<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <title>Calibration Format File (.cal)</title> <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1"> <meta name="author" content="Graeme Gill"> </head> <body> <h2>Description of the .cal format</h2> Device calibration information. This is ASCII text, <a href="File_Formats.html#CGATS">CGATS</a>, Argyll specific format, used to hold a description of device setup information that brings it to a desired calibration state. Currently only display output curves are defined. Created by <a href="dispcal.html">dispcal</a>.<br> <br> While fully compatible with the CGATS.5 Data Exchange Format, the particular required keywords and fields are unique to Argyll, hence an Argyll specific file identifier <span style="font-weight: bold;">CAL</span> is used to avoid confusion with standard ANSI or CGATS files.<br> <br> The <span style="font-weight: bold;">.cal</span> format changes from time to time with new releases, to add new functionality, but generally retains backwards compatibility. Note that in the description below, the word "may" indicates an optional component, while the word "shall" indicates a necessary component.<br> <br> Generally a .cal file contains only one table, the table containing the setup information. <br> <br> <br> The table contains the following:<br> <br> The file identifier (First 7 characters) shall be <span style="font-weight: bold;">CAL</span>.<br> <br> A <span style="font-weight: bold;">#</span> character introduces a comment.<br> <br> <span style="font-weight: bold;"><span style="font-weight: bold;"><span style="font-weight: bold;"></span></span></span>There may be <span style="font-weight: bold;">DESCRIPTOR</span>, <span style="font-weight: bold;">ORIGINATOR</span>, or <span style="font-weight: bold;">CREATED</span> keywords and values (as per CGATS).<br> <br> There shall be a <span style="font-weight: bold;">DEVICE_CLASS</span> keyword that has a value of <span style="font-weight: bold;">"OUTPUT</span>", "<span style="font-weight: bold;">DISPLAY</span>" or <span style="font-weight: bold;">"INPUT"</span>.<br> This indicates what type of device the calibration information is suitable for.<br> <br> The <span style="font-weight: bold;">NUMBER_OF_FIELDS</span> keyword shall have a value that indicates the number of fields in each data set, e.g. <span style="font-weight: bold;">4</span> (as per CGATS).<br> <br> The start of the declaration of the fields shall be marked by the <span style="font-weight: bold;">BEGIN_DATA_FORMAT</span> keyword (as per CGATS).<br> <br> For a <span style="font-weight: bold;">DISPLAY</span> device, the following fields shall be used:<br> <br> <span style="font-weight: bold;">RGB_I</span> index of the RAMDAC entry.<br> <span style="font-weight: bold;">RGB_R</span> RAMDAC Red value for that entry.<br> <span style="font-weight: bold;">RGB_G</span> RAMDAC Green value for that entry.<br> <span style="font-weight: bold;">RGB_B</span> RAMDAC Blue value for that entry.<br> <br> The definition of the fields shall be terminated by the <span style="font-weight: bold;">END_DATA_FORMAT</span> keyword (as per CGATS).<br> <br> The <span style="font-weight: bold;">NUMBER_OF_SETS</span> keyword shall have a value that indicates the number of sets of data, e.g. <span style="font-weight: bold;">256</span> (as per CGATS).<br> <br> The start of the values of the data sets shall be marked by the <span style="font-weight: bold;">BEGIN_DATA</span> keyword (as per CGATS).<br> <br> Each set of data shall be on one line, and shall be separated by white space. All values shall be normalized to lie between 0.0 and 1.0.<br> <br> The end of the values of the data sets shall be marked by the <span style="font-weight: bold;">END_DATA</span> keyword (as per CGATS).<br> <br> Generally any other keywords and values will be ignored.<br> <br> <br> </body> </html>
