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'\"
'\" Copyright (c) 1992 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
.TH text n 8.5 Tk "Tk Built-In Commands"
.so man.macros
.BS
'\" Note: do not modify the .SH NAME line immediately below!
.SH NAME
text, tk_textCopy, tk_textCut, tk_textPaste \- Create and manipulate 'text' hypertext editing widgets
.SH SYNOPSIS
.nf
\fBtext\fR \fIpathName \fR?\fIoptions\fR?
\fBtk_textCopy\fR \fIpathName\fR
\fBtk_textCut\fR \fIpathName\fR
\fBtk_textPaste\fR \fIpathName\fR
.SO
\-background \-highlightthickness \-relief
\-borderwidth \-insertbackground \-selectbackground
\-cursor \-insertborderwidth \-selectborderwidth
\-exportselection \-insertofftime \-selectforeground
\-font \-insertontime \-setgrid
\-foreground \-insertwidth \-takefocus
\-highlightbackground \-padx \-xscrollcommand
\-highlightcolor \-pady \-yscrollcommand
.SE
.SH "WIDGET-SPECIFIC OPTIONS"
.OP \-autoseparators autoSeparators AutoSeparators
Specifies a boolean that says whether separators are automatically inserted in
the undo stack. Only meaningful when the \fB\-undo\fR option is true.
.OP \-blockcursor blockCursor BlockCursor
Specifies a boolean that says whether the blinking insertion cursor should be
drawn as a character-sized rectangular block. If false (the default) a thin
vertical line is used for the insertion cursor.
.OP \-endline endLine EndLine
Specifies an integer line index representing the line of the underlying
textual data store that should be just after the last line contained in
the widget. This allows a text widget to reflect only a portion of a
larger piece of text. Instead of an integer, the empty string can be
provided to this configuration option, which will configure the widget
to end at the very last line in the textual data store.
.OP \-height height Height
Specifies the desired height for the window, in units of characters in the
font given by the \fB\-font\fR option. Must be at least one.
.OP \-inactiveselectbackground inactiveSelectBackground Foreground
Specifies the colour to use for the selection (the \fBsel\fR tag) when the
window does not have the input focus. If empty, \fB{}\fR, then no selection is
shown when the window does not have the focus.
.OP \-insertunfocussed insertUnfocussed InsertUnfocussed
.VS 8.6
Specifies how to display the insertion cursor when the widget does not have
the focus. Must be \fBnone\fR (the default) which means to not display the
cursor, \fBhollow\fR which means to display a hollow box, or \fBsolid\fR which
means to display a solid box. Note that \fBhollow\fR and \fBsolid\fR will
appear very similar when the \fB\-blockcursor\fR option is false.
.VE 8.6
.OP \-maxundo maxUndo MaxUndo
Specifies the maximum number of compound undo actions on the undo stack. A
zero or a negative value imply an unlimited undo stack.
.OP \-spacing1 spacing1 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 overridden with
\fB\-spacing1\fR options in tags.
.OP \-spacing2 spacing2 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 represent a single line of text. The value may have any of the standard
forms for screen distances. This option may be overridden with
\fB\-spacing2\fR options in tags.
.OP \-spacing3 spacing3 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 overridden with
\fB\-spacing3\fR options in tags.
.OP \-startline startLine StartLine
Specifies an integer line index representing the first line of the underlying
textual data store that should be contained in the widget. This allows a text
widget to reflect only a portion of a larger piece of text. Instead of an
integer, the empty string can be provided to this configuration option, which
will configure the widget to start at the very first line in the textual data
store.
.OP \-state state State
Specifies one of two states for the text: \fBnormal\fR or \fBdisabled\fR. 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.
.OP \-tabs tabs 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 of which
is a distance relative to the left edge of the widget (excluding borders,
padding, etc). Each position may optionally be followed in the next list
element by one of the keywords \fBleft\fR, \fBright\fR, \fBcenter\fR, or
\fBnumeric\fR, which specifies how to justify text relative to the tab stop.
\fBLeft\fR is the default; it causes the text following the tab character to
be positioned with its left edge at the tab position. \fBRight\fR means that
the right edge of the text following the tab character is positioned at the
tab position, and \fBcenter\fR means that the text is centered at the tab
position. \fBNumeric\fR 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 right-justified at the tab
position. For example,
.QW "\fB\-tabs {2c left 4c 6c center}\fR"
creates three tab stops at two-centimeter intervals; the first two use left
justification and the third uses center justification.
.RS
.PP
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. Tab distances must be strictly
positive, and must always increase from one tab stop to the next (if not, an
error is thrown). The value of the \fB\-tabs\fR option may be overridden by
\fB\-tabs\fR options in tags.
.PP
If no \fB\-tabs\fR option is specified, or if it is specified as an empty
list, then Tk uses default tabs spaced every eight (average size) characters.
To achieve a different standard spacing, for example every 4 characters,
simply configure the widget with
.QW "\fB\-tabs \N'34'[expr {4 * [font measure $font 0]}] left\N'34' \-tabstyle wordprocessor\fR" .
