Context

Context is Valo on one GPU device. Create it from a device and queue your application already owns. It holds pipelines, atlases, uploaded images, and reusable targets — not windows, files, or application content. Reuse it across frames.

let mut context = valo::Context::new(device, queue);
if let Some(frame) = surface.acquire() {
    context.render(&display_list, &frame.target(Some(Color::BLACK)));
    context.present(frame);
}

Native applications can also export pixels without a window:

let pixels = context.render_to_rgba(&display_list, [320, 220], Some(Color::BLACK));

render submits one command buffer and returns frame statistics. render_to_rgba is a blocking helper for tests and exports.

JavaScript: Device and Renderer

The same GPU owner is split across two objects. createDevice() is the shared Context. device.attach(canvas) is one canvas's swapchain and backing:

await initializeValo();
const device = await createDevice();
const renderer = device.attach(canvas);
const stats = renderer.render(list, true, 0.04, 0.04, 0.05, 1);

The true argument clears to the supplied colour. Pass false to draw incrementally over preserved pixels. Attach several canvases to one device so they share atlases — see One device, many canvases.

The live canvases on Paint and DisplayListBuilder already go through createDevice and attach. Change those scenes to see a render on this device.

Options

• set_text_tiers — bitmap, SDF, or outlines by font size. Defaults suit normal use.
• set_hide_missing_glyphs — blank instead of tofu for unresolved characters.
• set_text_raster_hold / set_raster_hold — reuse existing rasters during a zoom gesture; clear them when the view settles.

memory_report() estimates retained GPU memory. In JavaScript, call device.memoryReport().

Next: Surface.