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Project

`Project`

use qgis_render::Project;

The central object of the library. A Project owns a parsed .qgs/.qgz document and gives access to its layers, CRS, extent, print layouts, and the renderer.

Opening a project

// From a file
let project = Project::open("map.qgs")?;
let project = Project::open("map.qgz")?;

// From bytes, for example an upload
let project = Project::from_bytes(&xml_bytes)?;

// With options
let project = Project::open_with("map.qgs", OpenOptions::new()
    .trust_layer_metadata(true)
    .skip_invalid_layers(true)
    .bad_layer_handler(|uri| {
        eprintln!("bad layer: {uri}");
        None // or Some(replacement_uri)
    })
)?;

`OpenOptions` method	Default	Description
`.trust_layer_metadata(bool)`	`false`	Skip recomputing extents and CRS per layer. Faster for large projects.
`.skip_invalid_layers(bool)`	`false`	Keep going when a layer cannot be read.
`.bad_layer_handler(f)`	fail	Callback for missing data sources; return a replacement URI or `None`.

Metadata

Method	Returns
`title()`	`Option<&str>`
`crs()`	`Crs`
`extent()`	`Extent`
`path()`	`Option<&Path>`

Layers

Method	Returns
`layers()`	`Vec<&Layer>`
`layer(name)`	`Option<&Layer>`
`layer_by_id(id)`	`Option<&Layer>`
`layer_tree()`	`&LayerTree`
`layouts()`	`Vec<&PrintLayout>`
`layout(name)`	`Result<&PrintLayout, QgisError>`

let buildings = project.layer("buildings").unwrap();
println!("{} features", buildings.feature_count());

for group in project.layer_tree().groups() {
    println!("{}: {:?}", group.name(), group.layers());
}

Rendering

See the render module for the full surface:

let image = project.render_to_image(RenderSettings::new(1024, 768))?;
image.save("map.png")?;

Errors

Project::open and friends return Result<T, QgisError>:

Variant	Cause
`FileNotFound(path)`	The file does not exist.
`InvalidProject { message }`	The document could not be parsed.
`BadLayer { name, uri }`	A data source is missing and no handler replaced it.

See also

Layer — the objects layers() returns
render — rendering entry points
Working with Layers — practical layer access
Architecture — where Project sits in the stack