feat(k-ui): motion: ring springs to focus, toggle knob slides, screens slide+fade in (theme motion tokens, 0 = off); 16ms frame timer only while moving; motion-only frames drawn+presented in part (whole elements, pixel-snapped rects, == full draw); virtio fb flushes only damage; TICKS_PER_MS in types

crates/hw-virtio/src/gpu.rs

@@ -65,11 +65,13 @@ pub struct Rect {
     pub h: u32,
 }
 
-pub fn transfer_to_host(mmio: &impl MmioAccess, queue: &VirtioQueue, dma: &GpuDmaAddrs, resource_id: u32, rect: Rect) -> bool {
+/// Copies `rect` of the backing to the host; `offset` is where its top
+/// left pixel is in the backing, in bytes.
+pub fn transfer_to_host(mmio: &impl MmioAccess, queue: &VirtioQueue, dma: &GpuDmaAddrs, resource_id: u32, rect: Rect, offset: u64) -> bool {
     write_cmd_header(&dma.cmd, 0x0105);
     put_rect(&dma.cmd, rect);
     // Offset into the resource's memory, then the resource id.
-    dma.cmd.write(BODY + 16, 0u64);
+    dma.cmd.write(BODY + 16, offset);
     dma.cmd.write(BODY + 24, resource_id);
     submit_cmd(mmio, queue, dma, 56)
 }