► |  | The Racket Graphical Interface Toolkit

1 | Windowing
2 | Widget Gallery
3 | Windowing Classes
4 | Windowing Functions
5 | Editors
6 | Snip and Style Classes
7 | Editor Classes
8 | Editor Functions
9 | WXME Decoding
10 | Preferences
11 | Dynamic Loading
12 | Startup Actions
13 | Init Libraries
14 | Platform Dependencies
| Index

▼ | 7 | Editor Classes

7.1 | editor<%>
7.2 | editor-admin%
7.3 | editor-canvas%
7.4 | editor-data%
7.5 | editor-data-class%
7.6 | editor-data-class-list<%>
7.7 | editor-snip-editor-admin<%>
7.8 | editor-snip%
7.9 | editor-stream-in%
7.10 | editor-stream-in-base%
7.11 | editor-stream-in-bytes-base%
7.12 | editor-stream-out%
7.13 | editor-stream-out-base%
7.14 | editor-stream-out-bytes-base%
7.15 | editor-wordbreak-map%
7.16 | keymap%
7.17 | pasteboard%
7.18 | text%

On this page:

add-canvas
add-undo
adjust-cursor
after-edit-sequence
after-load-file
after-save-file
after-scroll-to
auto-wrap
begin-edit-sequence
begin-write-header-footer-to-file
blink-caret
can-do-edit-operation?
can-load-file?
can-save-file?
clear
clear-undos
copy
copy-self
copy-self-to
cut
dc-location-to-editor-location
default-style-name
do-edit-operation
editor-location-to-dc-location
end-edit-sequence
end-write-header-footer-to-file
find-first-snip
find-scroll-line
get-active-canvas
get-admin
get-canvas
get-canvases
get-dc
get-descent
get-extent
get-file
get-filename
get-flattened-text
get-focus-snip
get-inactive-caret-threshold
get-keymap
get-load-overwrites-styles
get-max-height
get-max-undo-history
get-max-view-size
get-max-width
get-min-height
get-min-width
get-paste-text-only
get-snip-data
get-snip-location
get-space
get-style-list
get-view-size
global-to-local
in-edit-sequence?
insert
insert-box
insert-file
insert-image
insert-port
invalidate-bitmap-cache
is-locked?
is-modified?
is-printing?
kill
load-file
local-to-global
locations-computed?
lock
locked-for-flow?
locked-for-read?
locked-for-write?
needs-update
num-scroll-lines
on-change
on-char
on-default-char
on-default-event
on-display-size
on-display-size-when-ready
on-edit-sequence
on-event
on-focus
on-load-file
on-local-char
on-local-event
on-new-box
on-new-image-snip
on-paint
on-save-file
on-scroll-to
on-snip-modified
own-caret
paste
paste-x-selection
print
print-to-dc
put-file
read-footer-from-file
read-from-file
read-header-from-file
redo
refresh
refresh-delayed?
release-snip
remove-canvas
resized
save-file
save-port
scroll-editor-to
scroll-line-location
scroll-to
select-all
set-active-canvas
set-admin
set-caret-owner
set-cursor
set-filename
set-inactive-caret-threshold
set-keymap
set-load-overwrites-styles
set-max-height
set-max-undo-history
set-max-width
set-min-height
set-min-width
set-modified
set-paste-text-only
set-snip-data
set-style-list
set-undo-preserves-all-history
size-cache-invalid
style-has-changed
undo
undo-preserves-all-history?
use-file-text-mode
write-footers-to-file
write-headers-to-file
write-to-file

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interface editor<%> : interface?

The editor<%> interface is implemented by text% and pasteboard%.

> method (send an-editor add-canvas canvas) → void?
> canvas : (is-a?/c editor-canvas%)

Adds a canvas to this editor’s list of displaying canvases. (See get-canvases.)

Normally, this method is called only by set-editor in editor-canvas%.

> method (send an-editor add-undo undoer) → void?
> undoer : (-> any)

Adds an undoer procedure to the editor’s undo stack. If an undo is currently being performed, the undoer is added to the editor’s redo stack. The undoer is called by the system when it is undoing (or redoing) changes to an editor, and when this undoer is the first item on the undo (or redo) stack.

Editor instances are created with no undo stack, so no undo operations will be recorded unless set-max-undo-history is used to change the size of the undo stack.

The system automatically installs undo records to undo built-in editor operations, such as inserts, deletes, and font changes. Install an undoer only when it is necessary to maintain state or handle operations that are not built-in. For example, in a program where the user can assign labels to snips in a pasteboard, the program should install an undoer to revert a label change. Thus, when a user changes a snip’s label and then selects Undo (from a standard menu bar), the snip’s label will revert as expected. In contrast, there is no need to install an undoer when the user moves a snip by dragging it, because the system installs an appropriate undoer automatically.

After an undoer returns, the undoer is popped off the editor’s undo (or redo) stack; if the return value is true, then the next undoer is also executed as part of the same undo (or redo) step. The undoer should return true if the action being undone was originally performed as part of a begin-edit-sequence and end-edit-sequence sequence. The return value should also be true if the undone action was implicitly part of a sequence. To extend the previous example, if a label change is paired with a move to realign the snip, then the label-change undoer should be added to the editor after the call to move, and it should return #t when it is called. As a result, the move will be undone immediately after the label change is undone. (If the opposite order is needed, use begin-edit-sequence and end-edit-sequence to create an explicit sequence.)

The system adds undoers to an editor (in response to other method calls) without calling this method.

> method (send an-editor adjust-cursor event)
> → (or/c (is-a?/c cursor%) #f)
> event : (is-a?/c mouse-event%)

Specification: Gets a cursor to be used in the editor’s display. If the return value is #f, a default cursor is used.

See also set-cursor.

Default implementation: If an overriding cursor has been installed with set-cursor, then the installed cursor is returned.

Otherwise, if the event is a dragging event, a snip in the editor has the focus, and the snip’s adjust-cursor method returns a cursor, that cursor is returned.

Otherwise, if the cursor is over a snip and the snip’s adjust-cursor method returns a cursor, that cursor is returned.

Otherwise, if a cursor has been installed with set-cursor, then the installed cursor is returned.

Otherwise, if the cursor is over a clickback region in an editor, an arrow cursor is returned.

Finally, if none of the above cases apply, a default cursor is returned. For a text editor, the default cursor is an I-beam. For a pasteboard editor, the default cursor is an arrow.

> method (send an-editor after-edit-sequence) → void?

Refine this method with augment.
Specification: Called after a top-level edit sequence completes (involving unnested begin-edit-sequence and end-edit-sequence).

See also on-edit-sequence.

Default implementation: Does nothing.

> method (send an-editor after-load-file success?) → void?
> success? : any/c

Refine this method with augment.
Specification: Called just after the editor is loaded from a file or during the exception escape when an attempt to load fails. The success? argument indicates whether the load succeeded.

See also can-load-file? and on-load-file.

Default implementation: Does nothing.

> method (send an-editor after-save-file success?) → void?
> success? : any/c

Refine this method with augment.
Specification: Called just after the editor is saved to a file or during the exception escape when a save fails. The success? argument indicates whether the save succeeded.

See also can-save-file? and on-save-file.

Default implementation: Does nothing.

> method (send an-editor after-scroll-to) → void?

Specification: Called when the editor has just scrolled, but the entire display may not have been refreshed. (If the editor scrolls but the entire window is redrawn, this method may not be called.)

See also get-scroll-via-copy.

Default implementation: Does nothing.

> method (send an-editor auto-wrap) → boolean?
> (send an-editor auto-wrap auto-wrap?) → void?
> auto-wrap? : any/c

Enables or disables automatically calling set-max-width in response to on-display-size, or gets the state of auto-wrapping. For text editors, this has the effect of wrapping the editor’s contents to fit in a canvas displaying the editor (the widest one if multiple canvases display the editor). For pasteboard editors, “auto-wrapping” merely truncates the area of the pasteboard to match its canvas display.

When the wrapping mode is changed, the on-display-size method is called immediately to update the editor’s maximum width.

Auto-wrapping is initially disabled.

> > method
> > (send an-editor begin-edit-sequence | [ | undoable? |  |  |  |
> > |  | interrupt-streak?]) |  | → |  | void?
> undoable? : any/c = #t
> interrupt-streak? : any/c = #t

Specification: The begin-edit-sequence and end-edit-sequence methods are used to bracket a set of editor modifications so that the results are all displayed at once. The commands may be nested arbitrarily deeply. Using these functions can greatly speed up displaying the changes.

When an editor contains other editors, using begin-edit-sequence and end-edit-sequence on the main editor brackets some changes to the sub-editors as well, but it is not as effective when a sub-editor changes as calling begin-edit-sequence and end-edit-sequence for the sub-editor.

