text(3)

NAME

Tk::Text - Create and manipulate Text widgets

SYNOPSIS

text $text ?options?
-background    -highlightbackground     -inserton
time  -selectborderwidth -borderwidth   -highlight
color     -insertwidth   -selectforeground -cur
sor   -highlightthickness -padx     -setgrid -exportselec
tion    -insertbackground   -pady     -takefocus
-font     -insertborderwidth  -relief   -xscrollcommand
-foreground    -insertofftime -selectback
ground   -yscrollcommand

WIDGET-SPECIFIC OPTIONS

Name: height
Class: Height
Switch: -height: Specifies the desired height for the window, in units
of characters in the font given by the -font option.
Must be at least one.
Name: spacing1
Class: Spacing1
Switch: -spacing1: Requests additional space above each text line in the
widget, using any of the standard forms for screen
distances. If a line wraps, this option only applies
to the first line on the display. This option may be
overriden with -spacing1 options in tags.
Name: spacing2
Class: Spacing2
Switch: -spacing2: For lines that wrap (so that they cover more than one
line on the display) this option specifies additional
space to provide between the display lines that repre
sent a single line of text. The value may have any of
the standard forms for screen distances. This option
may be overriden with -spacing2 options in tags.
Name: spacing3
Class: Spacing3
Switch: -spacing3: Requests additional space below each text line in the
widget, using any of the standard forms for screen
distances. If a line wraps, this option only applies
to the last line on the display. This option may be
overriden with -spacing3 options in tags.
Name: state
Class: State
Switch: -state: Specifies one of two states for the text: normal or
disabled. If the text is disabled then characters may not be inserted or deleted and no insertion cursor
will be displayed, even if the input focus is in the
widget.
Name: tabs
Class: Tabs
Switch: -tabs: Specifies a set of tab stops for the window. The
option's value consists of a list of screen distances
giving the positions of the tab stops. Each position
may optionally be followed in the next list element by
one of the keywords left, right, center, or numeric, which specifies how to justify text relative to the
tab stop. Left is the default; it causes the text
following the tab character to be positioned with its
left edge at the tab position. Right means that the
right edge of the text following the tab character is
positioned at the tab position, and center means that
the text is centered at the tab position. Numeric
means that the decimal point in the text is positioned
at the tab position; if there is no decimal point
then the least significant digit of the number is
positioned just to the left of the tab position; if
there is no number in the text then the text is rightjustified at the tab position. For example, -tabs => [qw/2c left 4c 6c center/] creates three tab stops at two-centimeter intervals; the first two use left jus
tification and the third uses center justification.
If the list of tab stops does not have enough elements
to cover all of the tabs in a text line, then Tk
extrapolates new tab stops using the spacing and
alignment from the last tab stop in the list. The
value of the tabs option may be overridden by -tabs options in tags. If no -tabs option is specified, or
if it is specified as an empty list, then Tk uses
default tabs spaced every eight (average size) charac
ters.
Name: width
Class: Width
Switch: -width: Specifies the desired width for the window in units of
characters in the font given by the -font option. If
the font doesn't have a uniform width then the width
of the character ``0'' is used in translating from
character units to screen units.
Name: wrap
Class: Wrap
Switch: -wrap: Specifies how to handle lines in the text that are too
long to be displayed in a single line of the text's
window. The value must be none or char or word. A wrap mode of none means that each line of text appears
as exactly one line on the screen; extra characters
that don't fit on the screen are not displayed. In
the other modes each line of text will be broken up
into several screen lines if necessary to keep all the
characters visible. In char mode a screen line break
may occur after any character; in word mode a line
break will only be made at word boundaries.

DESCRIPTION

The Text method creates a new window (given by the $text
argument) and makes it into a text widget. Additional
options, described above, may be specified on the command
line or in the option database to configure aspects of the
text such as its default background color and relief. The
text command returns the path name of the new window.

A text widget displays one or more lines of text and
allows that text to be edited. Text widgets support four
different kinds of annotations on the text, called tags,
marks, embedded windows or embedded images. Tags allow
different portions of the text to be displayed with dif
ferent fonts and colors. In addition, perl/Tk callbacks
can be associated with tags so that scripts are invoked
when particular actions such as keystrokes and mouse but
ton presses occur in particular ranges of the text. See
"TAGS" below for more details.

The second form of annotation consists of marks, which are
floating markers in the text. Marks are used to keep
track of various interesting positions in the text as it
is edited. See "MARKS" below for more details.

The third form of annotation allows arbitrary windows to
be embedded in a text widget. See "EMBEDDED WINDOWS"
below for more details.

The fourth form of annotation allows Tk images to be
embedded in a text widget. See "EMBEDDED IMAGES" below
for more details.

