Inside Macintosh: QuickDraw GX Objects /

Chapter 6 - Transform Objects / Transform Objects Reference

Functions / Transforming Shapes by Modifying Shape Geometries

GXMapShape

You can use the GXMapShape function to apply an arbitrary mapping matrix to a shape.

void GXMapShape(gxShape target, const gxMapping *map);

target

A reference to the shape you want to apply the mapping to.

map

A pointer to a mapping structure containing the matrix you want to apply to the target shape.

DESCRIPTION

The GXMapShape function applies to the target shape the mapping transformations represented by the mapping matrix pointed to by the map parameter.

This function applies the mapping in one of two ways:

• If the target shape's gxMapTransformShape attribute is cleared, the function applies the mapping matrix directly to the points of the shape's geometry.
• If the target shape's gxMapTransformShape attribute is set, this function is identical to the GXMapTransform function; it concatenates the target shape's transform mapping with the mapping matrix pointed to by the map parameter. If the target shape shares its transform object with other shapes, QuickDraw GX makes a copy of the transform object, associates the copy with the target shape, and makes changes to the copy.

The target shape can be any shape type. However, if the target shape is an empty
shape, a full shape, or a picture shape, this function has no effect unless the shape's gxMapTransformShape attribute is set.

ERRORS, WARNINGS, AND NOTICES

Errors
out_of_memory
shape_is_nil
shape_access_not_allowed	(debugging version)
Warnings
map_shape_out_of_range
graphic_type_cannot_be_moved
Notices (debugging version)
mapping_unaffected

SEE ALSO

To apply a mapping matrix to the mapping property of a transform object, you can also use the GXMapTransform function, described on page 6-64.