-// Copyright 1998-2017 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
-// file is missing or damaged, see the license at:
-//
-//     https://www.fltk.org/COPYING.php
-//
-// Please see the following page on how to report bugs and issues:
-//
-//     https://www.fltk.org/bugs.php
-//
-
-#include <FL/Fl.H>
-#include <FL/Fl_Window.H>
-#include <FL/Fl_Box.H>
-#include <FL/fl_ask.H>
-
-#include <stdio.h>
-
-static char version[8][80] = { "","","","","","","","" };
-
-int main(int argc, char **argv) {
-
-  int versions = 0;
-
-  sprintf(version[versions++],"FL_VERSION        = %6.4f",FL_VERSION);
-  sprintf(version[versions++],"Fl::version()     = %6.4f  %s",Fl::version(),
-    (FL_VERSION == Fl::version()) ? "" : "***");
-
-#ifdef FL_API_VERSION
-  sprintf(version[versions++],"FL_API_VERSION    = %6d",FL_API_VERSION);
-  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_ABI_VERSION    = %6d",FL_ABI_VERSION);
-  sprintf(version[versions++],"Fl::abi_version() = %6d  %s",Fl::abi_version(),
-    (FL_ABI_VERSION == Fl::abi_version()) ? "" : "***");
-#endif
-
-  for (int i=0; i<versions; i++) {
-    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());
-    fflush(stdout);
-    fl_message("*** FLTK ABI version mismatch: headers = %d, lib = %d ***",
-      FL_ABI_VERSION, Fl::abi_version());
-    // exit(1);
-  }
-#endif
-
-  Fl_Window *window = new Fl_Window(670,300);
-
-  Fl_Box *box[8];
-  for (int i=0; i<4; i++) {
-    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]);
-  }
-
-  for (int i=0; i<8; i++) {
-    box[i]->labelfont(FL_COURIER);
-    box[i]->align(FL_ALIGN_LEFT | FL_ALIGN_INSIDE);
-  }
-
-  window->end();
-  window->show(argc, argv);
-  return Fl::run();
-}