INDICES

Many of the methods for texts take one or more indices as arguments. An index is a string used to indicate a par ticular place within a text, such as a place to insert characters or one endpoint of a range of characters to delete. Indices have the syntax: base modifier modifier modifier ...
Where base gives a starting point and the modifiers adjust the index from the starting point (e.g. move forward or backward one character). Every index must contain a base, but the modifiers are optional.
The base for an index must have one of the following forms:
line.char: Indicates char'th character on line line. Lines are numbered from 1 for consistency with other UNIX pro
grams that use this numbering scheme. Within a line,
characters are numbered from 0. If char is end then it refers to the newline character that ends the line.
@x,y: Indicates the character that covers the pixel whose x
and y coordinates within the text's window are x and
y.
end Indicates the end of the text (the character just: after the last newline).
mark: Indicates the character just after the mark whose name
is mark.
tag.first: Indicates the first character in the text that has
been tagged with tag. This form generates an error if
no characters are currently tagged with tag.
tag.last: Indicates the character just after the last one in the
text that has been tagged with tag. This form
generates an error if no characters are currently
tagged with tag.
$widget: Indicates the position of the embedded window refer
enced by $widget. This form generates an error if
$widget does not reference to an embedded window.
imageName: Indicates the position of the embedded image whose
name is imageName. This form generates an error if there is no embedded image by the given name.; If the base could match more than one of the above
forms, such as a mark and imageName both having the same value, then the form earlier in the above list
takes precedence. If modifiers follow the base index,
each one of them must have one of the forms listed
below. Keywords such as chars and wordend may be abbreviated as long as the abbreviation is unambigu
ous.
+ count chars: Adjust the index forward by count characters, moving
to later lines in the text if necessary. If there are
fewer than count characters in the text after the cur
rent index, then set the index to the last character
in the text. Spaces on either side of count are
optional.
- count chars: Adjust the index backward by count characters, moving
to earlier lines in the text if necessary. If there
are fewer than count characters in the text before the
current index, then set the index to the first charac
ter in the text. Spaces on either side of count are
optional.
+ count lines: Adjust the index forward by count lines, retaining the
same character position within the line. If there are
fewer than count lines after the line containing the
current index, then set the index to refer to the same
character position on the last line of the text.
Then, if the line is not long enough to contain a
character at the indicated character position, adjust
the character position to refer to the last character
of the line (the newline). Spaces on either side of
count are optional.
- count lines: Adjust the index backward by count lines, retaining
the same character position within the line. If there
are fewer than count lines before the line containing
the current index, then set the index to refer to the
same character position on the first line of the text.
Then, if the line is not long enough to contain a
character at the indicated character position, adjust
the character position to refer to the last character
of the line (the newline). Spaces on either side of
count are optional.
linestart: Adjust the index to refer to the first character on
the line.
lineend: Adjust the index to refer to the last character on the
line (the newline).
wordstart: Adjust the index to refer to the first character of
the word containing the current index. A word con
sists of any number of adjacent characters that are
letters, digits, or underscores, or a single character
that is not one of these.
wordend: Adjust the index to refer to the character just after
the last one of the word containing the current index.
If the current index refers to the last character of
the text then it is not modified.; If more than one modifier is present then they are
applied in left-to-right order. For example, the
index ``end - 1 chars'' refers to the next-to-last character in the text and ``insert wordstart - 1 c'' refers to the character just before the first one in
the word containing the insertion cursor.

MARKS

The second form of annotation in text widgets is a mark.
Marks are used for remembering particular places in a
text. They are something like tags, in that they have
names and they refer to places in the file, but a mark
isn't associated with particular characters. Instead, a
mark is associated with the gap between two characters.
Only a single position may be associated with a mark at
any given time. If the characters around a mark are
deleted the mark will still remain; it will just have new
neighbor characters. In contrast, if the characters con
taining a tag are deleted then the tag will no longer have
an association with characters in the file. Marks may be
manipulated with the ``$text->mark'' text widget method, and their current locations may be determined by using the
mark name as an index in methods.

Each mark also has a gravity, which is either left or right. The gravity for a mark specifies what happens to
the mark when text is inserted at the point of the mark.
If a mark has left gravity, then the mark is treated as if
it were attached to the character on its left, so the mark
will remain to the left of any text inserted at the mark
position. If the mark has right gravity, new text
inserted at the mark position will appear to the right of
the mark. The gravity for a mark defaults to right.

The name space for marks is different from that for tags:
the same name may be used for both a mark and a tag, but
they will refer to different things.

Two marks have special significance. First, the mark
insert is associated with the insertion cursor, as
described under "THE INSERTION CURSOR" below. Second, the
mark current is associated with the character closest to the mouse and is adjusted automatically to track the mouse
position and any changes to the text in the widget (one
exception: current is not updated in response to mouse
motions if a mouse button is down; the update will be
deferred until all mouse buttons have been released).
Neither of these special marks may be deleted.

EMBEDDED WINDOWS

The third form of annotation in text widgets is an embed
ded window. Each embedded window annotation causes a win
dow to be displayed at a particular point in the text.
There may be any number of embedded windows in a text wid
get, and any widget may be used as an embedded window
(subject to the usual rules for geometry management, which
require the text window to be the parent of the embedded
window or a descendant of its parent). The embedded win
dow's position on the screen will be updated as the text
is modified or scrolled, and it will be mapped and
unmapped as it moves into and out of the visible area of
the text widget. Each embedded window occupies one char
acter's worth of index space in the text widget, and it
may be referred to either by the name of its embedded win
dow or by its position in the widget's index space. If
the range of text containing the embedded window is
deleted then the window is destroyed.

When an embedded window is added to a text widget with the
widgetCreate method, several configuration options may be associated with it. These options may be modified later
with the widgetConfigure method. The following options are currently supported:

-align => where: If the window is not as tall as the line in which it
is displayed, this option determines where the window
is displayed in the line. Where must have one of the
values top (align the top of the window with the top
of the line), center (center the window within the
range of the line), bottom (align the bottom of the
window with the bottom of the line's area), or base
line (align the bottom of the window with the baseline
of the line).
-create => callback: Specifies a callback that may be evaluated to create
the window for the annotation. If no -window option has been specified for the annotation this callback will be evaluated when the annotation is about to be
displayed on the screen. Callback must create a win dow for the annotation and return the name of that
window as its result. If the annotation's window
should ever be deleted, callback will be evaluated again the next time the annotation is displayed.
-padx => pixels: Pixels specifies the amount of extra space to leave on each side of the embedded window. It may have any of
the usual forms defined for a screen distance (see
Tk_GetPixels).
-pady => pixels: Pixels specifies the amount of extra space to leave on the top and on the bottom of the embedded window. It
may have any of the usual forms defined for a screen
distance (see Tk_GetPixels).
-stretch => boolean: If the requested height of the embedded window is less
than the height of the line in which it is displayed,
this option can be used to specify whether the window
should be stretched vertically to fill its line. If
the -pady option has been specified as well, then the
requested padding will be retained even if the window
is stretched.
-window => $widget: Specifies the name of a window to display in the anno
tation.

