GLG 2.7 Release: New Features and Enhancements

New GIS Map Server product
GLG GIS Object
New GIS Demo
GIS Zoom Mode and Coordinate Conversion Functions
New Utility Function for Transforming Objects
Save Image Builder Option and API Method
Headless Support for Server-Side Image Generation
Performance Improvements for the Java Version of the Toolkit
New Spline Type
New Type of a Path Transformation
New Undo Type in the Graphics Builder
New Integrated Zoom Modes
New Tooltip Messages
Extended Trace Callback Support
New C, C++ and Java Examples
Dropped Ext Suffix of the GLG Bean's Extended API Methods
Changed the GLG Library Layout

New GIS Map Server product

The GLG Map Server is a sophisticated GIS Map Server which complements the GLG Toolkit by providing real-time map display capabilities. It supports both vector and raster data and is optimized for real-time rendering of high-resolution maps with millions of objects. It is available on both Unix and Windows platforms and can be used in conjunction with the GLG Toolkit or stand-alone, via a library API interface or a web-server setup. Click here for more information on the GLG Map Server.

Both C/C++ and Java version of the GLG Toolkit may utilize the Map Server functionality via the integrated GLG GIS Object, which incorporates dynamic maps into a GLG drawing and the GLG Graphics Builder. 

GLG GIS Object

A new GLG GIS Object seamlessly integrates Map Server functionality into the GLG drawing, both in the application and the Graphics Builder. The GIS object displays a map image in a selected GIS projection inside of the GLG drawing and transparently handles all aspects of interaction with the Map Server, automatically issuing map requests every time the map is resized, panned or zoomed. Other GLG objects may be placed on top of the GIS Object to annotate the map with dynamic or static icons.

The GIS Object supports integrated zooming and panning, as well as utilities for converting from screen or world coordinates to
latitude/longitude in the selected projection and vise versa. The attributes of the GIS Object can be accessed using the GLG Standard API.

The GIS Object is supported in both C/C++, Java and ActiveX deployments on both Unix and Windows platforms.

New GIS Demo

A new GIS demo was added to show an example of using the GIS Object in a GLG application. The demo shows dynamic airplane icons on top of a GIS Object's map and demonstrates zooming, panning, object selection, coordinate conversion and dynamic icon positioning capabilities.

Both C/C++ and Java versions of the demo are provided. The C/C++ demo uses the map server in the form of a library API, while the Java version of the demo uses the map server installed on a web server as a CGI-bin executable.

GIS Zoom Mode and Coordinate Conversion Functions

A support for a new integrated GIS Zoom mode was added to the viewport object. The new zoom mode accommodates GIS applications which need to zoom the map inside of the GIS Object instead of zooming the whole drawing. The new GIS Demo demonstrates the use of the new zoom mode.

New coordinate conversion methods were added to the GLG Standard API to provide an easy way to convert from latitude/longitude to the GLG world coordinates and vise versa. The new GIS Demo provides an example of using the converted world coordinates to position dynamic airplane icons on top of the map.

New Utility Function for Transforming Objects

A new set of convenience functions for moving, scaling, rotating and positioning complex objects was added to the GLG Extended API. The new functions provide a simpler interface to the existing GlgTransformObject method.

A world-to-screen and screen-to-world conversion functions were added as well.

Save Image Builder Option and API Method

A new Save Image option was added to the File menu of the GLG Graphic Builder to save a JPEG image of the drawing (including all nested drawings in children viewports).

A new SaveImage method was added to the C/C++ Standard API to generate a JPEG image of the drawing under the control of an application.

In the Java version of the Toolkit, a new CreateImage method was added to the Standard API to generate and return a Java Image object containing the image of the GLG drawing or GLG bean.

Headless Support for Server-Side Image Generation

The Java version of the Toolkit now supports headless operation using headless support available in Java2. The headless mode may be used for Java applications running on a server to generate images of graphs, for example. If the server is headless (has no graphical console and no windowing system running), the headless mode uses OpenGL for image generation instead of the windowing system's drawing primitives used normally. A new SetHeadless method was added to the GLG Standard API for Java to facilitate headless mode support. A new image generation Java example is provided as well.

Performance Improvements for the Java Version of the Toolkit

An object cache for temporary objects was added to facilitate the temporary objects reuse. The reuse of temporary objects decreases garbage collection time and increased performance.

New Spline Type

A new Catmull Rom spline type was added to the GLG spline object. While the Bezier spline yields a smoother curve due to its continuous second derivative, the Catmull Rom spline passes through the control points, making it convenient for applications which need to draw a smooth curve through a set of points.

New Type of a Path Transformation

A new type of path transformation was added to allow using splines, arcs and other complex objects without exploding them. Previously, the path of the transformation could be constrained only to a polygon. While the spline or arc points could be used, they could not be constrained to, resulting in the transformation's path not reflecting changes to the spline's or arc's shape. Now the transformation allows using complex objects as the path, with the path reflecting any changes to the spline or arc objects used as the path (for example, a change of the arc's radius or spline's control point).

The new path transformation can be used for a series object, replicating objects along a spline or an arc.

New Undo Type in the Graphics Builder

An Attribute Value Change undo was added to the Graphics Builder to allow undo of an attribute value change (for example, color change undo). Previously, only shape and geometry changes were recorded.

New Integrated Zoom Modes

A support for a few new integrated zoom modes was added:

New Tooltip Messages

New tooltip messages were added into the Input callback to enable the application logic to display custom tooltips based on application-defined conditions.

Extended Trace Callback Support

The Trace Callback support was added to the C++ binding and the GLG ActiveX Control, enabling the application to handle native windowing events in these programming environment.

New C, C++ and Java Examples

A set of new C, C++ and Java examples was added to the GLG Toolkit installation to demonstrate the following common tasks: The new examples are located in the example_c_cpp and examples_java subdirectories of the GLG installation directory.

Dropped Ext Suffix of the GLG Bean's Extended API Methods

The Ext prefix of the GLG Bean's Extended API calls was removed. The old calls are still supported for back compatibility, but the new methods without the Ext suffix should be used for new development. All demos and examples were updated to use the new methods.

Changed the GLG Library Layout

The layout of the GLG library on Unix was changed to make it more modular. The libz compression library and the jpeg support library (libjpeg) need to be explicitly linked with. If the map server is used, the map server library (libglg_map) and the tiff support library (libtiff) need to be linked with as well. If the map server functionality is not used, a map server stub library (libglg_map_stub) can be used instead. Refer to the makefile in the glg/src directory for linking examples.

When migrating an application from the release 2.6 of GLG or earlier to the release 2.7, the makefile has to be modified by adding all libraries required for linking.