Java Doc for Area.java in  » 6.0-JDK-Core » AWT » java » awt » geom » Java Source Code / Java DocumentationJava Source Code and Java Documentation

The Area class implements the Shape interface and provides full support for all of its hit-testing and path iteration facilities, but an Area is more specific than a generalized path in a number of ways:

• Only closed paths and sub-paths are stored. Area objects constructed from unclosed paths are implicitly closed during construction as if those paths had been filled by the Graphics2D.fill method.
• The interiors of the individual stored sub-paths are all non-empty and non-overlapping. Paths are decomposed during construction into separate component non-overlapping parts, empty pieces of the path are discarded, and then these non-empty and non-overlapping properties are maintained through all subsequent CAG operations. Outlines of different component sub-paths may touch each other, as long as they do not cross so that their enclosed areas overlap.
• The geometry of the path describing the outline of the Area resembles the path from which it was constructed only in that it describes the same enclosed 2-dimensional area, but may use entirely different types and ordering of the path segments to do so.

• Creating an Area from an unclosed (open) Shape results in a closed outline in the Area object.
• Creating an Area from a Shape which encloses no area (even when "closed") produces an empty Area. A common example of this issue is that producing an Area from a line will be empty since the line encloses no area. An empty Area will iterate no geometry in its PathIterator objects.
• A self-intersecting Shape may be split into two (or more) sub-paths each enclosing one of the non-intersecting portions of the original path.
• An Area may take more path segments to describe the same geometry even when the original outline is simple and obvious. The analysis that the Area class must perform on the path may not reflect the same concepts of "simple and obvious" as a human being perceives.

The Area class will attempt to return the tightest bounding box possible for the Shape.

The Area class will attempt to return the tightest bounding box possible for the Shape.

 // Example:
 Area a1 = new Area([triangle 0,0 => 8,0 => 0,8]);
 Area a2 = new Area([triangle 0,0 => 8,0 => 8,8]);
 a1.add(a2);
 a1(before)     +         a2         =     a1(after)
 ################     ################     ################
 ##############         ##############     ################
 ############             ############     ################
 ##########                 ##########     ################
 ########                     ########     ################
 ######                         ######     ######    ######
 ####                             ####     ####        ####
 ##                                 ##     ##            ##
 

 // Example:
 Area a1 = new Area([triangle 0,0 => 8,0 => 0,8]);
 Area a2 = new Area([triangle 0,0 => 8,0 => 8,8]);
 a1.exclusiveOr(a2);
 a1(before)    xor        a2         =     a1(after)
 ################     ################
 ##############         ##############     ##            ##
 ############             ############     ####        ####
 ##########                 ##########     ######    ######
 ########                     ########     ################
 ######                         ######     ######    ######
 ####                             ####     ####        ####
 ##                                 ##     ##            ##
 

The Area class will attempt to return the tightest bounding box possible for the Shape. The bounding box will not be padded to include the control points of curves in the outline of the Shape, but should tightly fit the actual geometry of the outline itself. Since the returned object represents the bounding box with integers, the bounding box can only be as tight as the nearest integer coordinates that encompass the geometry of the Shape. the bounding Rectangle for theArea.
since:
   1.2

The Area class will attempt to return the tightest bounding box possible for the Shape. The bounding box will not be padded to include the control points of curves in the outline of the Shape, but should tightly fit the actual geometry of the outline itself. the bounding Rectangle2D for theArea.
since:
   1.2

 // Example:
 Area a1 = new Area([triangle 0,0 => 8,0 => 0,8]);
 Area a2 = new Area([triangle 0,0 => 8,0 => 8,8]);
 a1.intersect(a2);
 a1(before)   intersect     a2         =     a1(after)
 ################     ################     ################
 ##############         ##############       ############
 ############             ############         ########
 ##########                 ##########           ####
 ########                     ########
 ######                         ######
 ####                             ####
 ##                                 ##
 

 // Example:
 Area a1 = new Area([triangle 0,0 => 8,0 => 0,8]);
 Area a2 = new Area([triangle 0,0 => 8,0 => 8,8]);
 a1.subtract(a2);
 a1(before)     -         a2         =     a1(after)
 ################     ################
 ##############         ##############     ##
 ############             ############     ####
 ##########                 ##########     ######
 ########                     ########     ########
 ######                         ######     ######
 ####                             ####     ####
 ##                                 ##     ##