mirror of https://github.com/fltk/fltk
456 lines
15 KiB
Plaintext
456 lines
15 KiB
Plaintext
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FLUID .fl file format version 1.4
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=================================
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This text explains the history of the FLUID .fl format and faithfully describes
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all elements of the format and its caveats.
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History
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-------
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FLUID, the Fast Light User Interface Designer was started in the 1990's loosely
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based on 'fdesign', a GUI designer that came with the 'Forms Library', later
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'XForms Library'. FLUID's .fl file format was originally compatible with the
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fdesign '.fd' format, but evolved somewhat ad hoc to become what it is today.
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Basics
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======
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FLUID is a visual editor, storing the user interface description in .fl files
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with the ability to create ready-to-compile C++ code. FLUID can also be used
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as a command line tool to translate .fl files directly into source code. It
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can be integrated into build scripts and most IDEs as an external tool.
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.fl files describe a hierarchical graphical user interface for the 'FLTK'
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library as a tree structure. Elements in the tree can be FLTK Widgets as well
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as functional components like classes, C++ functions, variables, etc. .
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FLUID calls all elements in the hierarchy 'Type'.
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Line Endings
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------------
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Although FLUID writes all line endings as '\n', readers should tolerate '\r\n'
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MSWindows line endings as well. Except for the Header, the FLUID reader does not
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differentiate between a line ending and a space character outside of a 'word'.
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Unicode
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-------
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FLUID does not handle UTF-8 characters in any special manner (unescaped),
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but stores and reads them verbatim, making UTF-8 character sequences perfectly
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legal in .fl files. FLUID can translate UTF-8 into escape sequence when writing
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source code files.
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File Structure
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--------------
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.fl files start with a 'Header', followed by a list of 'Options', followed
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by a hierarchy of 'Type' entires, the 'Tree'. All elements besides the Header
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are composed of 'Words', 'Strings', and 'Groups'.
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Words
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-----
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Words can be any sequence of ASCII and UTF-8 characters. Words are always
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case-sensitive.
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Simple Words that are composed of 'a'-'z', 'A'-'Z', '0'-'9', and '_' only are
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written verbatim, followed by a space or newline.
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All other character sequences are bracketed between between ‘{‘ and ‘}’ without
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padding spaces. For example, "" is written as ‘{}’, and ".hello" is written as
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`{.hello}`.
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The special characters ‘\’ and ‘#’ are escaped by prepending the ‘\’ character,
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so "#define" is written as '{\#define}`.
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The characters ‘{‘ and ‘}’ are also escaped with a '\' unless every opening
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‘{‘ in the Word is matched with a closing ‘}’.
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Note: line endings are copied verbatim and become significant within a Word.
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Strings
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-------
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Strings are generated with 'printf' statements in the hope that the
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generated text can be read back as one Word, followed by a corresponding
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'scanf' to retrieve the original values.
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Note: As there are no defined start and end markers to a String, a reader must
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know when these Strings appear and be prepared to read them correctly,
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even if the String itself is not useful to the reader.
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Note: All Strings that are generated by the current FLUID source code
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can be read back as a single Word.
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Groups
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------
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To create a hierarchy, Types can be grouped within Types. A Group starts with
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a lone '{' and ends with a lone '}'.
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Note: To know whether a '{' character starts a Word or a Group, the reader must
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know its position within the Type sequence (see 'Types' below).
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Elements
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========
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Header
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------
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The Header for any .fl file is
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# data file for the Fltk User Interface Designer (fluid)
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followed by a newline, followed by
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version <float v>
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wehere 'v' is the version number as in FL_VERSION (major*1.0 + minor * 0.01
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+ patch * 0.0001). So for FLTK 1.3.4, 'v' would be 1.0304
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Note: the version number corresponds not so much to the version of FLUID, but
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to the version of the underlying FLTK library. So unless the version of
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FLTK is finalised, the file format in the GitHub master branch can still
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change unexpectedly.
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Note: if the version number is above the internal version number, FLUID will
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report an error and continue reading, hoping for the best.
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There are no other uses inside the FLUID reader except for fltk2 features
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which is beyond the scope of this document.
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Note: fdesign files (.fd) start with the text "Magic:". FLUID can read these
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files, but Forms/XForms files are beyond the scope of this document.
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Options
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-------
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Options are usually comprised of a Word, two Words, or a Word and a String. If
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an Option is missing, a default value is assumed.
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"Magic:" : used by fdesign, not written by FLUID
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"define_in_struct" : no longer used
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"do_not_include_H_from_C" : don’t generate #include “myDesign.h”
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"use_FL_COMMAND" : use macOS CMD key instead of Ctrl
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"utf8_in_src" : allow UTF-8 when writing source code, otherwise
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escape UTF-8 sequences in source code
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"avoid_early_includes" : generate the '#include <FL/Fl.H>' statement late
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"i18n_type" <word> : integer 0=default=none, 1=gettext, 2=catgets
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"i18n_function" <word> : function name, e.g. “gettext”
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"i18n_static_function" <word> : function name, e.g. “gettext_noop”
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"i18n_file" <word> : file name
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"i18n_set" <word> : string
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"i18n_include" <word> : file name, e.g. “<libintl.h>”
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"i18n_conditional" <word> : string
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"header_name" <word> : can be the full filename, or just the
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extension e.g. “.h” in which case FLUID will use the same filename
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as the .fl file.
