protected void appendTilesets(Document newDoc, Element rootElement) {
List<?> elements = tilesetsField.getElements();
int gid = 1;
for (Object object : elements) {
TileSet tileSet = (TileSet) object;
Element tileSetElement = newDoc.createElement("tileset");
tileSetElement.setAttribute("name",tileSet.getName());
tileSetElement.setAttribute("firstgid","" + gid);
tileSetElement.setAttribute("tilewidth",tileWidthCombo.getText());
tileSetElement.setAttribute("tileheight",tileHeightCombo.getText());
Element imageElement = newDoc.createElement("image");
IWorkspace workspace = ResourcesPlugin.getWorkspace();
IPath resourcePath = workspace.getRoot().getLocation().append(getContainerFullPath().append(
getFileName()));
String relativePath = Util.getRelativePath(resourcePath.toOSString(),tileSet.getTilebmpFile());
imageElement.setAttribute("source",relativePath);
tileSetElement.appendChild(imageElement);
rootElement.appendChild(tileSetElement);
gid++;
}