Inside Macintosh: QuickDraw GX Objects /

Chapter 7 - View-Related Objects / View-Related Objects Reference

View Device Functions / Manipulating View Device Object Properties

GXGetViewDeviceMapping

You can use the GXGetViewDeviceMapping function to examine the mapping property of a view device object.

gxMapping *GXGetViewDeviceMapping(gxViewDevice source, 
                                 gxMapping *map);

source

A reference to the view device whose mapping you wish to examine.

map

A pointer to a mapping structure. On return, the structure contains a copy of the mapping matrix of the source view device.

function result

A pointer to the mapping matrix of the source view device. (This value is the same as the value returned in the map parameter.)

DESCRIPTION

The GXGetViewDeviceMapping function copies the mapping matrix information from the mapping property of the source view device object into the mapping structure pointed to by the map parameter. The function also returns as its function result a pointer to this mapping structure.

To make changes to the source view device's mapping property, you can alter the information returned by this function, and then use the GXSetViewDeviceMapping function to reassign the altered mapping to the source view device.

ERRORS, WARNINGS, AND NOTICES

Errors
invalid_viewDevice_reference
parameter_is_nil	(debugging version)

SEE ALSO

For an example of the use of this function, see Listing 7-11 on page 7-57.

To set a view device's mapping, use the GXSetViewDeviceMapping function, described next.

For information about the gxMapping structure, see the mathematics chapter of Inside Macintosh: QuickDraw GX Environment and Utilities.