MapGuide RFC 40 - Support for using the AGG renderer

This page contains an change request (RFC) for the MapGuide Open Source project. More MapGuide RFCs can be found on the RFCs page.

Status

RFC Template Version	(1.0)
Submission Date	(Date/Time submitted)
Last Modified	Tom Fukushima Timestamp
Author	Tom Fukushima, Traian Stanev
RFC Status	draft <proposed, frozen for vote, adopted, retracted, or rejected>
Implementation Status	pending <under development, completed>
Proposed Milestone	2.0
Assigned PSC guide(s)	(when determined)
Voting History	(vote date)
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Overview

Provide support for using the AGG library to render the map and legend images.

Motivation

The GD renderer currently used to render the map and legend images works, but there are limitations to it in that the images it generates could be better. For example, when drawing a wide line, even though we have antialiasing turned on staircasing occurs. The AGG library will get us around these limitations.

Proposed Solution

An AGG renderer will be added to the server. When the server starts, it will read the serverconfig.ini file for a "Renderer" setting in the "GeneralProperties" section and:

1) if it is not there, default to the GD renderer

2) if it is set to "AGG" use the AGG renderer

3) otherwise use the GD renderer

The reason that we default to the GD renderer is because the AGG renderer needs to be tested and stabilized before exposing it to general community.

We will be forking the AGG renderer from the version where it was still under a compatible licensing model and storing this version in our subversion repository.

Implications

There are no backwards compatibility issues.

Test Plan

We are initially putting it in the product to get some testing done. Also, the unit tests that exist for the GD renderer will be replicated to use the AGG renderer.

Funding/Resources

Autodesk