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Diffstat (limited to 'src/mbgl/util/tile_cover.cpp')
| -rw-r--r-- | src/mbgl/util/tile_cover.cpp | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/src/mbgl/util/tile_cover.cpp b/src/mbgl/util/tile_cover.cpp index b53e91162c..c06634c9b2 100644 --- a/src/mbgl/util/tile_cover.cpp +++ b/src/mbgl/util/tile_cover.cpp @@ -169,5 +169,26 @@ std::vector<UnwrappedTileID> tileCover(const TransformState& state, int32_t z) { z); } +// Taken from https://github.com/mapbox/sphericalmercator#xyzbbox-zoom-tms_style-srs +// Computes the projected tiles for the lower left and uppoer right points of the bounds +// and uses that to compute the tile cover count +unsigned long tileCount(const LatLngBounds& bounds, uint8_t zoom, uint16_t tileSize_){ + + auto sw = Projection::project(bounds.southwest().wrapped(), zoom, tileSize_); + auto ne = Projection::project(bounds.northeast().wrapped(), zoom, tileSize_); + + auto x1 = floor(sw.x/ tileSize_); + auto x2 = floor((ne.x - 1) / tileSize_); + auto y1 = floor(sw.y/ tileSize_); + auto y2 = floor((ne.y - 1) / tileSize_); + + auto minX = std::fmax(std::min(x1, x2), 0); + auto maxX = std::max(x1, x2); + auto minY = (std::pow(2, zoom) - 1) - std::max(y1, y2); + auto maxY = (std::pow(2, zoom) - 1) - std::fmax(std::min(y1, y2), 0); + + return (maxX - minX + 1) * (maxY - minY + 1); +} + } // namespace util } // namespace mbgl |