14.22 Visual Line Mode

Another alternative to ordinary line continuation is to use word wrap. Here, each long logical line is divided into two or more screen lines, like in ordinary line continuation. However, Emacs attempts to wrap the line at word boundaries near the right window edge. (If the line’s direction is right-to-left, it is wrapped at the left window edge instead.) This makes the text easier to read, as wrapping does not occur in the middle of words.

Word wrap is enabled by Visual Line mode, an optional minor mode. To turn on Visual Line mode in the current buffer, type M-x visual-line-mode; repeating this command turns it off. You can also turn on Visual Line mode using the menu bar: in the Options menu, select the ‘ Line Wrapping in this Buffer’ submenu, followed by the ‘ Word Wrap (Visual Line mode)’ menu item. While Visual Line mode is enabled, the mode line shows the string ‘ wrap’ in the mode display. The command M-x global-visual-line-mode toggles Visual Line mode in all buffers.

Since word wrap and line truncation (described in the previous section) are contradictory, turning on visual-line-mode disables line truncation.

In Visual Line mode, some editing commands work on screen lines instead of logical lines: C-a ( beginning-of-visual-line) moves to the beginning of the screen line, C-e ( end-of-visual-line) moves to the end of the screen line, and C-k ( kill-visual-line) kills text to the end of the screen line.

To move by logical lines, use the commands M-x next-logical-line and M-x previous-logical-line. These move point to the next logical line and the previous logical line respectively, regardless of whether Visual Line mode is enabled. If you use these commands frequently, it may be convenient to assign key bindings to them. See Rebinding Keys in Your Init File.

By default, word-wrapped lines do not display fringe indicators. Visual Line mode is often used to edit files that contain many long logical lines, so having a fringe indicator for each wrapped line would be visually distracting. You can change this by customizing the variable visual-line-fringe-indicators.

By default, Emacs only breaks lines after whitespace characters. That produces incorrect results when CJK and Latin text are mixed together (because CJK characters don’t use whitespace to separate words). You can customize the option word-wrap-by-category to allow Emacs to break lines after any character with ‘ |’ category (see Categories in the Emacs Lisp Reference Manual), which provides better support for CJK characters. Also, if this variable is set using Customize, Emacs automatically loads kinsoku.el. When kinsoku.el is loaded, Emacs respects kinsoku rules when breaking lines. That means characters with the ‘ >’ category don’t appear at the beginning of a line (e.g., U+FF0C FULLWIDTH COMMA), and characters with the ‘ <’ category don’t appear at the end of a line (e.g., U+300A LEFT DOUBLE ANGLE BRACKET). You can view the category set of a character using the commands char-category-set and category-set-mnemonics, or by typing C-u C-x = with point on the character and looking at the “category” section in the report. You can add categories to a character using the command modify-category-entry.