See also refresh-delayed? and in-edit-sequence?, and see Editors and Threads for information about edit sequences and refresh requests.

If the undoable? flag is #f, then the changes made in the sequence cannot be reversed through the undo method. See below for more information on undo. The undoable? flag is only effective for the outermost begin-edit-sequence when nested sequences are used. Note that, for a text% object, the character-inserting version of insert interferes with sequence-based undo groupings.

If the interrupt-streak? flag is #f and the sequence is outermost, then special actions before and after the sequence count as consecutive actions. For example, kills just before and after the sequence are appended in the clipboard.

Undo details: The behavior of undoable? as #f is implemented by not adding entries to an undo log. For example, suppose that an a is inserted into the editor, a b is inserted, and then an un-undoable edit sequence begins, and the a is colored red, and then the edit sequence ends. An undo will remove the b, leaving the a colored red.

As another example, in the following interaction, undo removes the a instead of the b:

> > (define t (new text%))
> > (begin
> (send t set-max-undo-history 'forever)
> (send t insert "a")
> (send t insert "b")
> (send t begin-edit-sequence #f #f)
> (send t insert "c" 0 0)
> (send t end-edit-sequence)
> (send t get-text))
> "cab"
> > (begin
> (send t undo)
> (send t get-text))
> "cb"

Default implementation: Starts a sequence.

> > method
> > (send an-editor begin-write-header-footer-to-file |  | f |
> > |  | name |
> > |  | buffer) |
> → void?
> f : (is-a?/c editor-stream-out%)
> name : string?
> buffer : (box/c exact-integer?)

This method must be called before writing any special header data to a stream. See File Format and write-headers-to-file for more information.

The name string must be a unique name that can be used by a header reader to recognize the data. This method will store a value in buffer that should be passed on to end-write-header-footer-to-file.

> method (send an-editor blink-caret) → void?

Specification: Tells the editor to blink the selection caret. This method is called periodically when the editor’s display has the keyboard focus.

Default implementation: Propagates the request to any snip with the editor-local focus.

> > method
> > (send an-editor can-do-edit-operation? |  | op |  |  |  |
> > | [ | recursive?]) |  | → |  | boolean?
> | op |  | : |  |
> (or/c 'undo 'redo 'clear 'cut 'copy 'paste
> 'kill 'select-all 'insert-text-box
> 'insert-pasteboard-box 'insert-image)
> recursive? : any/c = #t

Specification: Checks whether a generic edit command would succeed for the editor. This check is especially useful for enabling and disabling menus on demand. See do-edit-operation for information about the op and recursive? arguments.

Default implementation: Allows the operation depending on the selection, whether the editor is locked, etc.

> > method
> > (send an-editor can-load-file? |  | filename |  |  |  |
> > |  | format) |  | → |  | boolean?
> filename : path?
> | format |  | : |  |
> (or/c 'guess 'same 'copy 'standard
> 'text 'text-force-cr)

Refine this method with augment.
Specification: Called just before the editor is loaded from a file. If the return value is #f, the file is not loaded. See also on-load-file and after-load-file.

The filename argument is the name the file will be loaded from. See load-file for information about format.

Note that the filename argument cannot be a string; it must be a path value.

Default implementation: Returns #t.

> > method
> > (send an-editor can-save-file? |  | filename |  |  |  |
> > |  | format) |  | → |  | boolean?
> filename : path?
> | format |  | : |  |
> (or/c 'guess 'same 'copy 'standard
> 'text 'text-force-cr)

Refine this method with augment.
Specification: Called just before the editor is saved to a file. If the return value is #f, the file is not saved. See also on-save-file and after-save-file.

The filename argument is the name the file will be saved to. See load-file for information about format.

Note that the filename argument cannot be a string; it must be a path value.

Default implementation: Returns #t.

> method (send an-editor clear) → void?

Deletes the currently selected items.

The content of an editor can be changed by the system in response to other method calls, and such changes do not go through this method; use on-delete in text% or on-delete in pasteboard% to monitor content deletions changes.

> method (send an-editor clear-undos) → void?

Destroys the undo history of the editor.

> method (send an-editor copy [extend? time]) → void?
> extend? : any/c = #f
> time : exact-integer? = 0

Copies items into the clipboard. If extend? is not #f, the old clipboard contents are appended.

The system may execute a copy (in response to other method calls) without calling this method. To extend or re-implement copying, override the do-copy in text% or do-copy in pasteboard% method of an editor.

See Cut and Paste Time Stamps for a discussion of the time argument. If time is outside the platform-specific range of times, an exn:fail:contract exception is raised.

> method (send an-editor copy-self)
> → (or/c (is-a?/c text%) (is-a?/c pasteboard%))

Creates a new editor with the same properties as this one. After an editor is created (either a text% or pasteboard% instance, as appropriate), the new editor is passed to copy-self-to.

> method (send an-editor copy-self-to dest) → void?
> dest : (or/c (is-a?/c text%) (is-a?/c pasteboard%))

Copies the properties of an-editor to dest.

Each snip in an-editor is copied and inserted into dest. In addition, an-editor’s filename, maximum undo history setting, keymap, interactive caret threshold, and overwrite-styles-on-load settings are installed into dest. Finally, an-editor’s style list is copied and the copy is installed as the style list for dest.

> method (send an-editor cut [extend? time]) → void?
> extend? : any/c = #f
> time : exact-integer? = 0

Copies and then deletes the currently selected items. If extend? is not #f, the old clipboard contents are appended.

The system may execute a cut (in response to other method calls) without calling this method. To extend or re-implement the copying portion of the cut, override the do-copy in text% or do-copy in pasteboard% method of an editor. To monitor deletions in an editor, override on-delete in text% or on-delete in pasteboard%.

See Cut and Paste Time Stamps for a discussion of the time argument. If time is outside the platform-specific range of times, an exn:fail:contract exception is raised.

> > method
> > (send an-editor dc-location-to-editor-location |  | x |  |  |  |
> > |  | y) |  | → |  |
> > real? |  | real?
> x : real?
> y : real?

Converts the given coordinates from top-level display coordinates (usually canvas coordinates) to editor location coordinates. The same calculation is performed by global-to-local.

The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f).

See also editor-location-to-dc-location.

> method (send an-editor default-style-name) → string?

Returns the name of a style to be used for newly inserted text, etc. The default is "Standard".

> > method
> > (send an-editor do-edit-operation |  | op |  |  |  |
> > | [ | recursive? |  |  |  |
> > |  | time]) |  | → |  | void?
> | op |  | : |  |
> (or/c 'undo 'redo 'clear 'cut 'copy 'paste
> 'kill 'select-all 'insert-text-box
> 'insert-pasteboard-box 'insert-image)
> recursive? : any/c = #t
> time : exact-integer? = 0

Performs a generic edit command. The op argument must be a valid edit command, one of:

- 'undo — undoes the last operation

- 'redo — undoes the last undo

- 'clear — deletes the current selection

- 'cut — cuts

- 'copy — copies

- 'paste — pastes

- 'kill — cuts to the end of the current line, or cuts a newline if there is only whitespace between the selection and end of line

- 'select-all — selects everything in the editor

- 'insert-text-box — inserts a text editor as an item in this editor; see also on-new-box .

- 'insert-pasteboard-box — inserts a pasteboard editor as an item in this editor; see also on-new-box .

- 'insert-image — gets a filename from the user and inserts the image as an item in this editor; see also on-new-image-snip .

If recursive? is not #f, then the command is passed on to any active snips of this editor (i.e., snips which own the caret).

See Cut and Paste Time Stamps for a discussion of the time argument. If time is outside the platform-specific range of times, an exn:fail:contract exception is raised.

> > method
> > (send an-editor editor-location-to-dc-location |  | x |  |  |  |
> > |  | y) |  | → |  |
> > real? |  | real?
> x : real?
> y : real?

Converts the given coordinates from editor location coordinates to top-level display coordinates (usually canvas coordinates). The same calculation is performed by local-to-global.

The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f).

See also dc-location-to-editor-location.

> method (send an-editor end-edit-sequence) → void?

See begin-edit-sequence.

> > method
> > (send an-editor end-write-header-footer-to-file |  | f |
> > |  | buffer-value) |
> → void?
> f : (is-a?/c editor-stream-out%)
> buffer-value : exact-integer?

This method must be called after writing any special header data to a stream. The buffer-value argument must be the value put in the buffer argument box by begin-write-header-footer-to-file.

See File Format and write-headers-to-file for more information.

> method (send an-editor find-first-snip) → (or/c (is-a?/c snip%) #f)

Returns the first snip in the editor, or #f if the editor is empty. To get all of the snips in the editor, use the next in snip% on the resulting snip.

