RenderSettings

RenderSettings

use qgis_render::RenderSettings;

The lightweight builder for a render. It answers “how big, which area, which CRS” and leaves everything else at a sensible default. Reach for MapSettings when you also need per-layer selection or filter overrides.

Construction

let settings = RenderSettings::new(1024, 768)
    .extent(project.extent())
    .crs(Crs::from_epsg(3857)?)
    .dpi(96)
    .background(Color::WHITE);

let image = project.render_to_image(settings)?;
image.save("map.png")?;

RenderSettings::new(width, height) takes the output size in pixels.

Builder methods

Method	Default	Description
.extent(Extent)	project extent	Area to render.
.crs(Crs)	project CRS	Output CRS. Reprojection is automatic.
.dpi(u32)	96	Drives label sizes and symbol scaling.
.background(Color)	Color::TRANSPARENT	Background fill.

Aspect ratio

The extent and the pixel size are independent: a non-matching ratio stretches the map. Compute one from the other when the output has to be undistorted.

let extent = project.extent();
let ratio = extent.width() / extent.height();
let (w, h) = (2048, (2048.0 / ratio) as u32);

let image = project.render_to_image(
    RenderSettings::new(w, h).extent(extent)
)?;

Choosing a DPI

DPI	Use
72–96	Screen and web maps.
150	Presentations and reports.
300	Print.

DPI scales labels and marker symbols, so a 300 DPI render of the same extent is legible when printed rather than tiny.

See also

• render — the render entry points and MapSettings
• Crs — output coordinate systems
• layout — print layouts, which carry their own scale
• Rendering Projects — worked examples