GCanvas
class, which is a lightweight
container that supports the addition of graphical objects that correspond to the
shapes attached to the board. These graphical objects come from a variety of
classes that represent geometrical shapes and other graphical entities including
lines, ovals, rectangles, images, and strings.
The standard approach to using the acm.graphics
package consists
of the following steps:
GCanvas
object to serve as the surface to which
subsequent graphical objects are attached.
JFrame
object and then add the GCanvas
at the center of that frame.
add
method in GCanvas
to add new graphical
objects from the GObject
hierarchy.
As an example, the following main program follows this outline to display a red square on the screen:
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Much of this boilerplate can be eliminated by using the
GraphicsProgram
class
in the acm.program
package.
The public classes in the acm.graphics
package can be diagrammed
as follows:
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