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"code_name" <word> : can be the full filename, or just the
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extension e.g. “.cxx”
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"snap" <word> : ignored
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"gridx" <word> : ignored
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"gridy" <word> : ignored
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Note: There is no keyword that marks the end of the Options section. The
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Option list ends when a Word is not in the Options list and it is in
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the list of known Types.
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If the Word is neither an Option nor a vaild Type, FLUID will give an
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error message and try to continue to read the file. Using new Option
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keywords makes .fl files incompatible to earlier versions of FLUID.
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Due to the forgiving interpreter, files may still be read correctly
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despite error messages.
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If a Word is in the list of known Types, the Type is read, including
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optional children. No more Options are allowed beyond this point.
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Tree
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====
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If a keyword is read that is not in the Option list, we start reading Types.
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Types represent all possible entries in the hierarchy including C functions,
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class definitions, and of course all Widgets. A Type is any of the supported
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Widgets classes, or one of the following:
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Function, code, codeblock, decl, data, declblock, comment, class, widget_class
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Every Type keyword is followed by a Word, which is usually interpreted as the
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C++ name of the Type, followed by an opening `{`, a list of properties, and
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a closing ‘}’. If the Type has children, they are stored in a Group between
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another opening ‘{‘, followed by a list of Types, followed by a closing ‘}’.
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Fl_Group MyGroup { Type name start_of_options
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label Surprise ... Option parameter
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} { end_of_options start_of_children
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Fl_Button {} { Type name start_of_options
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label {Don't panic...!} Option parameter
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hide Option
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} end_of_options
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} end_of_children
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The file ends when there are no more Types.
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Note: the "class" Type has an additional Word following immediately after
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the keyword. It contains the prefix for the class. A class definition may
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be written as:
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class FL_EXPORT MyClass { ...properties... } { ...children... }
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or without a prefix as
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class {} MyOtherClass { ...properties... } { ...children... }
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Types
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-----
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Type names are based on FLTK class names. Types derive properties from super
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Types loosely similar to FLTK.
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Note: the hierarchical dependency is implemented twice and somewhat conflicting
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in FLUID via the Fl_..._Type hierarchy, and by using '::is_some_type()'
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virtual functions, which does not always match the Type hierarchy.
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The list of known Types and their inheritance is:
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Fl_Type (note: can't be written)
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+-- Function
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+-- code
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+-- codeblock
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+-- decl
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+-- data
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+-- declblock
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+-- comment
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+-- class
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+-- Fl_Widget (note: can't be written)
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| +-- Fl_Window
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| | +-- widget_class
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| +-- Fl_Group
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| | +-- Fl_Pack
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| | +-- Fl_Flex
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| | +-- Fl_Table
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| | +-- Fl_Tabs
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| | +-- Fl_Scroll
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| | +-- Fl_Tile
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| | +-- Fl_Wizard
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| +-- Fl_Menu_Type (note: can't be written)
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| | +-- Fl_Menu_Button
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| | +-- Fl_Choice
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| | +-- Fl_Input_Choice
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| | +-- Fl_Menu_Bar
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| | +-- Fl_
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| +-- Fl_Box
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| +-- Fl_Button
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| | +-- Fl_Return_Button
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| | +-- Fl_Light_Button
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| | +-- Fl_Check_Button
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| | +-- Fl_Round_Button
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| +-- Fl_Repeat_Button
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| +-- Fl_Browser
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| +-- Fl_Check_Browser
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| +-- Fl_Tree
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| +-- Fl_File_Browser
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| +-- Fl_Counter
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| +-- Fl_Spinner
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| +-- Fl_Input
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| | +-- Fl_Output
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| +-- Fl_File_Input
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| +-- Fl_Text_Display
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| +-- Fl_Text_Editor
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| | +-- Fl_Simple_Terminal
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| +-- Fl_Clock
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| +-- Fl_Help_View
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| +-- Fl_Progress
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| +-- Fl_Adjuster
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| +-- Fl_Dial
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| +-- Fl_Roller
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| +-- Fl_Slider
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| | +-- Fl_Scrollbar
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| | +-- Fl_Value_Slider
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| +-- Fl_Value_Input
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| +-- Fl_Value_Output
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.
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Properties
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----------
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Properties have zero or one Words as their arguments. The number of arguments
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are defined per property per Type. The content of the argument Word is defined
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by the implementation of the property and can contain mutiple values, as
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described above in Strings.
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Properties are inherited from super Types. They can be limited to certain Types
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by calls to 'MyType->is_some_type()'. All properties are optional, some are
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mutually exclusive.
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Note: It is possible that the same property by name has different arguments
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when used in a different Type.
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Type Fl_Type <word>
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“label” <word> : text
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“user_data” <word> : a value or an expression
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“user_data_type” <word> : usually “void*” or “long”
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“callback” <word> : a function name or a function body
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“comment” <word> : one or many lines of text
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“open” : Group content visible in the FLUID tree browser
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“selected” : Type was selected in tree view
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Type "Function" <word> : function signature
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none or "private" or "protected" : for methods in classes, or to mark
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functions static in a file, default is public
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“C” : if set, function is extern “C”
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“return_type” <word> : C or C++ type descriptor, can start with “virtual”
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and/or “static” to further define the function.
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... : inherits more from Fl_Type
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Type codeblock <word> : C++ code, for example "if (test())"
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"after" <word> : C++ code or comment following the closing '}'
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... : inherits more from Fl_Type
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Type "decl" <word> : C++ code to declare a variable or class member
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none or "public" or "private" or "protected" : for declarations within classes
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defaults to "private"
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none or "local" or "global": for declaration in the code body
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defaults to "global"
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... : inherits more from Fl_Type
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Type "data" <word> : C++ variable name
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"filename" <word> : name or path as entered by user, forward slashes
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"textmode" : defaults to binary mode
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... : inherits more from decl
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Type "declblock" <word> : C++ code
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none or "public" or "protected" : defaults to private
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"after" <word> : C++ code or comment following the block
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... : inherits more from Fl_Type
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Type "comment" <word> : comment text
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"in_source" or "not_in_source": default to in_source
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"in_header" or "not_in_header": default to in_header
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... : inherits more from Fl_Type
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Type "class" <word> <word> : prefix, class name
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none or "private" or "protected" : defaults to public
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":" <word> : name of super class
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... : inherits more from Fl_Type
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Type "Fl_Widget" <word> : C++ variable name
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none or "private" or "protected" : default is public
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"xywh" <word> : "{%d %d %d %d}" x, y, w, h
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"tooltip" <word> : tooltip text
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"image" <word> : image name
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"compress_image" <word> : integer (1.4 and up, only if `image` is set)
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"bind_image" <word> : integer (1.4 and up)
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"deimage" <word> : deactivated image name
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"compress_deimage" <word> : integer (1.4 and up, only if `deimage` is set)
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"bind_deimage" <word> : integer (1.4 and up)
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"type" <word> : integer
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"box" <word> : text or integer (see FLTK boxtypes)
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"down_box" <word> : (is_button() or Fl_Input_choice" or is_menu_button())
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text or integer (see FLTK boxtypes)
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"value" <word> : (is_button()) integer
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"value" <word> : (is_valuator(), is_spinner()) double
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"color" <word> :
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If Word starts with "0x", the rest of the field is a hex number.
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If two integers follow, this is color and selection_color (deprecated).
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If one integer follows, it's the color index.
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"selection_color" <word> : integer color index
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"labeltype" <word> :
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If the Word is "image", TBD.
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Or one of "NORMAL_LABEL", "SHADOW_LABEL", "ENGRAVED_LABEL",
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"EMBOSSED_LABEL", or "NO_LABEL"
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"labelfont" <word> : integer, font index
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"labelsize" <word> : integer
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"labelcolor" <word> : integer, color index
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"align" <word> : integer, see Fl_Align
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"when" <word> : integer, see Fl_When
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"minimum" <word> : (is_valuator(), is_spinner()) double
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"maximum" <word> : (is_valuator(), is_spinner()) double
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"step" <word> : (is_valuator(), is_spinner()) double
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"slider_size" <word> : (is_valuator()==2) double
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"size" <word> : (is_valuator()==2) double
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"textfont" <word> : integer, font index
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"textsize" <word> : integer
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"textcolor" <word> : integer, color index
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"hide" : default visible
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"deactivate" : default active
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"resizable" : default fixed
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"hotspot" : make a Widget a hotspot
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"divider" : add a divider under a menu item
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"class" <word> : superclass
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"shortcut" <word> : integer
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"code0" or "code1" or "code2" or "code3" <word> : C++ extra code lines
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"extra_code" <word> : C++ extra code lines
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... : inherits more from Fl_Type
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Type "Fl_Flex" <word> : C++ variable name
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"margins" <word> : this Word is written with printf as "{%d %d %d %d}",
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left, top, right, bottom
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"gap" <word> : integer
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"fixed_size_tuples" <word> : this Word is written with printf "{%d", where %d
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encodes the number of tuples to follow, and zero or more " %d %d"
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containing the index and size of that child, followed by a '}'.
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... : inherits more from Fl_Group
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Type "Fl_Window" <word> : C++ variable name
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none or "modal", or "non_modal": defaults to not modal (which is
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different to non_modal!)
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"visible" : show window when opening file in FLUID
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"noborder" : borderless window
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"xclass" <word> : see FLTK
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"size_range" : this Word is written with printf as "{%d %d %d %d}",
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min_w, min_h, max_w, max_h
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"xywh" <word> : this Word is written with printf as "{%d %d %d %d}",
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x, y, w, h. This as actually read in the Fl_Widget Type, but here
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it ensures that window is not created as a subwindow.
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... : inherits more from Fl_Widget (not Fl_Group)
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Please report errors and omissions to the fltk.coredev or fltk.general
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Google group. Thank you.
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- Matthias
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