Fluid: restructuring and rejuvenation of the source code.

* Add classes for application and project
* Removed all globals from Fluid.h
* Extracting args and project history into their own classes
* Moving globals into Application class
* Initialize values inside headers for some classes.
* Undo functionality wrapped in a class inside Project.
* File reader and writer are now linked to a project.
* Avoid global project access
* Nodes (former Types) will be managed by a new Tree class.
* Removed static members (hidden globals) form Node/Fl_Type.
* Adding Tree iterator.
* Use nullptr instead of 0, NULL, or 0L
* Renamed Fl_..._Type to ..._Node, FL_OVERRIDE -> override
* Renaming ..._type to ...::prototype
* Splitting Widget Panel into multiple files.
* Moved callback code into widget panel file.
* Cleaning up Fluid_Image -> Image_asset
* Moving Fd_Snap_Action into new namespace fld::app::Snap_Action etc.
* Moved mergeback into proj folder.
* `enum ID` is now `enum class Type`.

1 files changed, 14 insertions, 8 deletions

diff --git a/fluid/io/Project_Writer.h b/fluid/io/Project_Writer.h
index c6e50ca7c..67aebb46e 100644
--- a/fluid/io/Project_Writer.h
+++ b/fluid/io/Project_Writer.h
@@ -1,7 +1,7 @@
 //
-// Fluid file routines for the Fast Light Tool Kit (FLTK).
+// Fluid Project File Writer header for the Fast Light Tool Kit (FLTK).
 //
-// Copyright 1998-2023 by Bill Spitzak and others.
+// 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
@@ -21,25 +21,31 @@
 
 #include <stdio.h>
 
-class Fl_Type;
+class Node;
 
 namespace fld {
+
+class Project;
+
 namespace io {
 
-int write_file(const char *, int selected_only = 0, bool to_codeview = false);
+int write_file(Project &proj, const char *, int selected_only = 0, bool to_codeview = false);
 
 class Project_Writer
 {
 protected:
+  /// Link Project_Writer class to the project.
+  Project &proj_;
+
   // Project output file, always opened in "wb" mode
-  FILE *fout;
+  FILE *fout = nullptr;
   /// If set, one space is written before text unless the format starts with a newline character
-  int needspace;
+  int needspace = 0;
   /// Set if this file will be used in the codeview dialog
-  bool write_codeview_;
+  bool write_codeview_ = false;
 
 public:
-  Project_Writer();
+  Project_Writer(Project &proj);
   ~Project_Writer();
   int open_write(const char *s);
   int close_write();