Inside Macintosh: QuickDraw GX Printing Extensions and Drivers /

Chapter 6 - Printing Resources / Printing Resources Reference

Resources Used Only for Printing Extensions

The Extension Optimization ('eopt') Resource

The extension optimization resource, of type gxExtensionOptimizationType, provides QuickDraw GX with additional information about the activities of an extension. The information in this resource allows QuickDraw GX to optimize its use. You must include an extension optimization resource in each printing extension. Figure 6-8 shows the structure of an extension optimization resource.

Figure 6-8 The extension optimization resource

• Optimization flag. The flags that define when your extension needs to be loaded into memory. Each extension optimization resource contains one or more optimization flags. The constants for these flags are shown in Table 6-11. The flags actually come in pairs: one that specifies that an extension needs to be activated during a certain phase of printing, and a complementary one that specifies that the extension does not need to be active during that phase. QuickDraw GX defines each flag as a Boolean value.

  Table 6-11 Extension optimization resource flags

  Constant	Value	Explanation
  gxExecuteDuringImaging	true	Use if your extension overrides any messages that are sent during the imaging phase of printing.
  gxDontExecuteDuringImaging	false	Use if your extension only overrides messages that are sent for working with dialog boxes or during the spooling phase of printing.
  gxNeedDeviceStatus	true	Use if your extension performs any form of two-way communications with the device. This applies mostly to extensions driving add-on devices.
  gxDontNeedDeviceStatus	false	Use if your extension does not need to perform two-way communications.
  gxChangePageAtGXDespoolPage	true	Use if your extension changes the contents of a page during processing of an override for the GXDespoolPage message.
  gxDontChangePageAtGXDespoolPage	false	Use if your extension does not change the contents of a page during processing of the GXDespoolPage message.
  gxChangePageAtGXImagePage	true	Use if your extension changes the contents of a page during processing of an override for the GXImagePage message.
  gxDontChangePageAtGXImagePage	false	Use if your extension does not change the contents of a page during processing of the GXImagePage message.
  gxChangePageAtGXRenderPage	true	Use if your extension changes the contents of a page during processing of an override for the GXRenderPage message.
  gxDontChangePageAtGXRenderPage	false	Use if your extension does not change the contents of a page during processing of the GXRenderPage message.
  gxServerPresenceRequired	true	Use if your extension must be available on the print server's system.
  gxNotServerPresenceRequired	false	Use if your extension does not have to be available on the print server's system.
  gxClientPresenceRequired	true	Use if your extension must be available on the user's system.
  gxNotClientPresenceRequired	false	Use if your extension does not have to be available on the user's system.

IMPORTANT

You need to be careful about setting these flags appropriately. Unnecessarily setting these flags can cause performance degradation during printing to certain devices.

The extension optimization resource ID needs to be the constant gxExtensionOptimizationID. Listing 6-7 shows an example of an extension optimization resource. You can also find an example of an extension optimization resource definition in Listing 2-23 on page 2-37 in the chapter "Printing Extensions."

Listing 6-7 An example of an extension optimization resource

resource gxExtensionOptimizationType (gxExtensionOptimizationID,
                                           sysHeap, purgeable)
{
   gxDontExecuteDuringImaging,
   gxDontNeedDeviceStatus,
   gxChangePageAtGXDespoolPage,
   gxDontChangePageAtGXImagePage,
   gxDontChangePageAtGXRenderPage,
   gxNotServerPresenceRequired,
   gxClientPresenceRequired
};

This example specifies that the extension does not have to be available during the imaging phase of printing, does not need to perform two-way communications, and
only changes the page during the despooling process of the imaging phase of printing. This extension does not need to be present on the server, but must be present on the client machine.

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