diff options
Diffstat (limited to 'lisp/composite.el')
| -rw-r--r-- | lisp/composite.el | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/lisp/composite.el b/lisp/composite.el index ce34336cede..77eea9cb4ec 100644 --- a/lisp/composite.el +++ b/lisp/composite.el @@ -185,8 +185,17 @@ RULE is a cons of global and new reference point symbols (defun compose-region (start end &optional components modification-func) "Compose characters in the current region. -Characters are composed relatively, i.e. composed by overstricking or -stacking depending on ascent, descent and other properties. +Characters are composed relatively, i.e. composed by overstriking +or stacking depending on ascent, descent and other metrics of +glyphs. + +For instance, if the region has three characters \"XYZ\", X is +regarded as BASE glyph, and Y is displayed: + (1) above BASE if Y's descent value is not positive + (2) below BASE if Y's ascent value is not positive + (3) on BASE (i.e. at the BASE position) otherwise +and Z is displayed with the same rule while regarding the whole +XY glyphs as BASE. When called from a program, expects these four arguments. |