EMBEDDED IMAGES

The final form of annotation in text widgets is an embed
ded image. Each embedded image annotation causes an image
to be displayed at a particular point in the text. There
may be any number of embedded images in a text widget, and
a particular image may be embedded in multiple places in
the same text widget. The embedded image's position on
the screen will be updated as the text is modified or
scrolled. Each embedded image occupies one character's
worth of index space in the text widget, and it may be
referred to either by its position in the widget's index
space, or the name it is assigned when the image is
inserted into the text widget with imageCreate. If the range of text containing the embedded image is deleted
then that copy of the image is removed from the screen.

When an embedded image is added to a text widget with the
image create method, a name unique to this instance of the
image is returned. This name may then be used to refer to
this image instance. The name is taken to be the value of
the -name option (described below). If the -name option is not provided, the -image name is used instead. If the
imageName is already in use in the text widget, then #nn is added to the end of the imageName, where nn is an arbi trary integer. This insures the imageName is unique. Once this name is assigned to this instance of the image,
it does not change, even though the -image or -name values can be changed with image configure.

When an embedded image is added to a text widget with the
imageCreate method, several configuration options may be associated with it. These options may be modified later
with the image configure method. The following options are currently supported:

-align => where: If the image is not as tall as the line in which it is
displayed, this option determines where the image is
displayed in the line. Where must have one of the
values top (align the top of the image with the top of
the line), center (center the image within the range
of the line), bottom (align the bottom of the image
with the bottom of the line's area), or baseline
(align the bottom of the image with the baseline of
the line).
-image => image: Specifies the name of the Tk image to display in the
annotation. If image is not a valid Tk image, then an
error is returned.
-name => ImageName: Specifies the name by which this image instance may be
referenced in the text widget. If ImageName is not supplied, then the name of the Tk image is used
instead. If the imageName is already in use, #nn is appended to the end of the name as described above.
-padx => pixels: Pixels specifies the amount of extra space to leave on each side of the embedded image. It may have any of
the usual forms defined for a screen distance.
-pady => pixels: Pixels specifies the amount of extra space to leave on the top and on the bottom of the embedded image. It
may have any of the usual forms defined for a screen
distance.

THE SELECTION

Selection support is implemented via tags. If the export
Selection option for the text widget is true then the sel tag will be associated with the selection:

[1] Whenever characters are tagged with sel the text wid: get will claim ownership of the selection.
[2] Attempts to retrieve the selection will be serviced by: the text widget, returning all the characters with the
sel tag.
[3] If the selection is claimed away by another applica: tion or by another window within this application,
then the sel tag will be removed from all characters
in the text.; The sel tag is automatically defined when a text wid
get is created, and it may not be deleted with the
``$text->tagDelete'' method. Furthermore, the select Background, selectBorderWidth, and selectForeground options for the text widget are tied to the -back
ground, -borderwidth, and -foreground options for the sel tag: changes in either will automatically be
reflected in the other.

THE INSERTION CURSOR

The mark named insert has special significance in text
widgets. It is defined automatically when a text widget
is created and it may not be unset with the
``$text->markUnset'' widget command. The insert mark rep resents the position of the insertion cursor, and the
insertion cursor will automatically be drawn at this point
whenever the text widget has the input focus.

WIDGET METHODS

The Text method creates a widget object. This object sup
ports the configure and cget methods described in Tk::options which can be used to enquire and modify the
options described above. The widget also inherits all the
methods provided by the generic Tk::Widget class.

The following additional methods are available for text
widgets:

