Generate code block documentation using FLTK (#1353)

The Doxygen-to-pdf toolchain can not easily generate
pdf's with Japanese and Chinese characters. This patch
generates code blocks by rendering them in FLTK.

1 files changed, 76 insertions, 0 deletions

diff --git a/util/CMakeLists.txt b/util/CMakeLists.txt
new file mode 100644
index 000000000..a89413a19
--- /dev/null
+++ b/util/CMakeLists.txt
@@ -0,0 +1,76 @@
+#
+# CMakeLists.txt to build utilities for the FLTK project using CMake (www.cmake.org)
+#
+# Copyright 1998-2025 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
+#
+
+# Build utilities for FLTK development
+
+# Note: utilities are only built internally during the build process
+# and not installed. They are tools used to generate source files or
+# assist in building documentation.
+
+#######################################################################
+# cmap - colormap generation program
+#######################################################################
+
+# This program produces the contents of "fl_cmap.h"
+# It's used during the build process to generate src/fl_cmap.h
+
+add_executable(cmap cmap.cxx)
+
+# cmap doesn't need to link against FLTK libraries - it's a standalone tool
+target_link_libraries(cmap PRIVATE m)
+
+# Set properties
+set_target_properties(cmap PROPERTIES
+  OUTPUT_NAME cmap
+  EXCLUDE_FROM_ALL TRUE
+)
+
+#######################################################################
+# PDF documentation tool to generate a png image from a
+# Doxygen `@code` segment with international characters
+#######################################################################
+
+if(FLTK_BUILD_PDF_DOCS)
+
+  # PDF documentation helper tool
+  add_executable(code_snapshot
+    code_snapshot.cxx
+    ../fluid/Widgets/Code_Viewer.cxx
+    ../fluid/Widgets/Code_Editor.cxx
+    ../fluid/Widgets/Style_Parser.cxx
+  )
+
+  target_link_libraries(code_snapshot PRIVATE fltk::images)
+
+  set_target_properties(code_snapshot PROPERTIES
+    OUTPUT_NAME code_snapshot
+    EXCLUDE_FROM_ALL FALSE
+  )
+
+  target_include_directories(code_snapshot PRIVATE
+    ../fluid
+  )
+
+  message(STATUS "PDF code snapshot tools will be built (FLTK_BUILD_PDF_DOCS=ON)")
+
+endif(FLTK_BUILD_PDF_DOCS)
+
+#######################################################################
+# Install rules (if any tools need to be installed)
+#######################################################################
+
+# Currently no utilities are installed as they are build-time tools only
+# If you need to install any utilities, add install() commands here