MLTE Glossary

• active end  

  The point at which the user releases the mouse button when selecting a range of text or other items. Compareanchor point.



• alignment  

  The horizontal placement of lines of text with respect to the left and right edges of the text area. Alignment can be left, right, centered, or justified (flush on both left and right edges.)



• anchor point  

  The point at which the user presses the mouse button to begin selecting a range of text or other items by dragging through them. The anchor point is at one corner of the range of objects. Compare active end.



• application font  

  The default font for use by applications. The application font is defined by each script system.



• ATSUI (Apple Type Services for Unicode Imaging)  

  A technology that enables the rendering of Unicode-encoded text with advanced typographic features. ATSUI automatically handles many of the complexities inherent in text layout, including how to correctly render text in bidirectional and vertical script systems.



• ATSUI style mask  

  A byte-length mask with one bit set for each ATSUI-supported style to be applied.



• auto-key event  

  An event indicating the user has held a key down for a certain amount of time.



• background  

  The part of a glyph bitmap that surrounds the pixels that constitute the glyph itself.



• base line  

  An imaginary horizontal line that coincides with the bottom of each character in a font, excluding descenders (tails on letters such as p).



• bidirectional script system  

  A script system in which text is generally right-aligned with most characters written from right to left, but with some left-to-right text as well. Arabic and Hebrew are bidirectional script systems.



• bidirectional text  

  The combination of text with both left-to-right and right-to-left directions within a single line of text.



• bottomline input  

  A type of input method in which the user enters text in a small window, called a floating input window, that appears near the bottom of the screen. Compare inline input.



• byte offset  

  The indexed position of a 2-byte Unicode character in a text buffer, starting at zero for the first character. Sequential values for character offset correspond to the storage order of the characters.



• caret  

  A vertical or slanted blinking bar, appearing at the caret position in the display text, that marks the point at which text is to be insert or deleted. See also split caret.



• caret position  

  A location onscreen, typically between glyphs, that relates directly to the offset (in memory) of the current text insertion point in the source text. At the boundary between a right-to-left and left-to-right direction run on a line, one character offset may correspond to two caret positions, and one caret position may correspond to two offsets.



• character  

  An atomic unit of content for text data. A character is an abstract entity without any particular appearance; characters include letters, digits, punctuation, and symbols. See alsocharacter code ; glyph.



• character code  

  In MLTE and ATSUI, a 16-bit value representing a Unicode text character. Text is stored in memory as character codes. Each script system’s keyboard-layout ('KCHR') resource converts the virtual key codes generated by the keyboard or numeric keypad into character codes; each script system’s fonts convert the character codes into glyphs for display or printing.



• character encoding  

  A conversion table for interpreting a specific character set. See also text encoding.



• character rendering  

  The process of preparing characters for display, taking into account line direction, contextual rules, and character reordering. For example, the formation of ligatures and diphthongs occurs during the display of text.



• CFString  

  An object that represents an array of Unicode characters (UniChar) along with a count of the number of characters. Unicode-based strings in Core Foundation provide a solid basis for internationalizing the software you develop. Unicode makes it possible to develop and localize a single version of an application for users who speak most of the world’s written languages, including Russian (Cyrillic), Arabic, Chinese, and Japanese. Although conceptually CFString objects store strings as arrays of Unicode characters, in practice they often store them more efficiently. The memory a CFString object requires is typically about the same or even less than that required by a simple UniChar array.



• continuous style  

  In MLTE, a style value that is constant over an entire selection range.



• cross-stream shift  

  Refers to a shift in a character’s position in the direction against the reading direction (that is, vertical for horizontal text and horizontal for vertical text).



• data run  

  See run; style run; text run.



• destination rectangle  

  The rectangle defining the area in which text is drawn.



• diphthong  

  A complex vowel sound that can be phonetically represented by 2 characters. The characters represent the initial and final sounds of the diphthong.



• direction boundary  

  A point between offsets in memory or glyphs on a display, at which the direction of the stored or displayed text changes.



• direction run  

  A contiguous (in memory) sequence of characters having the same right-to-left or left-to-right line direction.



• discontinuous highlighting  

  A highlighting effect that can occur when a selection range crosses one or more direction boundaries.



• display order  

  The order in which glyphs are drawn on a screen. Glyphs are always drawn in left-to-right order. Because not all text is read left-to-right, the display order of glyphs may be different from the storage order of their corresponding character codes in memory.



• embedded objects  

  Graphics, sound, or movie data that is in a text object along with text data.



• encoding  

  See text encoding.



• floating input window  

  A window used for text entry by an input method. See also floating window.



• floating window  

  A window that is similar to a standard Window Manager window except that is occupies a special layer so that it always remains in front of any application windows.



