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Rectangle Tiling Algorithm

2.09/5 (4 votes)
23 Jan 2011CPOL 33.9K  
A useful algorithm to divide a rectangular area into rectangular subregions. Good for tiling windows in a given area
This is an algorithm which takes as input, the number of small rectangles to divide a big rectangular area and outputs required number of rows and columns for each row.

C++
// num_rects : Specifies the number of small rectangle you want to divide a big rectangle into
// num_rows  : Output parameter to receive number of rows needed to divide the big rectangle
// cols_per_row : Output parameter to receive the number of varying columns per rows (just pass a int* data type, the function will create an array of integers where the index of the array is the row, and the value in that index is the columns per that row)

void DivideRectangularArea (unsigned int num_rects, /*OUT*/ int &num_rows, /*OUT*/ int * &cols_per_row)
{
    if (num_rects == 0)
        return false;

    if (num_rects < 4)
    {
        int sections = 1;
        cols_per_row = new int[sections];
        for (int i = 0; i < sections; i++)
        {
            cols_per_row[i] = num_rects;
        }
        num_rows = sections;
    }
    else
    {
        double root = num_rects;
        double sqr_root = sqrt(root);
        int rounded_root = (int) sqr_root;

        int row_count = rounded_root;
        int col_count = rounded_root;

        cols_per_row = new int[row_count];

        int leftover = ((int) num_rects) - row_count * col_count;

        int distrib = leftover / row_count;
        col_count += distrib;
        int left = num_rects - (row_count * col_count);

        int start_adding_index = row_count - left;

        for (int i = 0; i < row_count; i++)
        {
            if (i == start_adding_index)
            {
                col_count++;
                start_adding_index = -1;
            }
            cols_per_row[i] = col_count;
        }
        num_rows = row_count;
    }
}

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)