8.2 The Canvas Picture

As mentioned in The Graphical Object, the graphical objects drawn on the canvas are stored in a picture. When a graphical object is to be shown in a canvas, it is done by invoking the Draw operation of the canvas, whereby the graphical object is added to the picture of the canvas and displayed using the draw operation of the graphical object. It is not allowed, in the current version of Bifrost, to draw objects in the canvas that is not part of the canvas picture ^[8].

The following two attributes operate directly on the canvas picture:

scanThePicture.

Invokes the scanGOs on the Canvas picture.

scanThePictureReverse.

Invokes the scanGOsReverse on the Canvas picture.