• font  

  A collection of glyphs that usually have some element of design consistency such as the shapes of the counters, the design of the stem, the stroke thickness, or the use of serifs.



• font attributes  

  A group of flags that modify the behavior or identity of a font.



• font description  

  A table that contains data that fully describes a font.



• font family  

  A group of fonts that share certain characteristics and a common family name.



• font feature  

  The set of typographic and layout characteristics that create a specific appearance for a glyph.



• font run  

  A contiguous (in memory) sequence of characters having the same font.



• font variation  

  An algorithmic way to produce a range of typestyles along a particular variation axis.



• frame  

  The viewable area of a text object; the view rectangle. Compare destination rectangle.



• glyph  

  The distinct visual representation of a character in a form that a screen or printer can display. A glyph may represent one character (the lowercase a), more than one character (the fi ligature), part of a character (the dot over an i), or a nonprinting character (the space character). See also character.



• imaging system  

  The system used to render text or graphics.



• inline input  

  An input method that allows the user to enter text directly into a document. In inline input, entry and conversion of characters take place at the current line position—where the converted text is intended to appear—rather than in a separate window. Inline input is the principal example of the kind of text service supported by the Text Services Manager. Compare bottomline input.



• input method  

  A software module for 2-byte script systems that converts phonetic or syllabic characters, entered from a keyboard, into ideographic or other complex representation of text. Because 2-byte script systems have too many characters to be entered directly from a keyboard, the input method uses a conversion technique, such as translating sequences of phonetic characters that are typed into a special input window. For example, the Japanese script system provides software for transcribing Kana (phonetic Japanese) into ideographic Kanji.



• insertion point  

  The point in the source text at which text is to be inserted or deleted. An insertion point is specified by a single caret position. Compare caret.



• justification  

  A type of alignment that involves the spreading or compressing of printed text to fit into a given line width so that it is flush on both left and right edges of the text area.



• keyboard and font synchronization  

  A process by which the current keyboard script is compared to the script of the font at the current insertion point. If the two don’t match, one or the other is changed so the two scripts are the same. In most cases, when the user starts typing, the font is automatically replaced with one belonging to the keyboard script, although it is possible to synchronize in the other direction.



• key-down event  

  An event indicating the user pressed a key.



• key-up event  

  An event indicating the user released a key.



• keyboard script  

  The script system for keyboard input. It determines the character input method and the mapping of keystrokes to character codes. The keyboard script may be different from the script used to display text.



• ligature  

  A glyph that is created when two or more characters are combined to create a new character.



• line direction  

  The direction in which text in a particular language is written and read. The English language has a left-to-right line direction; Arabic and Hebrew have a (primarily) right-to-left line direction.



• localize  

  See localization.



• localization  

  The adaptation of system software or applications to a particular language or region. Localization involves translating strings and providing proper conventions for sorting, date and time formats, currency and measurement units, calendars, numbers, and other culturally specific items such as icons.



• missing character glyph  

  The glyph in a font that is drawn when no glyph is defined for a character code in a font.



• modifier key  

  A key that when pressed at the same time as another key, modifies the behavior of the other key.



• pass-through mode  

  A mode that does not modify data. With respect to keyboard-entry, pass-through mode allows users to enter ASCII characters in the context of a 2-byte script, without changing the keyboard script.



• primary line direction  

  The dominant line direction (right-to-left or left-to-right) of the current text. The primary line direction is typically specified by the value of the global system direction variable. See also line direction.



• private MLTE scrap  

  Scrap used exclusively by MLTE.



• Roman character set  

  A set of characters used for the Roman writing system. Roman character sets include the Standard Roman character set and the ASCII character set.



• Roman keyboard script  

  A keyboard script that uses the Roman character set.



• run  

  A sequence of glyphs that are contiguous in memory and share a set of common attributes. See also font run; style run.



• script  

  A method for depicting words visually. Some examples of scripts are Latin, Greek, Hiragana, Katakana, and Han.



• script system  

  A collection of software utilities that provides for the representation of a specific writing system. It consists of a set of keyboard resources, a set of international resources, and one or more fonts. Script systems include Roman, Japanese, Arabic, traditional Chinese, Simplified Chinese, Hebrew, Greek, Thai, and Korean.



• selection range  

  The contiguous sequence of characters in the source text that mark where the next editing operation is to occur. The glyphs corresponding to those characters are commonly highlighted onscreen.



• Shift JIS (Japanese Industrial Standard)  

  A character encoding based on two JIS standards: JIS X 0201 and JIS X 0208. Shift JIS consists of codes from the JIS X 0208 standard that are shifted to make room for older Hankakukana codes from the JIS X 0201 standard.



