diff options
Diffstat (limited to 'color.txi')
-rw-r--r-- | color.txi | 31 |
1 files changed, 27 insertions, 4 deletions
@@ -5,8 +5,8 @@ The @dfn{tristimulus} color spaces are those whose component values @cindex tristimulus are proportional measurements of light intensity. The CIEXYZ(1931) -system provides 3 sets of spectra to convolve with a spectrum of -interest. The result of those convolutions is coordinates in CIEXYZ +system provides 3 sets of spectra to dot-product with a spectrum of +interest. The result of those dot-products is coordinates in CIEXYZ space. All tristimuls color spaces are related to CIEXYZ by linear transforms, namely matrix multiplication. Of the color spaces listed here, CIEXYZ and RGB709 are tristimulus spaces. @@ -16,7 +16,7 @@ The CIEXYZ color space covers the full @dfn{gamut}. @cindex gamut It is the basis for color-space conversions. -CIEXYZ is a list of three inexact numbers between 0 and 1.1. +CIEXYZ is a list of three inexact numbers between 0.0 and 1.1. '(0. 0. 0.) is black; '(1. 1. 1.) is white. @end deftp @@ -27,6 +27,7 @@ CIEXYZ is a list of three inexact numbers between 0 and 1.1. then @code{ciexyz->color} returns the color specified by @var{xyz}; otherwise returns #f. @end defun + @defun color:ciexyz x y z Returns the CIEXYZ color composed of @var{x}, @var{y}, @var{z}. If the @@ -34,9 +35,11 @@ coordinates do not encode a valid CIEXYZ color, then an error is signaled. @end defun + @defun color->ciexyz color Returns the list of 3 numbers encoding @var{color} in CIEXYZ. @end defun + @deftp {Color Space} RGB709 BT.709-4 (03/00) @cite{Parameter values for the HDTV standards for production and international programme exchange} specifies parameter @@ -44,7 +47,7 @@ values for chromaticity, sampling, signal format, frame rates, etc., of high definition television signals. An RGB709 color is represented by a list of three inexact numbers -between 0 and 1. '(0. 0. 0.) is black '(1. 1. 1.) is white. +between 0.0 and 1.0. '(0. 0. 0.) is black '(1. 1. 1.) is white. @end deftp @@ -54,6 +57,7 @@ between 0 and 1. '(0. 0. 0.) is black '(1. 1. 1.) is white. then @code{rgb709->color} returns the color specified by @var{rgb}; otherwise returns #f. @end defun + @defun color:rgb709 r g b Returns the RGB709 color composed of @var{r}, @var{g}, @var{b}. If the @@ -61,9 +65,11 @@ coordinates do not encode a valid RGB709 color, then an error is signaled. @end defun + @defun color->rgb709 color Returns the list of 3 numbers encoding @var{color} in RGB709. @end defun + @subsubheading Perceptual Uniformity @noindent @@ -97,6 +103,7 @@ perception of color. It is a list of three numbers: then @code{l*a*b*->color} returns the color specified by @var{L*a*b*}; otherwise returns #f. @end defun + @defun color:l*a*b* L* a* b* white-point Returns the L*a*b* color composed of @var{L*}, @var{a*}, @var{b*} with @var{white-point}. @@ -106,6 +113,7 @@ Returns the L*a*b* color composed of @var{L*}, @var{a*}, @var{b*}. If the coord do not encode a valid L*a*b* color, then an error is signaled. @end defun + @defun color->l*a*b* color white-point Returns the list of 3 numbers encoding @var{color} in L*a*b* with @var{white-point}. @@ -113,6 +121,7 @@ Returns the list of 3 numbers encoding @var{color} in L*a*b* with @var{white-poi @defunx color->l*a*b* color Returns the list of 3 numbers encoding @var{color} in L*a*b*. @end defun + @deftp {Color Space} L*u*v* Is another CIE encoding designed to better match the human visual system's perception of color. @@ -125,6 +134,7 @@ system's perception of color. then @code{l*u*v*->color} returns the color specified by @var{L*u*v*}; otherwise returns #f. @end defun + @defun color:l*u*v* L* u* v* white-point Returns the L*u*v* color composed of @var{L*}, @var{u*}, @var{v*} with @var{white-point}. @@ -134,6 +144,7 @@ Returns the L*u*v* color composed of @var{L*}, @var{u*}, @var{v*}. If the coord do not encode a valid L*u*v* color, then an error is signaled. @end defun + @defun color->l*u*v* color white-point Returns the list of 3 numbers encoding @var{color} in L*u*v* with @var{white-point}. @@ -141,6 +152,7 @@ Returns the list of 3 numbers encoding @var{color} in L*u*v* with @var{white-poi @defunx color->l*u*v* color Returns the list of 3 numbers encoding @var{color} in L*u*v*. @end defun + @subsubheading Cylindrical Coordinates @noindent @@ -190,6 +202,7 @@ The colors by quadrant of h are: then @code{l*c*h->color} returns the color specified by @var{L*C*h}; otherwise returns #f. @end defun + @defun color:l*c*h L* C* h white-point Returns the L*C*h color composed of @var{L*}, @var{C*}, @var{h} with @var{white-point}. @@ -199,6 +212,7 @@ Returns the L*C*h color composed of @var{L*}, @var{C*}, @var{h}. If the coordin do not encode a valid L*C*h color, then an error is signaled. @end defun + @defun color->l*c*h color white-point Returns the list of 3 numbers encoding @var{color} in L*C*h with @var{white-point}. @@ -206,6 +220,7 @@ Returns the list of 3 numbers encoding @var{color} in L*C*h with @var{white-poin @defunx color->l*c*h color Returns the list of 3 numbers encoding @var{color} in L*C*h. @end defun + @subsubheading Digital Color Spaces @noindent @@ -251,12 +266,14 @@ should work very well with sRGB. then @code{srgb->color} returns the color specified by @var{rgb}; otherwise returns #f. @end defun + @defun color:srgb r g b Returns the sRGB color composed of @var{r}, @var{g}, @var{b}. If the coordinates do not encode a valid sRGB color, then an error is signaled. @end defun + @deftp {Color Space} xRGB Represents the equivalent sRGB color with a single 24-bit integer. The most significant 8 bits encode red, the middle 8 bits blue, and the @@ -269,14 +286,17 @@ least significant 8 bits green. Returns the list of 3 integers encoding @var{color} in sRGB. @end defun + @defun color->xrgb color Returns the 24-bit integer encoding @var{color} in sRGB. @end defun + @defun xrgb->color k Returns the sRGB color composed of the 24-bit integer @var{k}. @end defun + @deftp {Color Space} e-sRGB Is "Photography - Electronic still picture imaging - Extended sRGB color encoding" (PIMA 7667:2001). It extends the gamut of sRGB; and its @@ -302,6 +322,7 @@ numbers. If @var{rgb} is valid e-sRGB coordinates, then @code{e-srgb->color} re specified by @var{rgb}; otherwise returns #f. @end defun + @defun color:e-srgb 10 r g b Returns the e-sRGB10 color composed of integers @var{r}, @var{g}, @var{b}. @@ -315,6 +336,7 @@ If the coordinates do not encode a valid e-sRGB color, then an error is signaled. @end defun + @defun color->e-srgb precision color @var{precision} must be the integer 10, 12, or 16. @code{color->e-srgb} returns the list of 3 integers encoding @var{color} in sRGB10, sRGB12, or sRGB16. @@ -343,3 +365,4 @@ integers encoding @var{color} in sRGB10, sRGB12, or sRGB16. + |