Testing ground for GUI
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// This is an amalgamation of xgb-xrender.go and xgb-keys.go and more of a demo,
// some comments have been stripped.
package main
import (
"github.com/BurntSushi/xgb"
"github.com/BurntSushi/xgb/render"
"github.com/BurntSushi/xgb/xproto"
"github.com/golang/freetype"
"github.com/golang/freetype/truetype"
"golang.org/x/image/font"
"golang.org/x/image/font/gofont/goregular"
"golang.org/x/image/math/fixed"
"image"
"image/draw"
"io/ioutil"
"log"
"os"
"strings"
)
func glyphListBytes(buf []byte, runes []rune, size int) int {
b := 0
for _, r := range runes {
switch size {
default:
buf[b] = byte(r)
b += 1
case 2:
xgb.Put16(buf[b:], uint16(r))
b += 2
case 4:
xgb.Put32(buf[b:], uint32(r))
b += 4
}
}
return xgb.Pad(b)
}
// When the len is 255, a GLYPHABLE follows, otherwise a list of CARD8/16/32.
func glyphEltHeaderBytes(buf []byte, len byte, deltaX, deltaY int16) int {
b := 0
buf[b] = len
b += 4
xgb.Put16(buf[b:], uint16(deltaX))
b += 2
xgb.Put16(buf[b:], uint16(deltaY))
b += 2
return xgb.Pad(b)
}
type xgbCookie interface{ Check() error }
// compositeString makes an appropriate render.CompositeGlyphs request,
// assuming that glyphs equal Unicode codepoints.
func compositeString(c *xgb.Conn, op byte, src, dst render.Picture,
maskFormat render.Pictformat, glyphset render.Glyphset, srcX, srcY int16,
destX, destY int16, text string) xgbCookie {
runes := []rune(text)
var highest rune
for _, r := range runes {
if r > highest {
highest = r
}
}
size := 1
switch {
case highest > 1<<16:
size = 4
case highest > 1<<8:
size = 2
}
// They gave up on the XCB protocol API and we need to serialize explicitly.
// To spare us from caring about the padding, use the largest number lesser
// than 255 that is divisible by 4 (for size 2 and 4 the requirements are
// less strict but this works in the general case).
const maxPerChunk = 252
buf := make([]byte, (len(runes)+maxPerChunk-1)/maxPerChunk*8+len(runes)*size)
b := 0
for len(runes) > maxPerChunk {
b += glyphEltHeaderBytes(buf[b:], maxPerChunk, 0, 0)
b += glyphListBytes(buf[b:], runes[:maxPerChunk], size)
runes = runes[maxPerChunk:]
}
if len(runes) > 0 {
b += glyphEltHeaderBytes(buf[b:], byte(len(runes)), destX, destY)
b += glyphListBytes(buf[b:], runes, size)
}
switch size {
default:
return render.CompositeGlyphs8(c, op, src, dst, maskFormat, glyphset,
srcX, srcY, buf)
case 2:
return render.CompositeGlyphs16(c, op, src, dst, maskFormat, glyphset,
srcX, srcY, buf)
case 4:
return render.CompositeGlyphs32(c, op, src, dst, maskFormat, glyphset,
srcX, srcY, buf)
}
}
type textRenderer struct {
f *truetype.Font
opts *truetype.Options
face font.Face
bounds fixed.Rectangle26_6 // outer bounds for all the font's glyph
buf *image.RGBA // rendering buffer
X *xgb.Conn
gsid render.Glyphset
loaded map[rune]bool
}
func newTextRenderer(X *xgb.Conn, ttf []byte, opts *truetype.Options) (
*textRenderer, error) {
pformats, err := render.QueryPictFormats(X).Reply()
if err != nil {
return nil, err
}
// We use RGBA here just so that lines are padded to 32 bits.
// Since there's no subpixel antialiasing and alpha is premultiplied,
// it doesn't even mater that RGBA is interpreted as ARGB or BGRA.
var rgbFormat render.Pictformat
for _, pf := range pformats.Formats {
if pf.Depth == 32 && pf.Direct.AlphaMask != 0 {
rgbFormat = pf.Id
break
}
}
tr := &textRenderer{opts: opts, X: X, loaded: make(map[rune]bool)}
if tr.f, err = freetype.ParseFont(goregular.TTF); err != nil {
return nil, err
}
tr.face = truetype.NewFace(tr.f, opts)
tr.bounds = tr.f.Bounds(fixed.Int26_6(opts.Size * float64(opts.DPI) *
(64.0 / 72.0)))
if tr.gsid, err = render.NewGlyphsetId(X); err != nil {
return nil, err
}
if err := render.CreateGlyphSetChecked(X, tr.gsid, rgbFormat).