$text->bbox(index): Returns a list of four elements describing the screen
area of the character given by index. The first two
elements of the list give the x and y coordinates of
the upper-left corner of the area occupied by the
character, and the last two elements give the width
and height of the area. If the character is only par
tially visible on the screen, then the return value
reflects just the visible part. If the character is
not visible on the screen then the return value is an
empty list.
$text->compare(index1, op, index2): Compares the indices given by index1 and index2 according to the relational operator given by op, and
returns 1 if the relationship is satisfied and 0 if it
isn't. Op must be one of the operators <, <=, ==, >=,
>, or !=. If op is == then 1 is returned if the two
indices refer to the same character, if op is < then 1
is returned if index1 refers to an earlier character
in the text than index2, and so on.
$text->debug(?boolean?): If boolean is specified, then it must have one of the true or false values accepted by Tcl_GetBoolean. If
the value is a true one then internal consistency
checks will be turned on in the B-tree code associated
with text widgets. If boolean has a false value then the debugging checks will be turned off. In either
case the command returns an empty string. If boolean is not specified then the command returns on or off to
indicate whether or not debugging is turned on. There
is a single debugging switch shared by all text wid
gets: turning debugging on or off in any widget turns
it on or off for all widgets. For widgets with large
amounts of text, the consistency checks may cause a
noticeable slow-down.
$text->delete(index1, ?index2?): Delete a range of characters from the text. If both
index1 and index2 are specified, then delete all the characters starting with the one given by index1 and
stopping just before index2 (i.e. the character at
index2 is not deleted). If index2 doesn't specify a position later in the text than index1 then no charac
ters are deleted. If index2 isn't specified then the
single character at index1 is deleted. It is not
allowable to delete characters in a way that would
leave the text without a newline as the last charac
ter. The command returns an empty string.
$text->dlineinfo(index): Returns a list with five elements describing the area
occupied by the display line containing index. The
first two elements of the list give the x and y coor
dinates of the upper-left corner of the area occupied
by the line, the third and fourth elements give the
width and height of the area, and the fifth element
gives the position of the baseline for the line, mea
sured down from the top of the area. All of this
information is measured in pixels. If the current
wrap mode is none and the line extends beyond the
boundaries of the window, the area returned reflects
the entire area of the line, including the portions
that are out of the window. If the line is shorter
than the full width of the window then the area
returned reflects just the portion of the line that is
occupied by characters and embedded windows. If the
display line containing index is not visible on the
screen then the return value is an empty list.
$text->dump(?switches?, index1, ?index2?): Return the contents of the text widget from index1 up
to, but not including index2, including the text and
information about marks, tags, and embedded windows.
If index2 is not specified, then it defaults to one
character past index1. The information is returned in the following format:; key1 value1 index1 key2 value2 index2 ...
The possible key values are text, mark, tagon, tagoff, and $text. The corresponding value is the text, mark name, tag name, or window name. The index information is the
index of the start of the text, the mark, the tag transi
tion, or the window. One or more of the following
switches (or abbreviations thereof) may be specified to
control the dump:
-all: Return information about all elements: text, marks,
tags, and windows. This is the default.
-command => callback: Instead of returning the information as the result of
the dump operation, invoke the callback on each ele ment of the text widget within the range. The call
back has three arguments appended to it before it is
evaluated: the key, value, and index.
-mark: Include information about marks in the dump results.
-tag: Include information about tag transitions in the dump
results. Tag information is returned as tagon and
tagoff elements that indicate the begin and end of
each range of each tag, respectively.
-text: Include information about text in the dump results.
The value is the text up to the next element or the
end of range indicated by index2. A text element does not span newlines. A multi-line block of text that
contains no marks or tag transitions will still be
dumped as a set of text seqments that each end with a
newline. The newline is part of the value.
-window: Include information about embedded windows in the dump
results. The value of a window is its Tk pathname,
unless the window has not been created yet. (It must
have a create script.) In this case an empty string
is returned, and you must query the window by its
index position to get more information.
$text->get(index1, ?index2?): Return a range of characters from the text. The
return value will be all the characters in the text
starting with the one whose index is index1 and ending just before the one whose index is index2 (the
character at index2 will not be returned). If index2 is omitted then the single character at index1 is
returned. If there are no characters in the specified
range (e.g. index1 is past the end of the file or
index2 is less than or equal to index1) then an empty string is returned. If the specified range contains
embedded windows, no information about them is
included in the returned string.
$text->image(option, ?arg, arg, ...?) $text->imageOption(?arg, arg, ...?): This method is used to manipulate embedded images.
The behavior of the method depends on the option argu
ment that follows the image prefix. The following
forms of the methods are currently supported:; $text->imageCget(index, option)
Returns the value of a configuration option
for an embedded image. Index identifies the
embedded image, and option specifies a partic
ular configuration option, which must be one
of the ones listed in "EMBEDDED IMAGES".
$text->imageConfigure(index, ?option, value, ...?): Query or modify the configuration options for
an embedded image. If no option is specified, returns a list describing all of the available
options for the embedded image at index (see
Tk::options for information on the format of
this list). If option is specified with no
value, then the command returns a list
describing the one named option (this list
will be identical to the corresponding sublist
of the value returned if no option is speci
fied). If one or more option-value pairs are specified, then the command modifies the given
option(s) to have the given value(s); in this
case the command returns an empty string. See
"EMBEDDED IMAGES" for information on the
options that are supported.
$text->imageCreate(index, ?option, value, ...?): This command creates a new image annotation,
