A color nonogram puzzle.

A nonogram is a picture-based logic puzzle in which the player uses hints on the edge of the puzzle to reveal a picture. Unlike a more traditional monochrome nonogram, color nonograms use different colors with its hints to reveal a multi-colored image.

Representation

The IpuzCellType is used to determine whether a cell is filled in or blank. If it’s a BLOCK, then it’s filled in, while NORMAL indicates a blank cell. A NULL cell could indicate a shaped puzzle, though is not traditionally used with nonograms.

With color nonograms, if the cell is a block then the solution field is set to a string to indicate which grouping the cell belongs to. This grouping is also reflected in the IpuzNonogramClue segments. All other fields of IpuzCell (such as number and label) are ignored.

Color nonograms are expected to have a style with the same style_name as the group to indicate the color to be used with a given group. All other fields of the style are undefined. If a style with that name doesn’t exist, apps can choose an arbitrary color to define that group.

Representation Examples

For example, here’s a simple example of a color nonogram puzzle’s on-disk representation. In this example, there are two different colors in use.

 {
    "version": "http://ipuz.org/v2",
    "kind": [ "https://libipuz.org/nonogram#1", "https://libipuz.org/nonogram/colornonogram#1" ],
    "dimensions": { "width": 3, "height": 3 },
    "styles": {
        "A": {"color": "#f8e45c" },
        "B": {"color": "#813d9c" }
    },
    "puzzle": [ [ 0 , "A",  0  ],
                ["A", "B", "B" ],
                ["B" , 0 , "A" ] ]
}

Here’s an example of working with the styles:

static void
paint_cell (IpuzPuzzle    *puzzle,
            IpuzCellCoord *coord)
{
  IpuzCell *cell;

  cell = ipuz_grid_get_cell (IPUZ_GRID (puzzle), coord);

  if (ipuz_cell_get_cell_type (cell) == IPUZ_CELL_BLOCK)
    {
       IpuzStyle *style;

       style = ipuz_cell_get_style (cell);

       // If a puzzle doesn't have a style defined, then pick a random one for that group
       if (style == NULL)
         style = get_default_style (ipuz_cell_get_solution (cell));

       // Do something with the color
       paint_block_at_coord (coord, ipuz_style_get_bg_color (style));
    }
}

Note that ipuz_puzzle_get_style() can also return the style for a style_group. This is useful when matching to a group with a IpuzNonogramClue.

Guesses

IpuzNonogramColor objects follow a similar convention to regular nonograms to record player progress in solving a puzzle.

• A guess of a block uses the style name to indicate
• A guess of IpuzNonogram:space is used to indicate that a cell has been eliminated as a possible block. This defaults to the string ".".
• A guess of NULL is used to indicate that the player has yet to determine if a cell is a block or not.

In addition, IpuzNonogramColor uses the stride_guess of the guesses struct to keep track of whether the cells for the number hints have been found. This is required for puzzle games that let the user manually cross off numbers. See IpuzNonogram for full details.