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Layer

`Layer`

use qgis_render::Layer;

A single map layer, obtained from a Project. Layer covers metadata and styling for every layer kind, and narrows to VectorLayer or RasterLayer for data access.

Metadata

Method	Returns
`name()`	`&str`
`id()`	`&str`
`layer_type()`	`LayerType`
`crs()`	`Crs`
`extent()`	`Extent`
`feature_count()`	`u64`

LayerType is Vector, Raster, Mesh, PointCloud, or Annotation.

Data source

Method	Returns
`data_source()`	`&DataSource`
`provider()`	`&str` — `ogr`, `postgres`, `gdal`, `wms`, …

Visibility and styling

layer.set_visible(false);
layer.set_opacity(0.8);
println!("{:?}", layer.blend_mode());
println!("{:?}", layer.renderer());

Method	Description
`is_visible()` / `set_visible(bool)`	Layer visibility.
`opacity()` / `set_opacity(f64)`	`0.0` (transparent) to `1.0` (opaque).
`blend_mode()`	Compositing mode used when drawing.
`renderer()`	The symbology that decides how features are drawn.

Vector data

let vector = layer.as_vector().unwrap();

println!("{:?}", vector.fields());

for feature in vector.features() {
    println!("{} {:?}", feature.id(), feature.geometry());
}

Method	Returns
`as_vector()`	`Option<&VectorLayer>`
`VectorLayer::fields()`	`&[Field]`
`VectorLayer::features()`	`FeatureIterator`
`VectorLayer::features_with(request)`	`FeatureIterator` — see `features`
`VectorLayer::feature(id)`	`Result<Feature, QgisError>`
`VectorLayer::count_with(request)`	`Result<u64, QgisError>`

Raster data

let raster = layer.as_raster().unwrap();
let block = raster.read_block(1, extent, 512, 512)?;

Method	Returns
`as_raster()`	`Option<&RasterLayer>`
`RasterLayer::band_count()`	`usize`
`RasterLayer::width()` / `height()`	`u32`
`RasterLayer::read_block(band, extent, w, h)`	`Result<RasterBlock, QgisError>`

See also

Feature — what iteration yields
features — requests, filters, and selection
Working with Layers — practical examples