which will appear in the text at the position
given by index. Any number of option-value pairs may be specified to configure the anno
tation. Returns a unique identifier that may
be used as an index to refer to this image.
See "EMBEDDED IMAGES" for information on the
options that are supported, and a description
of the identifier returned.
$text->imageNames: Returns a list whose elements are the names of
all image instances currently embedded in
$text.
$text->index(index): Returns the position corresponding to index in the
form line.char where line is the line number and char is the character number. Index may have any of the
forms described under "INDICES" above.
$text->insert(index, chars, ?tagList, chars, tagList, ...?): Inserts all of the chars arguments just before the
character at index. If index refers to the end of the text (the character after the last newline) then the
new text is inserted just before the last newline
instead. If there is a single chars argument and no
tagList, then the new text will receive any tags that are present on both the character before and the char
acter after the insertion point; if a tag is present
on only one of these characters then it will not be
applied to the new text. If tagList is specified then it consists of a list of tag names; the new charac
ters will receive all of the tags in this list and no
others, regardless of the tags present around the
insertion point. If multiple chars-tagList argument pairs are present, they produce the same effect as if
a separate insert widget command had been issued for
each pair, in order. The last tagList argument may be omitted.
$text->mark(option, ?arg, arg, ...?): This command is used to manipulate marks. The exact
behavior of the command depends on the option argument that follows the mark argument. The following forms
of the command are currently supported:; $text->markGravity(markName, ?direction?)
If direction is not specified, returns left or right to indicate which of its adjacent char
acters markName is attached to. If direction is specified, it must be left or right; the gravity of markName is set to the given value.
$text->markNames: Returns a list whose elements are the names of
all the marks that are currently set.
$text->markNext(index): Returns the name of the next mark at or after
index. If index is specified in numerical form, then the search for the next mark begins
at that index. If index is the name of a
mark, then the search for the next mark begins
immediately after that mark. This can still
return a mark at the same position if there
are multiple marks at the same index. These
semantics mean that the mark next operation can be used to step through all the marks in a
text widget in the same order as the mark
information returned by the dump operation.
If a mark has been set to the special end
index, then it appears to be after end with respect to the mark next operation. An empty string is returned if there are no marks after
index.
$text->markPrevious(index): Returns the name of the mark at or before
index. If index is specified in numerical form, then the search for the previous mark
begins with the character just before that
index. If index is the name of a mark, then
the search for the next mark begins immedi
ately before that mark. This can still return
a mark at the same position if there are mul
tiple marks at the same index. These seman
tics mean that the mark previous operation can be used to step through all the marks in a
text widget in the reverse order as the mark
information returned by the dump operation.
An empty string is returned if there are no
marks before index.
$text->markSet(markName, index): Sets the mark named markName to a position just before the character at index. If mark_ Name already exists, it is moved from its old
position; if it doesn't exist, a new mark is
created. This command returns an empty
string.
$text->markUnset(markName?, markName, markName, ...?): Remove the mark corresponding to each of the
markName arguments. The removed marks will not be usable in indices and will not be
returned by future calls to ``$text->mark Names''. This command returns an empty
string.
$text->scan(option, args) or
$text->scanoption(args): This method is used to implement scanning on texts.
It has two forms, depending on option:; $text->scanMark(x, y)
Records x and y and the current view in the
text window, for use in conjunction with later
scanDragto method. Typically this method is associated with a mouse button press in the
widget. It returns an empty string.
$text->scanDragto(x, y): This command computes the difference between
its x and y arguments and the x and y argu
ments to the last scanMark method for the wid get. It then adjusts the view by 10 times the
difference in coordinates. This command is
typically associated with mouse motion events
in the widget, to produce the effect of drag
ging the text at high speed through the win
dow. The return value is an empty string.
$text->search(?switches,? pattern, index, ?stopIndex?): Searches the text in $text starting at index for a range of characters that matches pattern. If a match is found, the index of the first character in the
match is returned as result; otherwise an empty
string is returned. One or more of the following
switches (or abbreviations thereof) may be specified
to control the search:; -forwards
The search will proceed forward through the
text, finding the first matching range start
ing at or after the position given by index.
This is the default.
-backwards: The search will proceed backward through the
text, finding the matching range closest to
index whose first character is before index.
-exact Use exact matching: the characters in the: matching range must be identical to those in
pattern. This is the default.
-regexp Treat pattern as a regular expression and: match it against the text using the rules for
regular expressions (see the regexp command
for details).
-nocase Ignore case differences between the pattern: and the text.
-count varName: The argument following -count gives the name
of a variable; if a match is found, the number
of characters in the matching range will be
stored in the variable.
-hidden Find hidden text as well. By default only dis: played text is found.
-- This switch has no effect except to terminate: the list of switches: the next argument will
be treated as pattern even if it starts with -.
The matching range must be entirely within a single line of text. For regular expression matching the newlines are removed from the ends of the lines before matching: use the $ feature in regular expressions to match the end of a line. For exact matching the newlines are retained. If stopIndex is specified, the search stops at that index: for forward searches, no match at or after stopIndex will be considered; for backward searches, no match earlier in the text than stopIndex will be considered. If stopIndex is omitted, the entire text will be searched: when the beginning or end of the text is reached, the search con tinues at the other end until the starting location is reached again; if stopIndex is specified, no wrap-around will occur.
$text->see(index): Adjusts the view in the window so that the character