The first snip in a text editor is the one at position 0. The first snip in a pasteboard is the frontmost snip. (See Editor Structure and Terminology for information about snip order in pasteboards.)

> method (send an-editor find-scroll-line location)
> → exact-nonnegative-integer?
> location : real?

Maps a vertical location within the editor to a vertical scroll position.

For text% objects: Calling this method may force the recalculation of location information, even if the editor currently has delayed refreshing (see refresh-delayed?). The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f).

> method (send an-editor get-active-canvas)
> → (or/c (is-a?/c editor-canvas%) #f)

If the editor is displayed in a canvas, this method returns the canvas that most recently had the keyboard focus (while the editor was displayed). If no such canvas exists, #f is returned.

> method (send an-editor get-admin) → (or/c (is-a?/c editor-admin%) #f)

Returns the editor-admin% object currently managing this editor or #f if the editor is not displayed.

> method (send an-editor get-canvas)
> → (or/c (is-a?/c editor-canvas%) #f)

If get-active-canvas returns a canvas, that canvas is also returned by this method. Otherwise, if get-canvases returns a non-empty list, the first canvas in the list is returned, otherwise #f is returned.

> method (send an-editor get-canvases)
> → (listof (is-a?/c editor-canvas%))

Returns a list of canvases displaying the editor. An editor may be displayed in multiple canvases and no other kind of display, or one instance of another kind of display and no canvases. If the editor is not displayed or the editor’s current display is not a canvas, null is returned.

> method (send an-editor get-dc) → (or/c (is-a?/c dc<%>) #f)

Typically used (indirectly) by snip objects belonging to the editor. Returns a destination drawing context which is suitable for determining display sizing information, or #f if the editor is not displayed.

> method (send an-editor get-descent) → (and/c real? (not/c negative?))

Returns the font descent for the editor. This method is primarily used when an editor is an item within another editor. For a text editor, the reported descent includes the editor’s bottom padding (see set-padding).

The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f). For text% objects, calling this method may force the recalculation of location information if a maximum width is set for the editor, even if the editor currently has delayed refreshing (see refresh-delayed?).

> method (send an-editor get-extent w h) → void?
> w : (or/c (box/c (and/c real? (not/c negative?))) #f)
> h : (or/c (box/c (and/c real? (not/c negative?))) #f)

Gets the current extent of the editor’s graphical representation. The w box is filled with the editor’s width, unless w is #f. The h box is filled with the editor’s height, unless h is #f. For a text editor, the reported extent includes the editor’s padding (see set-padding).

The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f). For text% objects, calling this method may force the recalculation of location information if a maximum width is set for the editor, even if the editor currently has delayed refreshing (see refresh-delayed?).

> method (send an-editor get-file directory) → (or/c path-string? #f)
> directory : (or/c path? #f)

Specification: Called when the user must be queried for a filename to load an editor. A starting-directory path is passed in, but is may be #f to indicate that any directory is fine.

Note that the directory argument cannot be a string; it must be a path value or #f.

Default implementation: Calls the global get-file procedure.

If the editor is displayed in a single canvas, then the canvas’s top-level frame is used as the parent for the file dialog. Otherwise, the file dialog will have no parent.

> method (send an-editor get-filename [temp]) → (or/c path-string? #f)
> temp : (or/c (box/c any/c) #f) = #f

Returns the path name of the last file saved from or loaded into this editor, #f if the editor has no filename.

The temp box is filled with #t if the filename is temporary or #f otherwise.

> method (send an-editor get-flattened-text) → string?

Returns the contents of the editor in text form. See Flattened Text for a discussion of flattened vs. non-flattened text.

> method (send an-editor get-focus-snip) → (or/c (is-a?/c snip%) #f)

Returns the snip within the editor that gets the keyboard focus when the editor has the focus, or #f if the editor does not delegate the focus.

The returned snip might be an editor-snip% object. In that case, the embedded editor might delegate the focus to one of its own snips. However, the get-focus-snip method returns only the editor-snip% object, because it is the focus-owning snip within the immediate editor.

See also set-caret-owner.

> method (send an-editor get-inactive-caret-threshold)
> → (or/c 'no-caret 'show-inactive-caret 'show-caret)

Returns the threshold for painting an inactive selection. This threshold is compared with the draw-caret argument to refresh and if the argument is as least as large as the threshold (but larger than 'show-caret), the selection is drawn as inactive.

See also set-inactive-caret-threshold and Caret Ownership.

> method (send an-editor get-keymap) → (or/c (is-a?/c keymap%) #f)

Returns the main keymap currently used by the editor.

> method (send an-editor get-load-overwrites-styles) → boolean?

Reports whether named styles in the current style list are replaced by load-file when the loaded file contains style specifications.

See also set-load-overwrites-styles.

> method (send an-editor get-max-height)
> → (or/c (and/c real? (not/c negative?)) 'none)

Gets the maximum display height for the contents of the editor; zero or 'none indicates that there is no maximum.

> method (send an-editor get-max-undo-history)
> → (or/c (integer-in 0 100000) 'forever)

Returns the maximum number of undoables that will be remembered by the editor. Note that undoables are counted by insertion, deletion, etc. events, not by the number of times that undo can be called; a single undo call often reverses multiple events at a time (such as when the user types a stream of characters at once).

When an editor is in preserve-all-history mode (see set-undo-preserves-all-history), then any non-0 value is treated the same as 'forever.

> > method
> > (send an-editor get-max-view-size) |  | → |  |
> > real? |  | real?

Returns the maximum visible area into which the editor is currently being displayed, according to the editor’s administrators. If the editor has only one display, the result is the same as for get-view-size. Otherwise, the maximum width and height of all the editor’s displaying canvases is returned.

The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f).

If the display is an editor canvas, see also reflow-container.

> method (send an-editor get-max-width)
> → (or/c (and/c real? (not/c negative?)) 'none)

Gets the maximum display width for the contents of the editor; zero or 'none indicates that there is no maximum. In a text editor, zero of 'none disables automatic line breaking.

> method (send an-editor get-min-height)
> → (or/c (and/c real? (not/c negative?)) 'none)

Gets the minimum display height for the contents of the editor; zero or 'none indicates that there is no minimum.

> method (send an-editor get-min-width)
> → (or/c (and/c real? (not/c negative?)) 'none)

Gets the minimum display width for the contents of the editor; zero or 'none indicates that there is no minimum.

> method (send an-editor get-paste-text-only) → boolean?

If the result is #t, then the editor accepts only plain-text data from the clipboard. If the result is #f, the editor accepts both text and snip data from the clipboard.

> method (send an-editor get-snip-data thesnip)
> → (or/c (is-a?/c editor-data%) #f)
> thesnip : (is-a?/c snip%)

Specification: Gets extra data associated with a snip (e.g., location information in a pasteboard) or returns #f is there is no information. See Editor Data for more information.

Default implementation: Returns #f.

> > method
> > (send an-editor get-snip-location |  | thesnip |  |  |  |
> > | [ | x |  |  |  |
> > |  | y |  |  |  |
> > |  | bottom-right?]) |  | → |  | boolean?
> thesnip : (is-a?/c snip%)
> x : (or/c (box/c real?) #f) = #f
> y : (or/c (box/c real?) #f) = #f
> bottom-right? : any/c = #f

Gets the location of the given snip. If the snip is found in the editor, #t is returned; otherwise, #f is returned.

The x box is filled with the x-coordinate of the snip’s location, unless x is #f. The y box is filled with the y-coordinate of the snip’s location, unless y is #f.

If bottom-right? is not #f, the values in the x and y boxes are for the snip’s bottom right corner instead of its top-left corner.

Obtaining the location of the bottom-right corner may trigger delayed size calculations (including snips other than the one whose location was requested).

The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f). As a special case, however, a pasteboard% object always reports valid answers when bottom-right? is #f. For text% objects, calling this method may force the recalculation of location information if a maximum width is set for the editor, even if the editor currently has delayed refreshing (see refresh-delayed?).

> method (send an-editor get-space) → (and/c real? (not/c negative?))

Returns the maximum font space for the editor. This method is primarily used when an editor is an item within another editor. For a text editor, the reported space includes the editor’s top padding (see set-padding).

The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f). For text% objects, calling this method may force the recalculation of location information if a maximum width is set for the editor, even if the editor currently has delayed refreshing (see refresh-delayed?).

> method (send an-editor get-style-list) → (is-a?/c style-list%)

Returns the style list currently in use by the editor.