Check(); err != nil {
return nil, err
}
tr.buf = image.NewRGBA(image.Rect(
+tr.bounds.Min.X.Floor(),
-tr.bounds.Min.Y.Floor(),
+tr.bounds.Max.X.Ceil(),
-tr.bounds.Max.Y.Ceil(),
))
return tr, nil
}
func (tr *textRenderer) addRune(r rune) bool {
dr, mask, maskp, advance, ok := tr.face.Glyph(
fixed.P(0, 0) /* subpixel destination location */, r)
if !ok {
return false
}
for i := 0; i < len(tr.buf.Pix); i++ {
tr.buf.Pix[i] = 0
}
// Copying, since there are absolutely no guarantees.
draw.Draw(tr.buf, dr, mask, maskp, draw.Src)
_ = render.AddGlyphs(tr.X, tr.gsid, 1, []uint32{uint32(r)},
[]render.Glyphinfo{{
Width: uint16(tr.buf.Rect.Size().X),
Height: uint16(tr.buf.Rect.Size().Y),
X: int16(-tr.bounds.Min.X.Floor()),
Y: int16(+tr.bounds.Max.Y.Ceil()),
XOff: int16(advance.Ceil()),
YOff: int16(0),
}}, []byte(tr.buf.Pix))
return true
}
func (tr *textRenderer) render(src, dst render.Picture,
srcX, srcY, destX, destY int16, text string) xgbCookie {
// XXX: You're really supposed to handle tabs differently from this.
text = strings.Replace(text, "\t", " ", -1)
for _, r := range text {
if !tr.loaded[r] {
tr.addRune(r)
tr.loaded[r] = true
}
}
return compositeString(tr.X, render.PictOpOver, src, dst,
0 /* TODO: mask Pictureformat? */, tr.gsid,
srcX, srcY, destX, destY, text)
}
const (
ksEscape = 0xff1b
ksUp = 0xff52
ksDown = 0xff54
ksPageUp = 0xff55
ksPageDown = 0xff56
ksModeSwitch = 0xff7e
)
type keyMapper struct {
X *xgb.Conn
setup *xproto.SetupInfo
mapping *xproto.GetKeyboardMappingReply
modeSwitchMask uint16
}
func newKeyMapper(X *xgb.Conn) (*keyMapper, error) {
m := &keyMapper{X: X, setup: xproto.Setup(X)}
if err := m.update(); err != nil {
return nil, err
}
return m, nil
}
func (km *keyMapper) update() error {
var err error
km.mapping, err = xproto.GetKeyboardMapping(km.X, km.setup.MinKeycode,
byte(km.setup.MaxKeycode-km.setup.MinKeycode+1)).Reply()
if err != nil {
return err
}
km.modeSwitchMask = 0
// The order is "Shift, Lock, Control, Mod1, Mod2, Mod3, Mod4, and Mod5."
mm, err := xproto.GetModifierMapping(km.X).Reply()
if err != nil {
return err
}
perMod := int(mm.KeycodesPerModifier)
perKc := int(km.mapping.KeysymsPerKeycode)
for mod := 0; mod < 8; mod++ {
for _, kc := range mm.Keycodes[mod*perMod : (mod+1)*perMod] {
if kc == 0 {
continue
}
k := int(kc - km.setup.MinKeycode)
for _, ks := range km.mapping.Keysyms[k*perKc : (k+1)*perKc] {
if ks == ksModeSwitch {
km.modeSwitchMask |= 1 << uint(mod)
}
}
}
}
return nil
}
func (km *keyMapper) decode(e xproto.KeyPressEvent) (result xproto.Keysym) {
step := int(km.mapping.KeysymsPerKeycode)
from := int(e.Detail-km.setup.MinKeycode) * step
ks := km.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 since we
// don't have translation tables to Unicode here for brevity.
