Inside Macintosh: QuickDraw GX Objects /

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

View Port Functions / Manipulating View Port Object Properties

GXSetViewPortMapping

You can use the GXSetViewPortMapping function to assign a mapping to a view port object.

void GXSetViewPortMapping(gxViewPort target, 
                           const gxMapping *map);

target

A reference to the view port object you want to assign the mapping to.

map

A pointer to a mapping structure containing the mapping matrix to assign to the target view port.

DESCRIPTION

The GXSetViewPortMapping function copies information from the mapping structure pointed to by the map parameter into the mapping property of the target view port.

You can specify nil for the map parameter, in which case this function sets the mapping property of the target view port as follows:

• If the clip shape is a full shape, which specifies no clipping, the function sets the mapping property to the identity mapping.
• If a clip exists, the function sets the mapping's translation component to the upper-left corner of the clip. It sets the other components of the mapping to identity.

You can provide arbitrary values for the elements of the mapping structure pointed to by the map parameter, with one exception: the lower-right element of the matrix (element [2][2]) may not be 0.

ERRORS, WARNINGS, AND NOTICES

Errors
invalid_viewPort_reference
viewPort_is_a_window	(debugging version)

SEE ALSO

For examples of the use of this function, see Listing 7-3 on page 7-45 and Listing 7-5 on page 7-47.

To get a view port's mapping, use the GXGetViewPortMapping function, described in the previous section.

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