> method (send an-editor get-view-size w h) → void?
> w : (or/c (box/c (and/c real? (not/c negative?))) #f)
> h : (or/c (box/c (and/c real? (not/c negative?))) #f)

Returns the visible area into which the editor is currently being displayed (according to the editor’s administrator). See also get-view .

The w box is filled with the visible area width, unless w is #f. The h box is filled with the visible area height, unless h is #f.

The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f).

If the display is an editor canvas, see also reflow-container.

> method (send an-editor global-to-local x y) → void?
> x : (or/c (box/c real?) #f)
> y : (or/c (box/c real?) #f)

Converts the given coordinates from top-level display coordinates (usually canvas coordinates) to editor location coordinates. The same calculation is performed by dc-location-to-editor-location.

The x box is filled with the translated x-coordinate of the value initially in x, unless x is #f. The y box is filled with the translated x-coordinate of the value initially in y, unless y is #f.

The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f).

See also local-to-global.

> method (send an-editor in-edit-sequence?) → boolean?

Returns #t if updating on this editor is currently delayed because begin-edit-sequence has been called for this editor.

See also refresh-delayed?.

> method (send an-editor insert snip) → void?
> snip : (is-a?/c snip%)

Inserts data into the editor. A snip cannot be inserted into multiple editors or multiple times within a single editor.

The content of an editor can be changed by the system in response to other method calls, and such changes do not go through this method; use on-insert in text% or on-insert in pasteboard% to monitor content additions changes.

> method (send an-editor insert-box [type]) → void?
> type : (or/c 'text 'pasteboard) = 'text

Inserts a box (a sub-editor) into the editor by calling on-new-box, then passing along type and inserts the resulting snip into the editor.

The content of an editor can be changed by the system in response to other method calls, and such changes do not go through this method; use on-insert in text% or on-insert in pasteboard% to monitor content additions changes.

> > method
> > (send an-editor insert-file |  | filename |  |  |  |
> > | [ | format |  |  |  |
> > |  | show-errors?]) |  | → |  | boolean?
> filename : path-string?
> | format |  | : |  |
> (or/c 'guess 'same 'copy 'standard
> 'text 'text-force-cr)
> |  | = |  | 'guess
> show-errors? : any/c = #t

Inserts the content of a file or port into the editor (at the current selection position in text% editors). The result is #t; if an error occurs, an exception is raised.

For information on format, see load-file. The show-errors? argument is no longer used.

The content of an editor can be changed by the system in response to other method calls, and such changes do not go through this method; use on-insert in text% or on-insert in pasteboard% to monitor content additions changes.

> > method
> > (send an-editor insert-image | [ | filename |  |  |  |
> > |  | type |  |  |  |
> > |  | relative-path? |  |  |  |
> > |  | inline?]) |  | → |  | void?
> filename : (or/c path-string? #f) = #f
> | type |  | : |  |
> (or/c 'unknown 'unknown/mask 'unknown/alpha
> 'gif 'gif/mask 'gif/alpha
> 'jpeg 'png 'png/mask 'png/alpha
> 'xbm 'xpm 'bmp 'pict)
> |  |  | = |  | 'unknown/alpha
> relative-path? : any/c = #f
> inline? : any/c = #t

Inserts an image into the editor.

If filename is #f, then the user is queried for a filename. The kind must one of the symbols that can be passed to load-file.

After the filename has been determined, an image is created by calling on-new-image-snip. See also image-snip%.

The content of an editor can be changed by the system in response to other method calls, and such changes do not go through this method; use on-insert in text% or on-insert in pasteboard% to monitor content additions changes.

> > method
> > (send an-editor insert-port |  | port |
> > | [ | format |
> > |  | replace-styles?]) |
> → (or/c 'standard 'text 'text-force-cr)
> port : input-port?
> | format |  | : |  |
> (or/c 'guess 'same 'copy 'standard
> 'text 'text-force-cr)
> |  | = |  | 'guess
> replace-styles? : any/c = #t

Inserts the content of a port into the editor (at the current selection position in text% editors) without wrapping the insert operations as an edit sequence. The result is the actual format of the loaded content (which is different from the given format type if the given format is 'guess, 'same, or 'copy).

The port must support position setting with file-position.

For information on format, see load-file.

if replace-styles? is true, then styles in the current style list are replaced by style specifications in port’s stream.

See also insert-file.

> > method
> > (send an-editor invalidate-bitmap-cache | [ | x |  |  |  |
> > |  | y |  |  |  |
> > |  | width |  |  |  |
> > |  | height]) |  | → |  | void?
> x : real? = 0.0
> y : real? = 0.0
> | width |  | : |  | (or/c (and/c real? (not/c negative?)) 'end 'display-end)
> |  |  | = |  | 'end
> | height |  | : |  | (or/c (and/c real? (not/c negative?)) 'end 'display-end)
> |  |  | = |  | 'end

When on-paint is overridden, call this method when the state of on-paint’s drawing changes.

The x, y, width, and height arguments specify the area that needs repainting in editor coordinates. If width/height is 'end, then the total height/width of the editor (as reported by get-extent) is used. Note that the editor’s size can be smaller than the visible region of its display. If width/height is 'display-end, then the largest height/width of the editor’s views (as reported by get-max-view) is used. If width/height is not 'display-end, then the given width/height is constrained to the editor’s size.

The default implementation triggers a redraw of the editor, either immediately or at the end of the current edit sequence (if any) started by begin-edit-sequence.

See also size-cache-invalid.

> method (send an-editor is-locked?) → boolean?

Returns #t if the editor is currently locked, #f otherwise. See lock for more information.

> method (send an-editor is-modified?) → boolean?

Returns #t if the editor has been modified since the last save or load (or the last call to set-modified with #f), #f otherwise.

> method (send an-editor is-printing?) → boolean?

Returns #t if the editor is currently being printed through the print method, #f otherwise.

> method (send an-editor kill [time]) → void?
> time : exact-integer? = 0

In a text editor, cuts to the end of the current line, or cuts a newline if there is only whitespace between the selection and end of line. Multiple consecutive kills are appended. In a pasteboard editor, cuts the current selection.

See Cut and Paste Time Stamps for a discussion of the time argument. If time is outside the platform-specific range of times, an exn:fail:contract exception is raised.

See also cut.

The content of an editor can be changed by the system in response to other method calls, and such changes do not go through this method; use on-delete in text% or on-delete in pasteboard% to monitor content deletions changes.

> > method
> > (send an-editor load-file | [ | filename |  |  |  |
> > |  | format |  |  |  |
> > |  | show-errors?]) |  | → |  | boolean?
> filename : (or/c path-string? #f) = #f
> | format |  | : |  |
> (or/c 'guess 'same 'copy 'standard
> 'text 'text-force-cr)
> |  | = |  | 'guess
> show-errors? : any/c = #t

Loads a file into the editor and returns #t. If an error occurs, an exception is raised.

If filename is #f, then the internally stored filename will be used; if filename is "" or if the internal name is unset or temporary, then the user will be prompted for a name.

The possible values for format are listed below. A single set of format values are used for loading and saving files:

- 'guess — guess the format based on extension and/or contents; when saving a file, this is the same as 'standard

- 'same — read in whatever format was last loaded or saved

- 'standard — read/write a standard file (binary format)

- 'copy — write using whatever format was last loaded or saved, but do not change the modification flag or remember filename (saving only)

- 'text — read/write a text file (text% only); file writing uses the platform’s text-mode conventions (e.g., newlines as return–linefeed combinations on Windows) when not specifically disabled via use-file-text-mode

- 'text-force-cr — read/write a text file (text% only); when writing, change automatic newlines (from word-wrapping) into real carriage returns

In a text% instance, the format returned from get-file-format is always one of 'standard, 'text, or 'text-force-cr.

The show-errors? argument is no longer used.

The filename used to load the file can be retrieved with get-filename. For a text% instance, the format can be retrieved with get-file-format. However, if an error occurs while loading the file, the filename is set to #f.

See also on-load-file, after-load-file, can-load-file?, and set-load-overwrites-styles.

> method (send an-editor local-to-global x y) → void?
> x : (or/c (box/c real?) #f)
> y : (or/c (box/c real?) #f)

Converts the given coordinates from editor location coordinates to top-level display coordinates (usually canvas coordinates). The same calculation is performed by editor-location-to-dc-location.

The x box is filled with the translated x-coordinate of the value initially in x, unless x is #f. The y box is filled with the translated x-coordinate of the value initially in y, unless y is #f.

The result is only valid when the editor is displayed (see Editor Structure and Terminology). Editors are displayed when get-admin returns an administrator (not #f).

See also global-to-local.

> method (send an-editor locations-computed?) → boolean?

Returns #t if all location information has been computed after recent changes to the editor’s content or to its snips, #f otherwise.

