xgb-image: add support for the MIT-SHM extension

This commit is contained in:
Přemysl Eric Janouch 2018-08-25 23:17:15 +02:00
parent cea1792913
commit c8fd1068d1
Signed by: p
GPG Key ID: A0420B94F92B9493
1 changed files with 77 additions and 16 deletions

View File

@ -4,10 +4,13 @@ import (
"encoding/binary"
"github.com/BurntSushi/xgb"
"github.com/BurntSushi/xgb/render"
"github.com/BurntSushi/xgb/shm"
"github.com/BurntSushi/xgb/xproto"
"log"
"os"
"reflect"
"time"
"unsafe"
"image"
_ "image/gif"
@ -15,6 +18,10 @@ import (
_ "image/png"
)
// #include <sys/ipc.h>
// #include <sys/shm.h>
import "C"
func F64ToFixed(f float64) render.Fixed { return render.Fixed(f * 65536) }
func FixedToF64(f render.Fixed) float64 { return float64(f) / 65536 }
@ -182,13 +189,15 @@ func main() {
_ = xproto.CreateGC(X, cid, xproto.Drawable(pixid),
xproto.GcGraphicsExposures, []uint32{0})
// Load data into the pixmap. Also see xgbutil/xgraphics/xsurface.go.
// We're being lazy and resolve the 1<<16 limit of requests by sending
// a row at a time. The encoding is also done inefficiently.
bounds := img.Bounds()
Lstart := time.Now()
if err := shm.Init(X); err != nil {
log.Println("MIT-SHM unavailable")
// We're being lazy and resolve the 1<<16 limit of requests by sending
// a row at a time. The encoding is also done inefficiently.
// Also see xgbutil/xgraphics/xsurface.go.
row := make([]byte, bounds.Dx()*4)
for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
for x := bounds.Min.X; x < bounds.Max.X; x++ {
@ -201,11 +210,63 @@ func main() {
0, int16(y),
0, 32, row)
}
} else {
rep, err := shm.QueryVersion(X).Reply()
if err != nil {
log.Fatalln(err)
}
if rep.PixmapFormat != xproto.ImageFormatZPixmap ||
!rep.SharedPixmaps {
log.Fatalln("MIT-SHM configuration unfit")
}
shmSize := bounds.Dx() * bounds.Dy() * 4
// As a side note, to clean up unreferenced segments (orphans):
// ipcs -m | awk '$6 == "0" { print $2 }' | xargs ipcrm shm
shmID := int(C.shmget(C.IPC_PRIVATE,
C.size_t(shmSize), C.IPC_CREAT|0777))
if shmID == -1 {
// TODO: We should handle this case by falling back to PutImage,
// if only because the allocation may hit a system limit.
log.Fatalln("memory allocation failed")
}
dataRaw := C.shmat(C.int(shmID), nil, 0)
defer C.shmdt(dataRaw)
defer C.shmctl(C.int(shmID), C.IPC_RMID, nil)
data := *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
Data: uintptr(dataRaw), Len: shmSize, Cap: shmSize}))
for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
row := data[y*bounds.Dx()*4:]
for x := bounds.Min.X; x < bounds.Max.X; x++ {
r, g, b, a := img.At(x, y).RGBA()
encoding.PutUint32(row[x*4:],
(a>>8)<<24|(r>>8)<<16|(g>>8)<<8|(b>>8))
}
}
segid, err := shm.NewSegId(X)
if err != nil {
log.Fatalln(err)
}
// Need to have it attached on the server before we unload the segment.
c := shm.AttachChecked(X, segid, uint32(shmID), true /* RO */)
if err := c.Check(); err != nil {
log.Fatalln(err)
}
_ = shm.PutImage(X, xproto.Drawable(pixid), cid,
uint16(bounds.Dx()), uint16(bounds.Dy()), 0, 0,
uint16(bounds.Dx()), uint16(bounds.Dy()), 0, 0,
32, xproto.ImageFormatZPixmap,
0 /* SendEvent */, segid, 0 /* Offset */)
}
log.Println("uploading took", time.Now().Sub(Lstart))
// TODO: SHM, for an example see https://github.com/BurntSushi/xgb/issues/28
var scale float64 = 1
for {
ev, xerr := X.WaitForEvent()