VisClass

GEOS SDK TechDocs

1 Introduction to VisClass

The visible classes-- VisClass , VisCompClass , VisContentClass , and VisTextClass --can be extremely useful to application developers. They provide a flexibility of display and use that is unavailable with the generic UI objects. Among other features, visible objects provide the hooks for and basic functionality of custom drawing, custom input handling, and custom geometry management.

VisClass is the parent class of all the visible classes and all visible UI objects. VisClass objects, by themselves, do nothing; VisClass must be subclassed and the objects must be placed in a visible object tree as children of a VisCompClass object. Together, VisClass and VisCompClass provide a large amount of the functionality required for creating a hierarchy of non-overlapping objects.

Many applications will use both VisClass and VisCompClass as well as VisContentClass . Before reading this chapter, however, you should be familiar with the concepts of the generic UI and with basic GEOS applications. You should have created a simple application to get familiar with the GEOS system and Goc, and you should be relatively familiar with the GenView.

You should also become familiar with both VisContentClass and VisCompClass ; both of these classes and their relationship to VisClass

  1 Introduction to VisClass
  2 The Visible Class Tree
  3 VisClass Instance Data
    3.1 VI_bounds
    3.2 VI_typeFlags
    3.3 VI_attrs
    3.4 VI_optFlags
    3.5 VI_geoAttrs
    3.6 VI_specAttrs
    3.7 VI_link
  4 Using VisClass
    4.1 Basic VisClass Rules
    4.2 Drawing to the Screen
    4.3 Positioning Visible Objects
    4.4 Handling Input
  5 Working with Visible Object Trees
    5.1 Creating and Destroying
    5.2 Adding and Removing
    5.3 Getting Visible Tree Information
    5.4 Sending Messages Through the Tree
    5.5 Visible Object Window Operations
  6 Visible Layers and 32-Bit Graphics
    6.1 Using Visible Document Layers
    6.2 Using 16-Bit Drawing Commands
    6.3 The 16-Bit Limit on Visual Bounds
    6.4 Handling MSG_VIS_DRAW
    6.5 Managing 32-Bit Geometry
    6.6 Handling Mouse Events
    6.7 Setting Up the Objects
  7 VisClass Error Checking
  8 Creating Specific UIs
  9 Basic Summary

GEOS SDK TechDocs

1 Introduction to VisClass