📄 prototype-gamut-compression.html
字号:
<HTML><HEAD><TITLE>Xlib Programming Manual: Prototype Gamut Compression Procedure</TITLE></HEAD><BODY><H1 ALIGN=center>6.10.1 Prototype Gamut Compression Procedure</H1>The gamut compression callback interface must adhere to thefollowing:<!.IN "XcmsCompressionProc" "" "@DEF@"><CODE><PRE>typedef <B><A HREF="../conversion-contexts-and-gamut-mapping.html#cmsStatus">Status</A></B> (*XcmsCompressionProc)(<B>ccc</B>, <B>colors_in_out</B>, <B>ncolors</B>, <B>index</B>, <B>compression_flags_return</B>) <A HREF="../CCC/macros.html">XcmsCCC</A> <B>ccc</B>; <A HREF="../structures.html#XcmsColor">XcmsColor</A> <B>colors_in_out[]</B>; unsigned int <B>ncolors</B>; unsigned int <B>index</B>; Bool <B>compression_flags_return[]</B>;</PRE></CODE><TABLE><TR><TD> <B>ccc</B><TD> Specifies the <A HREF="../conversion-contexts-and-gamut-mapping.html">CCC</A>.<TR><TD> <B>colors_in_out</B><TD> Specifies an array of color specifications.Pixel members should be ignored and must remain unchanged upon return.<TR><TD> <B>ncolors</B><TD> Specifies the number of <A HREF="../structures.html#XcmsColor">XcmsColor</A>structures in the color specification array.<TR><TD> <B>index</B><TD> Specifies the index into the array of<A HREF="../structures.html#XcmsColor">XcmsColor</A>structures for the encountered color specification that lies outside the screen's color gamut.Valid values are 0 (for the first element) to ncolors - 1.<TR><TD> <B>compression_flags_return</B><TD> Returns an array of Boolean values for indicating compression status.If a non-NULL pointer is suppliedand a color at a given index is compressed, then<B>True</B>should be stored at the corresponding index in this array;otherwise, the array should not be modified.</TABLE>When implementing a gamut compression procedure, consider the followingrules and assumptions:<UL><P><LI>The gamut compression procedure can attempt to compress one or multiplespecifications at a time.<P><LI>When called, elements 0 to index - 1 in the color specificationarray can be assumed to fall within the screen's color gamut.In addition, these color specifications are already in some device-dependentformat (typically<B>XcmsRGBi</B>).If any modifications are made to these color specifications,they must be in their initial device-dependent format upon return.<P><LI>When called, the element in the color specification array specifiedby the index argument contains the color specification outside the screen's color gamut encountered by the calling routine.In addition, this color specification can be assumed to be in<B>XcmsCIEXYZ</B>.Upon return, this color specification must be in<B>XcmsCIEXYZ</B>.<P><LI>When called, elements from index to ncolors - 1 in the color specification array may or may not fall within thescreen's color gamut.In addition, these color specifications can be assumed to be in<B>XcmsCIEXYZ</B>.If any modifications are made to these color specifications, they must be in<B>XcmsCIEXYZ</B>upon return.<P><LI>The color specifications passed to the gamut compression procedurehave already been adjusted to the Screen White Point.This means that at this point the color specification's white pointis the Screen White Point.<P><LI>If the gamut compression procedure uses a device-independent color space notinitially accessible for use in the color management system, use <B><A HREF="../management-extensions/XcmsAddColorSpace.html">XcmsAddColorSpace()</A></B>to insure that it is added.</UL><H5 ALIGN=right><I>Next: <A HREF="supplied-gamut-compression.html">Supplied Gamut Compression Procedures</A></I></H5><HR><ADDRESS><A HREF="http://tronche.com/">Christophe Tronche</A>, <A HREF="mailto:ch.tronche@computer.org">ch.tronche@computer.org</A></ADDRESS></BODY></HTML>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -