A color is represented by a CLX color object, in which each of the red,
green, and blue values is specified by an
rgb-val
-- a floating point number between 0.0 and 1.0. (see
paragrpah
1.6, Data Types). The value 0.0
represents the minimum intensity, while 1.0 represents the maximum
intensity. CLX automatically converts
rgb-val
values into 16-bit integers when sending colors to an X server. The X
server, in turn, scales 16-bit color values to match the actual
intensity range supported by the screen.
Colors used on :gray-scale screens must have the same value for
each of red, green, and blue. Only one of these values is used by screen
hardware to determine intensity; however, CLX does not define which of
red, green, or blue is actually used.
The following paragraphs describe the CLX functions used to create,
access, and modify colors.
make-color |
&key
(:blue 1.0) (:green 1.0)
(:red 1.0) &allow-other-keys |
Function |
|
-
:blue, :green, :red
-
rgb-val
values that specify the saturation for each primary.
Creates, initializes, and returns a new
color
object with the specified values for red, green, and blue.
-
color
-
Type
color.
|
color-blue |
color |
Function |
|
-
color
-
A
color object.
Returns and (with setf) sets the value for blue in the
color.
-
blue-intensity
-
Type
rgb-val.
|
color-green |
color |
Function |
|
-
color
-
A
color object.
Returns and (with setf) sets the value for green in the
color.
-
green-intensity
-
Type
rgb-val.
|
|
Returns non-nil if the argument is a
color
object and nil otherwise.
-
color-p
-
Type
boolean.
|
|
-
color
-
A
color object.
Returns and (with setf) sets the value for red in the
color.
-
red-intensity
-
Type
rgb-val.
|
|
-
color
-
A
color object.
Returns the values for red, green, and blue in the color.
-
red, green, blue
-
Type
rgb-val.
|