======================================================================
0. Highlights of the New MrEd Toolbox
======================================================================

 * The wx/mred split has been eliminated. The wx methods for manually
   managing the position and size of windows have been eliminated;
   containers manage all window positions and sizes. The only way to
   set control positions explicitly is to derive a new container
   class.

   The windowing class hierarchy has been rerranged. For example,
   dialog% (formerly dialog-box%) is no longer a subclass of panel%,
   which is itself no longer a subclass of canvas%.

   Interfaces are widely used in the toolbox. The old toolbox provided
   many "classes" like wx:window% that could not be instantiated. The
   new toolbox has a window<%> interface (where "<%>" is the
   conventional suffix for interfaces).

 * Instead of null, #f is used for the "no appropriate value" value,
   such as the parent argument for a frame that does not have a parent
   window, or the result for get-label when the window does not have a
   label.

   There are no wx:const-... values. Instead, a method that used to
   take a single (numerical) wx:const- flag now takes a symbol, and a
   method that used to take bitwise-ior'd wx:const- integers now takes
   a list of symbols. For example, wx:const-horizontal was replaced by
   'horizontal, and wx:const-bitmap-type-gif was replaced with 'gif.

 * The old documentation described certain methods as consuming "small
   integer" values; the implementation actually accepted any sort of
   number and coerced it to a machine-word integer. Methods now
   consume a precisely defined class of numbers. For example, most
   windowing methods that formerly consumed "small integers" now
   consume "exact integers in [0, 10000]". The implementation signals
   an exception when provided an inexact number, a non-integer, or an
   integer outside the range [0, 10000]. A few methods consume
   arbitrary exact non-negative integers; those methods behave
   correctly when provided an integer represented as a bignum.

   In the windowing toolbox, object-specific out-of-range errors are
   now signalled by a mismatch exception. (In previous versions of
   MrEd, out-of-range errors were generally ignored.) For example, if
   a list-box% instance contains only 10 items, calling the
   set-selection method with the index 11 signals a mismatch
   exception.

 * The menu system was turned upside-down, giving it a structure more
   like rest of the toolbox. For example, instead of creating a menu
   bar and then calling a frame's set-menu-bar method, a menu bar is
   created by providing the frame as an initialization argument in
   (make-object menu-bar% ...). Similarly, a menu is created by
   supplying the parent menu bar as an initialization argument (or a
   parent menu to create a submenu). Finally, a menu item is created
   by instantiating menu-item% or checkable-menu-item% with a parent
   menu. Integer menu IDs have been eliminated; when a menu item is
   selected, a callback associated with the menu item is executed,
   just as when a button is clicked.

 * The "media" names have changed. Roughly, we replaced "media" with
   "editor", or dropped "media" when "editor" is not useful. The
   following is the name mapping for some commonly used classes:

            media-canvas%      =>  editor-canvas%
            media-buffer%      =>  editor<%>
            media-edit%        =>  text%
            media-pasteboard%  =>  pasteboard%
            snip%              =>  snip%
            media-snip%        =>  editor-snip%
            text-snip%         =>  string-snip% (to avoid confusion)

   Methods of text% (formerly media-edit%) check that position, line,
   and paragraph arguments are non-negative. In methods where -1
   (really any negative value) had a special meaning, a symbol is now
   used. For example, the old call
       (send (make-object media-edit%) insert "Hello" 0 -1)
   translates to using 'same instead of -1:
       (send (make-object text%) insert "Hello" 0 'same)

   Many of the old on-XXX methods for editors formerly returned a
   Boolean value to indicate whether the action should proceed (e.g.,
   on-insert in media-edit%), but that convention does not work well
   with composing class extensions. MrEd 100 provides a parallel set
   of can-XXX?  methods (e.g., can-insert? in text%) that first
   determines whether an operation should proceed; if so, on-XXX is
   called (its result is ignored), the operation is performed, and
   after-XXX is called.

   Beside renaming and checking, little else has changed in the editor
   toolbox, but it is a little better integrated with system-wide
   keyboard focus methods. For example, frame% provides a
   get-focus-window method, which returns the frame's subwindow with
   the current focus, but it also provides a get-focus-object method,
   which returns an editor<%> object if an editor-canvas% has the
   keyboard focus.

 * The text-field% control (formerly wx:text% and wx:multi-text%) now
   works well on all platforms, because it is implemented using the
   editor classes. (The equivalent of a wx:multi-text% instance is
   created via a style flag for text-field%.)

 * The command-event% class was changed to control-event%. It has very
   few methods, since the information that was formerly encapsulated
   in a command-event% object can be extracted just as easily from the
   control.

 * Navigating controls (in a frame or dialog) with the keyboard works
   on all platforms. Mnemonic characters (underlined letters in a
   control label) now work correctly under Windows, and now also work
   under X. Windows keyboard events involving the Alt key are now
   reported to on-char et al. (as a Meta key event).