.RE
.OP \-tabstyle tabStyle TabStyle
Specifies how to interpret the relationship between tab stops on a line and
tabs in the text of that line. The value must be \fBtabular\fR (the default)
or \fBwordprocessor\fR. Note that tabs are interpreted as they are encountered
in the text. If the tab style is \fBtabular\fR then the \fIn\fR'th tab
character in the line's text will be associated with the \fIn\fR'th tab stop
defined for that line. If the tab character's x coordinate falls to the right
of the \fIn\fR'th tab stop, then a gap of a single space will be inserted as a
fallback. If the tab style is \fBwordprocessor\fR then any tab character being
laid out will use (and be defined by) the first tab stop to the right of the
preceding characters already laid out on that line. The value of the
\fB\-tabstyle\fR option may be overridden by \fB\-tabstyle\fR options in tags.
.OP \-undo undo Undo
Specifies a boolean that says whether the undo mechanism is active or not.
.OP \-width width Width
Specifies the desired width for the window in units of characters in the font
given by the \fB\-font\fR option. If the font does not have a uniform width
then the width of the character
.QW 0
is used in translating from character units to screen units.
.OP \-wrap wrap 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 \fBnone\fR or \fBchar\fR
or \fBword\fR. A wrap mode of \fBnone\fR means that each line of text appears
as exactly one line on the screen; extra characters that do not 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 \fBchar\fR mode a screen line break may occur after any character; in
\fBword\fR mode a line break will only be made at word boundaries.
.BE
.SH DESCRIPTION
.PP
The \fBtext\fR command creates a new window (given by the \fIpathName\fR
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 \fBtext\fR command returns the path name of the new window.
.PP
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 different fonts and colors. In
addition, Tcl commands can be associated with tags so that scripts are invoked
when particular actions such as keystrokes and mouse button presses occur in
particular ranges of the text. See \fBTAGS\fR below for more details.
.PP
The second form of annotation consists of floating markers in the text called
.QW marks .
Marks are used to keep track of various interesting positions in the text as
it is edited. See \fBMARKS\fR below for more details.
.PP
The third form of annotation allows arbitrary windows to be embedded in a text
widget. See \fBEMBEDDED WINDOWS\fR below for more details.
.PP
The fourth form of annotation allows Tk images to be embedded in a text
widget. See \fBEMBEDDED IMAGES\fR below for more details.
.PP
The text widget also has a built-in undo/redo mechanism. See
\fBTHE UNDO MECHANISM\fR below for more details.
.PP
The text widget allows for the creation of peer widgets. These are other text
widgets which share the same underlying data (text, marks, tags, images, etc).
See \fBPEER WIDGETS\fR below for more details.
.SH INDICES
.PP
Many of the widget commands for texts take one or more indices as arguments.
An index is a string used to indicate a particular 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
.CS
\fIbase modifier modifier modifier ...\fR
.CE
Where \fIbase\fR gives a starting point and the \fImodifier\fRs adjust the
index from the starting point (e.g. move forward or backward one character).
Every index must contain a \fIbase\fR, but the \fImodifier\fRs are optional.
Most modifiers (as documented below) allow an optional submodifier. Valid
submodifiers are \fBany\fR and \fBdisplay\fR. If the submodifier is
abbreviated, then it must be followed by whitespace, but otherwise there need
be no space between the submodifier and the following \fImodifier\fR.
Typically the \fBdisplay\fR submodifier adjusts the meaning of the following
\fImodifier\fR to make it refer to visual or non-elided units rather than
logical units, but this is explained for each relevant case below. Lastly,
where \fIcount\fR is used as part of a modifier, it can be positive or
negative, so
.QW "\fIbase\fR \- \-3 lines"
is perfectly valid (and equivalent to
.QW "\fIbase\fR +3lines" ).
.PP
The \fIbase\fR for an index must have one of the following forms:
.TP 12
\fIline\fB.\fIchar\fR
.
Indicates \fIchar\fR'th character on line \fIline\fR. Lines are numbered from
1 for consistency with other UNIX programs that use this numbering scheme.
Within a line, characters are numbered from 0. If \fIchar\fR is \fBend\fR then
it refers to the newline character that ends the line.
.TP 12
\fB@\fIx\fB,\fIy\fR
.
Indicates the character that covers the pixel whose x and y coordinates within
the text's window are \fIx\fR and \fIy\fR.
.TP 12
\fBend\fR
.
Indicates the end of the text (the character just after the last newline).
.TP 12
\fImark\fR
.
Indicates the character just after the mark whose name is \fImark\fR.
.TP 12
\fItag\fB.first\fR
.
Indicates the first character in the text that has been tagged with \fItag\fR.
This form generates an error if no characters are currently tagged with
\fItag\fR.
.TP 12
\fItag\fB.last\fR
.
Indicates the character just after the last one in the text that has been
tagged with \fItag\fR. This form generates an error if no characters are
currently tagged with \fItag\fR.
.TP 12
\fIpathName\fR
.
Indicates the position of the embedded window whose name is \fIpathName\fR.
This form generates an error if there is no embedded window by the given name.
.TP 12
\fIimageName\fR
.
Indicates the position of the embedded image whose name is \fIimageName\fR.
