GEOS SDK TechDocs
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6 Visible Layers and 32-Bit Graphics
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6.2 Using 16-Bit Drawing Commands
The first issue with large documents is the basic structure of the visible tree. The topmost object of a large visible tree must be able to keep track of information about the current translations and coordinates being used. Typically, the topmost object would be a subclass of
VisContentClass
; this does not change with large trees, though another consideration has to be taken care of.
A content object should not contain any information about the document itself; the content object should not be stored along with other document information. Thus, the object that acts as the content can not be the object that also manages the 32-bit document space. Instead, it is easiest to use a
VisCompClass
object to manage the document space and to place this object as a child of the content.
In addition, you can set up several different composite children of the content, each one managing its own large document space. Each one of these composites is called a "layer object" and manages a "layer" of the document. This way, you can have several different layers (such as a spreadsheet layer and a graphic layer) in the same document. The layer object should manage the calculations and translations necessary for supporting the large document space.
GEOS SDK TechDocs
|
| 6 Visible Layers and 32-Bit Graphics
| 6.2 Using 16-Bit Drawing Commands