Location information is often computed on demand, and begin-edit-sequence tends to delay the computation.

When the editor is locked for reflowing, location information cannot be recomputed. See also Internal Editor Locks.

> method (send an-editor lock lock?) → void?
> lock? : any/c

Locks or unlocks the editor for modifications. If an editor is locked, all modifications are blocked, not just user modifications.

See also is-locked?.

This method does not affect internal locks, as discussed in Internal Editor Locks.

> method (send an-editor locked-for-flow?) → boolean?

Reports whether the editor is internally locked for flowing. See Internal Editor Locks for more information.

> method (send an-editor locked-for-read?) → boolean?

Reports whether the editor is internally locked for reading. See Internal Editor Locks for more information.

> method (send an-editor locked-for-write?) → boolean?

Reports whether the editor is internally locked for writing. See Internal Editor Locks for more information.

> > method
> > (send an-editor needs-update |  | snip |  |  |  |
> > |  | localx |  |  |  |
> > |  | localy |  |  |  |
> > |  | w |  |  |  |
> > |  | h) |  | → |  | void?
> snip : (is-a?/c snip%)
> localx : real?
> localy : real?
> w : (and/c real? (not/c negative?))
> h : (and/c real? (not/c negative?))

Typically called (indirectly) by a snip within the editor to force the editor to be redrawn.

The localx, localy, width, and height arguments specify the area that needs repainting in the coordinate system of snip.

For text% objects, calling this method may force the recalculation of location information if a maximum width is set for the editor, even if the editor currently has delayed refreshing (see refresh-delayed?).

> method (send an-editor num-scroll-lines) → exact-nonnegative-integer?

Reports the number of scroll positions available within the editor.

For text% objects: Calling this method may force the recalculation of location information, even if the editor currently has delayed refreshing (see refresh-delayed?). If the editor is not displayed and the editor has a maximum width, line breaks are calculated as for line-start-position (which handles specially the case of no display when the editor has a maximum width).

> method (send an-editor on-change) → void?

Refine this method with augment.
Specification: Called whenever any change is made to the editor that affects the way the editor is drawn or the values reported for the location/size of some snip in the editor. The on-change method is called just before the editor calls its administrator’s needs-update method to refresh the editor’s display, and it is also called just before and after printing an editor.

The editor is locked for writing and reflowing during the call to on-change.

Default implementation: Does nothing.

> method (send an-editor on-char event) → void?
> event : (is-a?/c key-event%)

Specification: Handles keyboard input to the editor.

Consider overriding on-local-char or on-default-char instead of this method.

Default implementation: Either passes this event on to a caret-owning snip or calls on-local-char. In the latter case, text% first calls hide-cursor-until-moved.

> method (send an-editor on-default-char event) → void?
> event : (is-a?/c key-event%)

Specification: Called by on-local-char when the event is not handled by a caret-owning snip or by the keymap.

Default implementation: Does nothing.

> method (send an-editor on-default-event event) → void?
> event : (is-a?/c mouse-event%)

Specification: Called by on-local-event when the event is not handled by a caret-owning snip or by the keymap.

Default implementation: Does nothing. See also on-default-event in text% and on-default-event in pasteboard%.

> method (send an-editor on-display-size) → void?

Refine this method with augment.
Specification: This method is called by the editor’s display whenever the display’s size (as reported by get-view-size) changes, but it is called indirectly through on-display-size-when-ready.

Default implementation: If automatic wrapping is enabled (see auto-wrap ) then set-max-width is called with the maximum width of all of the editor’s canvases (according to the administrators; call-as-primary-owner in editor-canvas% is used with each canvas to set the administrator and get the view size). If the editor is displayed but not in a canvas, the unique width is obtained from the editor’s administrator (there is only one). If the editor is not displayed, the editor’s maximum width is not changed.

> method (send an-editor on-display-size-when-ready) → void?

Calls on-display-size unless the editor is currently in an edit sequence or currently being refreshed. In the latter cases, the call to on-display-size is delegated to another thread; see Editors and Threads for more information.

> method (send an-editor on-edit-sequence) → void?

Refine this method with augment.
Specification: Called just after a top-level (i.e., unnested) edit sequence starts.

During an edit sequence, all callbacks methods are invoked normally, but it may be appropriate for these callbacks to delay computation during an edit sequence. The callbacks must manage this delay manually. Thus, when overriding other callback methods, such as on-insert in text%, on-insert in pasteboard%, after-insert in text%, or after-insert in pasteboard%, consider overriding on-edit-sequence and after-edit-sequence as well.

“Top-level edit sequence” refers to an outermost pair of begin-edit-sequence and end-edit-sequence calls. The embedding of an editor within another editor does not affect the timing of calls to on-edit-sequence, even if the embedding editor is in an edit sequence.

Pairings of on-edit-sequence and after-edit-sequence can be nested if an after-edit-sequence starts a new edit sequence, since after-edit-sequence is called after an edit sequence ends. However, on-edit-sequence can never start a new top-level edit sequence (except through an unpaired end-edit-sequence), because it is called after a top-level edit sequence starts.

Default implementation: Does nothing.

> method (send an-editor on-event event) → void?
> event : (is-a?/c mouse-event%)

Specification: Handles mouse input to the editor. The event’s x and y coordinates are in the display’s co-ordinate system; use the administrator’s get-dc method to obtain translation arguments (or use dc-location-to-editor-location).

Consider overriding on-local-event or on-default-event instead of this method.

Default implementation: Either passes this event on to a caret-owning snip, selects a new caret-owning snip (text% only) and passes the event on to the selected snip, or calls on-local-event. A new caret-owning snip is selected in a text% object when the click is on an event-handling snip, and not too close to the space between snips (see get-between-threshold ).

> method (send an-editor on-focus on?) → void?
> on? : any/c

Called when the keyboard focus changes into or out of this editor (and not to/from a snip within the editor) with #t if the focus is being turned on, #f otherwise.

> > method
> > (send an-editor on-load-file |  | filename |  |  |  |
> > |  | format) |  | → |  | void?
> filename : path?
> | format |  | : |  |
> (or/c 'guess 'same 'copy 'standard
> 'text 'text-force-cr)

Refine this method with augment.
Specification: Called just before the editor is loaded from a file, after calling can-load-file? to verify that the load is allowed. See also after-load-file.

The filename argument is the name the file will be loaded from. See load-file for information about format.

Note that the filename argument cannot be a string; it must be a path value.

Default implementation: Does nothing.

> method (send an-editor on-local-char event) → void?
> event : (is-a?/c key-event%)

Specification: Called by on-char when the event is not handled by a caret-owning snip.

Consider overriding on-default-char instead of this method.

Default implementation: Either lets the keymap handle the event or calls on-default-char.

> method (send an-editor on-local-event event) → void?
> event : (is-a?/c mouse-event%)

Specification: Called by on-event when the event is not handled by a caret-owning snip.

Consider overriding on-default-event instead of this method.

Default implementation: Either lets the keymap handle the event or calls on-default-event.

> method (send an-editor on-new-box type) → (is-a?/c snip%)
> type : (or/c 'text 'pasteboard)

Specification: Creates and returns a new snip for an embedded editor. This method is called by insert-box.

Default implementation: Creates a editor-snip% with either a sub-editor from text% or sub-pasteboard from pasteboard%, depending on whether type is 'text or 'pasteboard. The keymap (see keymap%) and style list (see style-list%) for of the new sub-editor are set to the keymap and style list of this editor.

> > method
> > (send an-editor on-new-image-snip |  | filename |
> > |  | kind |
> > |  | relative-path? |
> > |  | inline?) |
> → (is-a?/c image-snip%)
> filename : path?
> | kind |  | : |  |
> (or/c 'unknown 'unknown/mask 'unknown/alpha
> 'gif 'gif/mask 'gif/alpha
> 'jpeg 'png 'png/mask 'png/alpha
> 'xbm 'xpm 'bmp 'pict)
> relative-path? : any/c
> inline? : any/c

Specification: Creates and returns a new instance of image-snip% for insert-image.

Note that the filename argument cannot be a string; it must be a path value.

Default implementation: Returns (make-object image-snip% filename kind relative-path? inline?).

> > method
> > (send an-editor on-paint |  | before? |  |  |  |
> > |  | dc |  |  |  |
> > |  | left |  |  |  |
> > |  | top |  |  |  |
> > |  | right |  |  |  |
> > |  | bottom |  |  |  |
> > |  | dx |  |  |  |
> > |  | dy |  |  |  |
> > |  | draw-caret) |  | → |  | void?
> before? : any/c
> dc : (is-a?/c dc<%>)
> left : real?
> top : real?
> right : real?
> bottom : real?
> dx : real?
> dy : real?
> | draw-caret |  | : |  |
> (or/c 'no-caret 'show-inactive-caret 'show-caret
> (cons/c exact-nonnegative-integer?
> exact-nonnegative-integer?))