given by index is completely visible. If index is already visible then the command does nothing. If
index is a short distance out of view, the command
adjusts the view just enough to make index visible at
the edge of the window. If index is far out of view,
then the command centers index in the window.
$text->tag(option, ?arg, arg, ...?): This command is used to manipulate tags. The exact
behavior of the command depends on the option argument that follows the tag argument. The following forms of
the command are currently supported:; $text->tagAdd(tagName, index1, ?index2, index1, index2, ...?)
Associate the tag tagName with all of the
characters starting with index1 and ending
just before index2 (the character at index2 isn't tagged). A single command may contain
any number of index1-index2 pairs. If the last index2 is omitted then the single charac
ter at index1 is tagged. If there are no
characters in the specified range (e.g. index1 is past the end of the file or index2 is less
than or equal to index1) then the command has
no effect.
$text->tagBind(tagName, ?sequence?, ?script?): This command associates script with the tag
given by tagName. Whenever the event sequence given by sequence occurs for a character that has been tagged with tagName, the script will be invoked. This method is similar to the
bind command except that it operates on char
acters in a text rather than entire widgets.
See the Tk::bind documentation for complete
details on the syntax of sequence and the sub stitutions performed on script before invoking it. If all arguments are specified then a new
binding is created, replacing any existing
binding for the same sequence and tagName (if the first character of script is ``+'' then
script augments an existing binding rather
than replacing it). In this case the return
value is an empty string. If script is omit
ted then the command returns the script asso
ciated with tagName and sequence (an error occurs if there is no such binding). If both
script and sequence are omitted then the com mand returns a list of all the sequences for
which bindings have been defined for tagName.; The only events for which bindings may be
specified are those related to the mouse and
keyboard (such as Enter, Leave, ButtonPress, Motion, and KeyPress) or virtual events. Event bindings for a text widget use the cur
rent mark described under "MARKS" above. An
Enter event triggers for a tag when the tag
first becomes present on the current charac
ter, and a Leave event triggers for a tag when
it ceases to be present on the current charac
ter. Enter and Leave events can happen either because the current mark moved or because the character at that position changed. Note that
these events are different than Enter and
Leave events for windows. Mouse and keyboard
events are directed to the current character.
If a virtual event is used in a binding, that
binding can trigger only if the virtual event
is defined by an underlying mouse-related or
keyboard-related event.; It is possible for the current character to
have multiple tags, and for each of them to
have a binding for a particular event
sequence. When this occurs, one binding is
invoked for each tag, in order from lowestpriority to highest priority. If there are
multiple matching bindings for a single tag,
then the most specific binding is chosen (see
the the documentation for the bind command for
details). continue and break commands within binding scripts are processed in the same way
as for bindings created with the bind command.; If bindings are created for the widget as a
whole using the bind command, then those bind
ings will supplement the tag bindings. The
tag bindings will be invoked first, followed
by bindings for the window as a whole.
$text->tagCget(tagName, option): This command returns the current value of the
option named option associated with the tag
given by tagName. Option may have any of the values accepted by the tag configure method.
$text->tagConfigure(tagName, ?option?, ?value?, ?option, value, ...?): This command is similar to the configure method except that it modifies options associ
ated with the tag given by tagName instead of modifying options for the overall text widget.
If no option is specified, the command returns a list describing all of the available options
for tagName (see Tk::options for information on the format of this list). If option is
specified with no value, then the command
returns a list describing the one named option
(this list will be identical to the corre
sponding sublist of the value returned if no
option is specified). If one or more optionvalue pairs are specified, then the command
modifies the given option(s) to have the given
value(s) in tagName; in this case the command returns an empty string. See "TAGS" above for
details on the options available for tags.
$text->tagDelete(tagName, ?tagName, ...?): Deletes all tag information for each of the
tagName arguments. The command removes the
tags from all characters in the file and also
deletes any other information associated with
the tags, such as bindings and display infor
mation. The command returns an empty string.
$text->tagLower(tagName?, belowThis?): Changes the priority of tag tagName so that it is just lower in priority than the tag whose
name is belowThis. If belowThis is omitted, then tagName's priority is changed to make it lowest priority of all tags.
$text->tagNames(?index?): Returns a list whose elements are the names of
all the tags that are active at the character
position given by index. If index is omitted, then the return value will describe all of the
tags that exist for the text (this includes
all tags that have been named in a
``$text->tag'' widget command but haven't been deleted by a ``$text->tagDelete'' method, even if no characters are currently marked with the
tag). The list will be sorted in order from
lowest priority to highest priority.
$text->tagNextrange(tagName, index1, ?index2?): This command searches the text for a range of
characters tagged with tagName where the first character of the range is no earlier than the
character at index1 and no later than the
character just before index2 (a range starting at index2 will not be considered). If several matching ranges exist, the first one is cho
sen. The command's return value is a list
containing two elements, which are the index
of the first character of the range and the
index of the character just after the last one
in the range. If no matching range is found
then the return value is an empty string. If
index2 is not given then it defaults to the
end of the text.
$text->tagPrevrange(tagName, index1, ?index2?): This command searches the text for a range of
characters tagged with tagName where the first character of the range is before the character
at index1 and no earlier than the character at index2 (a range starting at index2 will be considered). If several matching ranges
exist, the one closest to index1 is chosen.
The command's return value is a list contain
ing two elements, which are the index of the
first character of the range and the index of
the character just after the last one in the
range. If no matching range is found then the
return value is an empty string. If index2 is not given then it defaults to the beginning of