 * The device context system has been changed to provide a larger set
   of methods that paint consistently on all platforms. Most "logical
   functions" (e.g., 'invert, 'src-and, 'no-op) have been eliminated,
   but non-rectangular clipping regions and region operations (e.g.,
   union and intersect) were added.

   The old canvas-dc% class was eliminated. The memory-dc% class was
   renamed to bitmap-dc%.

   The blit method was replaced by draw-bitmap and draw-bitmap-region,
   which operate directly on bitmaps. Monochrome bitmaps can be drawn
   with either a transparent or solid background. The icon% class and
   draw-icon method were removed, since bitmaps provide all of the
   same functionality.

   The xor drawing mode was removed from device contexts and added as
   a style for pens and brushs. Brush stipples work on all platforms
   (with consistent opaqueness and colorization). Pen stipples also
   work, but are restricted to 8x8 monochrome bitmaps. The 'stipple
   and 'opaque-stipple styles were eliminated; instead, installing a
   stipple bitmap into a pen or brush overrides other style settings.

   The arguments to draw-arc were changed; draw-arc now reliably draws
   sections of non-circular ellipses.

   The initialization arguments for post-script-dc% and printer-dc%
   where changed. Global PostScript settings were replaced with a
   parameter containing a ps-setup% object.

   The canvas% class no longer supplies drawing methods. Instead, all
   canvas drawing must use get-dc to get a drawing context (which
   always had a more complete set of methods, anyway).

 * Initialization arguments for creating windows have been re-ordered.
   In general, the order is as follows:
      label [sub-labels] parent callback [init-value] style
              ^- e.g., items in a radio box
   where style is a list of symbols.

   Some methods have been renamed to be either more (accurately)
   descriptive or more consistent with other method names. American
   spelling is used everywhere: colour -> color, centre -> center,
   grey -> gray.

MzScheme's class syntax also changed slightly:

 * In MzScheme 53, the empty list could be provided as a class's
   "superclass", indicating that the class has no superclass. In 100,
   every new class must have a superclass (and super-init must always
   be called). MzScheme 100 provides a built-in empty class called
   object%.

 * In MzScheme 53, a `public' instance variable declaration would
   either override an existing instance variable or declare a new one,
   depending on the set of instance variables provided by the
   superclass. In 100, a `public' declaration always introduces a new
   instance variable; if the superclass already provides the instance
   variable, an exception is raised. The new `override' clause
   declares instance variables to override existing definitions; an
   exception is raised if the superclass does not provide the instance
   variable to override.

======================================================================
1. Interface/Class Type Hierarchy (Selected Excerpts)
======================================================================

[To avoid lines that cross or go in the wrong direction, the following
type hierarchy picture is drawn on a cylinder, with lines from
subarea<%> and subwindow<%> wrapping from the left of the diagram to
the right.]

                           area<%>
        _____________________|_______________
        |               |                   |
      subarea<%>     window<%>     area-container<%>      
<<<____|____       _____|_________     _|__  ________________________<<<
            |      |             |    |   |  |                  
           subwindow<%>          |    |   |  |                  
<<<______________|___________    |    |   pane%                     _<<<
            |               |    |    |    |- horizontal-pane%      |
       control<%>           |    |    |    |- vertical-pane%        |
        |- message%         |    |    |    |- grow-box-spacer-pane% |
        |- button%          |    |    |                             |
        |- check-box%       |  area-container-window<%>             |
        |- slider%          |        |                              |
        |- gauge%           |        |            __________________|
        |- text-field%      |        |            |   
        |- radio-box%       |        |-------- panel%       
        |- list-control<%>  |        |          |- horizontal-panel%
            |- choice%      |        |          |- vertical-panel%
            |- list-box%    |        |          
                            |        |- top-level-window<%>
                            |           |- frame% 
                            |           |- dialog%
                         canvas<%>
                          |- canvas%
                          |- editor-canvas%


  menu-item<%>                menu-item-container<%>
      |                              |
      |- separator-menu-item%   _____|___
      |- labelled-menu-item<%>  |       |- menu-bar%
          _________|_________   |       |- popup-menu%
          |                 |   | 
          |                 menu%
          |
          |- selectable-menu-item<%>
              |- menu-item%
              |- checkable-menu-item%


dc<%> (canvas<%>'s get-dc returns a dc<%>)
 |- bitmap-dc%  (formerly memory-dc%)
 |- printer-dc%
 |- postscript-dc%

editor<%> (maybe has an edit-admin% and some editor-canvas<%>s)
 |- text%
 |- pasteboard%

snip% (as a snip-admin%)
 |- text-snip%
 |    |- tab-snip%
 |- image-snip%
 |- editor-snip% (formerly media-snip%; has an editor<%>)

editor-admin%  (formerly media-admin%)
 |- snip-editor-admin%

snip-admin%

event%
 |- control-event% (formerly command-event%; for control/menu-item callbacks)
 |- mouse-event%
 |- key-event%
 |- scroll-event% (new; used for on-scroll)

