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, 145 insertions, 0 deletions

diff --git a/fluid/Project.h b/fluid/Project.h
new file mode 100644
index 000000000..e60f7bc26
--- /dev/null
+++ b/fluid/Project.h
@@ -0,0 +1,145 @@
+//
+// Fluid Project header for the Fast Light Tool Kit (FLTK).
+//
+// 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
+//
+
+
+#ifndef FLUID_PROJECT_H
+#define FLUID_PROJECT_H
+
+#include "proj/undo.h"
+#include "nodes/Tree.h"
+
+#include <string>
+
+// ---- project class declaration
+
+
+namespace fld {
+
+namespace app {
+  class Layout_Preset;
+  extern Layout_Preset *default_layout_preset;
+} // namespace app
+
+/**
+ Enumeration of available internationalization types.
+ */
+enum class I18n_Type {
+  NONE = 0, ///< No i18n, all strings are litearals
+  GNU,      ///< GNU gettext internationalization
+  POSIX     ///< Posix catgets internationalization
+};
+
+
+/**
+ Data and settings for a FLUID project file.
+ */
+class Project
+{
+public: // Member Variables
+  // Undo actions for this Project.
+  proj::Undo undo { *this };
+
+  // Manage the node tree of the project.
+  node::Tree tree { *this };
+
+  /// One of the available internationalization types.
+  fld::I18n_Type i18n_type = I18n_Type::NONE;
+  /// Include file for GNU i18n, writes an #include statement into the source
+  /// file. This is usually `<libintl.h>` or `"gettext.h"` for GNU gettext.
+  std::string i18n_gnu_include = "<libintl.h>";
+  // Optional name of a macro for conditional i18n compilation.
+  std::string i18n_gnu_conditional = "";
+  /// For the gettext/intl.h options, this is the function that translates text
+  /// at runtime. This is usually "gettext" or "_".
+  std::string i18n_gnu_function = "gettext";
+  /// For the gettext/intl.h options, this is the function that marks the translation
+  /// of text at initialisation time. This is usually "gettext_noop" or "N_".
+  std::string i18n_gnu_static_function = "gettext_noop";
+
+  /// Include file for Posix i18n, write a #include statement into the source
+  /// file. This is usually `<nl_types.h>` for Posix catgets.
+  std::string i18n_pos_include = "<nl_types.h>";
+  // Optional name of a macro for conditional i18n compilation.
+  std::string i18n_pos_conditional = "";
+  /// Name of the nl_catd database
+  std::string i18n_pos_file = "";
+  /// Message set ID for the catalog.
+  std::string i18n_pos_set = "1";
+
+  /// If set, generate code to include the header file form the c++ file
+  int include_H_from_C = 1;
+  /// If set, handle keyboard shortcut Ctrl on macOS using Cmd instead
+  int use_FL_COMMAND = 0;
+  /// Clear if UTF-8 characters in statics texts are written as escape sequences
+  int utf8_in_src = 0;
+  /// If set, <FL/Fl.H> will not be included from the header code before anything else
+  int avoid_early_includes = 0;
+  /// If set, command line overrides header file name in .fl file.
+  int header_file_set = 0;
+  ///  If set, command line overrides source code file name in .fl file.
+  int code_file_set = 0;
+  /// later
+  int write_mergeback_data = 0;
+  /// Filename of the current .fl project file
+  const char *proj_filename { nullptr };
+  /// Hold the default extension for header files, or the entire filename if set via command line.
+  std::string header_file_name = ".h";
+  /// Hold the default extension for source code  files, or the entire filename if set via command line.
+  std::string code_file_name = ".cxx";
+
+  /// Used as a counter to set the .fl project dir as the current directory.
+  int in_project_dir { 0 };
+  /// Application work directory, stored here when temporarily changing to the source code directory.
+  std::string app_work_dir = "";
+
+  /// Set if the current design has been modified compared to the associated .fl design file.
+  int modflag { 0 };
+  /// Set if the code files are older than the current design.
+  int modflag_c { 0 };
+
+  /// Currently used layout preset.
+  app::Layout_Preset *layout { app::default_layout_preset };
+
+public: // Methods
+  Project();
+  ~Project();
+  void reset();
+  void update_settings_dialog();
+
+  std::string projectfile_path() const;
+  std::string projectfile_name() const;
+  std::string codefile_path() const;
+  std::string codefile_name() const;
+  std::string headerfile_path() const;
+  std::string headerfile_name() const;
+  std::string stringsfile_path() const;
+  std::string stringsfile_name() const;
+  std::string basename() const;
+
+  void enter_project_dir();
+  void leave_project_dir();
+  
+  void set_filename(const char *c);
+  void write_strings();
+
+  void set_modflag(int mf, int mfc = -1);
+};
+
+} // namespace fld
+
+#endif // FLUID_PROJECT_H
+
+