xgb-keys: minimal example of reading keys

This commit is contained in:
Přemysl Eric Janouch 2018-08-24 20:45:16 +02:00
parent 9e070e9648
commit ff7518c74d
Signed by: p
GPG Key ID: A0420B94F92B9493
1 changed files with 213 additions and 0 deletions

213
prototypes/xgb-keys.go Normal file
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package main
import (
"github.com/BurntSushi/xgb"
//"github.com/BurntSushi/xgb/xkb"
"github.com/BurntSushi/xgb/xproto"
"log"
)
func main() {
X, err := xgb.NewConn()
if err != nil {
log.Fatalln(err)
}
/*
// Use the extension if available, makes better use of state bits.
if err := xkb.Init(X); err == nil {
if _, err := xkb.UseExtension(X, 1, 0).Reply(); err != nil {
log.Fatalln(err)
}
}
*/
setup := xproto.Setup(X)
screen := setup.DefaultScreen(X)
visual, depth := screen.RootVisual, screen.RootDepth
// TODO: We should check that we find it, though we don't /need/ alpha here,
// it's just a minor improvement--affects the backpixel value.
for _, i := range screen.AllowedDepths {
for _, v := range i.Visuals {
// TODO: Could/should check other parameters.
if i.Depth == 32 && v.Class == xproto.VisualClassTrueColor {
visual, depth = v.VisualId, i.Depth
break
}
}
}
mid, err := xproto.NewColormapId(X)
if err != nil {
log.Fatalln(err)
}
_ = xproto.CreateColormap(
X, xproto.ColormapAllocNone, mid, screen.Root, visual)
wid, err := xproto.NewWindowId(X)
if err != nil {
log.Fatalln(err)
}
// Border pixel and colormap are required when depth differs from parent.
_ = xproto.CreateWindow(X, depth, wid, screen.Root,
0, 0, 500, 500, 0, xproto.WindowClassInputOutput,
visual, xproto.CwBackPixel|xproto.CwBorderPixel|xproto.CwEventMask|
xproto.CwColormap, []uint32{0x80808080, 0,
xproto.EventMaskStructureNotify | xproto.EventMaskKeyPress |
/* KeymapNotify */ xproto.EventMaskKeymapState, uint32(mid)})
title := []byte("Keys")
_ = xproto.ChangeProperty(X, xproto.PropModeReplace, wid, xproto.AtomWmName,
xproto.AtomString, 8, uint32(len(title)), title)
_ = xproto.MapWindow(X, wid)
mapping, err := xproto.GetKeyboardMapping(X, setup.MinKeycode,
byte(setup.MaxKeycode-setup.MinKeycode+1)).Reply()
if err != nil {
log.Fatalln(err)
}
// The order is "Shift, Lock, Control, Mod1, Mod2, Mod3, Mod4, and Mod5."
mm, err := xproto.GetModifierMapping(X).Reply()
if err != nil {
log.Fatalln(err)
}
// XXX: This seems pointless, the key will just end up switching groups
// instead of levels without full XKB handling. Though perhaps it might
// at least work as intended when there's only one XKB group.
const MODE_SWITCH = 0xff7e
var modeSwitchMask uint16
for mod := 0; mod < 8; mod++ {
perMod := int(mm.KeycodesPerModifier)
for _, kc := range mm.Keycodes[mod*perMod : (mod+1)*perMod] {
if kc == 0 {
continue
}
perKc := int(mapping.KeysymsPerKeycode)
k := int(kc - setup.MinKeycode)
for _, ks := range mapping.Keysyms[k*perKc : (k+1)*perKc] {
if ks == MODE_SWITCH {
modeSwitchMask |= 1 << uint(mod)
}
}
}
}
for {
ev, xerr := X.WaitForEvent()
if xerr != nil {
log.Printf("Error: %s\n", xerr)
return
}
if ev == nil {
return
}
log.Printf("Event: %s\n", ev)
switch e := ev.(type) {
case xproto.UnmapNotifyEvent:
return
case xproto.KeymapNotifyEvent:
// e.Keys is a 32 * 8 large bitmap indicating which keys are
// currently pressed down. This is sent "after every EnterNotify
// and FocusIn" but it also seems to fire when the keyboard layout
// changes. aixterm manual even speaks of that explicitly.
//
// But since changing the effective group involves no changes to
// the compatibility mapping, there's nothing for us to do.
case xproto.MappingNotifyEvent:
// e.FirstKeyCode .. e.Count changes have happened but rereading
// everything is the simpler thing to do.
mapping, err = xproto.GetKeyboardMapping(X, setup.MinKeycode,
byte(setup.MaxKeycode-setup.MinKeycode+1)).Reply()
if err != nil {
log.Fatalln(err)
}
// TODO: We should also repeat the search for MODE SWITCH.
case xproto.KeyPressEvent:
step := int(mapping.KeysymsPerKeycode)
from := int(e.Detail-setup.MinKeycode) * step
ks := mapping.Keysyms[from : from+step]
// Strip trailing NoSymbol entries.
for len(ks) > 0 && ks[len(ks)-1] == 0 {
ks = ks[:len(ks)-1]
}
// Expand back to at least 4.
switch {
case len(ks) == 1:
ks = append(ks, 0, ks[0], 0)
case len(ks) == 2:
ks = append(ks, ks[0], ks[1])
case len(ks) == 3:
ks = append(ks, 0)
}
// Other silly expansion rules, only applied to basic ASCII.
if ks[1] == 0 {
ks[1] = ks[0]
if ks[0] >= 'A' && ks[0] <= 'Z' ||
ks[0] >= 'a' && ks[0] <= 'z' {
ks[0] = ks[0] | 32
ks[1] = ks[0] &^ 32
}
}
if ks[3] == 0 {
ks[3] = ks[2]
if ks[2] >= 'A' && ks[2] <= 'Z' ||
ks[2] >= 'a' && ks[2] <= 'z' {
ks[2] = ks[2] | 32
ks[3] = ks[2] &^ 32
}
}
// We only have enough information to switch between two groups.
offset := 0
if e.State&modeSwitchMask != 0 {
offset += 2
}
var result xproto.Keysym
shift := e.State&xproto.ModMaskShift != 0
lock := e.State&xproto.ModMaskLock != 0
switch {
case !shift && !lock:
result = ks[offset+0]
case !shift && lock:
if ks[offset+0] >= 'a' && ks[offset+0] <= 'z' {
result = ks[offset+1]
} else {
result = ks[offset+0]
}
case shift && lock:
if ks[offset+1] >= 'a' && ks[offset+1] <= 'z' {
result = ks[offset+1] &^ 32
} else {
result = ks[offset+1]
}
case shift:
result = ks[offset+1]
}
if result <= 0xff {
log.Printf("%c (Latin-1)\n", rune(result))
} else {
log.Println(result)
}
}
}
}