======================================================================
2. Interface/Class Methods (Selected Excerpts)

 Method arguments are not generally shown, but the new initialization
 arguments are listed after "<=" for classes.
======================================================================

area<%>
    get-parent
    get-top-level-window - returns the area's frame/dialog
    min-width min-height
    get-graphical-min-size
    stretchable-width stretchable-height

subarea<%> : area<%>
    horiz-margin vert-margin

window<%> : area<%>
    focus has-focus? - focus replaces set-focus
    on-focus - on-focus replaces on-set-focus and on-kill-focus
    enable is-enabled?
    on-size
    on-subwindow-char on-subwindow-event - formerly pre-on-...
    client->screen screen->client - takes two and returns two values
    get-label set-label
    get-plain-label - e.g., "Button" instead of "&Button"
    get-client-size - returns two values
    get-size - returns two values
    get-width get-height get-x get-y
    get-cursor set-cursor 
    show is-shown?
    refresh
    accept-drop-files on-drop-file

area-container<%> : area<%>
    container-size
    get-children change-children place-children
    add-child delete-child
    after-new-child
    border - parameter-like
    spacing - parameter-like
    set-alignment - takes two syms: 'left/'center/'right 'top/'center/'bottom
    get-alignment - returns two syms...

area-container-window<%> : container<%> window<%>
    set-control-font get-control-font
    set-label-font get-label-font
    set-label-position get-label-position

subwindow<%> : subarea<%> window<%>

panel% : area-container-window<%> subwindow<%>
    <= parent [style null]
       styles: 'border

horizontal-panel%: panel%
    <= parent [style null]
       styles: 'border

vertical-panel%: panel%
    <= parent [style null]
       styles: 'border

pane% : container<%> subwindow<%>
    <= parent

horizontal-pane%: pane%
    <= parent

vertical-pane%: pane%
    <= parent

gorw-box-spacer-pane%: pane%
    <= parent

top-level-window<%> : area-container-window<%>
    get-eventspace
    on-activate
    can-close? on-close
    can-exit? on-exit - called when the OS asks MrEd to exit
    get-focus-window - the window with the current focus (or #f)
    get-edit-target-window - the window to last have the focus (or #f)
    get-focus-object - the window/editor with the curent focus (or #f)
    get-edit-target-object - the window/editor to last have the focus (or #f)
    on-traverse-char on-system-menu-char
    center move resize

frame% : top-level-window<%>
   <= label [parent #f] [width #f] [height #f] [x #f] [y #f] [style null]
      styles: 'no-resize-border 'no-caption 'no-system-menu
              'mdi-parent 'mdi-child
   create-status-line set-status-text has-status-line?
   get-menu-bar
   iconize is-iconized? set-icon maximize
   on-menu-char

dialog% : top-level-window<%>
   <= label [parent #f] [width #f] [height #f] [x #f] [y #f] [style null]
      styles: 'no-caption 'resize-border

control<%> : subwindow<%>
   command - just invokes the callback; no longer changes the control value

message% : control<%>
   <= label parent [style null]
      styles: none

button% : control<%>
   <= label parent callback [style null]
      styles: 'default

check-box% : control<%>
   <= label parent callback [style null]
      styles: none
   set-value get-value

slider% : control<%>
   <= label min-val max-val parent callback [value min-val]
            [style '(horizontal)]
      styles: 'horizontal 'vertical
   set-value get-value

gauge% : control<%>
   <= label range parent [style '(horizontal)]
      styles: 'horizontal 'vertical
   set-value get-value
   set-range get-range

text-field% : control<%>
   <= label parent callback [init-val ""] [style '(single)]
      styles: 'single, 'multiple, 'hscroll
   get-value set-value
   get-editor

radio-box% : control<%>
   <= label choices parent callback [style '(vertical)]
      styles: 'horizontal 'vertical
   get-number
   get-item-label - label for one of the choices
   get-item-plain-label - e.g., "Cut" intsead of "Cut  Cmd-X"
   get-selection set-selection

list-control<%> : control<%>
   clear append
   get-number
   get-string find-string
   get-selection
   get-string-selection
   set-selection
   set-string-selection

choice% : list-control<%>
   <= label choices parent callback [style null]
      styles: none

list-box% : list-control<%>
   <= label choices parent callback [style '(single)]
      styles: 'single 'multiple 'extended 'always-vscroll 'hscroll
   delete
   get-data set-data
   get-selections
   select is-selected?
   set set-string set-data
   number-of-visible-items
   get-first-visible set-first-visible

canvas<%> : subwindow<%>
    on-char on-event on-paint on-scroll on-tab-in
    popup-menu warp-pointer get-dc
    client-min-width client-min-height

