16.3.3 Glyphs and Glyphsets

A glyph in XRENDER is an alpha mask and an associated orgin, advancement and numeric id. The application refers to them by the numeric id.

Glyphs are stored in a glyph-set. The client is responsible for making sure the glyphs it uses are stored in the glyph-set, or there will be a Glyph-error.

Function: render-create-glyph-set format &key glyph-set

format

A picture-format for the alpha masks that this font will use.

glyph-set

An optional glyph-set object to initialize with a server side glyphset resource.

Creates an initially empty glyph-set for the client to use. Format must be a Direct format. When it contains RGB values, the glyphs are composited using component-alpha True, otherwise they are composited using component-alpha False.

Function: render-reference-glyph-set existing-glyph-set &key glyph-set

existing-glyph-set

An existing glyph-set

glyph-set

An optional glyph-set, just like in render-create-glyph-set

Creates a new id refering to the existing-glyph-set. The glyph-set itself will not be freed until all ids has been removed.

Function: render-free-glyph-set glyph-set

glyph-set

A glyphset resource to free

Removes an id to a glyph-set. When all ids have been removed the glyph-set itself is removed.

Function: render-add-glyph glyph-set id &key x-origin y-origin x-advance y-advance data

glyph-set

A glyph-set

id

card32

x-orgin

int16

y-orgin

int16

x-advance

int16

y-advance

int16

data

An array of card8 bytes.

Associates id with the given description of a glyph. An existing glyph with the same id is replaced.

At the time of writing, only 8bit alpha masks are supported. Experimentation with glyph-sets in other pict-formats needed.

Function: render-add-glyph-from-picture glyph-set picture &key x-origin y-origin x-advance y-advance width height

glyph-set

glyph-set

picture

picture

x-origin

int16

y-origin

int16

x-advance

int16

y-advance

int16

x

int16

y

int16

width

card16

height

card16

This request add a glyph to glyph-set by copying it from the x,y location in the picture.

Existing glyphs with the same names are replaced. The source picture may be in a different picture-format than glyph-set, in which case the images are converted to the glyph-set’s format.

Function: render-free-glyphs glyph-set glyphs

glyph-set

A glyph-set

glyphs

sequence of card32

This request removes glyphs from glyph-set. Each glyph must exist in glyph-set (else a Match error results).