devices.go RawHistoryFolder

1package ports
2
3import (
4	"errors"
5	"image"
6	"os"
7	"time"
8)
9
10// MaxCaptureInflight bounds the capture requests admitted but not yet
11// answered, across outputs. The reply channel of the production app has
12// at least this capacity, so an output never blocks on a reply.
13const MaxCaptureInflight = 32
14
15// ErrCaptureBusy: every capture slot of the renderer is leased.
16var ErrCaptureBusy = errors.New("capture: no free slot")
17
18// CaptureFrame is a lease on one renderer readback slot holding a GPU
19// copy of a rendered frame. Done and Read make no Vulkan call: a worker
20// goroutine waits on Done, then reads. EndCapture returns the lease.
21type CaptureFrame interface {
22	// Done is the sync file signalled when the copy finished; nil means it
23	// had finished when BeginCapture returned. The frame owns it.
24	Done() *os.File
25	// Read copies region (output pixels) as opaque sRGB8 BGRA rows into
26	// dst, stride bytes per row. Valid after Done signalled and before
27	// EndCapture.
28	Read(region image.Rectangle, dst []byte, stride int) error
29}
30
31// Renderer draws scenes for an output. One goroutine owns it. Frames go
32// to its own image until ExportTargets gives it scanout images; then each
33// Render draws into the target chosen by UseTarget (ADR 014: no CPU pass).
34type Renderer interface {
35	// SetHDR selects the HDR10 output transform (0 disables it).
36	// The DRM output calls this before ExportTargets.
37	SetHDR(sdrNits float64)
38	// Render draws the scene. done is a sync file signalled when the GPU
39	// finished the frame (nil: already finished); the caller closes it.
40	Render(Scene, map[WindowID]SurfaceContent) (done *os.File, err error)
41	// ExportTargets allocates n images of the renderer's size that the
42	// display can scan out, with one of the given XRGB8888 (SDR) or
43	// XRGB2101010 (HDR) modifiers (none: any the device exports),
44	// and returns them as dmabufs.
45	// n = 0 drops the targets.
46	ExportTargets(n int, modifiers []uint64) ([]DMABuf, error)
47	// UseTarget selects the exported image the next Render draws into.
48	UseTarget(i int)
49	// CursorBuffers allocates two linear ARGB8888 images of size×size the
50	// display can show on its cursor plane, and returns them as dmabufs.
51	CursorBuffers(size int) ([2]DMABuf, error)
52	// WriteCursor fills cursor image i with premultiplied ARGB8888 pixels
53	// (w×h, w*4 per row), cropped to the image and cleared around it.
54	WriteCursor(i int, pixels []byte, w, h int) error
55	// Pixels reads the last frame back (headless screenshots, tests). It
56	// waits for the GPU: debug only. Nil when it cannot (every capture
57	// slot leased, or the copy failed).
58	Pixels() *image.RGBA
59	// BeginCapture submits a GPU copy of the last rendered frame into a
60	// free slot and returns without waiting. ErrCaptureBusy when every
61	// slot is leased; another error when the copy cannot be tracked (no
62	// sync file): the caller fails the request.
63	BeginCapture() (CaptureFrame, error)
64	// EndCapture returns a lease. It never waits: a slot whose copy may
65	// still run is reused only once the renderer sees it finished.
66	EndCapture(CaptureFrame)
67	// Trim frees client buffer caches left undrawn for a while and what
68	// finished frames held, without rendering. Outputs call it
69	// periodically: an idle output renders no frame to free them.
70	Trim(now time.Time) error
71	Close()
72}
73
74// Seat is the device broker (libseat) input devices are opened through.
75type Seat interface {
76	OpenDevice(path string) (int, error)
77	CloseDevice(fd int)
78	SwitchVT(vt int)
79}