CPU rendering backend for truce plugins (tiny-skia + fontdue).
Parallels truce-gpu at the same level of the
crate graph: both implement [truce_gui_types::RenderBackend] on
their respective primitives ([CpuBackend] uses tiny-skia
software rasterization; truce_gpu::WgpuBackend uses wgpu). The
built-in editor (truce_gui::BuiltinEditor) holds an internal
CpuBackend for its iOS / pre-blit rendering path; GpuEditor
routes through WgpuBackend for non-iOS.
Plugin authors don't usually depend on this crate directly -
truce-gui::default_editor pulls it in. Custom-editor plugins
(egui / iced / slint) that want a software RenderBackend for
testing without a GPU can opt in here.