ArcGIS Engine Developer Guide

BUILDING APPLICATIONS WITH C++ AND CONTROL WIDGETS
Each Motif ArcGIS control widget has a
corresponding GTK ArcGIS control widget.
A buddy control is a control that is designed to
work in conjunction with another control. For
example, the Table of Contents, or TOC, Control
is a buddy of the MapControl.
Although the GUI design will be different for
GTK developers, the majority of the rest of the
application code will be the same. Throughout
the scenario, sidebars will highlight areas where
GTK programmers will take different steps.
The ArcGIS Engine C++ API provides reusable Motif widget components
corresponding to each ArcGIS Engine control. This developer scenario will show
how these components can be embedded in a Motif form to build a map viewer
application.
Motif itself is a specification for how graphical user interfaces should look and
feel. The Open Software Foundation (OSF) Motif Toolkit, used with the
ArcGIS Engine C++ API in this scenario, uses X as the window system and X
Toolkit Intrinsics as the API platform. The Motif widgets discussed here are one
part of the Motif toolkit. Each widget is a reusable and configurable component
of the user interface. The Motif toolkit provides widgets for common tasks, such
as the toggle button used in this scenario. Each built-in Motif widget knows how
to draw itself as well as some generic behavior; for example, the toggle button
knows to call a function when it is clicked. However, it is up to the programmer
to implement the callback function, giving the widget its specific behavior. In
addition to providing widgets the Motif toolkit does other work for the developer,
including handling many user interactions, managing window layout, and
redrawing.
The Motif widget ArcGIS controls are custom widgets made available through
the C++ API of the ArcGIS Engine Developer Kit. Placed in a top-level application
widget, the controls have events, properties, and methods that the developer
can access, and like the built-in Motif toolkit widgets, each ESRI control widget
knows how to draw itself. The objects and functionality within each control can
be combined with other ESRI ArcObjects as well as with custom controls to
easily create customized end user applications.
This scenario was written in C++ using the Motif toolkit from the Open Software
Foundation. It was chosen to create an application that would run on a
Solaris or Linux platform. The same application could also be written in Java.
Whichever API you use, your future success with the ArcGIS controls depends
on your skill in both the language and ArcObjects.
DESIGN
This scenario has been designed to highlight how the ArcGIS controls interact
with each other and to expose a part of each ArcGIS control’s object model to
the developer.
The scenario starts with building a GUI using Motif to place and manage the
controls. The controls are then connected to each other through the SetBuddy
methods. At this stage, the application is ready to function as a simple map
viewer. The GUI functionality is then extended through a custom tool and event
handling. To achieve this, the scenario further explores the API of the visual
Motif widgets, as well as the other nonvisual ArcGIS Engine components.
REQUIREMENTS
To successfully follow this scenario you need the following (the requirements for
deployment are covered later in the ‘Deployment’ section):
• An installation of the ESRI ArcGIS Engine Developer Kit with an authorization
file enabling it for development use.
358 • ArcGIS Engine Developer Guide