canvas% : canvas<%>
    <= parent [style null]
       styles: 'border 'vscroll 'hscroll
    get-virtual-size get-view-start
    init-manual-scrollbars init-auto-scrollbars
    scroll
    get-scroll-pos set-scroll-pos
    get-scroll-range set-scroll-range
    get-scroll-page set-scroll-page

editor-canvas% : canvas<%>
   <= parent [editor #f] [style null] [scrolls-per-page 100]
      styles: 'no-hscroll 'no-vscroll 'hide-hscroll 'hide-vscroll
   call-as-primary-owner
   allow-scroll-to-last - parameter-like
   scroll-with-bottom-base - parameter-like
   lazy-refresh - parameter-like
   force-display-focus - parameter-like
   get-editor set-editor - formerly get-media and set-media
   set-line-count

menu-item<%>
   get-parent
   delete restore is-deleted?

separator-menu-item%
   <= parent

labelled-menu-item<%>
   get-label set-label
   get-plain-label
   get-help-string set-help-string
   enable is-enabled?

selectable-menu-item<%>
   command
   get-shortcut set-shortcut
   get-x-shortcut-prefix set-x-shortcut-prefix

menu-item%
   <= label parent callback [shortcut #f] [help-string #f]

checkable-menu-item%
   <= label parent callback [shortcut #f] [help-string #f]
   check is-checked?

menu-item-container<%>
   get-items

menu%
   <= label parent [help-string #f]

popup-menu%
   <= title

menu-bar%
   <= frame
   get-frame
   enable is-enabled?

editor<%>
   [ all the old wx:media-buffer% stuff, plus... ]
   get-canvases - a list of canvases displaying the editor
   get-active-canvas - the canvas that most recently had the focus (or #f)
   get-canvas - the active canvas, or the first canva (or #f)
   set-active-canvas add-canvas remove-canvas
   auto-wrap - parameter-like
   on-display-size - called when a display for the editor changes its size

event%
   <=
   get-time-stamp set-time-stamp

control-event%
   <= event-type
   get-event-type set-event-type

mouse-event%
   <= event-type
   get-event-type set-event-type
   button-down?  - specify a button with 'left, 'middle, 'right, or 'all
   button-up?
   dragging?
   entering?
   leaving?
   moving?
   button-changed?
   get-left-down set-left-down
   get-middle-down set-middle-down
   get-right-down set-right-down
   get-x get-y set-x set-y
   get-shift-down set-shift-down
   get-control-down set-control-down
   get-meta-down set-meta-down
   get-alt-down set-alt-down

key-event%
   <=
   get-key-code set-key-code  - key code is a char or a symbol
   get-shift-down set-shift-down
   get-control-down set-control-down
   get-meta-down set-meta-down
   get-alt-down set-alt-down
   get-x get-y set-x set-y

scroll-event%
   <=
   get-position set-position
   get-event-type set-event-type
   get-direction set-direction

======================================================================
3. Procedures

  This is a complete list, although the arguments are only shown for a
  few procedures. 

  If an old procedure isn't listed here, we got rid of it.
======================================================================

get-file
   <= [message #f] [parent #f] [directory #f] [filename #f] [extension #f]
      [style null]
      styles: none

put-file
   <= [message #f] [parent #f] [directory #f] [filename #f] [extension #f]
      [style null]
      styles: none

message-box
   <= title message [parent #f] [style '(ok)]
      styles: 'yes-no 'ok 'ok-cancel

get-text-from-user
   <= title message [init-val #f] [parent #f] [style null]
      styles: none

get-choices-from-user (returns index integers, not the values)
   <= title message choices [parent #f] [init-choices null] [style null]
      styles: 'single 'multiple 'extended

get-ps-setup-from-user
   <= [message #f] [parent #f] [init-setup #f] [style null]
      styles: none

get-color-from-user   - now supported for all platforms
   <= [message #f] [parent #f] [init-color #f] [style null]
      styles: none

get-font-from-user   - now supported for all platforms
   <= [message #f] [parent #f] [init-font #f] [style null]
      styles: none

color-display? get-display-depth get-display-size
begin-busy-cursor end-busy-cursor is-busy-cursor?
bell
label->plain-label
get-resource write-resource
get-face-list - formerly wx:get-font-list

yield sleep/yield flush-display
queue-callback

find-graphical-system-path - formerly wx:find-path

current-ps-setup

get-top-level-windows
get-top-level-focus-window
get-top-level-edit-target-window
current-new-top-level-window-handler
get-window-text-extent
get-panel-background

graphical-read-eval-print-loop

make-eventspace
eventspace?
current-eventspace
eventspace-shutdown?
event-dispatch-handler

check-for-break
special-control-key

read-editor-global-header
read-editor-global-footer
write-editor-global-header
write-editor-global-footer

append-editor-operation-menu-items
append-editor-font-menu-items

add-editor-keymap-functions
add-text-keymap-functions
add-pasteboard-keymap-functions

current-text-keymap-initializer

editor-set-x-selection-mode

get-the-snip-class-list
get-the-buffer-data-class-list

======================================================================
4. Constant Mapping