This form generates an error if there is no embedded image by the given name.
.PP
If the \fIbase\fR could match more than one of the above forms, such as a
\fImark\fR and \fIimageName\fR 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 \fBchars\fR and \fBwordend\fR may be abbreviated as long as the
abbreviation is unambiguous.
.TP
\fB+ \fIcount\fR ?\fIsubmodifier\fR? \fBchars\fR
.
Adjust the index forward by \fIcount\fR characters, moving to later lines in
the text if necessary. If there are fewer than \fIcount\fR characters in the
text after the current index, then set the index to the last index in the
text. Spaces on either side of \fIcount\fR are optional. If the \fBdisplay\fR
submodifier is given, elided characters are skipped over without being
counted. If \fBany\fR is given, then all characters are counted. For
historical reasons, if neither modifier is given then the count actually takes
place in units of index positions (see \fBINDICES\fR for details). This
behaviour may be changed in a future major release, so if you need an index
count, you are encouraged to use \fBindices\fR instead wherever possible.
.TP
\fB\- \fIcount\fR ?\fIsubmodifier\fR? \fBchars\fR
.
Adjust the index backward by \fIcount\fR characters, moving to earlier lines
in the text if necessary. If there are fewer than \fIcount\fR characters in
the text before the current index, then set the index to the first index in
the text (1.0). Spaces on either side of \fIcount\fR are optional. If the
\fBdisplay\fR submodifier is given, elided characters are skipped over without
being counted. If \fBany\fR is given, then all characters are counted. For
historical reasons, if neither modifier is given then the count actually takes
place in units of index positions (see \fBINDICES\fR for details). This
behavior may be changed in a future major release, so if you need an index
count, you are encouraged to use \fBindices\fR instead wherever possible.
.TP
\fB+ \fIcount\fR ?\fIsubmodifier\fR? \fBindices\fR
.
Adjust the index forward by \fIcount\fR index positions, moving to later lines
in the text if necessary. If there are fewer than \fIcount\fR index positions
in the text after the current index, then set the index to the last index
position in the text. Spaces on either side of \fIcount\fR are optional. Note
that an index position is either a single character or a single embedded image
or embedded window. If the \fBdisplay\fR submodifier is given, elided indices
are skipped over without being counted. If \fBany\fR is given, then all
indices are counted; this is also the default behaviour if no modifier is
given.
.TP
\fB\- \fIcount\fR ?\fIsubmodifier\fR? \fBindices\fR
.
Adjust the index backward by \fIcount\fR index positions, moving to earlier
lines in the text if necessary. If there are fewer than \fIcount\fR index
positions in the text before the current index, then set the index to the
first index position (1.0) in the text. Spaces on either side of \fIcount\fR
are optional. If the \fBdisplay\fR submodifier is given, elided indices are
skipped over without being counted. If \fBany\fR is given, then all indices
are counted; this is also the default behaviour if no modifier is given.
.TP
\fB+ \fIcount\fR ?\fIsubmodifier\fR? \fBlines\fR
.
Adjust the index forward by \fIcount\fR lines, retaining the same character
position within the line. If there are fewer than \fIcount\fR 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 \fIcount\fR are optional. If the \fBdisplay\fR
submodifier is given, then each visual display line is counted separately.
Otherwise, if \fBany\fR (or no modifier) is given, then each logical line (no
matter how many times it is visually wrapped) counts just once. If the
relevant lines are not wrapped, then these two methods of counting are
equivalent.
.TP
\fB\- \fIcount\fR ?\fIsubmodifier\fR? \fBlines\fR
.
Adjust the index backward by \fIcount\fR logical lines, retaining the same
character position within the line. If there are fewer than \fIcount\fR 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 \fIcount\fR are optional. If the
\fBdisplay\fR submodifier is given, then each visual display line is counted
separately. Otherwise, if \fBany\fR (or no modifier) is given, then each
logical line (no matter how many times it is visually wrapped) counts just
once. If the relevant lines are not wrapped, then these two methods of
counting are equivalent.
.TP
?\fIsubmodifier\fR? \fBlinestart\fR
.
Adjust the index to refer to the first index on the line. If the \fBdisplay\fR
submodifier is given, this is the first index on the display line, otherwise
on the logical line.
.TP
?\fIsubmodifier\fR? \fBlineend\fR
.
Adjust the index to refer to the last index on the line (the newline). If the
\fBdisplay\fR submodifier is given, this is the last index on the display
line, otherwise on the logical line.
.TP
?\fIsubmodifier\fR? \fBwordstart\fR
.
Adjust the index to refer to the first character of the word containing the
current index. A word consists of any number of adjacent characters that are
letters, digits, or underscores, or a single character that is not one of
these. If the \fBdisplay\fR submodifier is given, this only examines
non-elided characters, otherwise all characters (elided or not) are examined.
.TP
?\fIsubmodifier\fR? \fBwordend\fR
.
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 the \fBdisplay\fR
submodifier is given, this only examines non-elided characters, otherwise all
characters (elided or not) are examined.