Specification: Provides a way to add arbitrary graphics to an editor’s display. This method is called just before and just after every painting of the editor.

The before? argument is #t when the method is called just before painting the contents of the editor or #f when it is called after painting. The left, top, right, and bottom arguments specify which region of the editor is being repainted, in editor coordinates. To get the coordinates for dc, offset editor coordinates by adding (dx, dy). See Caret Ownership for information about draw-caret.

The on-paint method, together with the snips’ draw methods, must be able to draw the entire state of an editor. Never paint directly into an editor’s display canvas except from within on-paint or draw. Instead, put all extra drawing code within on-paint and call invalidate-bitmap-cache when part of the display needs to be repainted.

If an on-paint method uses cached location information, then the cached information should be recomputed in response to a call of invalidate-bitmap-cache.

The on-paint method must not make any assumptions about the state of the drawing context (e.g., the current pen), except that the clipping region is already set to something appropriate. Before on-paint returns, it must restore any drawing context settings that it changes.

The editor is internally locked for writing and reflowing during a call to this method (see also Internal Editor Locks). The on-paint method is called during a refresh; see Editors and Threads.

See also invalidate-bitmap-cache.

Default implementation: Does nothing.

> > method
> > (send an-editor on-save-file |  | filename |  |  |  |
> > |  | format) |  | → |  | void?
> filename : path?
> | format |  | : |  |
> (or/c 'guess 'same 'copy 'standard
> 'text 'text-force-cr)

Refine this method with augment.
Specification: Called just before the editor is saved to a file, after calling can-save-file? to verify that the save is allowed. See also after-save-file.

The filename argument is the name the file will be saved to. See load-file for information about format.

Note that the filename argument cannot be a string; it must be a path value.

Default implementation: Does nothing.

> method (send an-editor on-scroll-to) → void?

Specification: Called when the editor is about to scroll, but the entire display is may not be refreshed. (If the editor scrolls but the entire window is redrawn, this method may not be called.)

See also get-scroll-via-copy.

Default implementation: Does nothing.

> > method
> > (send an-editor on-snip-modified |  | snip |  |  |  |
> > |  | modified?) |  | → |  | void?
> snip : (is-a?/c snip%)
> modified? : any/c

Refine this method with augment.
Specification: This method is called whenever a snip within the editor reports that it has been modified (by calling its adminstrator’s modified method). The method arguments are the snip that reported a modification-state change, and the snip’s new modification state.

See also set-modified.

Default implementation: If modified? is true and the editor was not already modified (i.e., its is-modified? method reports #f), then the set-modified method is called with #t. If the editor was already modified, then the internal modify-counter is incremented.

If modified? is #f, and if the modify-counter is 1, then the set-modified method is called with #f (on the assumption that the modify-counter was set to 1 by an earlier call to this method for the same snip).

> method (send an-editor own-caret own?) → void?
> own? : any/c

Specification: Tells the editor to display or not display the caret or selection.

The focus state of an editor can be changed by by the system, and such changes do not go through this method; use on-focus to monitor focus changes.

Default implementation: Propagates the flag to any snip with the editor-local focus. If no sub-editors are active, the editor assumes the caret ownership.

> method (send an-editor paste [time]) → void?
> time : exact-integer? = 0

Pastes the current contents of the clipboard into the editor.

See Cut and Paste Time Stamps for a discussion of the time argument. If time is outside the platform-specific range of times, an exn:fail:contract exception is raised.

The system may execute a paste (in response to other method calls) without calling this method. To extend or re-implement copying, override the do-paste in text% or do-paste in pasteboard% method.

See also get-paste-text-only.

> method (send an-editor paste-x-selection [time]) → void?
> time : exact-integer? = 0

Like paste, but on Unix, uses the X11 selection instead of the clipboard.

See Cut and Paste Time Stamps for a discussion of the time argument. If time is outside the platform-specific range of times, an exn:fail:contract exception is raised.

To extend or re-implement copying, override the do-paste-x-selection in text% or do-paste-x-selection in pasteboard% method.

> > method
> > (send an-editor print | [ | interactive? |  |  |  |
> > |  | fit-on-page? |  |  |  |
> > |  | output-mode |  |  |  |
> > |  | parent |  |  |  |
> > |  | force-ps-page-bbox? |  |  |  |
> > |  | as-eps?]) |  | → |  | void?
> interactive? : any/c = #t
> fit-on-page? : any/c = #t
> output-mode : (or/c 'standard 'postscript 'pdf) = 'standard
> | parent |  | : |  | (or/c (or/c (is-a?/c frame%) (is-a?/c dialog%)) #f)
> |  |  | = |  | #f
> force-ps-page-bbox? : any/c = #t
> as-eps? : any/c = #f

Prints the editor.

If interactive? is true and a PostScript file is created, the is given a dialog for adjusting printing parameters; see also get-ps-setup-from-user. Otherwise, if a PostScript file is created, the settings returned by current-ps-setup are used. (The user may still get a dialog to select an output file name; see post-script-dc% for more details.)

If fit-on-page? is a true value, then during printing for a text% editor, the editor’s maximum width is set to the width of the page (less margins) and the autowrapping bitmap is removed.

The output-mode setting determines whether the output is generated directly as a PostScript file, generated directly as a PDF file, or generated using the platform-specific standard printing mechanism. The possible values are

- 'standard — print using the platform-standard mechanism (via a printer-dc%)

- 'postscript — print to a PostScript file (via a post-script-dc%)

- 'pdf — print to a PDF file (via a pdf-dc%)

If parent is not #f, it is used as the parent window for configuration dialogs (for either PostScript or platform-standard printing). If parent is #f and if the editor is displayed in a single canvas, then the canvas’s top-level frame is used as the parent for configuration dialogs. Otherwise, configuration dialogs will have no parent.

The force-ps-page-bbox? argument is used for PostScript and PDF printing, and is used as the third initialization argument when creating the post-script-dc% or pdf-dc% instance. Unless it is #f, the bounding-box of the resulting PostScript/PDF file is set to the current paper size.

The as-eps? argument is used for PostScript and PDF printing, and is used as the fourth initialization argument when creating the post-script-dc% or pdf-dc% instance. Unless it is #f, a resulting PostScript file is identified as Encapsulated PostScript (EPS).

The printing margins are determined by get-editor-margin in the current ps-setup% object (as determined by current-ps-setup), but they are ignored when as-eps? is true.

> method (send an-editor print-to-dc dc [page-number]) → void?
> dc : (is-a?/c dc<%>)
> page-number : exact-integer? = -1

Prints the editor into the given drawing context. See also print.

If page-number is a positive integer, then just the indicated page is printed, where pages are numbered from 1. If page-number is 0, then the entire content of the editor is printed on a single page. When page-number is negative, then the editor content is split across pages as needed to fit, and the start-page and end-page methods of dc<%> are called for each page.

> > method
> > (send an-editor put-file |  | directory |  |  |  |
> > |  | default-name) |  | → |  | (or/c path-string? #f)
> directory : (or/c path? #f)
> default-name : (or/c path? #f)

Specification: Called when the user must be queried for a filename to save an editor. Starting-directory and default-name paths are passed in, but either may be #f to indicate that any directory is fine or there is no default name.

Note that the directory and filename arguments cannot be strings; each must be a path value.

Default implementation: Calls the global put-file procedure.

If the editor is displayed in a single canvas, then the canvas’s top-level frame is used as the parent for the file dialog. Otherwise, the file dialog will have no parent.

> > method
> > (send an-editor read-footer-from-file |  | stream |  |  |  |
> > |  | name) |  | → |  | boolean?
> stream : (is-a?/c editor-stream-in%)
> name : string?

See read-header-from-file.

> > method
> > (send an-editor read-from-file |  | stream |  |  |  |
> > | [ | overwrite-styles?]) |  | → |  | boolean?
> stream : (is-a?/c editor-stream-in%)
> overwrite-styles? : any/c = #f

Reads new contents for the editor from a stream. The return value is #t if there are no errors, #f otherwise. See also File Format.

The stream provides either new mappings for names in the editor’s style list, or it indicates that the editor should share a previously-read style list (depending on how style lists were shared when the editor was written to the stream; see also write-to-file).

- In the former case, if the overwrite-styles? argument is #f, then each style name in the loaded file that is already in the current style list keeps its current style. Otherwise, existing named styles are overwritten with specifications from the loaded file.

- In the latter case, the editor’s style list will be changed to the previously-read list.