 The following table maps old wx:const- identifiers to new symbols.
======================================================================

  wx:const-align-bottom                      'bottom
  wx:const-align-center                      'center
  wx:const-align-top                         'top
  wx:const-always-sb                         'always-hscroll
  wx:const-and                               'and
  wx:const-and-invert                        'and-invert
  wx:const-and-reverse                       'and-reverse
  wx:const-base                              'base
  wx:const-bdiagonal-hatch                   'bdiagonal-hatch
  wx:const-bitmap-type-bmp                   'bmp
  wx:const-bitmap-type-bmp-resource          'bmp-resource
  wx:const-bitmap-type-gif                   'gif
  wx:const-bitmap-type-pict                  'pict
  wx:const-bitmap-type-pict-resource         'pict-resource
  wx:const-bitmap-type-xbm                   'xbm
  wx:const-bitmap-type-xpm                   'xpm
  wx:const-bold                              'bold
  wx:const-border                            'border
  wx:const-both                              'both
  wx:const-break-for-caret                   'caret
  wx:const-break-for-line                    'line
  wx:const-break-for-selection               'selection
  wx:const-break-for-user-1                  'user1
  wx:const-break-for-user-2                  'user2
  wx:const-cancel                            'cancel
  wx:const-cap-butt                          'butt
  wx:const-cap-projecting                    'projecting
  wx:const-cap-round                         'round
  wx:const-caption                           'caption
  wx:const-centre                            'centre
  wx:const-change-alignment                  'change-alignment
  wx:const-change-bigger                     'change-bigger
  wx:const-change-bold                       'change-bold
  wx:const-change-family                     'change-family
  wx:const-change-italic                     'change-italic
  wx:const-change-normal                     'change-normal
  wx:const-change-normal-colour              'change-normal-color
  wx:const-change-nothing                    'change-nothing
  wx:const-change-size                       'change-size
  wx:const-change-smaller                    'change-smaller
  wx:const-change-style                      'change-style
  wx:const-change-toggle-style               'change-toggle-style
  wx:const-change-toggle-underline           'change-toggle-underline
  wx:const-change-toggle-weight              'change-toggle-weight
  wx:const-change-underline                  'change-underline
  wx:const-change-weight                     'change-weight
  wx:const-clear                             'clear
  wx:const-colour                            'color
  wx:const-copy                              'copy
  wx:const-cross-hatch                       'cross-hatch
  wx:const-crossdiag-hatch                   'crossdiag-hatch
  wx:const-cursor-arrow                      'arrow
  wx:const-cursor-bullseye                   'bullseye
  wx:const-cursor-char                       (NO LONGER USED)
  wx:const-cursor-cross                      'cross
  wx:const-cursor-hand                       'hand
  wx:const-cursor-ibeam                      'ibeam
  wx:const-cursor-left-button                (NO LONGER USED)
  wx:const-cursor-magnifier                  (NO LONGER USED)
  wx:const-cursor-middle-button              (NO LONGER USED)
  wx:const-cursor-no-entry                   (NO LONGER USED)
  wx:const-cursor-paint-brush                (NO LONGER USED)
  wx:const-cursor-pencil                     (NO LONGER USED)
  wx:const-cursor-point-left                 (NO LONGER USED)
  wx:const-cursor-point-right                (NO LONGER USED)
  wx:const-cursor-question-arrow             (NO LONGER USED)
  wx:const-cursor-right-button               (NO LONGER USED)
  wx:const-cursor-sizenesw                   (NO LONGER USED)
  wx:const-cursor-sizens                     (NO LONGER USED)
  wx:const-cursor-sizenwse                   (NO LONGER USED)
  wx:const-cursor-sizewe                     (NO LONGER USED)
  wx:const-cursor-sizing                     (NO LONGER USED)
  wx:const-cursor-spraycan                   (NO LONGER USED)
  wx:const-cursor-wait                       (NO LONGER USED)
  wx:const-cursor-watch                      'watch
  wx:const-decorative                        'decorative
  wx:const-default                           'default
  wx:const-default-select                    'default
  wx:const-dot                               'dot
  wx:const-dot-dash                          'dot-dash
  wx:const-edit-buffer                       'text
  wx:const-edit-clear                        'clear
  wx:const-edit-copy                         'copy
  wx:const-edit-cut                          'cut
  wx:const-edit-insert-graphic-box           'insert-graphic-box
  wx:const-edit-insert-image                 'insert-image
  wx:const-edit-insert-text-box              'insert-text-box
  wx:const-edit-kill                         'kill
  wx:const-edit-paste                        'paste
  wx:const-edit-redo                         'redo
  wx:const-edit-select-all                   'select-all
  wx:const-edit-undo                         'undo
  wx:const-equiv                             'equiv
  wx:const-event-type-button-command         'button
  wx:const-event-type-checkbox-command       'checkbox
  wx:const-event-type-choice-command         'choice
  wx:const-event-type-enter-window           'enter
  wx:const-event-type-kill-focus             'kill-focus
  wx:const-event-type-leave-window           'leave
  wx:const-event-type-left-dclick            (NO LONGER USED)
  wx:const-event-type-left-down              'left-down
  wx:const-event-type-left-up                'left-up
  wx:const-event-type-listbox-command        'list-box
  wx:const-event-type-menu-command           (NO LONGER USED)
  wx:const-event-type-middle-dclick          (NO LONGER USED)
  wx:const-event-type-middle-down            'middle-down
  wx:const-event-type-middle-up              'middle-up
