231 lines
9.5 KiB
HTML
231 lines
9.5 KiB
HTML
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<HTML>
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<BODY>
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<H1 ALIGN=RIGHT><A NAME="forms">E - Forms Compatibility</A></H1>
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<a href="#fluid">Fluid</a> (the Fast Light User Interface Designer)
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can read the .fd files put out by all versions of Forms and XForms
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fdesign. However, it will mangle them a bit, but it prints a warning
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message about anything it does not understand. Fluid cannot write
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fdesign files, so you should save to a new name so you don't write
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over the old one.
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<p>You will need to edit your main code considerably to get it to link
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with the output from fluid. If you are not interested in this you may
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have more immediate luck with the forms compatability header,
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<tt><FL/forms.H></tt>.
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<p>You should be able to compile existing Forms or XForms source code
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by changing the -I switch to your compiler so that the forms.h file
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supplied with FLTK is included. Take a look at forms.h to see how it
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works, but the basic trick is lots of inline functions.
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Most of the XForms demo programs work without changes.
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<p>Although FLTK was designed to be compatable with the GL Forms library
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(version 0.3 or so), XForms has bloated severely and it's interface is
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X specific. Therefore, XForms compatability is no longer a goal of
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FLTK. Compatability was limited to things that were free, or that
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would add code that would not be linked in if the feature is unused.
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I did not add anything that would make the FLTK widgets bigger, or that
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used X types as arguments.
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<p>To use any new features of FLTK, you should rewrite your code to not
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use the inline functions and instead use "pure" FLTK. This
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will make it a lot cleaner and make it easier to figure out how to
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call the FLTK functions. Unfortunately this conversion is harder than I
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expeceted and even our inhouse code still uses forms.H a lot.
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<h2>Problems you will encounter</h2>
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<ul>
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<p><li>Many parts of XForms use X-specific structures like XEvent in
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their interface. I did not emulate these! Unfortunately these
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features (such as the "canvas" widget) are needed by most large
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programs. You will need to rewrite these to use FLTK subclasses.
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<p><li><a href=Fl_Free.html>Fl_Free</a> widgets emulate the <i>old</i>
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Forms "free" widget. It may be useful for porting programs that
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change the handle() function on widgets, but you will still need to
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rewrite things.
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<P><li><a href=Fl_Timer.html>Fl_Timer</a> widgets are provided to
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emulate the XForms timer. These work, but are quite inefficient
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and inaccurate compared to using Fl::add_timeout().
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<p><li><i>All instance variables are hidden.</i>
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If you directly refer to the x, y, w, h, label, or other fields of
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your Forms widgets you will have to add empty parenthesis after each
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reference. The easiest way to do this is to globally replace "->x"
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with "->x()", etc. Replace "boxtype" with box().
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<p><li>const char* arguments to most FLTK methods are simply stored, while
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Forms would strdup() the passed string. This is most noticable with the
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label of widgets. Your program must always pass static data such as a
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string constant or malloc'd buffer to label(). If you are using
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labels to display program output you may want to try the <a
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href=Fl_Output.html>Fl_Output</a> widget.
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<p><li>The default fonts and sizes are matched to the older GL version of
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Forms, so all labels will draw somewhat larger than an XForms program
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does.
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<p><li>fdesign outputs a setting of a "fdui" instance variable to the main
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window. I did not emulate this because I wanted all instance
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variables to be hidden. You can store the same information in the
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user_data() field of a window. To do this,
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search through the fdesign output for all occurances
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of "->fdui" and edit to use "->user_data()" instead. This will
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require casts and is not trivial.
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<p><li>The prototype for the functions passed to fl_add_timeout() and
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fl_set_idle_callback() callback are different.
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<p><li><b>All the following XForms calls are missing:</b><p>
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<li><code>FL_VERSION, FL_REVISION</code>, fl_library_version()
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<li><code>FL_RETURN_DBLCLICK</code> (use Fl::event_clicks())
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<li>fl_add_signal_callback()
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<li>fl_set_form_atactivate() & fl_set_form_atdeactivate()
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<li>fl_set_form_property()
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<li>fl_set_app_mainform(), fl_get_app_mainform()
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<li>fl_set_form_minsize(), fl_set_form_maxsize()
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<li>fl_set_form_event_cmask(), fl_get_form_event_cmask()
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<li>fl_set_form_dblbuffer(), fl_set_object_dblbuffer() (use an
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Fl_Double_Window instead)
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<li>fl_adjust_form_size()
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<li>fl_register_raw_callback()
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<li>fl_set_object_bw(), fl_set_border_width()
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<li>fl_set_object_resize(), fl_set_object_gravity()
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<li>fl_set_object_shortcutkey()
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<li>fl_set_object_automatic()
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<li>fl_get_object_bbox() (maybe FLTK should do this)
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<li>fl_set_object_prehandler(), fl_set_object_posthandler()
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<li>fl_enumerate_fonts()
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<li>Most drawing functions
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<li>fl_set_coordunit() (FLTK uses pixels all the time)
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<li>fl_ringbell()
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<li>fl_gettime()
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<li>fl_win*() (all these functions)
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<li>fl_initialize(argc,argv,x,y,z) ignores last 3 arguments
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<li>fl_read_bitmapfile(), fl_read_pixmapfile()
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<li>fl_addto_browser_chars()
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<li>FL_MENU_BUTTON just draws normally
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<li>fl_set_bitmapbutton_file(), fl_set_pixmapbutton_file()
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<li>FL_CANVAS objects
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<li>FL_DIGITAL_CLOCK (comes out analog)
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<li>fl_create_bitmap_cursor(), fl_set_cursor_color()
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<li>fl_set_dial_angles()
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<li>fl_show_oneliner()
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<li>fl_set_choice_shortcut(a,b,c)
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<li>command log
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<li>Only some of file selector is emulated
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<li>FL_DATE_INPUT
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<li>fl_pup*() (all these functions)
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<li>textbox object (should be easy but I had no sample programs)
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<li>xyplot object
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</ul>
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<h2>Additional notes for porting old Forms programs</h2>
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<p>These notes were written for porting programs written with the
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older GL version of Forms. Most of these problems are the same ones
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encountered when going from old Forms to XForms:
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<h4>Does not go into background</h4>
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The GL library always forked when you created the first window, unless
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"foreground()" was called. FLTK acts like "foreground()" is called all
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the time. If you really want the fork behavior do "if (fork())
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exit(0)" right at the start of your program.