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
}
}
offset := 0
if e.State&km.modeSwitchMask != 0 {
offset += 2
}
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]
}
return
}
func main() {
if len(os.Args) < 2 {
log.Fatalln("no filename given")
}
text, err := ioutil.ReadFile(os.Args[1])
if err != nil {
log.Fatalln(err)
}
lines := strings.Split(string(text), "\n")
X, err := xgb.NewConn()
if err != nil {
log.Fatalln(err)
}
if err := render.Init(X); 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 {
// TODO: Could/should check other parameters.
for _, v := range i.Visuals {
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{0xf0f0f0f0, 0,
xproto.EventMaskStructureNotify | xproto.EventMaskKeyPress |
/* KeymapNotify */ xproto.EventMaskKeymapState |
xproto.EventMaskExposure | xproto.EventMaskButtonPress,
uint32(mid)})
title := []byte("Viewer")
_ = xproto.ChangeProperty(X, xproto.PropModeReplace, wid, xproto.AtomWmName,
xproto.AtomString, 8, uint32(len(title)), title)
_ = xproto.MapWindow(X, wid)
pformats, err := render.QueryPictFormats(X).Reply()
if err != nil {
log.Fatalln(err)
}
// Similar to XRenderFindVisualFormat.
// The DefaultScreen is almost certain to be zero.
var pformat render.Pictformat
for _, pd := range pformats.Screens[X.DefaultScreen].Depths {
// This check seems to be slightly extraneous.
if pd.Depth != depth {
continue
}
for _, pv := range pd.Visuals {
if pv.Visual == visual {
pformat = pv.Format
}
}
}
pid, err := render.NewPictureId(X)
if err != nil {
log.Fatalln(err)
}
render.CreatePicture(X, pid, xproto.Drawable(wid), pformat, 0, []uint32{})
blackid, err := render.NewPictureId(X)
if err != nil {
log.Fatalln(err)
}
_ = render.CreateSolidFill(X, blackid, render.Color{Alpha: 0xffff})
tr, err := newTextRenderer(X, goregular.TTF, &truetype.Options{
Size: 10,
DPI: float64(screen.WidthInPixels) /
float64(screen.WidthInMillimeters) * 25.4,
Hinting: font.HintingFull,
})
if err != nil {
log.Fatalln(err)
}
scroll := 0 // index of the top line
var w, h uint16
redraw := func() {
y, ascent, step := 5, tr.bounds.Max.Y.Ceil(),
tr.bounds.Max.Y.Ceil()-tr.bounds.Min.Y.Floor()
for _, line := range lines[scroll:] {
if uint16(y) >= h {
break
}
_ = tr.render(blackid, pid, 0, 0, 5, int16(y+ascent), line)
y += step
}
vis := float64(h-10) / float64(step)
if vis < float64(len(lines)) {
length := float64(step) * (vis + 1) * vis / float64(len(lines))
start := float64(step) * float64(scroll) * vis / float64(len(lines))
_ = render.FillRectangles(X, render.PictOpSrc, pid,
render.Color{Alpha: 0xffff}, []xproto.Rectangle{{
X: int16(w - 15), Y: int16(start),
Width: 15, Height: uint16(length + 10)}})
}
}
km, err := newKeyMapper(X)
if err != nil {
log.Fatalln(err)
}
for {
ev, xerr := X.WaitForEvent()
if xerr != nil {
log.Printf("Error: %s\n", xerr)
return
}
if ev == nil {
return
}
switch e := ev.(type) {
case xproto.UnmapNotifyEvent:
return
case xproto.ConfigureNotifyEvent:
w, h = e.Width, e.Height
case xproto.MappingNotifyEvent:
_ = km.update()
case xproto.KeyPressEvent:
_ = xproto.ClearArea(X, true /* ExposeEvent */, wid, 0, 0, w, h)
const pageJump = 40
switch km.decode(e) {
case ksEscape:
return
case ksUp:
if scroll >= 1 {
scroll--
}
case ksDown:
if scroll+1 < len(lines) {
scroll++
}
case ksPageUp:
if scroll >= pageJump {
scroll -= pageJump
}
case ksPageDown:
if scroll+pageJump < len(lines) {
scroll += pageJump
}
}
case xproto.ButtonPressEvent:
_ = xproto.ClearArea(X, true /* ExposeEvent */, wid, 0, 0, w, h)
switch e.Detail {
case xproto.ButtonIndex4:
if scroll > 0 {
scroll--
}
case xproto.ButtonIndex5:
if scroll+1 < len(lines) {
scroll++
}
}
case xproto.ExposeEvent:
// FIXME: The window's context haven't necessarily been destroyed.
if e.Count == 0 {
redraw()
}
}
}
}