public GridRange[] getVertexColumnRanges() {
		if (gridBounds.minRow() < 0) {
			throw new IllegalStateException(
				"getVertexColumnRanges not defined for grids with negative rows!");
		}
		GridRange[] rowRanges = new GridRange[height()];

		for (int i = 0; i < rowRanges.length; i++) {
			rowRanges[i] = new GridRange();
		}

		for (GridPoint p : vertexPoints.values()) {
			rowRanges[p.row].add(p.col);
		}
		return rowRanges;
	}
Returns the minimum/max column for all rows in the grid. This method is only defined for
grids that have no negative rows. This is because the array returned will be 0 based, with
the entry at index 0 containing the column bounds for row 0 and so on.
@return the minimum/max column for all rows in the grid
@throws IllegalStateException if this method is called on a grid with negative rows.
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/layout/GridLocationMap.java