the text.
$text->tagRaise(tagName, ?aboveThis?): Changes the priority of tag tagName so that it is just higher in priority than the tag whose
name is aboveThis. If aboveThis is omitted, then tagName's priority is changed to make it highest priority of all tags.
$text->tagRanges(tagName): Returns a list describing all of the ranges of
text that have been tagged with tagName. The first two elements of the list describe the
first tagged range in the text, the next two
elements describe the second range, and so on.
The first element of each pair contains the
index of the first character of the range, and
the second element of the pair contains the
index of the character just after the last one
in the range. If there are no characters
tagged with tag then an empty string is
returned.
$text->tagRemove(tagName, index1, ?index2, index1, index2, ...?): Remove the tag tagName from all of the charac ters starting at index1 and ending just before index2 (the character at index2 isn't affected). A single command may contain any
number of index1-index2 pairs. If the last index2 is omitted then the single character at index1 is tagged. If there are no characters
in the specified range (e.g. index1 is past
the end of the file or index2 is less than or
equal to index1) then the command has no
effect. This command returns an empty string.
$text->widget(option?, arg, arg, ...?) $text->widgetOption(?arg, arg, ...?): This method is used to manipulate embedded windows.
The behavior of the method depends on the option argu
ment that follows the window argument. The following
forms of the method are currently supported:; $text->windowCget(index, option)
Returns the value of a configuration option
for an embedded window. Index identifies the
embedded window, and option specifies a par
ticular configuration option, which must be
one of the ones listed in "EMBEDDED WINDOWS"
above.
$text->windowConfigure(index?, option, value, ...?): Query or modify the configuration options for
an embedded window. If no option is speci
fied, returns a list describing all of the
available options for the embedded window at
index (see Tk::options for information on the
format of this list). If option is specified
with no value, then the command returns a list
describing the one named option (this list
will be identical to the corresponding sublist
of the value returned if no option is speci
fied). If one or more option-value pairs are specified, then the command modifies the given
option(s) to have the given value(s); in this
case the command returns an empty string. See
"EMBEDDED WINDOWS" above for information on
the options that are supported.
$text->windowCreate(index?, option, value, ...?): This command creates a new window annotation,
which will appear in the text at the position
given by index. Any number of option-value pairs may be specified to configure the anno
tation. See "EMBEDDED WINDOWS" above for
information on the options that are supported.
Returns an empty string.
$text->windowNames: Returns a list whose elements are the names of
all windows currently embedded in $text.
$text->xview(option, args): This command is used to query and change the horizon
tal position of the text in the widget's window. It
can take any of the following forms:; $text->xview
Returns a list containing two elements. Each
element is a real fraction between 0 and 1;
together they describe the portion of the doc
ument's horizontal span that is visible in the
window. For example, if the first element is
.2 and the second element is .6, 20% of the
text is off-screen to the left, the middle 40%
is visible in the window, and 40% of the text
is off-screen to the right. The fractions
refer only to the lines that are actually vis
ible in the window: if the lines in the win
dow are all very short, so that they are
entirely visible, the returned fractions will
be 0 and 1, even if there are other lines in
the text that are much wider than the window.
These are the same values passed to scrollbars
via the -xscrollcommand option.
$text->xviewMoveto(fraction): Adjusts the view in the window so that frac_
tion of the horizontal span of the text is
off-screen to the left. Fraction is a frac tion between 0 and 1.
$text->xviewScroll(number, what): This command shifts the view in the window
left or right according to number and what. Number must be an integer. What must be either units or pages or an abbreviation of one of these. If what is units, the view adjusts left or right by number average-width
characters on the display; if it is pages
then the view adjusts by number screenfuls.
If number is negative then characters farther
to the left become visible; if it is positive
then characters farther to the right become
visible.
$text->yview(?args?): This command is used to query and change the vertical
position of the text in the widget's window. It can
take any of the following forms:; $text->yview
Returns a list containing two elements, both
of which are real fractions between 0 and 1.
The first element gives the position of the
first character in the top line in the window,
relative to the text as a whole (0.5 means it
is halfway through the text, for example).
The second element gives the position of the
character just after the last one in the bot
tom line of the window, relative to the text
as a whole. These are the same values passed
to scrollbars via the -yscrollcommand option.
$text->yviewMoveto(fraction): Adjusts the view in the window so that the
character given by fraction appears on the top line of the window. Fraction is a fraction between 0 and 1; 0 indicates the first char
acter in the text, 0.33 indicates the charac
ter one-third the way through the text, and so
on.
$text->yviewScroll(number, what): This command adjust the view in the window up
or down according to number and what. Number must be an integer. What must be either units or pages. If what is units, the view adjusts up or down by number lines on the display; if it is pages then the view adjusts by number screenfuls. If number is negative then ear
lier positions in the text become visible; if
it is positive then later positions in the
text become visible.
$text->yview(?-pickplace,? index): Changes the view in the $text's window to make
index visible. If the -pickplace option isn't specified then index will appear at the top of
the window. If -pickplace is specified then the widget chooses where index appears in the
window:; [1] If index is already visible some
where in the window then the
command does nothing.
[2] If index is only a few lines off: screen above the window then it
will be positioned at the top of
the window.
[3] If index is only a few lines off: screen below the window then it
will be positioned at the bottom
of the window.
[4] Otherwise, index will be centered: in the window.
The -pickplace option has been obsoleted by the see widget command (see handles both x- and y-motion to make a loca
tion visible, whereas -pickplace only handles motion in y).
$text->yview(number): This command makes the first character on the line
after the one given by number visible at the top of
the window. Number must be an integer. This command
used to be used for scrolling, but now it is obsolete.

