The Window Tool Kit

Glossary

active region

A region that is sensitive to specified mouse events. When a mouse event occurs within the active region, a specified method is invoked.

active region method

A five-argument function that is invoked when a specified mouse event occurs within an active region.

ascender

The part of the character in a font that is above the baseline.

background

Part of a window frame that includes the inner border and the text of the title (if any), which are generally white.

baseline

The horizontal line on which characters in the font are positioned.

bitmap

A rectangular array of values that can be associated with a screen area.

bitmap clipping region

A region of a bitmap that is viewed by a viewport.

bitmap output stream

A stream that sends output to a bitmap.

block transfer

An operation by which bit settings within a specified bitmap region are copied onto another bitmap region.

boolean operation

An operation by which bit settings are combined according to one of the 16 boolean constants that can be the argument to the Common Lisp functionboole.

border

A window outline that consists of the black strip around the edge of the window and the white strip inside the black strip. See also inner border and outer border.

bubble

An object that appears on each of a window's scroll bars and represents the position of the bitmap clipping region relative to the overall bitmap.

child

Any viewport in the viewport hierarchy that has a parent.

clicking the mouse

Pressing a mouse button.

CLX

The Common Lisp language interface to the X Window System.

color number

The index of a registered color in the color map.

color registry

A structure that allows you to define and reference colors symbolically.

component shades

The colors red, green, and blue on the system color map.

current root viewport

The root viewport that you most recently created or the one that most recently contained the mouse.

delta of a color

The amount that a color differs from its defined value.

descender

The part of a character in a font that is below the baseline.

dragging the bubble

A procedure for scrolling a window by dragging a bubble along one of the window's scroll bars.

exposing

A procedure for bringing a viewport to the top of its sibling stack and thereby exposing it on the screen.

fixed-width font

A font in which all characters take up the same amount of horizontal space.

font

A set of character images that can be used for character output operations.

font registry

A registry that stores all of the current system fonts.

foreground

Part of a window frame that includes the outer border and the title bar (if any), which are usually black.

frame

A bitmap-like object that provides a functional means of drawing a window's border, title, and scroll bars.

frame viewport

The viewport that holds a window's frame.

handler

A function that is invoked when you type an associated keyboard interrupt character.

hiding

A procedure for placing a viewport at the bottom of its sibling stack and thereby hiding it from the screen.

horizontal scroll ratio

The ratio of the current to the maximum possible degree to which a window has been scrolled horizontally over its underlying bitmap.

hot spot

The location under the mouse cursor to which the mouse is pointing at any moment.

inner border

The white strip inside the outer border. See also outer border and border.

keyboard input

All characters, code, and interrupts that are typed at the keyboard.

keyboard interrupt characters

Characters associated with a mouse input stream and used to invoke a function.

keyword

A symbol preceded by a colon (:mode,:value, and so forth).

linefeed distance

The distance between lines of text in an output stream. Initially the linefeed distance associated with an output stream is the character height of the initial font.

mapping

The process of associating the members of one set of items with the members of another set of items, such as the bits in a bitmap with the pixels on the screen by means of a viewport or window.

mdc

Machine-dependent color.

mic

Machine-independent color.

mouse

A two- or three-button accessory that can be used to manage the window environment.

mouse cursor

An object defined by the mouse cursor object.

mouse cursor object

A bitmap that allows mouse movement to be represented by the mouse cursor on the screen.

mouse documentation

A string that is used for prompting and to explain the effects of various mouse actions.

mouse events

Structures that describe the physical change to the status of the mouse.

mouse event structures

Encodings of mouse events that are queued on a mouse input stream and that can be used to invoke functions.

mouse input stream

A stream used to carry input to the Window Tool Kit. A mouse input stream can always carry character input; it can also be specified to carry mouse events.

occlusion

The effect whereby one object overlaps and covers another.

optional parameter

A symbol that is not required for a function to work properly; in the syntactic description, the symbol&optional precedes the optional parameter.

off

A pixel whose corresponding bit has a value of 0.

on

A pixel whose corresponding bit has a value of 1.

origin

The top left corner of a region.

outer border

The black strip around the edge of a window. See also inner border and border.

parameter

A symbol whose value is determined by the arguments that you supply when you invoke a function.

parent

Any viewport in the viewport hierarchy that has a child viewport.

pixel

A picture image screen-element that can be switched on and off and which can be made to correspond to a bit on a specified bitmap.

polling the mouse

A procedure for using the status of the mouse to control the windows environment.

polyline

A sequence of positions that are connected by a line.

polypoint

A sequence of positions on which a dot of a specified size is drawn.

pop-up menu

A viewport that appears temporarily on the screen and offers a set of options. The options can be selected with the mouse.

position

A data structure specified by Cartesian coordinates either in terms of the root viewport or in terms of the current viewport. The coordinates represent the distance to the right of the origin and the distance below the origin respectively.

primary root viewport

The root viewport that is created when you initialize the Window Tool Kit.

queuing mouse events

A procedure whereby physical changes to the status of the mouse are encoded as data structures and are placed in sequence on a specified mouse input stream.

read from a mouse input stream

A procedure whereby queued mouse event characters are examined by the Window Tool Kit in the sequence in which they appear on the current mouse input stream.

regions

A data structure that describes a rectangular area. A region has an origin, a corner, and a size.

reshaping

A procedure whereby the height and width of a viewport can be changed.

rest parameter

A construct that allows a function to have an unspecified number of arguments; it is indicated by the symbol&rest in the syntactic description.

root viewport

A basic viewport that is automatically created when the Window Tool Kit is initialized.

rubberbanding

The effect that occurs when an edge of a shape follows the mouse, often in the context of resizing the shape, so that the shape appears to be stretching or contracting as the mouse moves.

saturations

Amounts of red, green, and blue light that produce a color.

screen clipping region

The region of the screen that is specified by a viewport.

scroll bars

Bars that appear on the right-hand side and the bottom of a scrollable window. Each bar contains a bubble that can be used for scrolling the window.

scrolling

A procedure whereby a window's bitmap clipping region is moved vertically or horizontally on the overall bitmap by use of the mouse.

siblings

Any viewports that have the same parent in the viewport hierarchy.

sibling stack

A stack into which siblings are automatically placed. Unless otherwise specified, the most recently created sibling is placed at the top of the stack, while the earliest created is located at the bottom.

syntax

Standardized grammatical rules and patterns.

system color map

A mapping of pixel values onto the machine-dependent colors of the host window system.

variable-width font

A font in which characters can have different widths.

vertical scroll ratio

The ratio of the current to the maximum possible degree to which a window has been scrolled vertically over its underlying bitmap.

viewport

A data structure that specifies an area of the screen for the display of a specified bitmap and its bit settings.

viewport hierarchy

A hierarchy in which all viewports are automatically placed according to parent-child relationships. The root of the hierarchy is the root viewport.

who window

A window at the bottom of the root viewport that displays information about the state of the mouse.

who process

The process that updates and displays the who window.

Window Tool Kit

An enhancement of Liquid Common Lisp that allows windows facilities to be customized for use with specialized applications.

window

A viewport that is surrounded by a border and is automatically attached to a bitmap, a bitmap output stream, and a mouse input stream.

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