.PP
If more than one modifier is present then they are applied in left-to-right
order. For example, the index
.QW "\fBend \- 1 chars\fR"
refers to the next-to-last character in the text and
.QW "\fBinsert wordstart \- 1 c\fR"
refers to the character just before the first one in the word containing the
insertion cursor. Modifiers are applied one by one in this left to right
order, and after each step the resulting index is constrained to be a valid
index in the text widget. So, for example, the index
.QW "\fB1.0 \-1c +1c\fR"
refers to the index
.QW \fB2.0\fR .
.PP
Where modifiers result in index changes by display lines, display chars or
display indices, and the \fIbase\fR refers to an index inside an elided tag,
that base index is considered to be equivalent to the first following
non-elided index.
.SH TAGS
.PP
The first form of annotation in text widgets is a tag. A tag is a textual
string that is associated with some of the characters in a text. Tags may
contain arbitrary characters, but it is probably best to avoid using the
characters
.QW " "
(space), \fB+\fR, or \fB\-\fR: these characters have special meaning in
indices, so tags containing them cannot be used as indices. There may be any
number of tags associated with characters in a text. Each tag may refer to a
single character, a range of characters, or several ranges of characters. An
individual character may have any number of tags associated with it.
.PP
A priority order is defined among tags, and this order is used in implementing
some of the tag-related functions described below. When a tag is defined (by
associating it with characters or setting its display options or binding
commands to it), it is given a priority higher than any existing tag. The
priority order of tags may be redefined using the
.QW "\fIpathName \fBtag raise\fR"
and
.QW "\fIpathName \fBtag lower\fR"
widget commands.
.PP
Tags serve three purposes in text widgets. First, they control the way
information is displayed on the screen. By default, characters are displayed
as determined by the \fB\-background\fR, \fB\-font\fR, and \fB\-foreground\fR
options for the text widget. However, display options may be associated with
individual tags using the
.QW "\fIpathName \fBtag configure\fR"
widget command. If a character has been tagged, then the display options
associated with the tag override the default display style. The following
options are currently supported for tags:
.TP
\fB\-background \fIcolor\fR
.
\fIColor\fR specifies the background color to use for characters associated
with the tag. It may have any of the forms accepted by \fBTk_GetColor\fR.
.TP
\fB\-bgstipple \fIbitmap\fR
.
\fIBitmap\fR specifies a bitmap that is used as a stipple pattern for the
background. It may have any of the forms accepted by \fBTk_GetBitmap\fR. If
\fIbitmap\fR has not been specified, or if it is specified as an empty string,
then a solid fill will be used for the background.
.TP
\fB\-borderwidth \fIpixels\fR
.
\fIPixels\fR specifies the width of a border to draw around the tag using any
of the forms accepted by \fBTk_GetPixels\fR. This option should be used in
conjunction with the \fB\-relief\fR option to provide the desired border.
.TP
\fB\-elide \fIboolean\fR
.
\fIElide\fR specifies whether the data should be elided. Elided data
(characters, images, embedded windows, etc.) is not displayed and takes no
space on screen, but further on behaves just as normal data.
.TP
\fB\-fgstipple \fIbitmap\fR
.
\fIBitmap\fR specifies a bitmap that is used as a stipple pattern when drawing
text and other foreground information such as underlines. It may have any of
the forms accepted by \fBTk_GetBitmap\fR. If \fIbitmap\fR has not been
specified, or if it is specified as an empty string, then a solid fill will be
used.
.TP
\fB\-font \fIfontName\fR
.
\fIFontName\fR is the name of a font to use for drawing characters. It may
have any of the forms accepted by \fBTk_GetFont\fR.
.TP
\fB\-foreground \fIcolor\fR
.
\fIColor\fR specifies the color to use when drawing text and other foreground
information such as underlines. It may have any of the forms accepted by
\fBTk_GetColor\fR.
.TP
\fB\-justify \fIjustify\fR
.
If the first non-elided character of a display line has a tag for which this
option has been specified, then \fIjustify\fR determines how to justify the
line. It must be one of \fBleft\fR, \fBright\fR, or \fBcenter\fR. If a line
wraps, then the justification for each line on the display is determined by
the first non-elided character of that display line.
.TP
\fB\-lmargin1 \fIpixels\fR
.
If the first non-elided character of a text line has a tag for which this
option has been specified, then \fIpixels\fR specifies how much the line
should be indented from the left edge of the window. \fIPixels\fR may have any
of the standard forms for screen distances. If a line of text wraps, this
option only applies to the first line on the display; the \fB\-lmargin2\fR
option controls the indentation for subsequent lines.
.TP
\fB\-lmargin2 \fIpixels\fR
.
If the first non-elided character of a display line has a tag for which this
option has been specified, and if the display line is not the first for its
text line (i.e., the text line has wrapped), then \fIpixels\fR specifies how
much the line should be indented from the left edge of the window.
\fIPixels\fR may have any of the standard forms for screen distances. This
option is only used when wrapping is enabled, and it only applies to the
second and later display lines for a text line.
.TP
\fB\-offset \fIpixels\fR
.