• single caret  

  In unidirectional text, the standard text-insertion caret. In mixed-directional text, one caret that appears at the place where the user will insert the next character, given the current keyboard script. At a boundary between two direction runs, the single caret can correspond to either the primary line direction or the secondary line direction. Because changing the keyboard script in that situation changes the caret location, the single caret is also called a moving caret or jumping caret.



• split caret  

  A type of caret that, at the boundary between text of opposite directions, divides into two parts: a high caret and a low caret, each measuring half the line’s height. The two separate half-carets merge into one in unidirectional text. Compare single caret.



• Standard Roman character set  

  The 256 characters and character codes that are supplied with the Macintosh Roman script system. The Standard Roman character set consists of the Macintosh character set plus additional defined characters with character codes between $D9 and $FF.



• storage order  

  The order in which character codes are stored in memory. Storage order may be different from display order.



• style  

  A visual attribute, other than size, applied as a systematic variation to the plain (unstyled) characteristics of a font glyph. For example bold, italic, underline, outline, shadow, condense, and extend.



• style run  

  A sequence of text that is contiguous in memory and in which all the characters are in the same style. Compare text run.



• synchronization  

  See keyboard and font synchronization.



• system direction  

  The horizontal placement of interface elements, including the default line direction (left-to-right or right-to-left) for text in the system script. System direction is specified by the global system direction variable.



• system font  

  The font used to display text in menus, dialog boxes, alert boxes, and so forth in a given script system. For example, in the Roman script system, the system font is Chicago on Mac OS 9 and earlier versions.



• system script  

  The primary script system used by the operating system, such as in dialogs and menu bars. The system script affects system defaults, such as the system font, line direction, and text-formatting rules. All other scripts are secondary to the system script.



• text  

  A set of specific symbols that, when displayed in a meaningful order, conveys information.



• text area  

  The space on the display device within which the text should fit.



• text direction  

  The direction in which reading proceeds. Roman text has a left-to-right direction; Hebrew and Arabic have a (predominantly) right-to-left direction; Chinese and Japanese can have a vertical direction.



• text encoding  

  The coded character set or character encoding scheme used to represent a particular piece of text.



• Text Encoding Conversion (TEC) Manager   

  A pair of shared library extensions—namely, the Text Encoding Converter and the Unicode Utilities—that facilitate text encoding conversion on Mac OS–based computers.



• Text Encoding Converter   

  A shared library extension that provides the services for general and algorithmic encoding conversions or multi-encoding streams. The Text Encoding Converter sometimes uses Unicode Utilities.



• text manipulation  

  System-level procedures used to order and compare characters, determine line breaks, determine text directionality, and keep track of character properties, such as case.



• text object  

  An opaque structure that the Multilingual Text Engine uses to handle text formatting at a document level.



• text run  

  A sequence of text that is contiguous in memory and in which all characters are in the same font. Compare style run.



• text segment  

  For text layout, the portion of a style run that falls on a single text line. (It may be the entire style run.) Most text measuring and drawing routines work on a single text segment at a time.



• Text Services Manager (TSM)  

  The Mac OS technology that provides text services such as input methods. TSM handles communication between client applications that request text services and the software modules, known as text service components, that provide them.



• tick  

  1/60 second.



• Unicode  

  Unicode is an ISO standard for 16-bit universal worldwide character encoding developed by a consortium that includes Apple. Unicode has enough capacity to handle unique encodings for all characters available in all scripts, including the 2-byte script systems such as Chinese, Japanese, and Korean.



• Unicode Utilities  

  A shared library extension that provides table-based conversion between Unicode and other encodings.



• unidirectional text  

  A sequence of text that has a single line direction. Compare bidirectional text.



• UTF-16 (Unicode Transformation Format)  

  A form of Unicode in which 16-bits are used to encode a character.



• variation axis  

  A range of values used to produce different type styles for a font. For example, a font that has a weighting axis could be displayed with weights that range from 0.7 point (light) to 1.3 points (bold). It is possible to combine variations. For example, font width variations can be combined with weighting variations to produce font variations ranging from light, narrow to bold, wide.



• view rectangle  

  In MLTE, the rectangle defining the portion of the window within which text is actually displayed. Text drawn in the destination rectangle is made visible to the application user in the view rectangle.



• WorldScript  

  A group of Mac OS managers, extensions, and resources that facilitate multilingual text processing.



• writing system  

  A set of characters and the basic rules for their use in creating a visual depiction of language. Writing systems may differ in the direction in which their characters and lines run, the size of the character set used, and the context sensitivity of character selection. Writing systems include Roman, Japanese, Arabic, and Hebrew. Compare script system.