> > method
> > (send an-editor read-header-from-file |  | stream |  |  |  |
> > |  | name) |  | → |  | boolean?
> stream : (is-a?/c editor-stream-in%)
> name : string?

Called to handle a named header that is found when reading editor data from a stream. The return value is #t if there are no errors, #f otherwise.

Override this method only to embellish the file format with new header information. Always call the inherited method if the derived reader does not recognize the header.

See also File Format.

> method (send an-editor redo) → void?

Undoes the last undo, if no other changes have been made since. See undo for information about Emacs-style undo. If the editor is currently performing an undo or redo, the method call is ignored.

The system may perform a redo without calling this method in response to other method calls. Use methods such as on-change to monitor editor content changes.

See also add-undo.

> > method
> > (send an-editor refresh |  | x |  |  |  |
> > |  | y |  |  |  |
> > |  | width |  |  |  |
> > |  | height |  |  |  |
> > |  | draw-caret |  |  |  |
> > |  | background) |  | → |  | void?
> x : real?
> y : real?
> width : (and/c real? (not/c negative?))
> height : (and/c real? (not/c negative?))
> | draw-caret |  | : |  |
> (or/c 'no-caret 'show-inactive-caret 'show-caret
> (cons/c exact-nonnegative-integer?
> exact-nonnegative-integer?))
> background : (or/c (is-a?/c color%) #f)

Repaints a region of the editor, generally called by an editor administrator. The x, y, width, and height arguments specify the area that needs repainting in editor coordinates. The get-dc method of the editor’s administrator (as returned by get-admin) supplies the target dc<%> object and offset for drawing.

See Caret Ownership for information about draw-caret.

The background color corresponds to the background of the display; if it is #f, then the display is transparent. An editor should use the given background color as its own background (or not paint the background of background is #f).

See Editors and Threads for information about edit sequences and refresh requests.

> method (send an-editor refresh-delayed?) → boolean?

Returns #t if updating on this editor is currently delayed. Updating may be delayed because begin-edit-sequence has been called for this editor, or because the editor has no administrator, or because the editor’s administrator returns #t from its refresh-delayed? method. (The administrator might return #t because an enclosing editor’s refresh is delayed.)

See also in-edit-sequence?.

> method (send an-editor release-snip snip) → boolean?
> snip : (is-a?/c snip%)

Requests that the specified snip be deleted and released from the editor. If this editor is not the snip’s owner or if the snip cannot be released, then #f is returned. Otherwise, #t is returned and the snip is no longer owned.

See also release-snip in snip-admin% .

> method (send an-editor remove-canvas canvas) → void?
> canvas : (is-a?/c editor-canvas%)

Removes a canvas from this editor’s list of displaying canvases. (See get-canvases.)

Normally, this method is called only by set-editor in editor-canvas%.

> method (send an-editor resized snip redraw-now?) → void?
> snip : (is-a?/c snip%)
> redraw-now? : any/c

Called (indirectly) by snips within the editor: it forces a recalculation of the display information in which the specified snip has changed its size.

If redraw-now? is #f, the editor will require another message to repaint itself. (See also needs-update.)

> > method
> > (send an-editor save-file | [ | filename |  |  |  |
> > |  | format |  |  |  |
> > |  | show-errors?]) |  | → |  | boolean?
> filename : (or/c path-string? #f) = #f
> | format |  | : |  |
> (or/c 'guess 'same 'copy 'standard
> 'text 'text-force-cr)
> |  | = |  | 'same
> show-errors? : any/c = #t

Saves the editor into a file and returns #t. If an error occurs, an exception is raised.

If filename is #f, then the internally stored filename will be used; if filename is "" or if the internal name is unset or temporary, then the user will be prompted for a name. The possible values for format are described at load-file.

The filename and format used to save the file can be retrieved with get-filename unless the format is 'copy – see also load-file for more information on the format argument.

In a text% instance, the format can be retrieved with get-file-format.

See also on-save-file, after-save-file, and can-save-file?.

On Mac OS, the file’s type signature is set to "TEXT" for a text-format file or "WXME" for a standard-format (binary) file.

The show-errors? argument is no longer used.

> > method
> > (send an-editor save-port |  | port |  |  |  |
> > | [ | format |  |  |  |
> > |  | show-errors?]) |  | → |  | boolean?
> port : output-port?
> | format |  | : |  |
> (or/c 'guess 'same 'copy 'standard
> 'text 'text-force-cr)
> |  | = |  | 'same
> show-errors? : any/c = #t

Saves the editor into a port and returns #t. If an error occurs, an exception is raised.

The possible values for format are described at load-file.

The show-errors? argument is no longer used.

> > method
> > (send an-editor scroll-editor-to |  | localx |  |  |  |
> > |  | localy |  |  |  |
> > |  | width |  |  |  |
> > |  | height |  |  |  |
> > |  | refresh? |  |  |  |
> > |  | bias) |  | → |  | boolean?
> localx : real?
> localy : real?
> width : (and/c real? (not/c negative?))
> height : (and/c real? (not/c negative?))
> refresh? : any/c
> bias : (or/c 'start 'end 'none)

Causes the editor to be scrolled so that a given location is visible. If the editor is scrolled, #t is returned, otherwise #f is returned.

This method is normally called indirectly by scroll-to or scroll-to-position in text% to implement scrolling.

The default implementation forwards the request to the scroll-to method of the current administrator, if any (see get-admin). If a text editor has padding (see set-padding), then the padding is added to the given location before forwarding to the administrator. If the editor has no administrator, #f is returned.

> method (send an-editor scroll-line-location pos)
> → (and/c real? (not/c negative?))
> pos : exact-nonnegative-integer?

Maps a vertical scroll position to a vertical location within the editor.

For text% objects: Calling this method may force the recalculation of location information, even if the editor currently has delayed refreshing (see refresh-delayed?). If the editor is not displayed and the editor has a maximum width, line breaks are calculated as for line-start-position (which handles specially the case of no display when the editor has a maximum width).

> > method
> > (send an-editor scroll-to |  | snip |  |  |  |
> > |  | localx |  |  |  |
> > |  | localy |  |  |  |
> > |  | width |  |  |  |
> > |  | height |  |  |  |
> > |  | refresh? |  |  |  |
> > | [ | bias]) |  | → |  | boolean?
> snip : (is-a?/c snip%)
> localx : real?
> localy : real?
> width : (and/c real? (not/c negative?))
> height : (and/c real? (not/c negative?))
> refresh? : any/c
> bias : (or/c 'start 'end 'none) = 'none

Called (indirectly) by snips within the editor: it causes the editor to be scrolled so that a given location range within a given snip is visible. If the editor is scrolled immediately, #t is returned, otherwise #f is returned.

If refreshing is delayed (see refresh-delayed?), then the scroll request is saved until the delay has ended. The scroll is performed (immediately or later) by calling scroll-editor-to.

The localx, localy, width, and height arguments specify the area that needs to be visible in snip’s coordinate system.

When the specified region cannot fit in the visible area, bias indicates which end of the region to display. When bias is 'start, then the top-left of the region is displayed. When bias is 'end, then the bottom-right of the region is displayed. Otherwise, bias must be 'none.

> method (send an-editor select-all) → void?

Selects all data in the editor

> method (send an-editor set-active-canvas canvas) → void?
> canvas : (is-a?/c editor-canvas%)

Sets the active canvas for this editor. (See get-active-canvas.)

Normally, this method is called only by on-focus in editor-canvas% in an editor canvas that is displaying an editor.

> method (send an-editor set-admin admin) → void?
> admin : (or/c (is-a?/c editor-admin%) #f)

Sets the editor’s administrator. This method is only called by an administrator.

The administrator of an editor can be changed by by the system, and such changes do not go through this method. A program cannot detect when the administrator changes except by polling get-admin.

> > method
> > (send an-editor set-caret-owner |  | snip |  |  |  |
> > | [ | domain]) |  | → |  | void?
> snip : (or/c (is-a?/c snip%) #f)
> domain : (or/c 'immediate 'display 'global) = 'immediate

Attempts to give the keyboard focus to snip. If snip is #f, then the caret is taken away from any snip in the editor that currently has the caret and restored to this editor.

If the keyboard focus is moved to snip and the editor has the real keyboard focus, the own-caret method of the snip will be called.

If #f is provided as the new owner, then the local focus is moved to the editor itself. Otherwise, the local focus is moved to the specified snip.

The domain of focus-setting is one of:

- 'immediate — only set the focus owner within the editor

- 'display — make this editor or the new focus owner get the keyboard focus among the editors in this editor’s display (if this is an embedded editor)

- 'global — make this editor or the new focus owner get the keyboard focus among all elements in the editor’s frame

The focus state of an editor can be changed by by the system, and such changes do not go through this method; use on-focus to monitor focus changes.

