The Raster Package ('rpck') Resource(IM:XP)

Inside Macintosh: QuickDraw GX Printing Extensions and Drivers /

Chapter 6 - Printing Resources / Printing Resources Reference

Resources Used Only in Printer Drivers

The Raster Package ('rpck') Resource
The raster package ('rpck') resource, of type gxRasterPackType, controls how bitmap data is packed into rasters for raster drivers. This resource is optional.
Figure 6-24 shows the structure of a raster package resource.
Figure 6-24 The raster package resource

The raster package resource contains the following elements:

Packaging buffer size. The number of bytes in the packing buffer. This value must be greater than or equal to the maximum number of bytes needed for one head pass on the printer.
Number of color passes. The number of color passes required by the device to print an image. This value is typically 1 (for monochrome printers) or 4 (for CMYK printers).
Height of print head. The height of the print head, in pixels.
Passes per head height. The number of head passes required to achieve the height of the print head.
Offset between passes. The offset, in pixels, between head passes.
Flags. The raster package options, which can be combined together into a single value. The constants for the raster packing options are shown in Table 6-32.
Table 6-32 Raster package options
Constant Value Explanation
gxSendAllColors 0x00000001 Send raster bands even if all clear
gxInterlaceColor 0x00000002 Interlace colors because ribbon contamination is of concern
gxOverlayColor 0x00000004 This is a color printer that does not have a ribbon contamination problem

The ID of the raster package resource must be the constant gxRasterPackID.
Listing 6-22 shows an example of a raster package resource for an ImageWriter II printer.
Listing 6-22 An example of a raster package resource
resource gxRasterPackType (gxRasterPackID, sysHeap, purgeable)
{
   2500,             /* ImageWriter packing buffer size */
   4,                /* 4 color passes */
   16,               /* print head is 16 pixels high */
   2,                /* requires 2 passes to achieve 16 pixels */
   1,                /* 1 pixel difference between passes */
   gxInterlaceColor  /* use interlace to avoid contamination */
};
This resource specifies that the ImageWriter II printer uses a packing buffer that is 2500 bytes long, which is long enough for the largest line packaged by the driver. Since the driver uses CMYK color, 4 passes are required to print an image. The print head is 16 pixels high, and it requires 2 printing passes to print 16 pixels of data.
If you use the default implementation of the GXRasterDataIn message, you must define a raster package ('rpck') resource. The GXRasterDataIn message is described on page 4-97 in the chapter "Printing Messages" in this book.

**Table 6-32 Raster package options**
Constant	Value	Explanation
gxSendAllColors	0x00000001	Send raster bands even if all clear
gxInterlaceColor	`0x00000002`	Interlace colors because ribbon contamination is of concern
gxOverlayColor	`0x00000004`	This is a color printer that does not have a ribbon contamination problem