►The Racket Graphical Interface Toolkit
▼3 Windowing Classes
On this page:
new
auto-resize
set-label
set-color
get-color
Inherited methods:
from control<%>
command
from subwindow<%>
reparent
from window<%>
accept-drop-files
client->screen
enable
focus
get-client-handle
get-client-size
get-cursor
get-handle
get-height
get-label
get-plain-label
get-size
get-width
get-x
get-y
has-focus?
is-enabled?
is-shown?
on-drop-file
on-focus
on-move
on-size
on-subwindow-char
on-subwindow-event
on-subwindow-focus
on-superwindow-activate
on-superwindow-enable
on-superwindow-show
popup-menu
refresh
screen->client
set-cursor
show
warp-pointer
wheel-event-mode
from area<%>
get-graphical-min-size
get-parent
get-top-level-window
min-height
min-width
stretchable-height
stretchable-width
from subarea<%>
horiz-margin
vert-margin
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class

message% : class?

  superclass: object%

  extends: control<%>
A message control is a static line of text or a static bitmap. The text or bitmap corresponds to the message’s label (see set-label).

constructor

(new message% 
    [label label] 
    [parent parent] 
    [[style style] 
    [font font] 
    [color color] 
    [enabled enabled] 
    [vert-margin vert-margin] 
    [horiz-margin horiz-margin] 
    [min-width min-width] 
    [min-height min-height] 
    [stretchable-width stretchable-width] 
    [stretchable-height stretchable-height] 
    [auto-resize auto-resize]]) 
 → (is-a?/c message%)
  label : 
(or/c label-string? (is-a?/c bitmap%)
      (or/c 'app 'caution 'stop))
  parent : 
(or/c (is-a?/c frame%) (is-a?/c dialog%)
      (is-a?/c panel%) (is-a?/c pane%))
  style : (listof (or/c 'deleted)) = null
  font : (is-a?/c font%) = normal-control-font
  color : (or/c #f string? (is-a?/c color%)) = #f
  enabled : any/c = #t
  vert-margin : spacing-integer? = 2
  horiz-margin : spacing-integer? = 2
  min-width : (or/c dimension-integer? #f) = #f
  min-height : (or/c dimension-integer? #f) = #f
  stretchable-width : any/c = #f
  stretchable-height : any/c = #f
  auto-resize : any/c = #f
Creates a string or bitmap message initially showing label. If label is a bitmap, and if the bitmap has a mask (see get-loaded-mask in bitmap%) that is the same size as the bitmap, then the mask is used for the label. Modifying a bitmap while it is used as a label has an unspecified effect on the displayed label. An 'app, 'caution, or 'stop symbol for label indicates an icon; 'app is the application icon (Windows and Mac OS) or a generic “info” icon (X), 'caution is a caution-sign icon, and 'stop is a stop-sign icon.

If & occurs in label, it is specially parsed; under Windows and X, the character following & is underlined in the displayed control to indicate a keyboard mnemonic. (Under Mac OS, mnemonic underlines are not shown.) The mnemonic is meaningless for a message (as far as on-traverse-char in top-level-window<%> is concerned), but it is supported for consistency with other control types. A programmer may assign a meaning to the mnemonic (e.g., by overriding on-traverse-char).

If style includes 'deleted, then the message is created as hidden, and it does not affect its parent’s geometry; the message can be made active later by calling parent’s add-child method.

The font argument determines the font for the control. For information about the enabled argument, see window<%>. For information about the horiz-margin and vert-margin arguments, see subarea<%>. For information about the min-width, min-height, stretchable-width, and stretchable-height arguments, see area<%>.

The color argument determines the color of the text label. It has no effect on symbol and bitmap labels. If it is #f, the system default text color is used. If it is a string, then the color is looked up in the-color-database.

If auto-resize is not #f, then automatic resizing is initially enabled (see auto-resize), and the message% object’s graphical minimum size is as small as possible.

Changed in version 1.58 of package gui-lib: Added the color argument.

method

(send a-message auto-resize) → boolean?

(send a-message auto-resize on?) → void?
  on? : any/c
Reports or sets whether the message%’s min-width and min-height are automatically set when the label is changed via set-label.

method

(send a-message set-label label) → void?

  label : (or/c label-string? (is-a?/c bitmap%))
Overrides set-label in window<%>.
The same as set-label in window<%> when label is a string.

Otherwise, sets the bitmap label for a bitmap message. Since label is a bitmap, if the bitmap has a mask (see get-loaded-mask in bitmap%) that is the same size as the bitmap, then the mask is used for the label. Modifying a bitmap while it is used as a label has an unspecified effect on the displayed label. The bitmap label is installed only if the control was originally created with a bitmap label.

method

(send a-message set-color color) → void?

  color : (or/c #f (is-a?/c color%))
(send a-message set-color color-name) → void?
  color-name : string?
Sets the label’s text color. When color is #f, sets the label’s text color to the platform default. This method has no effect if the label is a symbol or a bitmap.

Added in version 1.58 of package gui-lib.
Changed in version 1.71: Added support for setting the color to the system default.

method

(send a-message get-color) → (or/c #f (is-a?/c color%))

Returns the current user-specified label color or #f if the system default is used.

Added in version 1.58 of package gui-lib.

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