Tk Built-In Commands - message manual page

## message

Create and manipulate message widgets

### SYNOPSIS

(message widget-name ?options?)

### STANDARD OPTIONS

    :anchor                                :background
    :borderwidth                           :cursor
    :font                                  :foreground
    :highlightbackground                   :highlightcolor
    :highlightthickness                    :padx
    :pady                                  :relief
    :takefocus                             :text
    :textvariable                          :width

### WIDGET-SPECIFIC OPTIONS

Name: aspect
Class: Aspect
Option keyword: :aspect
STklos slot name: aspect
  Specifies a non-negative integer value indicating desired aspect ratio for the text. The aspect ratio is specified as 100*width/height. 100 means the text should be as wide as it is tall, 200 means the text should be twice as wide as it is tall, 50 means the text should be twice as tall as it is wide, and so on. Used to choose line length for text if width option isn't specified. Defaults to 150.

Name: justify
Class: Justify
Option keyword: :justify
STklos slot name: justify
  Specifies how to justify lines of text. Must be one of left, center, or right. Defaults to left. This option works together with the anchor, aspect, padX, padY, and width options to provide a variety of arrangements of the text within the window. The aspect and width options determine the amount of screen space needed to display the text. The anchor, padX, and padY options determine where this rectangular area is displayed within the widget's window, and the justify option determines how each line is displayed within that rectangular region. For example, suppose anchor is e and justify is left, and that the message window is much larger than needed for the text. The the text will displayed so that the left edges of all the lines line up and the right edge of the longest line is padX from the right side of the window; the entire text block will be centered in the vertical span of the window.

Name: width
Class: Width
Option keyword: :width
STklos slot name: width
  Specifies the length of lines in the window. The value may have any of the forms acceptable to Tk_GetPixels. If this option has a value greater than zero then the aspect option is ignored and the width option determines the line length. If this option has a value less than or equal to zero, then the aspect option determines the line length.

### DESCRIPTION

The message procedure creates a new window (given by the widget-name argument) and makes it into a message widget. Additional options, described above, may be specified on the procedure line or in the option database to configure aspects of the message such as its colors, font, text, and initial relief. The message procedure returns its widget-name argument. At the time this procedure is invoked, there must not exist a window named widget-name, but widget-name's parent must exist.

A message is a widget that displays a textual string. A message widget has three special features. First, it breaks up its string into lines in order to produce a given aspect ratio for the window. The line breaks are chosen at word boundaries wherever possible (if not even a single word would fit on a line, then the word will be split across lines). Newline characters in the string will force line breaks; they can be used, for example, to leave blank lines in the display.

The second feature of a message widget is justification. The text may be displayed left-justified (each line starts at the left side of the window), centered on a line-by-line basis, or right-justified (each line ends at the right side of the window).

The third feature of a message widget is that it handles control characters and non-printing characters specially. Tab characters are replaced with enough blank space to line up on the next 8-character boundary. Newlines cause line breaks. Other control characters (ASCII code less than 0x20) and characters not defined in the font are displayed as a four-character sequence \xhh where hh is the two-digit hexadecimal number corresponding to the character. In the unusual case where the font doesn't contain all of the characters in ``0123456789abcdef\x'' then control characters and undefined characters are not displayed at all.

### WIDGET PROCEDURE

The message procedure creates a new STk procedure whose name is widget-name. This procedure may be used to invoke various operations on the widget. It has the following general form:

    (widget-name option ?arg arg ...?)

Option and the args determine the exact behavior of the procedure. The following procedures are possible for message widgets:

(widget-name 'cget option)
  Returns the current value of the configuration option given by option. Option may have any of the values accepted by the message procedure.

(widget-name 'configure ?option? ?value option value ...?)
  Query or modify the configuration options of the widget. If no option is specified, returns a list describing all of the available options for widget-name (see Tk_ConfigureInfo for information on the format of this list). If option is specified with no value, then the procedure 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 specified). If one or more option-value pairs are specified, then the procedure modifies the given widget option(s) to have the given value(s); in this case the procedure returns an empty string. Option may have any of the values accepted by the message procedure.

### DEFAULT BINDINGS

When a new message is created, it has no default event bindings: messages are intended for output purposes only.

### BUGS

Tabs don't work very well with text that is centered or right-justified. The most common result is that the line is justified wrong.

### KEYWORDS

message, widget

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