Page 49 Table of Contents Index Page 51
Chapters
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
A, B, C, D, E


CHAPTER 7. PROPERTIES OF SHEETS

This function returns fresh objects that may be modified.

7.2.2 Sheet Genealogy Classes

Different "mixin" classes are provided that implement the relationship protocol.

=> sheet-parent-mixin [Class]
This class is mixed into sheet classes that have a parent.

=> sheet-leaf-mixin [Class]
This class is mixed into sheet classes that will never have children.

=> sheet-single-child-mixin [Class]
This class is mixed into sheet classes that have at most a single child.

=> sheet-multiple-child-mixin [Class]
This class is mixed into sheet classes that may have zero or more children.

7.3 Sheet Geometry

Every sheet has a region and a coordinate system. A sheet's region refers to its position and
extent on the display device, and is represented by some sort of a region object, frequently
a rectangle. A sheet's coordinate system is represented by a coordinate transformation that
converts coordinates in its coordinate system to coordinates in its parent's coordinate system.

7.3.1 Sheet Geometry Functions

=> sheet-transformation sheet [Generic Function]
=> (setf sheet-transformation) transformation sheet [Generic Function]
Returns a transformation that converts coordinates in the sheet sheet's coordinate system into
coordinates in its parent's coordinate system. Using setf on this accessor will modify the sheet's
coordinate system, including moving its region in its parent's coordinate system.

When the sheet's transformation is changed, note-sheet-region-changed is called to notify
the sheet of the change.

=> sheet-region sheet [Generic Function]
=> (setf sheet-region) region sheet [Generic Function]
Returns a region object that represents the set of points to which the sheet sheet refers. The

Page 49 Table of Contents Index Page 51
Chapters
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
A, B, C, D, E