H
- hairline
- The thinnest possible line that can be drawn on a device.
- halftone
- A QuickDraw GX data structure"also a property of a view port object"that specifies a pattern and a set of colors. A halftone is used to achieve a greater range of colors than may be available on a display device
See also: angle, background color, dot color, dot type, frequency, tint type
- half-duplex dialog
- A transmission method that permits communication in either direction, but in only one direction at a time.
- half-open connection
- A connection state in which one connection end is established but the other connection end is unreachable or has disposed of its connection information
See also: closed connection, open connection
- Han
- A general term for Chinese-derived ideographic characters. Includes Hanzi, Kanji, and Hanja.
- handle
- A variable containing the address of a nonrelocatable pointer, which in turn refers to the address of a relocatable block of data
See also: pointer
- handler
- A recipient and processor of messages. It can be a printing extension, a printer driver, QuickDraw GX printing, or an application. For example, an application can supply a handler for errors, warnings, and messages
See also: message chain
- handshake
- The exchange of predetermined signals between two processes engaged in establishing a connection.
- hanging baseline
- The baseline used by Devanagari and similar scripts, where most of the glyph is below the baseline.
- hanging glyphs
- A set of glyphs, usually punctuation, that typically extend beyond the left and right margins of the text area and whose widths are not counted when line length is measured.
- Hangul
- A Korean subscript which consists of blocks of component glyphs called Jamo that are arranged and transformed into boxes. Hangul characters differ from typical character clusters in that they are treated as singular units in memory; there are no principal characters and attachments.
- Hanja
- Korean ideographic characters borrowed from Chinese.
- Hanzi
- Native Chinese ideographic characters.
- hard import
- An imported symbol that must be defined at run time and whose corresponding code or data must therefore be available in an import library on the host machine
See also: import, weak symbol
- hashing
- A method of organizing symbol information in tables that allows them to be searched for quickly.
- hash word
- An 4-byte value that contains the length and encoded name of a symbol.
- HBA
See: host bus adapter (HBA)
- header
- The information that comes at the beginning of a frame or a packet before the message text. It often includes control and addressing information.
- header component
- The portion of a help resource in which you supply information that applies to all help balloons specified in the resource"information such as the version number of the Help Manager, the balloon definition function, and the variation code.
- header node
- The first node in a B*-tree file; it contains essential information about the entire B*-tree file.
- head patch
- A patch that, upon completion does not regain control. A head patch jumps to the next routine
See also: tail patch
- heap
- An area of memory in which space is dynamically allocated and released on demand, using the Memory Manager
See also: application heap, graphics client heap
- heap compaction
- The process of moving allocated blocks within a heap to collect the free space into a single block.
- heap fragmentation
- The state of a heap when the available free space is scattered throughout the heap in numerous unused blocks.
- heap zone
- An area of memory initialized by the Memory Manager for heap allocation. A heap zone consists of a zone header, a heap, and a zone trailer.
- help balloon
- A rounded-rectangle window that contains explanatory information for the user. With tips pointing at the objects they annotate, help balloons look like the bubbles used for dialog in comic strips. Help balloons are turned on by the user from the Help menu; when Balloon Help assistance is on, a help balloon appears whenever the user moves the cursor over the balloon's hot rectangle
See also: alternate rectangle, hot rectangle
- Help Manager
- A collection of routines that your application can use to provide Balloon Help assistance to your application's users.
- Help menu
- The menu which provides access to on-screen help information.
- help messages
- Descriptive text or pictures that appear inside help balloons.
- help resources
- Application-supplied resources that describe help messages, balloon definition functions, variation codes, and, when necessary, the tips and the hot rectangles or alternate rectangles for the Help Manager to use in drawing help balloons. These help resources are the menu help ('hmnu') resource, the dialog item help ('hdlg') resource, the rectangle help ('hrct') resource, the window help ('hwin') resource, the Finder icon help ('hfdr') resource, and the default help override ('hovr') resource.
- hertz (Hz)
- A unit of frequency, equal to one cycle per second.
- HFS
See: hierarchical file system (HFS)
- HFS volume
- A volume that is organized according to the hierarchical file system.
- hicharge counter
- A counter in portable Macintosh computers that measures the time required to raise the battery voltage to 7.2 volts.
- hierarchical file system (HFS)
- A method of organizing files and directories on a volume in a hierarchical or tree-like structure.
- hierarchical menu
- A menu in which one or more items is the menu title for submenu
See also: submenu
- hierarchy
See: view port hierarchy
- highlight
- To make something visually distinct, typically when it's selected. This is generally done by reversing black and white or changing colors to provide a sharp contrast.