  wx:const-event-type-motion                 'motion
  wx:const-event-type-multitext-command      (NO LONGER USED)
  wx:const-event-type-radiobox-command       'radio-box
  wx:const-event-type-right-dclick           (NO LONGER USED)
  wx:const-event-type-right-down             'right-down
  wx:const-event-type-right-up               'right-up
  wx:const-event-type-scroll-bottom          'scroll-bottom
  wx:const-event-type-scroll-linedown        'scroll-line-down
  wx:const-event-type-scroll-lineup          'scroll-line-up
  wx:const-event-type-scroll-pagedown        'scroll-page-down
  wx:const-event-type-scroll-pageup          'scroll-page-up
  wx:const-event-type-scroll-thumbtrack      'scroll-thumb
  wx:const-event-type-scroll-top             'scroll-top
  wx:const-event-type-scrollbar-command      (NO LONGER USED)
  wx:const-event-type-set-focus              'set-focus
  wx:const-event-type-slider-command         'slider
  wx:const-event-type-text-command           'text
  wx:const-event-type-text-enter-command     'text-field-enter
  wx:const-event-type-virt-listbox-command   (NO LONGER USED)
  wx:const-extended                          'extended
  wx:const-fdiagonal-hatch                   'fdiagonal-hatch
  wx:const-focus-display                     'display
  wx:const-focus-global                      'global
  wx:const-focus-immediate                   'immediate
  wx:const-hide-readonly                     'hide-readonly
  wx:const-horizontal                        'horizontal
  wx:const-horizontal-hatch                  'horizontal-hatch
  wx:const-hscroll                           'hscroll
  wx:const-icon-exclamation                  'icon-exclamation
  wx:const-icon-hand                         'icon-hand
  wx:const-icon-information                  'icon-information
  wx:const-icon-question                     'icon-question
  wx:const-iconize                           'iconize
  wx:const-invert                            'invert
  wx:const-italic                            'italic
  wx:const-join-bevel                        'bevel
  wx:const-join-miter                        'miter
  wx:const-join-round                        'round
  wx:const-k-add                             'add
  wx:const-k-back                            (NO LONGER USED)
  wx:const-k-cancel                          'cancel
  wx:const-k-capital                         'capital
  wx:const-k-clear                           'clear
  wx:const-k-control                         'control
  wx:const-k-decimal                         'decimal
  wx:const-k-delete                          (NO LONGER USED)
  wx:const-k-divide                          'divide
  wx:const-k-down                            'down
  wx:const-k-end                             'end
  wx:const-k-escape                          (NO LONGER USED)
  wx:const-k-execute                         'execute
  wx:const-k-f1                              'f1
  wx:const-k-f10                             'f10
  wx:const-k-f11                             'f11
  wx:const-k-f12                             'f12
  wx:const-k-f13                             'f13
  wx:const-k-f14                             'f14
  wx:const-k-f15                             'f15
  wx:const-k-f16                             'f16
  wx:const-k-f17                             'f17
  wx:const-k-f18                             'f18
  wx:const-k-f19                             'f19
  wx:const-k-f2                              'f2
  wx:const-k-f20                             'f20
  wx:const-k-f21                             'f21
  wx:const-k-f22                             'f22
  wx:const-k-f23                             'f23
  wx:const-k-f24                             'f24
  wx:const-k-f3                              'f3
  wx:const-k-f4                              'f4
  wx:const-k-f5                              'f5
  wx:const-k-f6                              'f6
  wx:const-k-f7                              'f7
  wx:const-k-f8                              'f8
  wx:const-k-f9                              'f9
  wx:const-k-help                            'help
  wx:const-k-home                            'home
  wx:const-k-insert                          'insert
  wx:const-k-lbutton                         'lbutton
  wx:const-k-left                            'left
  wx:const-k-mbutton                         'mbutton
  wx:const-k-menu                            'menu
  wx:const-k-multiply                        'multiply
  wx:const-k-next                            'next
  wx:const-k-numlock                         'numlock
  wx:const-k-numpad0                         'numpad0
  wx:const-k-numpad1                         'numpad1
  wx:const-k-numpad2                         'numpad2
  wx:const-k-numpad3                         'numpad3
  wx:const-k-numpad4                         'numpad4
  wx:const-k-numpad5                         'numpad5
  wx:const-k-numpad6                         'numpad6
  wx:const-k-numpad7                         'numpad7
  wx:const-k-numpad8                         'numpad8
  wx:const-k-numpad9                         'numpad9
  wx:const-k-pause                           'pause
  wx:const-k-print                           'print
  wx:const-k-prior                           'prior
  wx:const-k-rbutton                         'rbutton
  wx:const-k-return                          (NO LONGER USED)
  wx:const-k-right                           'right
  wx:const-k-scroll                          'scroll
  wx:const-k-select                          'select
  wx:const-k-separator                       'separator
  wx:const-k-shift                           'shift
  wx:const-k-snapshot                        'snapshot
  wx:const-k-space                           (NO LONGER USED)
  wx:const-k-start                           'start
  wx:const-k-subtract                        'subtract
  wx:const-k-tab                             (NO LONGER USED)
  wx:const-k-up                              'up
  wx:const-light                             'light
  wx:const-local-select                      'local
  wx:const-long-dash                         'long-dash
