Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 | 15x 15x 3x 2x 2x 2x 2x 2x 2x 2x 1x 1x 1x 1x 1x 1x 4x 4x 1x 4x 4x 2x 1x 1x 3x 9x 9x 9x 1x | /** Web map tile boundaries at about one tile per 256 to 512 screen pixels. */
import {
type Box,
type GridGeometry,
type GridLabel,
type GridPath,
type Position,
boxPath,
densify,
} from '../../geo/geometry'
import {
MAX_TILE_LATITUDE,
MAX_TILE_ZOOM,
type Tile,
tileCell,
tileColumnLongitude,
tilePath,
tileRowLatitude,
toTile,
} from './tile'
const MAX_LINES = 400
const MAX_LABELS = 300
/**
* MapLibre draws a 512-pixel world at zoom 0, so 256-pixel tiles one level deeper than the
* map zoom are drawn between 256 and 512 pixels wide.
*/
export function gridTileZoom(zoom: number): number {
return Math.min(MAX_TILE_ZOOM, Math.max(0, Math.floor(zoom) + 1))
}
export function tileGrid(view: Box, zoom: number): GridGeometry {
const z = gridTileZoom(zoom)
const paths: GridPath[] = []
const labels: GridLabel[] = []
const [w, s, e, n] = view
const south = Math.max(s, -MAX_TILE_LATITUDE)
const north = Math.min(n, MAX_TILE_LATITUDE)
if (south >= north) return { paths, labels }
const northWest = toTile({ lat: north, lon: w }, z)
const southEast = toTile({ lat: south, lon: Math.min(e, 179.999999) }, z)
const columns = southEast.x - northWest.x + 1
const rows = southEast.y - northWest.y + 1
Iif (columns + rows > MAX_LINES) return { paths, labels }
for (let x = northWest.x; x <= southEast.x + 1; x++) {
const lon = tileColumnLongitude(x, z)
paths.push({
path: densify(
[lon, south],
[lon, north],
Math.max(0.01, (north - south) / 32),
),
width: 1,
})
}
for (let y = northWest.y; y <= southEast.y + 1; y++) {
const lat = tileRowLatitude(y, z)
if (lat < south || lat > north) continue
paths.push({
path: densify([w, lat], [e, lat], Math.max(0.01, (e - w) / 32)),
width: 1,
})
}
Eif (columns * rows <= MAX_LABELS) {
for (let x = northWest.x; x <= southEast.x; x++) {
for (let y = northWest.y; y <= southEast.y; y++) {
const tile: Tile = { z, x, y }
const cell = tileCell(tile)
labels.push({
position: [
(cell.west + cell.east) / 2,
(cell.south + cell.north) / 2,
],
text: tilePath(tile),
size: 11,
})
}
}
}
return { paths, labels }
}
export function tileOutline(tile: Tile): Position[] {
const cell = tileCell(tile)
return boxPath([cell.west, cell.south, cell.east, cell.north], 0.01)
}
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