Improve CMake build configuration summary

- simplify and unify build option output
- alignment can be changed in only 2 macros in CMake/fl_summary.cmake
- output system library location of image libraries if applicable

2 files changed, 91 insertions, 0 deletions

diff --git a/CMake/fl_debug_var.cmake b/CMake/fl_debug_var.cmake
index e3423b2ef..8f429889b 100644
--- a/CMake/fl_debug_var.cmake
+++ b/CMake/fl_debug_var.cmake
@@ -43,6 +43,8 @@ function(fl_expand_name out in min_len)
     set(temp "${in}${spaces}${spaces}")
     string(SUBSTRING "${temp}" 0 ${min_len} temp)
     set(${out} "${temp}" PARENT_SCOPE)
+  else()
+    set(${out} "${in}" PARENT_SCOPE)
   endif()
 endfunction(fl_expand_name)
 
diff --git a/CMake/fl_summary.cmake b/CMake/fl_summary.cmake
new file mode 100644
index 000000000..33490a0c6
--- /dev/null
+++ b/CMake/fl_summary.cmake
@@ -0,0 +1,89 @@
+#
+# Macros used by the CMake build system for the Fast Light Tool Kit (FLTK).
+#
+# Copyright 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
+# 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
+#
+
+########################################################################
+# The macros in this file are used to generate the CMake build summary.
+# Fixed widths of title fields are intentionally hard coded in two of
+# these macros so we can easily change the alignment.
+########################################################################
+
+include(${CMAKE_CURRENT_LIST_DIR}/fl_debug_var.cmake)
+
+########################################################################
+# Output a summary line like "<title> <value>"
+########################################################################
+# <title>  will be expanded to a fixed width (can be empty)
+# <value>  text to be displayed
+########################################################################
+
+macro(fl_summary title value)
+  fl_expand_name(label "${title}" 24)
+  message(STATUS "${label} ${value}")
+endmacro(fl_summary title value)
+
+########################################################################
+# Output a summary line like "<title>   will be built ..."
+#                         or "<title>   will not be built ..."
+########################################################################
+# title   will be expanded to a fixed width (must not be empty)
+# subdir  = relative build directory (e.g. lib or bin/test)
+# build   = CMake variable name (bool): whether <title> is built
+# option  = option name the user can set to build <title>
+########################################################################
+
+macro(fl_summary_build title subdir build option)
+  if(${build})
+    set(value "will be built in: ${CMAKE_CURRENT_BINARY_DIR}/${subdir}")
+  else()
+    set(value "will not be built (set ${option}=ON to build)")
+  endif()
+  fl_expand_name(label "${title}" 19)
+  message(STATUS "${label} ${value}")
+endmacro(fl_summary_build title var subdir)
+
+########################################################################
+# Output a simple summary line like "<title>   {Yes|No}"
+########################################################################
+# title   will be expanded to a fixed width (must not be empty)
+# var     = CMake variable name, must evaluate to true or false
+########################################################################
+
+macro(fl_summary_yn title var)
+  if(${var})
+    set(value "Yes")
+  else()
+    set(value "No")
+  endif()
+  fl_summary("${title}" ${value})
+endmacro(fl_summary_yn title var)
+
+########################################################################
+# Output summary line for image libs (bundled or system libs)
+########################################################################
+# title = "Image Libraries" or empty
+# name  = displayed name = { JPEG | PNG | ZLIB }
+# lib   = CMake library name (system library, if it was found)
+########################################################################
+
+macro(fl_summary_image title name lib)
+  fl_expand_name(name4 "${name}" 4)
+  if(FLTK_USE_BUNDLED_${name})
+    set(value "${name4} = Bundled")
+  else()
+    set(value "${name4} = System: ${${lib}}")
+  endif()
+  fl_summary("${title}" "${value}")
+endmacro(fl_summary_image title name lib)