Working With Printer Objects(IM:XP)

Inside Macintosh: QuickDraw GX Printing /: Chapter 4 - Advanced Printing Features / Using Advanced Printing Features

Working With Printer Objects
Each job object references two printer objects, a formatting printer and an output printer. A printer object is implicitly created by the GXNewJob function. There is no external application interface to create or dispose of printer objects.
Examples of how to retrieve a printer object's properties, such as the printer name, printer type, driver name, and driver type are shown in Listing 4-1 on page 4-22. The following sections show you how to obtain the view devices associated with a printer and use them to determine a printer's resolution, color space, and color profile.

Determining a Printer's Resolution
You can determine a printer's resolution from the view devices to which the printer refers. The mapping property of the view device object contains a matrix in which the scaling information is stored. Listing 4-5 shows how to obtain the highest resolution that a printer supports.
Listing 4-5 Determining a printer's resolution
void MyGetFormatDeviceResolution(gxJob whichJob, 
                                       fixed *hRes, fixed *vRes)
{
   gxPrinter      formatPrinter;
   long           numViewDevices, idx;
   gxViewDevice   printerVDev;
   gxMapping      vDevMapping;

   *hRes = 0;
   *vRes = 0;

   /*
      Get the formatting printer and the number of
      view devices for that printer.
   */
   formatPrinter = GXGetJobFormattingPrinter(whichJob);
   numViewDevices = GXCountPrinterViewDevices (formatPrinter);

   /* Loop through the view devices that this printer supports. */
   for (idx = 1; idx <= numViewDevices; idx++)
   {
      printerVDev = GXGetPrinterViewDevice(formatPrinter, idx);
      GXGetViewDeviceMapping(printerVDev, &vDevMapping);

      if ((vDevMapping.map[0][0] > *hRes) &&                                 (vDevMapping.map[1][1] > *vRes))
      {
         *hRes = vDevMapping.map[0][0];
         *vRes = vDevMapping.map[1][1];
      }
   }

   /*
      Convert scaling factors (multiples of 72 dpi) into
      resolutions.
   */
   *hRes = FixedMultiply(*hRes, ff(72));
   *vRes = FixedMultiply(*vRes, ff(72));
}
Retrieving the Color Profile and Color Space for a Printer
If you wish to retrieve the color profile for a printer, you can call the GXFindPrinterProfile function to obtain the reference to a printer's color profile object, or you can call the GXFindFormatProfile function to obtain the reference to a format's color profile object. You can set these color profiles with the GXSetPrinterProfile and GXSetFormatProfile functions, respectively. These functions are described in the reference section of this chapter, starting on page 4-84.
If you want to obtain the color profile of a printer associated with a job object, you can obtain the printer object and, with this reference, you can obtain a reference to the printer's view device. The view device's bitmap shape points to both the color set and the color profile for the printer. Listing 4-6 shows how to retrieve the color profile and color space for the formatting printer.
Listing 4-6 Retrieving the printer's color profile and color space
gxColorProfile MyGetFormattingPrinterProfile
               (MyDocumentPtr myDocument, gxColorSpace *theSpace)
{
   gxShape           deviceBitMap;
   gxBitmap          deviceBits;
   gxPrinter         formattingPrinter;
   gxColorProfile    theProfile;
   gxViewDevice      printerDevice;

   /* Get the first profile for the formatting printer. */
   formattingPrinter =
               GXGetJobFormattingPrinter(myDocument->documentJob);
   GXFindPrinterProfile(formattingPrinter, nil, 1, &theProfile);

   /*
      Look at the characteristics of the formatting printer's
      view device and retrieve the printer's color space.
   */
   printerDevice = GXGetPrinterViewDevice(formattingPrinter, 0);
   deviceBitMap = GXGetViewDeviceBitmap(printerDevice);
   GXGetBitmap(deviceBitMap, &deviceBits, nil);
   *theSpace = deviceBits.space;
   GXDisposeShape(deviceBitMap);

   return theProfile;
}
Listing 4-7 shows how the printer's color profile and color space may be used to determine if a color to be printed is in gamut and to convert the color into the printer's color space.
Listing 4-7 Using the printer's color profile to convert colors
Boolean MyMakePrinterColor(gxJob theJob,  gxColor *sourceColor,
                                          gxColor *printedColor)
{
   gxColorProfile    printerProfile;
   gxColorSpace      printerSpace;
   Boolean           inGamut;

   /* Get the printer's profile. */
   printerProfile = MyGetFormattingPrinterProfile(theJob,
                                               &printerSpace);

   /*
      Copy the source color, see if it is in gamut, and convert it
      into the device's color space.
   */
   *printedColor = *sourceColor;
   inGamut = GXCheckColor(printedColor, printerSpace, nil,
                                                printerProfile);
   GXConvertColor(printedColor, printerSpace, nil,
                                                printerProfile);
   return inGamut;
}
Note
For more information about colors, color profiles, and color spaces, see the color and color-related objects chapter of Inside Macintosh: QuickDraw GX Objects.