Legacy Document

Inside Macintosh: QuickDraw GX Environment and Utilities /

Chapter 8 - QuickDraw GX Mathematics / QuickDraw GX Mathematics Reference

Mapping Functions / Manipulating and Applying Mappings

MapMapping

You can use the MapMapping function to concatenate two mappings.

gxMapping *MapMapping(gxMapping *target, const gxMapping *source);

target

A pointer to the mapping to be modified. On return, contains the result of the concatenation.

source

A pointer to the mapping to be concatenated with the target mapping.

function result

A pointer to the resultant mapping, which is also the target mapping.

DESCRIPTION

The MapMapping function postmultiplies the target mapping by the source mapping, and returns the result in the target parameter.

The result of passing the function result of MapMapping tothe GXMapShape function is equivalent to passing the result of one call to GXMapShape to another call to GXMapShape, as shown below (for the shape s):

GXMapShape(s, target);
GXMapShape(s, source);

The same results would be obtained more efficiently and perhaps more accurately by making these calls:

MapMapping(target, source);
GXMapShape(s, target);

ERRORS, WARNINGS, AND NOTICES

Errors

mapping_is_nil

SEE ALSO

The GXMapShape function is described in the chapter Transform Objects in Inside Macintosh: QuickDraw GX Objects.