6.1 Creating Graphics Contexts

To create a graphics context, use create-gcontext.

Function: create-gcontext &key :arc-mode :background (:cache-p t) :cap-style :clip-mask :clip-ordering :clip-x :clip-y :dash-offset :dashes :drawable :exposures :fill-rule :fill-style :font :foreground :function :join-style :line-style :line-width :plane-mask :stipple :subwindow-mode :tile :ts-x :ts-y

:cache-p

Specifies if this graphics context should be cached locally by CLX. If nil then the state is not cached, otherwise a local cache is kept.

:drawable

The drawable whose root and depth are to be associated with this graphics context. This is a required keyword argument.

:arc-mode

:background

:cap-style

:clip-mask

:clip-ordering

:clip-x

:clip-y

:dash-offset

:dashes

:exposures

:fill-rule

:fill-style

:font

:foreground

:function

:join-style

:line-style

:line-width

:plane-mask

:stipple

:subwindow-mode

:tile

:ts-x

:ts-y

Initial attribute values for the graphics context.

Creates, initializes, and returns a graphics context (gcontext). The graphics context can only be used with destination drawables having the same root and depth as the specified :drawable. If :cache-p is non-nil, the graphics context state is cached locally, and changing a component has no effect unless the new value differs from the cached value. Changes to a graphics context (setf and with-gcontext) are always deferred regardless of the cache mode and sent to the server only when required by a local operation or by an explicit call to force-gcontext-changes.

All of the graphics context components are set to the values that are specified by the keyword arguments, except that a value of nil causes the default value to be used. These default values are as follows:

arc-mode	:pie-slice
background	1
cap-style	:butt
clip-mask	:none
clip-ordering	:unsorted
clip-x	0
clip-y	0
dash-offset	0
dashes	4 (that is, the list ’(4, 4))
exposures	:on
fill-rule	:even-odd
fill-style	:solid
font	server dependent
foreground	0
function	boole-1
join-style	:miter
line-style	:solid
line-width	0
plane-mask	A bit mask of all ones
stipple	Pixmap of unspecified size filled with ones
subwindow-mode	:clip-by-children
tile	Pixmap of an unspecified size filled with the foreground pixel (that is, the client-specified pixel if any, or else 0)
ts-x	0
ts-y	0

Note that foreground and background do not default to any values that are likely to be useful on a color display. Since specifying a nil value means use the default, this implies for clip-mask that an empty rectangle sequence cannot be specified as an empty list; :none must be used instead. Specifying a stringable for font causes an implicit open-font call to occur.

gcontext

Type gcontext.