\fIPixels\fR specifies an amount by which the text's baseline should be offset
vertically from the baseline of the overall line, in pixels. For example, a
positive offset can be used for superscripts and a negative offset can be used
for subscripts. \fIPixels\fR may have any of the standard forms for screen
distances.
.TP
\fB\-overstrike \fIboolean\fR
.
Specifies whether or not to draw a horizontal rule through the middle of
characters. \fIBoolean\fR may have any of the forms accepted by
\fBTcl_GetBoolean\fR.
.TP
\fB\-relief \fIrelief\fR
.
\fIRelief\fR specifies the relief style to use for drawing the border, in any
of the forms accepted by \fBTk_GetRelief\fR. This option is used in
conjunction with the \fB\-borderwidth\fR option to enable to the desired
border appearance.
.TP
\fB\-rmargin \fIpixels\fR
.
If the first non-elided character of a display line has a tag for which this
option has been specified, then \fIpixels\fR specifies how wide a margin to
leave between the end of the line and the right edge of the window.
\fIPixels\fR may have any of the standard forms for screen distances. This
option is only used when wrapping is enabled. If a text line wraps, the right
margin for each line on the display is determined by the first non-elided
character of that display line.
.TP
\fB\-spacing1 \fIpixels\fR
.
\fIPixels\fR specifies how much additional space should be left above each
text line, using any of the standard forms for screen distances. If a line
wraps, this option only applies to the first line on the display.
.TP
\fB\-spacing2 \fIpixels\fR
.
For lines that wrap, this option specifies how much additional space to leave
between the display lines for a single text line. \fIPixels\fR may have any of
the standard forms for screen distances.
.TP
\fB\-spacing3 \fIpixels\fR
.
\fIPixels\fR specifies how much additional space should be left below each
text line, using any of the standard forms for screen distances. If a line
wraps, this option only applies to the last line on the display.
.TP
\fB\-tabs \fItabList\fR
.
\fITabList\fR specifies a set of tab stops in the same form as for the
\fB\-tabs\fR option for the text widget. This option only applies to a display
line if it applies to the first non-elided character on that display line. If
this option is specified as an empty string, it cancels the option, leaving it
unspecified for the tag (the default). If the option is specified as a
non-empty string that is an empty list, such as \fB\-tags\0{\0}\fR, then it
requests default 8-character tabs as described for the \fB\-tags\fR widget
option.
.TP
\fB\-tabstyle \fIstyle\fR
.
\fIStyle\fR specifies either the \fItabular\fR or \fIwordprocessor\fR style of
tabbing to use for the text widget. This option only applies to a display line
if it applies to the first non-elided character on that display line. If this
option is specified as an empty string, it cancels the option, leaving it
unspecified for the tag (the default).
.TP
\fB\-underline \fIboolean\fR
.
\fIBoolean\fR specifies whether or not to draw an underline underneath
characters. It may have any of the forms accepted by \fBTcl_GetBoolean\fR.
.TP
\fB\-wrap \fImode\fR
.
\fIMode\fR specifies how to handle lines that are wider than the text's
window. It has the same legal values as the \fB\-wrap\fR option for the text
widget: \fBnone\fR, \fBchar\fR, or \fBword\fR. If this tag option is
specified, it overrides the \fB\-wrap\fR option for the text widget.
.PP
If a character has several tags associated with it, and if their display
options conflict, then the options of the highest priority tag are used. If a
particular display option has not been specified for a particular tag, or if
it is specified as an empty string, then that option will never be used; the
next-highest-priority tag's option will used instead. If no tag specifies a
particular display option, then the default style for the widget will be used.
.PP
The second purpose for tags is event bindings. You can associate bindings with
a tag in much the same way you can associate bindings with a widget class:
whenever particular X events occur on characters with the given tag, a given
Tcl command will be executed. Tag bindings can be used to give behaviors to
ranges of characters; among other things, this allows hypertext-like features
to be implemented. For details, see the description of the
.QW "\fIpathName \fBtag bind\fR"
widget command below. Tag bindings are shared between all peer widgets
(including any bindings for the special \fBsel\fR tag).
.PP
The third use for tags is in managing the selection. See \fBTHE SELECTION\fR
below. With the exception of the special \fBsel\fR tag, all tags are shared
between peer text widgets, and may be manipulated on an equal basis from any
such widget. The \fBsel\fR tag exists separately and independently in each
peer text widget (but any tag bindings to \fBsel\fR are shared).
.SH MARKS
.PP
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 is not
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 containing a tag are deleted then the tag will no longer have
an association with characters in the file. Marks may be manipulated with the
.QW "\fIpathName \fBmark\fR"
widget command, and their current locations may be determined by using the
mark name as an index in widget commands.
.PP
Each mark also has a
.QW gravity ,
which is either \fBleft\fR or \fBright\fR. 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 left of the mark (so that the
mark remains rightmost). The gravity for a mark defaults to \fBright\fR.
.PP
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.
.PP
Two marks have special significance. First, the mark \fBinsert\fR is
associated with the insertion cursor, as described under
\fBTHE INSERTION CURSOR\fR
below. Second, the mark \fBcurrent\fR 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:
\fBcurrent\fR 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. With the exception of these two
special marks, all marks are shared between peer text widgets, and may be
manipulated on an equal basis from any peer.
