Жолды автоматты түрде бөлу мүмкіндігі

Feature of continuing on a new line when a line is full

Line breaking, also known as word wrapping, is breaking a section of text into lines so that it will fit into the available width of a page, window or other display area. In text display, line wrap is continuing on a new line when a line is full, so that each line fits into the viewable window, allowing text to be read from top to bottom without any horizontal scrolling. Word wrap is the additional feature of most text editors, word processors, and web browsers, of breaking lines between words rather than within words, where possible. Word wrap makes it unnecessary to hard code newline delimiters within paragraphs, and allows the display of text to adapt flexibly and dynamically to displays of varying sizes.

A soft return or soft wrap is the break resulting from line wrap or word wrap (whether automatic or manual), whereas a hard return or hard wrap is an intentional break, creating a new paragraph. With a hard return, paragraph break formatting can (and should) be applied (either indenting or vertical whitespace). Soft wrapping allows line lengths to adjust automatically with adjustments to the width of the user's window or margin settings, and is a standard feature of all modern text editors, word processors, and email clients. Manual soft breaks are unnecessary when word wrap is done automatically, so hitting the "Enter" key usually produces a hard return. Alternatively, "soft return" can mean an intentional, stored line break that is not a paragraph break. For example, it is common to print postal addresses in a multiple line format, but the several lines are understood to be a single paragraph. Line breaks are needed to divide the words of the address into lines of the appropriate length. In the contemporary graphical word processors Microsoft Word and Libreoffice Writer, users are expected to type a carriage return between each paragraph. Formatting settings, such as first line indentation or spacing between paragraphs, take effect where the carriage return marks the break. A non paragraph line break, which is a soft return, is inserted using or via the menus, and is provided for cases when the text should start on a new line but none of the other side effects of starting a new paragraph are desired. In text oriented markup languages, a soft return is typically offered as a markup tag. For example, in HTML there is a <br> tag that has the same purpose as the soft return in word processors described above.

The soft returns are usually placed after the ends of complete words, or after the punctuation that follows complete words. However, word wrap may also occur following a hyphen inside of a word. This is sometimes not desired, and can be blocked by using a non breaking hyphen, or hard hyphen, instead of a regular hyphen. A word without hyphens can be made wrappable by having soft hyphens in it. When the word isn't wrapped (i. e., isn't broken across lines), the soft hyphen isn't visible. But if the word is wrapped across lines, this is done at the soft hyphen, at which point it is shown as a visible hyphen on the top line where the word is broken. (In the rare case of a word that is meant to be wrappable by breaking it across lines but without making a hyphen ever appear, a zero width space is put at the permitted breaking point(s) in the word.) Sometimes word wrap is undesirable between adjacent words. In such cases, word wrap can usually be blocked by using a hard space or non breaking space between the words, instead of regular spaces.

Word wrapping is an optimization problem. Depending on what needs to be optimized for, different algorithms are used.

A different algorithm, used in TeX, minimizes the sum of the squares of the lengths of the spaces at the end of lines to produce a more aesthetically pleasing result than the greedy algorithm, which does not always minimize squared space.

A primitive line breaking feature was used in 1955 in a "page printer control unit" developed by Western Union. This system used relays rather than programmable digital computers, and therefore needed a simple algorithm that could be implemented without data buffers. In the Western Union system, each line was broken at the first space character to appear after the 58th character, or at the 70th character if no space character was found. The greedy algorithm for line breaking predates the dynamic programming method outlined by Donald Knuth in an unpublished 1977 memo describing his TeX typesetting system and later published in more detail by Knuth & Plass (1981).