42 if (!(prec >= 0 && prec <= maxprec_))
46 if (isnan(x) || isnan(y)) {
50 char grid[2 + 2 * maxprec_];
52 xh = int(floor(x / tile_)),
53 yh = int(floor(y / tile_));
60 grid[z++] = letters_[(tilegrid_ - (yh / tilegrid_) - 1)
61 * tilegrid_ + (xh / tilegrid_)];
62 grid[z++] = letters_[(tilegrid_ - (yh % tilegrid_) - 1)
63 * tilegrid_ + (xh % tilegrid_)];
65 real mult = real(pow(real(base_), max(tilelevel_ - prec, 0)));
67 ix = int(floor(xf / mult)),
68 iy = int(floor(yf / mult));
69 for (
int c = min(prec,
int(tilelevel_)); c--;) {
70 grid[z + c] = digits_[ ix % base_ ];
72 grid[z + c + prec] = digits_[ iy % base_ ];
75 if (prec > tilelevel_) {
76 xf -= floor(xf / mult);
77 yf -= floor(yf / mult);
78 mult = real(pow(real(base_), prec - tilelevel_));
79 ix = int(floor(xf * mult));
80 iy = int(floor(yf * mult));
81 for (
int c = prec - tilelevel_; c--;) {
82 grid[z + c + tilelevel_] = digits_[ ix % base_ ];
84 grid[z + c + tilelevel_ + prec] = digits_[ iy % base_ ];
88 int mlen = z + 2 * prec;
90 copy(grid, grid + mlen, gridref.begin());