.SH "EMBEDDED WINDOWS"
.PP
The third form of annotation in text widgets is an embedded window. Each
embedded window annotation causes a window to be displayed at a particular
point in the text. There may be any number of embedded windows in a text
widget, 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).
.PP
The embedded window'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
unit's worth of index space in the text widget, and it may be referred to
either by the name of its embedded window 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. Similarly if the text widget as a whole is
deleted, then the window is destroyed.
.PP
Eliding an embedded window immediately after scheduling it for creation via
\fIpathName \fBwindow create \fIindex \fB-create\fR will prevent it from being
effectively created. Uneliding an elided embedded window scheduled for creation
via \fIpathName \fBwindow create \fIindex \fB-create\fR will automatically
trigger the associated creation script. After destroying an elided embedded
window, the latter won't get automatically recreated.
.PP
When an embedded window is added to a text widget with the \fIpathName
\fBwindow create\fR widget command, several configuration options may be
associated with it. These options may be modified later with the \fIpathName
\fBwindow configure\fR widget command. The following options are currently
supported:
.TP
\fB\-align \fIwhere\fR
.
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. \fIWhere\fR must have
one of the values \fBtop\fR (align the top of the window with the top of the
line), \fBcenter\fR (center the window within the range of the line),
\fBbottom\fR (align the bottom of the window with the bottom of the line's
area), or \fBbaseline\fR (align the bottom of the window with the baseline of
the line).
.TP
\fB\-create \fIscript\fR
.
Specifies a Tcl script that may be evaluated to create the window for the
annotation. If no \fB\-window\fR option has been specified for the annotation
this script will be evaluated when the annotation is about to be displayed on
the screen. \fIScript\fR must create a window for the annotation and return
the name of that window as its result. Two substitutions will be performed in
\fIscript\fR before evaluation. \fI%W\fR will be substituted by the name of
the parent text widget, and \fI%%\fR will be substituted by a single \fI%\fR.
If the annotation's window should ever be deleted, \fIscript\fR will be
evaluated again the next time the annotation is displayed.
.TP
\fB\-padx \fIpixels\fR
.
\fIPixels\fR 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.
.TP
\fB\-pady \fIpixels\fR
.
\fIPixels\fR 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.
.TP
\fB\-stretch \fIboolean\fR
.
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 \fB\-pady\fR
option has been specified as well, then the requested padding will be retained
even if the window is stretched.
.TP
\fB\-window \fIpathName\fR
.
Specifies the name of a window to display in the annotation. Note that if a
\fIpathName\fR has been set, then later configuring a window to the empty
string will not delete the widget corresponding to the old \fIpathName\fR.
Rather it will remove the association between the old \fIpathName\fR and the
text widget. If multiple peer widgets are in use, it is usually simpler to use
the \fB\-create\fR option if embedded windows are desired in each peer.
.SH "EMBEDDED IMAGES"
.PP
The final form of annotation in text widgets is an embedded 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.
.PP
The embedded image's position on the screen will be updated as the text is
modified or scrolled. Each embedded image occupies one unit'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 \fIpathName \fBimage create\fR. If the range of text
containing the embedded image is deleted then that copy of the image is removed
from the screen.
.PP
Eliding an embedded image immediately after scheduling it for creation via
\fIpathName \fBimage create \fIindex \fB-create\fR will prevent it from being
effectively created. Uneliding an elided embedded image scheduled for creation
via \fIpathName \fBimage create \fIindex \fB-create\fR will automatically
trigger the associated creation script. After destroying an elided embedded
image, the latter won't get automatically recreated.
.PP
When an embedded image is added to a text widget with the \fIpathName \fBimage
create\fR widget command, 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 \fB\-name\fR option (described below). If the
\fB\-name\fR option is not provided, the \fB\-image\fR name is used instead.
If the \fIimageName\fR is already in use in the text widget, then \fB#\fInn\fR
is added to the end of the \fIimageName\fR, where \fInn\fR is an arbitrary
integer. This insures the \fIimageName\fR is unique. Once this name is
assigned to this instance of the image, it does not change, even though the
\fB\-image\fR or \fB\-name\fR values can be changed with \fIpathName \fBimage
configure\fR.
.PP
When an embedded image is added to a text widget with the \fIpathName \fBimage
create\fR widget command, several configuration options may be associated with
it. These options may be modified later with the \fIpathName \fBimage
configure\fR widget command. The following options are currently supported:
.TP
\fB\-align \fIwhere\fR
.
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. \fIWhere\fR must have one
of the values \fBtop\fR (align the top of the image with the top of the line),
\fBcenter\fR (center the image within the range of the line), \fBbottom\fR
(align the bottom of the image with the bottom of the line's area), or
\fBbaseline\fR (align the bottom of the image with the baseline of the line).
.TP
\fB\-image \fIimage\fR
.
Specifies the name of the Tk image to display in the annotation. If
\fIimage\fR is not a valid Tk image, then an error is returned.
.TP
\fB\-name \fIImageName\fR
.