See also get-focus-snip.

> > method
> > (send an-editor set-cursor |  | cursor |  |  |  |
> > | [ | override?]) |  | → |  | void?
> cursor : (or/c (is-a?/c cursor%) #f)
> override? : any/c = #t

Sets the custom cursor for the editor to cursor. If override? is a true value and cursor is not #f, then this cursor overrides cursor settings in embedded editors.

If the custom cursor is #f, the current cursor is removed, and a cursor is selected automatically by the editor (depending on whether the cursor is pointing at a clickback). See adjust-cursor for more information about the default selection.

An embedding editor’s custom cursor can override the cursor of an embedded editor—even if the embedded editor has the caret—if the cursor is specified as an overriding cursor.

> > method
> > (send an-editor set-filename |  | filename |  |  |  |
> > | [ | temporary?]) |  | → |  | void?
> filename : (or/c path-string? #f)
> temporary? : any/c = #f

Sets the filename to filename. If filename is #f or temporary? is a true value, then the user will still be prompted for a name on future calls to save-file and load-file.

This method is also called when the filename changes through any method (such as load-file).

> method (send an-editor set-inactive-caret-threshold threshold) → void?
> threshold : (or/c 'no-caret 'show-inactive-caret 'show-caret)

Sets the threshold for painting an inactive selection. See get-inactive-caret-threshold for more information.

> method (send an-editor set-keymap [keymap]) → void?
> keymap : (or/c (is-a?/c keymap%) #f) = #f

Sets the current keymap for the editor. A #f argument removes all key mapping.

> method (send an-editor set-load-overwrites-styles overwrite?) → void?
> overwrite? : any/c

Determines whether named styles in the current style list are replaced by load-file when the loaded file contains style specifications.

See also get-load-overwrites-styles and read-from-file.

> method (send an-editor set-max-height width) → void?
> width : (or/c (and/c real? (not/c negative?)) 'none)

Sets the maximum display height for the contents of the editor. A value less or equal to 0 indicates that there is no maximum.

Setting the height is disallowed when the editor is internally locked for reflowing (see also Internal Editor Locks).

> method (send an-editor set-max-undo-history count) → void?
> count : (or/c exact-nonnegative-integer? 'forever)

Sets the maximum number of undoables that will be remembered by the editor. The default is 0, which disables undo. The symbol 'forever is accepted as a synonym for a very large number.

When an editor is in preserve-all-history mode (see set-undo-preserves-all-history), then any non-0 value is treated the same as 'forever.

> method (send an-editor set-max-width width) → void?
> width : (or/c (and/c real? (not/c negative?)) 'none)

Sets the maximum display width for the contents of the editor; zero or 'none indicates that there is no maximum. In a text editor, having no maximum disables automatic line breaking, and the minimum (positive) maximum width depends on the width of the autowrap bitmap. The maximum width of a text editor includes its left and right padding (see set-padding) and its autowrap bitmap (see set-autowrap-bitmap).

Setting the width is disallowed when the editor is internally locked for reflowing (see also Internal Editor Locks).

> method (send an-editor set-min-height width) → void?
> width : (or/c (and/c real? (not/c negative?)) 'none)

Sets the minimum display height for the contents of the editor; zero or 'none indicates that there is no minimum.

Setting the height is disallowed when the editor is internally locked for reflowing (see also Internal Editor Locks).

> method (send an-editor set-min-width width) → void?
> width : (or/c (and/c real? (not/c negative?)) 'none)

Sets the minimum display width for the contents of the editor; zero or 'none indicates that there is no minimum.

Setting the width is disallowed when the editor is internally locked for reflowing (see also Internal Editor Locks).

> method (send an-editor set-modified modified?) → void?
> modified? : any/c

Sets the modified state of the editor. Usually, the state is changed automatically after an insertion, deletion, or style change by calling this method. (This method is also called when the modification state changes through any method.) This method is usually not called when the state of the flag is not changing.

See also is-modified? and on-snip-modified.

When modified? is true, then an internal modify-counter is set to 1.

When modified? is #f and the editor’s undo or redo stack contains a system-created undoer that resets the modified state (because the preceding undo or redo action puts the editor back to a state where the modification state was #f), the undoer is disabled.

Regardless of the value of modified?, the editor’s adminstrator’s modified method is called.

Finally, if modified? is #f and the internal modify-counter is set to 0, then the set-unmodified method is called on every snip within the editor.

> method (send an-editor set-paste-text-only text-only?) → void?
> text-only? : any/c

Sets whether the editor accepts only text from the clipboard, or both text and snips. By default, an editor accepts both text and snips.

See also get-paste-text-only.

> method (send an-editor set-snip-data thesnip data) → void?
> thesnip : (is-a?/c snip%)
> data : (is-a?/c editor-data%)

Sets extra data associated with the snip (e.g., location information in a pasteboard). See Editor Data for more information.

> method (send an-editor set-style-list style-list) → void?
> style-list : (is-a?/c style-list%)

Sets the editor’s style list. Styles currently in use with the old style list will be “moved” to the new style list. In this “move,” if a named style already exists in the new style list, then the new style with the same name will be used in place of the old style.

Setting the style list is disallowed when the editor is internally locked for reflowing (see also Internal Editor Locks).

> method (send an-editor set-undo-preserves-all-history on?) → void?
> on? : any/c

When on? is true, configures the editor to preserve all editing history, including operations that have been undone, as long as the maximum undo history is non-zero (see set-max-undo-history). Otherwise, operations that are undone (and not redone) before another operation are lost from the editor’s history.

The default mode is determined by the 'GRacket:emacs-undo preference preference (see Preferences).

Added in version 1.1 of package gui-lib.

> method (send an-editor size-cache-invalid) → void?

This method is called when the drawing context given to the editor by its administrator changes in a way that makes cached size information (such as the width of a string) invalid.

The default implementation eventually propagates the message to snips, and, more generally, causes location information to be recalculated on demand.

See also invalidate-bitmap-cache.

> method (send an-editor style-has-changed style) → void?
> style : (or/c (is-a?/c style<%>) #f)

Notifies the editor that a style in its style list has changed. This method is automatically registered with the editor’s style list using notify-on-change in style-list% and automatically deregistered when the style list is removed from the editor.

See notify-on-change in style-list% for more information.

> method (send an-editor undo) → void?

Undoes the last editor change, if undos have been enabled by calling set-max-undo-history with a non-zero integer or 'forever.

If the editor is currently performing an undo or redo, the method call is ignored.

The user may enable Emacs-style undo for editors; see Preferences. Normally, undo operations add to the redo stack (see redo), and any undoable (non-undo) operation clears the redo stack. With Emacs-style undo, the redo stack is added back to the undo stack, along with the original undos, so that a complete history is kept in the undo stack.

The system may perform an undo without calling this method in response to other method calls. Use methods such as on-change to monitor editor content changes.

See also add-undo.

> method (send an-editor undo-preserves-all-history?) → boolean?

Reports whether the editor is in preserve-all-history mode. See set-undo-preserves-all-history for more information.

Added in version 1.1 of package gui-lib.

> method (send an-editor use-file-text-mode) → boolean?
> (send an-editor use-file-text-mode on?) → void?
> on? : any/c

Gets or sets a boolean that controls if files are saved in 'text or 'binary mode (as in open-input-file’s #:mode argument). This flag is consulted only when the format is 'text or 'text-force-cr. See load-file for information on formats.

The setting is consulted by save-file after on-save-file is called.

Overriding this method is a reliable way to detect changes to the internal boolean.

> method (send an-editor write-footers-to-file stream) → boolean?
> stream : (is-a?/c editor-stream-out%)

See write-headers-to-file.

> method (send an-editor write-headers-to-file stream) → boolean?
> stream : (is-a?/c editor-stream-out%)

Specification: Called when the editor is being saved to a file. The return value is #t if there are no errors, #f otherwise. Override this method to add custom header data to a file, but always call the inherited method so that it can write its own extra headers.

To write a header item, call begin-write-header-footer-to-file, passing a box for an integer. Then write the header data and end by calling end-write-header-footer-to-file, passing back the integer that was put into the box. Follow this procedure correctly or the file will be corrupted.

Default implementation: Does nothing.

> method (send an-editor write-to-file stream) → boolean?
> stream : (is-a?/c editor-stream-out%)

Writes the current editor contents to the given stream. The return value is #t if there are no errors, #f otherwise. See also File Format.

If the editor’s style list has already been written to the stream, it is not re-written. Instead, the editor content indicates that the editor shares a previously-written style list. This sharing will be recreated when the stream is later read.
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