Update FLTK colormap (src/fl_cmap.h) w/o changing colors

- update comments, including filenames
- update build instructions for developers in util/cmap.cxx
- update CMakeLists.txt (comments only)

1 files changed, 7 insertions, 2 deletions

diff --git a/util/README.txt b/util/README.txt
index c71f6b147..08714c4f7 100644
--- a/util/README.txt
+++ b/util/README.txt
@@ -3,7 +3,8 @@ Utility programs used to build the FLTK library.
 
 Contents:
 
-  cmap.cxx              generate src/fl_cmap.h
+  cmap.cxx              generate the built-in colormap (src/fl_cmap.h)
+
   code_snapshot.cxx     PDF documentation tool to generate a png image from a
                         Doxygen `@code` segment with international characters
 
@@ -13,7 +14,11 @@ Build System:
   automatically during the build process when needed. Some utilities
   are only built when specific features are enabled:
 
-  - the PDF documentation helper is only built when FLTK_BUILD_PDF_DOCS=ON
+  - The colormap generator `bin/cmap` is only built manually if needed
+    to generate a new colormap (src/fl_cmap.h).
+    See instructions in util/cmap.cxx.
+
+  - The PDF documentation helper is only built when FLTK_BUILD_PDF_DOCS=ON.
 
   To add a new utility, edit util/CMakeLists.txt and follow the existing
   patterns for conditional building and target configuration.