Specifies the name by which this image instance may be referenced in the text
widget. If \fIImageName\fR is not supplied, then the name of the Tk image is
used instead. If the \fIimageName\fR is already in use, \fI#nn\fR is appended
to the end of the name as described above.
.TP
\fB\-padx \fIpixels\fR
.
\fIPixels\fR 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.
.TP
\fB\-pady \fIpixels\fR
.
\fIPixels\fR 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.
.SH "THE SELECTION"
.PP
Selection support is implemented via tags. If the \fB\-exportselection\fR option
for the text widget is true then the \fBsel\fR tag will be associated with the
selection:
.IP [1]
Whenever characters are tagged with \fBsel\fR the text widget will claim
ownership of the selection.
.IP [2]
Attempts to retrieve the selection will be serviced by the text widget,
returning all the characters with the \fBsel\fR tag.
.IP [3]
If the selection is claimed away by another application or by another window
within this application, then the \fBsel\fR tag will be removed from all
characters in the text.
.IP [4]
Whenever the \fBsel\fR tag range changes a virtual event \fB<<Selection>>\fR
is generated.
.PP
The \fBsel\fR tag is automatically defined when a text widget is created, and
it may not be deleted with the
.QW "\fIpathName \fBtag delete\fR"
widget command. Furthermore, the \fB\-selectbackground\fR,
\fB\-selectborderwidth\fR, and \fB\-selectforeground\fR options for the text
widget are tied to the \fB\-background\fR, \fB\-borderwidth\fR, and
\fB\-foreground\fR options for the \fBsel\fR tag: changes in either will
automatically be reflected in the other. Also the
\fB\-inactiveselectbackground\fR option for the text widget is used instead of
\fB\-selectbackground\fR when the text widget does not have the focus. This
allows programmatic control over the visualization of the \fBsel\fR tag for
foreground and background windows, or to have \fBsel\fR not shown at all (when
\fB\-inactiveselectbackground\fR is empty) for background windows. Each peer
text widget has its own \fBsel\fR tag which can be separately configured and
set.
.SH "THE INSERTION CURSOR"
.PP
The mark named \fBinsert\fR has special significance in text widgets. It is
defined automatically when a text widget is created and it may not be unset
with the
.QW "\fIpathName \fBmark unset\fR"
widget command. The \fBinsert\fR mark represents 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.
.SH "THE MODIFIED FLAG"
.PP
The text widget can keep track of changes to the content of the widget by
means of the modified flag. Inserting or deleting text will set this flag. The
flag can be queried, set and cleared programmatically as well. Whenever the
flag changes state a \fB<<Modified>>\fR virtual event is generated. See the
\fIpathName \fBedit modified\fR widget command for more details.
.SH "THE UNDO MECHANISM"
.PP
The text widget has an unlimited undo and redo mechanism (when the
\fB\-undo\fR widget option is true) which records every insert and delete
action on a stack.
.PP
Boundaries (called
.QW separators )
are inserted between edit actions. The purpose of these separators is to group
inserts, deletes and replaces into one compound edit action. When undoing a
change everything between two separators will be undone. The undone changes
are then moved to the redo stack, so that an undone edit can be redone again.
The redo stack is cleared whenever new edit actions are recorded on the undo
stack. The undo and redo stacks can be cleared to keep their depth under
control.
.PP
Separators are inserted automatically when the \fB\-autoseparators\fR widget
option is true. You can insert separators programmatically as well. If a
separator is already present at the top of the undo stack no other will be
inserted. That means that two separators on the undo stack are always
separated by at least one insert or delete action.
.PP
The undo mechanism is also linked to the modified flag. This means that
undoing or redoing changes can take a modified text widget back to the
unmodified state or vice versa. The modified flag will be set automatically to
the appropriate state. This automatic coupling does not work when the modified
flag has been set by the user, until the flag has been reset again.
.PP
See below for the \fIpathName \fBedit\fR widget command that controls the undo
mechanism.
.SH "PEER WIDGETS"
.PP
The text widget has a separate store of all its data concerning each line's
textual contents, marks, tags, images and windows, and the undo stack.
.PP
While this data store cannot be accessed directly (i.e. without a text widget
as an intermediary), multiple text widgets can be created, each of which
present different views on the same underlying data. Such text widgets are
known as peer text widgets.
.PP
As text is added, deleted, edited and coloured in any one widget, and as
images, marks, tags are adjusted, all such changes will be reflected in all
peers.
.PP
All data and markup is shared, except for a few small details. First, the
\fBsel\fR tag may be set and configured (in its display style) differently for
each peer. Second, each peer has its own \fBinsert\fR and \fBcurrent\fR mark
positions (but all other marks are shared). Third, embedded windows, which are
arbitrary other widgets, cannot be shared between peers. This means the
\fB\-window\fR option of embedded windows is independently set for each peer
(it is advisable to use the \fB\-create\fR script capabilities to allow each
peer to create its own embedded windows as needed). Fourth, all of the
configuration options of each peer (e.g. \fB\-font\fR, etc) can be set
independently, with the exception of \fB\-undo\fR, \fB\-maxundo\fR,
\fB\-autoseparators\fR (i.e. all undo, redo and modified state issues are
shared).
