#!F-adobe-helvetica-medium-r-normal--18* #!N #!N #!Rdlacoop Delayed Colors and Opacities (Color and Opacity Lookup Tables) #!N Delayed colors are a way of compactly storing color and opacity information. By default, whenever you use one of the coloring modules (AutoColor, AutoGrayScale, Color), the colors and opacities are stored one-per-data value as a floating point RGB 3-vector or floating point value, respectively, ranging from 0 to 1. However, if you have unsigned byte data, then it is much more efficient to use "delayed colors" and "delayed opacities." When you use delayed colors or opacities, the "colors" or "opacities" component is simply a copy of (actually a reference to) the "data" component. When rendering occurs, these components are interpreted as indices with which to look up a color or opacity value in a table. #!N #!N If you specify the #!F-adobe-times-bold-r-normal--18* delayed #!EF parameter as 1 to any of the coloring modules, they will automatically perform this "copy" of the "data" component, and will attach a "color map" or "opacity map" component which contains 256 RGB colors, or 256 opacities. If you already have a color or opacity map, either imported or created using the Colormap Editor, and wish to use delayed colors or delayed opacities, you can pass your color map or opacity map to the Color module as the #!F-adobe-times-bold-r-normal--18* color #!EF or #!F-adobe-times-bold-r-normal--18* opacity #!EF parameter, and set the #!F-adobe-times-bold-r-normal--18* delayed #!EF parameter to Color as 1. #!N #!N The structure of a color map or opacity map is described in #!Lcolor,dxall792 h Color #!EL . The Colormap Editor produces as its two outputs well-formed color maps and opacity maps. Alternatively, if you already have a simple list of 3-vectors or list of scalar values, and want to create a color map or opacity map, you can do this using Construct. The first parameter to Construct should be [0], the second should be [1], and the third should be 256. This will create a "positions" component with positions from 0 to 255. The last parameter to Construct should be your list of 256 colors or opacities. #!N #!N If you are reading a stored image using ReadImage, and the image is stored with a colormap, you can specify that the image should be stored internally in Data Explorer with delayed colors by using the #!F-adobe-times-bold-r-normal--18* delayed #!EF parameter to ReadImage. #!N #!N You can also convert an image (or object) to a delayed colors version by using QuantizeImage. #!N #!N #!N #!F-adobe-times-medium-i-normal--18* Next Topic #!EF #!N #!N #!Ludcmps,dxall813 h Using Direct Color Maps #!EL #!N #!F-adobe-times-medium-i-normal--18* #!N
Generated by dwww version 1.15 on Sat Jun 22 13:00:29 CEST 2024.