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<h4>You cannot use GL windows or fl_queue</h4>
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<P>If a Forms (not XForms) program if you wanted your own window for
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displaying things you would create a GL window and draw in it,
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periodically calling Forms to check if the user hit buttons on the
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panels. If the user did things to the GL window, you would find this
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out by having the value FL_EVENT returned from the call to Forms.
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<p>None of this works with FLTK. Nor will it compile, the necessary
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calls are not in the interface.
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<p>You have to make a subclass of <a
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href=Fl_Gl_Window.html>Fl_Gl_Window</a> and write a draw() method and
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handle() method. This may require anywhere from a trivial to a major
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rewrite. See the example program <a href=shape.C.html>shape.C</a> for
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how this is structured.
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<p>If you draw into the overlay planes you will have to also write a
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draw_overlay() routine and call redraw_overlay() on the gl window.
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<p>One easy way to hack your program so it works is to make the draw()
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and handle() methods on your window set some static variables, storing
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what event happened. Then in the main loop of your program, call
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Fl::wait() and then check these variables, acting on them as
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though they are events read from fl_queue.
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<h4>You must use OpenGL to draw everything</h4>
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<p>The file <FL/gl.h> defines replacements for a lot of gl calls,
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translating them to OpenGL. There are much better translators
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available that you might want to investigate.
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<h4>You cannot make Forms subclasses</h4>
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Programs that call fl_make_object or directly setting the handle
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routine will not compile. You have to rewrite them to use a subclass
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of Fl_Widget. It is important to note that the handle() method is not
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exactly the same as the handle() function of Forms. Where a Forms
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handle() returned non-zero, your handle() must call do_callback().
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And your handle() must return non-zero if it "understood" the event.
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<p>An attempt has been made to emulate the "free" widget. This
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appears to work quite well. It may be quicker to modify your subclass
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into a "free" widget, since the "handle" functions match.
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<p>If your subclass draws into the overlay you are in trouble and will
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have to rewrite things a lot.
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<h4>You cannot use <device.h></h4>
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If you have written your own "free" widgets you will probably get a
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lot of errors about "getvaluator". You should substitute:
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<table>
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<tr><td align=center>Forms <td align=center>FLTK
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<tr><td>MOUSE_X <td>Fl::event_x_root()
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<tr><td>MOUSE_Y<td> Fl::event_y_root()
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<tr><td>LEFTSHIFTKEY,RIGHTSHIFTKEY<td> Fl::event_shift()
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<tr><td>CAPSLOCKKEY<td> Fl::event_capslock()
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<tr><td>LEFTCTRLKEY,RIGHTCTRLKEY<td> Fl::event_ctrl()
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<tr><td>LEFTALTKEY,RIGHTALTKEY<td> Fl::event_alt()
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<tr><td>MOUSE1,RIGHTMOUSE<td> Fl::event_state()&(1<<10)
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<tr><td>MOUSE2,MIDDLEMOUSE<td> Fl::event_state()&(1<<9)
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<tr><td>MOUSE3,LEFTMOUSE<td> Fl::event_state()&(1<<8)
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</table>
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<p>Anything else in getvaluator and you are on your own...
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<h4>Font numbers are different</h4>
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The "style" numbers have been changed because I wanted to insert
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bold-italic versions of the normal fonts. If you use Times, Courier,
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or Bookman to display any text you will get a different font out of
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FLTK. If you are really desperate to fix this use the following code:<ul>
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<pre>
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fl_font_name(3,"*courier-medium-r-no*");
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fl_font_name(4,"*courier-bold-r-no*");
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fl_font_name(5,"*courier-medium-o-no*");
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fl_font_name(6,"*times-medium-r-no*");
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fl_font_name(7,"*times-bold-r-no*");
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fl_font_name(8,"*times-medium-i-no*");
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fl_font_name(9,"*bookman-light-r-no*");
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fl_font_name(10,"*bookman-demi-r-no*");
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fl_font_name(11,"*bookman-light-i-no*");
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</pre></ul>
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</BODY>
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</HTML>
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