  wx:const-maximize                          'maximize
  wx:const-maximize-box                      'maximize-box
  wx:const-mcanvas-hide-h-scroll             'hide-hscroll
  wx:const-mcanvas-hide-v-scroll             'hide-vscroll
  wx:const-mcanvas-no-h-scroll               'no-hscroll
  wx:const-mcanvas-no-v-scroll               'no-vscroll
  wx:const-mdi-child                         'mdi-child
  wx:const-mdi-parent                        'mdi-parent
  wx:const-media-ff-copy                     'copy
  wx:const-media-ff-guess                    'guess
  wx:const-media-ff-same                     'same
  wx:const-media-ff-std                      'standard
  wx:const-media-ff-text                     'text
  wx:const-media-ff-text-force-cr            'text-force-cr
  wx:const-minimize                          'minimize
  wx:const-minimize-box                      'minimize-box
  wx:const-mm-lometric                       (NO LONGER USED)
  wx:const-mm-metric                         (NO LONGER USED)
  wx:const-mm-points                         (NO LONGER USED)
  wx:const-mm-text                           (NO LONGER USED)
  wx:const-mm-twips                          (NO LONGER USED)
  wx:const-modern                            'modern
  wx:const-move-line                         'line
  wx:const-move-page                         'page
  wx:const-move-simple                       'simple
  wx:const-move-word                         'word
  wx:const-msnipbox-xinset                   (NO LONGER USED: use 1)
  wx:const-msnipbox-xmargin                  (NO LONGER USED: use 5)
  wx:const-msnipbox-yinset                   (NO LONGER USED: use 1)
  wx:const-msnipbox-ymargin                  (NO LONGER USED: use 5)
  wx:const-multiple                          'multiple
  wx:const-nand                              'nand
  wx:const-no                                'no
  wx:const-no-op                             'no-op
  wx:const-nor                               'nor
  wx:const-normal                            'normal
  wx:const-oddeven-rule                      'odd-even
  wx:const-ok                                'ok
  wx:const-opaque-stipple                    'opaque-stipple
  wx:const-open                              'open
  wx:const-or                                'or
  wx:const-or-invert                         'or-invert
  wx:const-or-reverse                        'or-reverse
  wx:const-overwrite-prompt                  'overwrite-prompt
  wx:const-password                          (NO LONGER USED)
  wx:const-pasteboard-buffer                 'pasteboard
  wx:const-pos-use-minus-one                 (NO LONGER USED)
  wx:const-print-ask                         (NO LONGER USED)
  wx:const-print-postscript                  'postscript
  wx:const-print-standard                    'standard
  wx:const-process-enter                     (NO LONGER USED)
  wx:const-ps-file                           'file
  wx:const-ps-landscape                      'landscape
  wx:const-ps-portrait                       'portrait
  wx:const-ps-preview                        'preview
  wx:const-ps-printer                        'printer
  wx:const-readonly                          (NO LONGER USED)
  wx:const-resize-border                     'resize-border
  wx:const-roman                             'roman
  wx:const-save                              'save
  wx:const-script                            'script
  wx:const-sdi                               'sdi
  wx:const-set                               'set
  wx:const-short-dash                        'short-dash
  wx:const-single                            'single
  wx:const-size-auto                         (NO LONGER USED)
  wx:const-size-auto-height                  (NO LONGER USED)
  wx:const-size-auto-width                   (NO LONGER USED)
  wx:const-size-use-exsiting                 (NO LONGER USED)
  wx:const-slant                             'slant
  wx:const-snip-after                        'after
  wx:const-snip-after-or-null                'after-or-none
  wx:const-snip-anchored                     'anchored
  wx:const-snip-before                       'before
  wx:const-snip-before-or-null               'before-or-none
  wx:const-snip-can-append                   'can-append
  wx:const-snip-draw-no-caret                'no-caret
  wx:const-snip-draw-show-caret              'show-caret
  wx:const-snip-draw-show-inactive-caret     'show-inactive-caret
  wx:const-snip-handles-events               'handles-events
  wx:const-snip-hard-newline                 'hard-newline
  wx:const-snip-height-depends-on-x          'height-depends-on-x
  wx:const-snip-height-depends-on-y          'height-depends-on-y
  wx:const-snip-invisible                    'invisible
  wx:const-snip-is-text                      'is-text
  wx:const-snip-newline                      'newline
  wx:const-snip-uses-buffer-path             'uses-buffer-path
  wx:const-snip-width-depends-on-x           'width-depends-on-x
  wx:const-snip-width-depends-on-y           'width-depends-on-y
  wx:const-solid                             'solid
  wx:const-src-invert                        'src-invert
  wx:const-stipple                           'stipple
  wx:const-swiss                             'swiss
  wx:const-system                            'system
  wx:const-system-menu                       'system-menu
  wx:const-teletype                          'teletype
  wx:const-thick-frame                       'thick-frame
  wx:const-transparent                       'transparent
  wx:const-type-command-event                'command
  wx:const-type-key-event                    'key
  wx:const-type-mouse-event                  'mouse
  wx:const-vertical                          'vertical
  wx:const-vertical-hatch                    'vertical-hatch
  wx:const-vscroll                           'vscroll
  wx:const-winding-rule                      'winding
  wx:const-x-select                          'x
  wx:const-xor                               'xor
  wx:const-yes                               'yes
  wx:const-yes-no                            'yes-no


