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, 149 insertions, 0 deletions

diff --git a/fluid/nodes/Button_Node.h b/fluid/nodes/Button_Node.h
new file mode 100644
index 000000000..ecdc8cc24
--- /dev/null
+++ b/fluid/nodes/Button_Node.h
@@ -0,0 +1,149 @@
+//
+// Button Node header file 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_NODES_BUTTON_NODE_H
+#define FLUID_NODES_BUTTON_NODE_H
+
+#include "nodes/Widget_Node.h"
+
+/**
+ \brief A handler for the simple push button and a base class for all other buttons.
+ */
+class Button_Node : public Widget_Node
+{
+public:
+  typedef Widget_Node super;
+  static Button_Node prototype;
+private:
+  Fl_Menu_Item *subtypes() override;
+public:
+  void ideal_size(int &w, int &h) override;
+  const char *type_name() override { return "Fl_Button"; }
+  const char *alt_type_name() override { return "fltk::Button"; }
+  Fl_Widget *widget(int x, int y, int w, int h) override;
+  Widget_Node *_make() override { return new Button_Node(); }
+  int is_button() const override { return 1; }
+  Type type() const override { return Type::Button; }
+  bool is_a(Type inType) const override { return (inType==Type::Button) ? true : super::is_a(inType); }
+  void write_properties(fld::io::Project_Writer &f) override;
+  void read_property(fld::io::Project_Reader &f, const char *) override;
+  void copy_properties() override;
+};
+
+// ---- Return Button ----
+
+/**
+ \brief The Return Button is simply a Button with the return key as a hotkey.
+ */
+class Return_Button_Node : public Button_Node
+{
+public:
+  typedef Button_Node super;
+  static Return_Button_Node prototype;
+public:
+  void ideal_size(int &w, int &h) override;
+  const char *type_name() override { return "Fl_Return_Button"; }
+  const char *alt_type_name() override { return "fltk::ReturnButton"; }
+  Fl_Widget *widget(int x, int y, int w, int h) override;
+  Widget_Node *_make() override { return new Return_Button_Node(); }
+  Type type() const override { return Type::Return_Button; }
+  bool is_a(Type inType) const override { return (inType==Type::Return_Button) ? true : super::is_a(inType); }
+};
+
+// ---- Repeat Button ----
+
+/**
+ \brief Handler for Fl_Repeat_Button.
+ \note Even though Fl_Repeat_Button is somewhat limited compared to Fl_Button,
+ and some settings may not make much sense, it is still derived from it,
+ so the wrapper should be as well.
+ */
+class Repeat_Button_Node : public Button_Node
+{
+public:
+  typedef Button_Node super;
+  static Repeat_Button_Node prototype;
+public:
+  const char *type_name() override { return "Fl_Repeat_Button"; }
+  const char *alt_type_name() override { return "fltk::RepeatButton"; }
+  Fl_Widget *widget(int x, int y, int w, int h) override;
+  Widget_Node *_make() override { return new Repeat_Button_Node(); }
+  Type type() const override { return Type::Repeat_Button; }
+  bool is_a(Type inType) const override { return (inType==Type::Repeat_Button) ? true : super::is_a(inType); }
+};
+
+// ---- Light Button ----
+
+/**
+ \brief A handler for a toggle button with an indicator light.
+ */
+class Light_Button_Node : public Button_Node
+{
+public:
+  typedef Button_Node super;
+  static Light_Button_Node prototype;
+public:
+  void ideal_size(int &w, int &h) override;
+  const char *type_name() override { return "Fl_Light_Button"; }
+  const char *alt_type_name() override { return "fltk::LightButton"; }
+  Fl_Widget *widget(int x, int y, int w, int h) override;
+  Widget_Node *_make() override { return new Light_Button_Node(); }
+  Type type() const override { return Type::Light_Button; }
+  bool is_a(Type inType) const override { return (inType==Type::Light_Button) ? true : super::is_a(inType); }
+};
+
+// ---- Check Button ----
+
+/**
+ \brief Manage buttons with a check mark on its left.
+ */
+class Check_Button_Node : public Button_Node
+{
+public:
+  typedef Button_Node super;
+  static Check_Button_Node prototype;
+public:
+  void ideal_size(int &w, int &h) override;
+  const char *type_name() override { return "Fl_Check_Button"; }
+  const char *alt_type_name() override { return "fltk::CheckButton"; }
+  Fl_Widget *widget(int x, int y, int w, int h) override;
+  Widget_Node *_make() override { return new Check_Button_Node(); }
+  Type type() const override { return Type::Check_Button; }
+  bool is_a(Type inType) const override { return (inType==Type::Check_Button) ? true : super::is_a(inType); }
+};
+
+// ---- Round Button ----
+
+/**
+ \brief Manage buttons with a round indicator on its left.
+ */
+class Round_Button_Node : public Button_Node
+{
+public:
+  typedef Button_Node super;
+  static Round_Button_Node prototype;
+public:
+  void ideal_size(int &w, int &h) override;
+  const char *type_name() override { return "Fl_Round_Button"; }
+  const char *alt_type_name() override { return "fltk::RadioButton"; }
+  Fl_Widget *widget(int x, int y, int w, int h) override;
+  Widget_Node *_make() override { return new Round_Button_Node(); }
+  Type type() const override { return Type::Round_Button; }
+  bool is_a(Type inType) const override { return (inType==Type::Round_Button) ? true : super::is_a(inType); }
+};
+
+
+#endif // FLUID_NODES_BUTTON_NODE_H