text.n

linux系统下的音频通信

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'\" Copyright (c) 1992 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
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'\" SCCS: @(#) text.n 1.68 97/10/31 12:58:41
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.so man.macros
.TH text n 4.0 Tk "Tk Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
text \- Create and manipulate text widgets
.SH SYNOPSIS
\fBtext\fR \fIpathName \fR?\fIoptions\fR?
.SO
\-background	\-highlightbackground	\-insertontime	\-selectborderwidth
\-borderwidth	\-highlightcolor	\-insertwidth	\-selectforeground
\-cursor	\-highlightthickness	\-padx	\-setgrid
\-exportselection	\-insertbackground	\-pady	\-takefocus
\-font	\-insertborderwidth	\-relief	\-xscrollcommand
\-foreground	\-insertofftime	\-selectbackground	\-yscrollcommand
.SE
.SH "WIDGET-SPECIFIC OPTIONS"
.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 \-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 overriden 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 overriden 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 overriden with \fB\-spacing3\fR options in
tags.
.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
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, \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.
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 \fBtabs\fR option may be overridden by \fB\-tabs\fR
options in tags.
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.
.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 doesn't have a uniform width then the width of the
character ``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 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 \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.
.VS
Text widgets support four different kinds of annotations on the
text, called tags, marks, embedded windows or embedded images.
.VE
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 TAGS below for more details.
.PP
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.
.PP
The third form of annotation allows arbitrary windows to be
embedded in a text widget.
See EMBEDDED WINDOWS below for more details.
.PP
.VS
The fourth form of annotation allows Tk images to be embedded in a text
widget.
See EMBEDDED IMAGES below for more details.
.VE

.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.
.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
.VS
\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.
.VE
.PP
If the \fIbase\fP could match more than one of the above forms, such
as a \fImark\fP and \fIimageName\fP 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\fB chars\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 character in the text.
Spaces on either side of \fIcount\fR are optional.
.TP
\fB\- \fIcount\fB chars\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 character in the text.
Spaces on either side of \fIcount\fR are optional.
.TP
\fB+ \fIcount\fB lines\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.
.TP
\fB\- \fIcount\fB lines\fR
Adjust the index backward by \fIcount\fR 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.
.TP
\fBlinestart\fR
Adjust the index to refer to the first character on the line.
.TP
\fBlineend\fR
Adjust the index to refer to the last character on the line (the newline).
.TP
\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.
.TP
\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.
.PP
If more than one modifier is present then they are applied in
left-to-right order.  For example, the index ``\fBend \- 1 chars\fR''
refers to the next-to-last character in the text and
``\fBinsert wordstart \- 1 c\fR'' refers to the character just before
the first one in the word containing the insertion cursor.

.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 the characters `` '' (space), \fB+\fR, or \fB\-\fR:
these characters have special meaning in indices, so tags containing
them can't 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
``\fIpathName \fBtag raise\fR'' and ``\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.