======================================================================
5. Relatively subtle and potentially confusing changes
======================================================================

Added queue-callback: (queue-callback proc [hi-priority?])
 and removed MzScheme's semaphore-callback. Added low-priority
 callbacks in addition to the old high-priority callbacks.

key-event%'s key-code method was removed.

key-event%'s get-key-code returns a character or a symbol
 instead of a number.

window<%>'s set-cursor no longer returns the cursor; added get-cursor,
 instead.

key-event% for a numpad Enter key in Xt reports 'numpad-enter for the
 key code instead of #\return.

Added 'unknown image kind for bitmap%'s load-file, etc., which
 examines the file to determine the type automatically.

'wx flag for MzScheme's make-namespace changed to 'mred.

canvas%'s get-view-start returns values in pixels, not scroll units.

dc<%>'s get-text-extent and get-size return multiple values
 instead of mutating boxes.

dc<%>'s get-/set-background-mode changed to get-/set-text-mode.

A text editor's selection caret now blinks; added a blink-caret method
 to editor<%> and snip%.

In editor<%>'s scroll-to, text%'s scroll-to-position and
 set-position-bias-scroll, editor-admin%'s scroll-to, and
 snip-admin%'s scroll-to, bias changed from an integer to a symbol
 (see the docs for details).

media-buffer%'s do-edit changed to editor<%>'s do-edit-operation,
 which takes a symbol instead of a number.

Changed editor<%>'s modified? to is-modified?, added is-locked?.

Added add-undo method to editor<%>, and introduced editor-undo% class.

editor-wordbreak-map%'s get-map and set-map now work on characters
 instead of integers.

text%'s find-string and find-string-all use symbols to specify the
 direction, 'forward or 'backward instead of -1 or 1.

Changed arguments and default value of fit-on-page? for print in
 editor<%>.

pasteboard%'s {on,after}-interactive-move takes a mouse-event% object.

pasteboard% is now locked for writing during calls to on-paint

editor-snip%'s resize method no longer calls the embedded buffer's
 set-max-size and set-min-size; now it calls on-display-size.

clipboard% changed to clipboard<%> and font-name-directory% changed to
 font-name-directory<%>; there is just once instance, the-clipboard
 and the-font-name-directory.

the-color-database only has a find-color method; the others were
 removed. Certain color names with mappings under X (e.g.,
 "FORESTGREEN") are no longer available; instead, the only availabale
 colors are the ones defined in the manual.

Changed the syntax for keymap%'s map-function. f a modifier is not
 mentioned in a state string, it matches states where the modifier is
 pressed or not pressed. A tilde (~) preceding a modifier makes the
 string match only states where the corresponding modifier is not
 pressed.

Changed keymap%'s add-key-function and add-mouse-function to
 add-function (eliminating the different namespaces for key and mouse
 event functions).

Removed keymap%'s set-error-callback; the keymap errors are instead
 reported by raising an exception. The exception handler can't escape,
 but it can at least print the error to the current error port.