BINDINGS

Tk automatically creates class bindings for texts that
give them the following default behavior. In the descrip
tions below, ``word'' refers to a contiguous group of let
ters, digits, or ``_'' characters, or any single character
other than these.

[1] Clicking mouse button 1 positions the insertion cursor: just before the character underneath the mouse cursor,
sets the input focus to this widget, and clears any
selection in the widget. Dragging with mouse button 1
strokes out a selection between the insertion cursor
and the character under the mouse.
[2] Double-clicking with mouse button 1 selects the word: under the mouse and positions the insertion cursor at
the beginning of the word. Dragging after a double
click will stroke out a selection consisting of whole
words.
[3] Triple-clicking with mouse button 1 selects the line: under the mouse and positions the insertion cursor at
the beginning of the line. Dragging after a triple
click will stroke out a selection consisting of whole
lines.
[4] The ends of the selection can be adjusted by dragging: with mouse button 1 while the Shift key is down; this
will adjust the end of the selection that was nearest
to the mouse cursor when button 1 was pressed. If the
button is double-clicked before dragging then the
selection will be adjusted in units of whole words;
if it is triple-clicked then the selection will be
adjusted in units of whole lines.
[5] Clicking mouse button 1 with the Control key down will: reposition the insertion cursor without affecting the
selection.
[6] If any normal printing characters are typed, they are: inserted at the point of the insertion cursor.
[7] The view in the widget can be adjusted by dragging: with mouse button 2. If mouse button 2 is clicked
without moving the mouse, the selection is copied into
the text at the position of the mouse cursor. The
Insert key also inserts the selection, but at the
position of the insertion cursor.
[8] If the mouse is dragged out of the widget while button: 1 is pressed, the entry will automatically scroll to
make more text visible (if there is more text offscreen on the side where the mouse left the window).
[9] The Left and Right keys move the insertion cursor one: character to the left or right; they also clear any
selection in the text. If Left or Right is typed with
the Shift key down, then the insertion cursor moves
and the selection is extended to include the new char
acter. Control-Left and Control-Right move the inser
tion cursor by words, and Control-Shift-Left and Con
trol-Shift-Right move the insertion cursor by words
and also extend the selection. Control-b and Controlf behave the same as Left and Right, respectively.
Meta-b and Meta-f behave the same as Control-Left and
Control-Right, respectively.
[10]: The Up and Down keys move the insertion cursor one
line up or down and clear any selection in the text.
If Up or Right is typed with the Shift key down, then
the insertion cursor moves and the selection is
extended to include the new character. Control-Up and
Control-Down move the insertion cursor by paragraphs
(groups of lines separated by blank lines), and Con
trol-Shift-Up and Control-Shift-Down move the inser
tion cursor by paragraphs and also extend the selec
tion. Control-p and Control-n behave the same as Up
and Down, respectively.
[11]: The Next and Prior keys move the insertion cursor for
ward or backwards by one screenful and clear any
selection in the text. If the Shift key is held down
while Next or Prior is typed, then the selection is
extended to include the new character. Control-v
moves the view down one screenful without moving the
insertion cursor or adjusting the selection.
[12]: Control-Next and Control-Prior scroll the view right
or left by one page without moving the insertion cur
sor or affecting the selection.
[13]: Home and Control-a move the insertion cursor to the
beginning of its line and clear any selection in the
widget. Shift-Home moves the insertion cursor to the
beginning of the line and also extends the selection
to that point.
[14]: End and Control-e move the insertion cursor to the end
of the line and clear any selection in the widget.
Shift-End moves the cursor to the end of the line and
extends the selection to that point.
[15]: Control-Home and Meta-< move the insertion cursor to
the beginning of the text and clear any selection in
the widget. Control-Shift-Home moves the insertion
cursor to the beginning of the text and also extends
the selection to that point.
[16]: Control-End and Meta-> move the insertion cursor to
the end of the text and clear any selection in the
widget. Control-Shift-End moves the cursor to the end
of the text and extends the selection to that point.
[17]: The Select key and Control-Space set the selection
anchor to the position of the insertion cursor. They
don't affect the current selection. Shift-Select and
Control-Shift-Space adjust the selection to the cur
rent position of the insertion cursor, selecting from
the anchor to the insertion cursor if there was not
any selection previously.
[18]: Control-/ selects the entire contents of the widget.
[19]: Control- clears any selection in the widget.
[20]: The F16 key (labelled Copy on many Sun workstations)
or Meta-w copies the selection in the widget to the
clipboard, if there is a selection.
[21]: The F20 key (labelled Cut on many Sun workstations) or
Control-w copies the selection in the widget to the
clipboard and deletes the selection. If there is no
selection in the widget then these keys have no
effect.
[22]: The F18 key (labelled Paste on many Sun workstations)
or Control-y inserts the contents of the clipboard at
the position of the insertion cursor.
[23]: The Delete key deletes the selection, if there is one
in the widget. If there is no selection, it deletes
the character to the right of the insertion cursor.
[24]: Backspace and Control-h delete the selection, if there
is one in the widget. If there is no selection, they
delete the character to the left of the insertion cur
sor.
[25]: Control-d deletes the character to the right of the
insertion cursor.
[26]: Meta-d deletes the word to the right of the insertion
cursor.
[27]: Control-k deletes from the insertion cursor to the end
of its line; if the insertion cursor is already at the
end of a line, then Control-k deletes the newline
character.
[28]: Control-o opens a new line by inserting a newline
character in front of the insertion cursor without
moving the insertion cursor.
[29]: Meta-backspace and Meta-Delete delete the word to the
left of the insertion cursor.
[30]: Control-x deletes whatever is selected in the text
widget.
[31]: Control-t reverses the order of the two characters to
the right of the insertion cursor.; If the widget is disabled using the -state option,
then its view can still be adjusted and text can still
be selected, but no insertion cursor will be displayed
and no text modifications will take place.; The behavior of texts can be changed by defining new
bindings for individual widgets or by redefining the
class bindings.

PERFORMANCE ISSUES

Text widgets should run efficiently under a variety of
conditions. The text widget uses about 2-3 bytes of main
memory for each byte of text, so texts containing a
megabyte or more should be practical on most workstations.
Text is represented internally with a modified B-tree
structure that makes operations relatively efficient even
with large texts. Tags are included in the B-tree struc
ture in a way that allows tags to span large ranges or
have many disjoint smaller ranges without loss of effi
ciency. Marks are also implemented in a way that allows
large numbers of marks. In most cases it is fine to have
large numbers of unique tags, or a tag that has many dis
tinct ranges.

One performance problem can arise if you have hundreds or
thousands of different tags that all have the following
characteristics: the first and last ranges of each tag are
near the beginning and end of the text, respectively, or a
single tag range covers most of the text widget. The cost
of adding and deleting tags like this is proportional to
the number of other tags with the same properties. In
contrast, there is no problem with having thousands of
distinct tags if their overall ranges are localized and
spread uniformly throughout the text.

Very long text lines can be expensive, especially if they
have many marks and tags within them.

The display line with the insert cursor is redrawn each
time the cursor blinks, which causes a steady stream of
graphics traffic. Set the -insertofftime option to 0 avoid this.

KEYWORDS

text, widget

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