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Inside Macintosh: Advanced Color Imaging Reference /

Chapter 3 - ColorSync Manager Reference for Applications and Device Drivers / Constants and Data Types

PostScript CRD Virtual Memory Size Tag Structure

To specify the maximum virtual memory (VM) size of the color rendering dictionary (CRD) for a specific rendering intent for a particular PostScript\x89 Level 2 printer type, a printer profile can include the Apple-defined 'psvm' optional tag. This tag's element data includes an array containing one entry for each rendering intent and its virtual memory size.

If a PostScript printer profile includes this tag, the Apple CMM uses the tag and returns the values specified by the tag when your application or device driver calls the CMGetPS2ColorRenderingVMSize function (page 3-163).

If a PostScript printer profile does not include this tag, the CMM uses an algorithm to determine the VM size of the CRD. This may result in a size that is greater than the actual VM size.

The CMIntentCRDVMSize data type defines the rendering intent and its maximum VM size. The CMPS2CRDVMSizeType data type for the tag includes an array containing one or more members of type CMIntentCRDVMSize.

struct CMIntentCRDVMSize {
   long        renderingIntent;/* rendering intent value */
   unsigned long VMSize;      /* virtual memory size of CRD */
};

Field Description

renderingIntent

The rendering intent whose CRD virtual memory size you want to obtain. The following rendering intent values are described in "Rendering Intent Values for Version 2.x Profiles" (page 3-35):

0 (cmPerceptual)
1 (cmRelativeColorimetric )
2 (cmSaturation)
3 (cmAbsoluteColorimetric)

VMSize

The virtual memory size of the CRD for the rendering intent specified for the renderingIntent field.

The CMPS2CRDVMSizeType data type defines the Apple-defined 'psvm' optional tag.

struct CMPS2CRDVMSizeType {
   OSType         typeDescriptor; /* PostScript VM signature */
   unsigned long  reserved;   /* reserved */
   unsigned long  count;      /* entries in CRD array */
   CMIntentCRDVMSizeintentCRD[1];/* variable-sized array */
};

Field Description

typeDescriptor

The 'psvm' tag signature.

reserved

Reserved for future use.

count

The number of entries in the intentCRD array. You should specify at least four entries: 0, 1, 2, and 3.

intentCRD

A variable-sized array of four or more members defined by the CMIntentCRDVMSize data type.