Grid

o1.grid.Grid

trait Grid[Element](val width: Int, val height: Int)

The trait Grid represents rectangular grids that contain elements of a particular kind. Each element in a grid is located at a unique pair of coordinates, represented as a GridPos.

X coordinates run from 0 to width-1, y coordinates from 0 to height-1. (0,0) corresponds to the upper left corner of the grid.

There are different kinds of grids: the type of element that a grid contains is defined by the grid’s type parameter. For instance, Grid[Square] is a grid where each pair of x and y coordinates contains a Square object, and Grid[House] is a grid containing House objects.

A Grid is mutable: it is possible to replace an element at a particular GridPos with another. (Depending on the element type, the elements may be individually mutable, too.) The width and height of a grid never change, however.

Upon creation, a Grid initializes itself by calling initialElements, which produces an initial state for the grid.

This trait has an alias in the top-level package o1, so it’s accessible to students simply via import o1.*.

Parameters

height: the number of elements in each column of the grid
width: the number of elements in each row of the grid

Attributes

Graph
Supertypes: class Object

trait Matchable

class Any
Known subtypes: class CityMap

Members list

Value members

Abstract methods

Generates the elements that initially occupy the grid. This method is automatically invoked by every Grid object upon creation. Subtypes should implement this method as appropriate for the particular sort of grid desired.

Note that since this method produces the Grid’s initial contents, it gets called during initialization before the Grid actually has any elements as content. Therefore, subtypes’ implementations of this method must not depend on the state of the new Grid (by calling neighbors or elementAt, for instance) or attempt to modify the Grid (with update, for instance).

This method is meant for initialization purposes only. To access all the elements of an already-initialized Grid, call allElements instead.

Attributes

Returns: a collection of size width times height that contains the initial grid elements. The first element in the collection will appear at GridPos (0,0), the second at (1,0), and so on, filling in the first row before continuing on the second row at (0,1).

Concrete methods

Returns a collection of all the elements currently in the grid.

Attributes

Returns a collection of all the locations on the grid.

Attributes

Returns the element at the given pair of coordinates. (This does the same as elementAt.)

Parameters

location: a location on the grid (which must be within range or this method will fail with an error)

Attributes

Determines whether the grid contains the given pair of coordinates. For instance, a grid with a width and height of 5 will contain (0, 0) and (4, 4) but not (-1, -1), (4, 5) or (5, 4).

Attributes

Returns the element at the given pair of coordinates. (This does the same as apply.)

Parameters

location: a location on the grid (which must be within range or this method will fail with an error)

Attributes

Returns a vector of all the neighboring elements of the element indicated by the first parameter. Depending on the second parameter, either only the four neighbors in cardinal compass directions (north, east, south, west) are considered, or the four diagonals as well.

Note that an element at the grid’s edge has fewer neighbors than one in the middle. For instance, the element at (0, 0) of a 5-by-5 grid has only three neighbors, diagonals included.

Parameters

includeDiagonals: true if diagonal neighbors also count (resulting in up to eight neighbors), false if only cardinal directions count (resulting in up to four)
middleLoc: the location between the neighbors

Attributes

Swaps the elements at two given locations on the grid. The given locations must be within range or this method will fail with an error.

Attributes

Modifies the grid by replacing the existing element at the given location with the new element.

Parameters

location: a location on the grid (which must be within range or this method will fail with an error)
newElement: the new element that replaces the old one at location

Attributes

Concrete fields

the number of elements in this grid, in total. (Equals width times height.)

Attributes

Generated with

This document is part of the ebook for O1 (aka CS-A1110 Programming 1), a course at Aalto University.