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tiles

`qgis_render::tiles`

Pre-rendered XYZ tile pyramids: single tiles on demand, or whole pyramids to a directory, MBTiles, or PMTiles.

use qgis_render::tiles::*;

Single tile

let tile = project.render_tile(
    TileCoord { z: 12, x: 2190, y: 1362 },
    TileOptions::new(256, 256)
        .crs(Crs::from_epsg(3857)?),
)?;

let bytes = tile.png_bytes();

`TileOptions` method	Default	Description
`.crs(Crs)`	`EPSG:3857`	Tile CRS. XYZ pyramids are normally Web Mercator.
`.format(TileFormat)`	`Png`	`Png`, `Jpeg`, or `WebP`.
`.dpi(u32)`	`96`	Raise for retina tiles.

Tile plans

A TilePlan describes the pyramid: which zoom levels, which area, how big the tiles are.

let plan = TilePlan::new()
    .zoom_range(10..=14)
    .bounds(Extent::new(14.0, 50.0, 15.0, 51.0))
    .tile_size(256)
    .crs(Crs::from_epsg(3857)?);

println!("{} tiles", plan.tile_count());

Rendering a plan

// Loose {z}/{x}/{y}.png files
plan.render_to_dir(&project, "./tiles/", RenderOptions::new()
    .parallel(8)
    .progress(|done, total| println!("{done}/{total}"))
)?;

// MBTiles
plan.render_to_mbtiles(&project, "output.mbtiles", RenderOptions::new()
    .parallel(8)
    .format(TileFormat::Png)
)?;

// PMTiles
plan.render_to_pmtiles(&project, "output.pmtiles", RenderOptions::new()
    .parallel(8)
    .format(TileFormat::WebP)
)?;

`RenderOptions` method	Default	Description
`.parallel(usize)`	CPU count	Worker threads; each owns a QGIS instance.
`.format(TileFormat)`	`Png`	Output encoding.
`.progress(f)`	none	Called after each tile with `(done, total)`.

Choosing an output

Target	Good for
Directory	Debugging, serving through any static file server or CDN.
MBTiles	Single portable file, well supported by tooling.
PMTiles	Single file served over HTTP range requests, no tile server needed.

See also

render — render_to_tile for one-off tiles
qgis-cli tiles — pyramids from the command line
qgis-cli serve — render tiles on demand instead
Rendering Projects