- highlighting
- (1) The display of text in inverse video or with a colored background, to designate a selection range. (2) A QuickDraw capability that displays background bits or pixels in a distinctive visual way, such as inverting them.
- highlight mode
- A transfer mode type in which the source component and operand component are swapped in the destination. Other component values in the destination are ignored.
- highlight type
- The angular character of carets and edges of highlighting areas. Highlighting and carets are either straight or angled. See angled caret, straight caret.
- high caret
See: primary caret
- high-level event
- An event sent from one application to another requesting transfer of information or performance of some action.
- high-level event queue
- A separate queue that the Event Manager maintains to store high-level events transmitted to an application. The Event Manager maintains a high-level event queue for each open application capable of receiving high-level events.
- high-order bit
- The bit contributing the greatest value in a string of bits. For example, in the MC680x0 numbering scheme bit number 7 contributes a value of 27, or 128. Same as most significant bit
See also: low-order bit
- high-quality printing
- Printing that produces documents using all of the fonts and formatting that the user has included.
- Hiragana
- A cursive, phonetic subscript of the Japanese writing system, with 50 syllables that represent all sounds of the Japanese language
See also: Katakana
- histogram
- A color bank composed of frequency counts of each color within a picture, pixel map, or bitmap at a particular resolution.
- hit point
- In hit-testing, the point (commonly corresponding to a mouse-down location) to be tested for coincidence with a shape or part of a shape.
- hit-testing
- The conversion of a specific geometric location, such as pixel position in a view port, to logical location (part, control point, or glyph) in the geometry of a shape object. Hit-testing is used to highlight or activate parts of geometric shapes or to highlight or draw a caret within the displayed text of a typographic shape.
- hit-test info structure
- A structure, filled out by a hit-testing function, that contains the results of a hit-test.
- hit-test parameters
- A property of a transform object. They consist of a shape-parts mask and a tolerance that together specify the conditions of a hit-test.
- HLS space
- A transformation of RGB space that allow colors to be described in terms more natural to an artist. The name HLS stands for hue, lightness, and saturation.
- hold
- To temporarily prevent a range of physical memory from being paged out by the Virtual Memory Manager.
- hollow fill
See: closed-frame fill
- hop count
- The number of internet routers that a datagram passes through in transit to its destination; each internet router counts as one hop.
- host
See: Internet host
- host bus adapter (HBA)
- The hardware that controls a SCSI bus.
- hot rectangle
- An area defined to display a help balloon. When the user moves the cursor over this area, the Help Manager displays the help balloon associated with the hot rectangle
See also: alternate rectangle
- hot spot
- The portion of the cursor that must be positioned over a screen object before mouse clicks can have an effect on that object. Designated as a point (not a bit) in the image of the cursor. The mouse driver uses the hot spot to align the cursor with the mouse location.
- hot-rectangle component
- The portion of an 'hrct' resource in which you specify hot rectangles and the help messages associated with each hot rectangle.
- HSV space
- A transformation of RGB space that allow colors to be described in terms more natural to an artist. The name HSV stands for hue, saturation, and value.
- HTML
See: Hypertext Markup Language (HTML)
- HTTP
See: HyperText Transport Protocol
- hue
- The name of the color that places the color in its correct position in the spectrum. For example, if a color is described as blue, it is distinguished from yellow, red, green, or other colors
See also: brightness, saturation
- hue value
- A setting that is similar to the tint control on a television. Hue value can be specified in degrees with complementary colors set 180
º
apart (red is 0
º
, green is +120
º
, and blue is _120
º
). Video digitizer components support hue values that range from 0 (_180
º
shift in hue) to 65,535 (+179
º
shift in hue), where 32,767 represents a 0
º
shift in hue. Hue value is set with the video digitizer component's VDSetHue function.
- human interface
- The facilities by which a user interacts with programs running on a computer. Because most human interface elements (such as windows, menus, and icons) are visual in the Mac OS, the term human interface is generally synonymous with graphical user interface. However, user voice input, sounds that alert the user, and other nonvisual elements are part of the human interface as well.
- Human Interface Toolbox
- The part of the Mac OS that allows you to implement the standard Macintosh user interface in your application or other software.
- hybrid environment
See: mixed environment
- Hypertext Markup Language (HTML)
- A standard for describing the layout and contents of a hypertext document. An HTML document can contain an applet tag that specifies the name and location of an applet
See also: applet tag
- HyperText Transport Protocol
- The Internet standard that supports the exchange of data on the World Wide Web.
- hyphenation point
- An entry in an array of edge offsets in the source text at which it is appropriate to break a line of display text.
- Hz
See: hertz (Hz)