public void centerRows() {
		zeroAlignGrid();
		GridRange[] vertexColumnRanges = getVertexColumnRanges();
		int maxRowWidth = getMaxRowWidth(vertexColumnRanges);

		for (GridPoint p : allPoints()) {
			GridRange range = vertexColumnRanges[p.row];
			int extraSpace = maxRowWidth - range.width();
			int shift = extraSpace / 2 - range.min;
			p.col += shift;
		}
	}
Updates each row within the grid such that it's column values are set to center the row in
the grid.  Each row will be updated so that all its columns start at zero.  After that, 
each column will be centered in the grid.
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/layout/GridLocationMap.java