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.

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

When used with an IpuzGuesses object, guesses are tested against the solution group. Since implementations will want to record additional information per-cell, any guess not matching a group indicator will be ignored.