.PP
Finally any single peer need not contain all lines from the underlying data
store. When creating a peer, a contiguous range of lines (e.g. only lines 52
through 125) may be specified. This allows a peer to contain just a small
portion of the overall text. The range of lines will expand and contract as
text is inserted or deleted. The peer will only ever display complete lines of
text (one cannot share just part of a line). If the peer's contents contracts
to nothing (i.e. all complete lines in the peer widget have been deleted from
another widget), then it is impossible for new lines to be inserted. The peer
will simply become an empty shell on which the background can be configured,
but which will never show any content (without manual reconfiguration of the
start and end lines). Note that a peer which does not contain all of the
underlying data store still has indices numbered from
.QW 1.0
to
.QW end .
It is simply that those indices reflect a subset of the total data, and data
outside the contained range is not accessible to the peer. This means that the
command \fIpeerName \fBindex end\fR may return quite different values in
different peers. Similarly, commands like \fIpeerName \fBtag ranges\fR will
not return index ranges outside that which is meaningful to the peer. The
configuration options \fB\-startline\fR and \fB\-endline\fR may be used to
control how much of the underlying data is contained in any given text widget.
.PP
Note that peers are really peers. Deleting the
.QW original
text widget will not cause any other peers to be deleted, or otherwise
affected.
.PP
See below for the \fIpathName \fBpeer\fR widget command that controls the
creation of peer widgets.
.SH "WIDGET COMMAND"
.PP
The \fBtext\fR command creates a new Tcl command whose name is the same as the
path name of the text's window. This command may be used to invoke various
operations on the widget. It has the following general form:
.CS
\fIpathName option \fR?\fIarg arg ...\fR?
.CE
\fIPathName\fR is the name of the command, which is the same as the text
widget's path name. \fIOption\fR and the \fIarg\fRs determine the exact
behavior of the command. The following commands are possible for text widgets:
.TP
\fIpathName \fBbbox \fIindex\fR
.
Returns a list of four elements describing the screen area of the character
given by \fIindex\fR. 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 partially 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.
.TP
\fIpathName \fBcget\fR \fIoption\fR
.
Returns the current value of the configuration option given by \fIoption\fR.
\fIOption\fR may have any of the values accepted by the \fBtext\fR command.
.TP
\fIpathName \fBcompare\fR \fIindex1 op index2\fR
.
Compares the indices given by \fIindex1\fR and \fIindex2\fR according to the
relational operator given by \fIop\fR, and returns 1 if the relationship is
satisfied and 0 if it is not. \fIOp\fR must be one of the operators <, <=, ==,
>=, >, or !=. If \fIop\fR is == then 1 is returned if the two indices refer to
the same character, if \fIop\fR is < then 1 is returned if \fIindex1\fR refers
to an earlier character in the text than \fIindex2\fR, and so on.
.TP
\fIpathName \fBconfigure\fR ?\fIoption\fR? \fI?value option value ...\fR?
.
Query or modify the configuration options of the widget. If no \fIoption\fR is
specified, returns a list describing all of the available options for
\fIpathName\fR (see \fBTk_ConfigureInfo\fR for information on the format of
this list). If \fIoption\fR is specified with no \fIvalue\fR, 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 \fIoption\fR is
specified). If one or more \fIoption\-value\fR pairs are specified, then the
command modifies the given widget option(s) to have the given value(s); in
this case the command returns an empty string. \fIOption\fR may have any of
the values accepted by the \fBtext\fR command.
.TP
\fIpathName \fBcount\fR \fI?options\fR? \fIindex1 index2\fR
.
Counts the number of relevant things between the two indices. If \fIindex1\fR
is after \fIindex2\fR, the result will be a negative number (and this holds
for each of the possible options). The actual items which are counted depend
on the options given. The result is a list of integers, one for the result of
each counting option given. Valid counting options are \fB\-chars\fR,
\fB\-displaychars\fR, \fB\-displayindices\fR, \fB\-displaylines\fR,
\fB\-indices\fR, \fB\-lines\fR, \fB\-xpixels\fR and \fB\-ypixels\fR. The
default value, if no option is specified, is \fB\-indices\fR. There is an
additional possible option \fB\-update\fR which is a modifier. If given, then
all subsequent options ensure that any possible out of date information is
recalculated. This currently only has any effect for the \fB\-ypixels\fR count
(which, if \fB\-update\fR is not given, will use the text widget's current
cached value for each line). The count options are interpreted as follows:
.RS
.IP \fB\-chars\fR
count all characters, whether elided or not. Do not count embedded windows or
images.
.IP \fB\-displaychars\fR
count all non-elided characters.
.IP \fB\-displayindices\fR
count all non-elided characters, windows and images.
.IP \fB\-displaylines\fR
count all display lines (i.e. counting one for each time a line wraps) from
the line of the first index up to, but not including the display line of the
second index. Therefore if they are both on the same display line, zero will
be returned. By definition displaylines are visible and therefore this only
counts portions of actual visible lines.
.IP \fB\-indices\fR
count all characters and embedded windows or images (i.e. everything which
counts in text-widget index space), whether they are elided or not.