xgb-image: add a demo that shows a scaled picture
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A0420B94F92B9493
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@ -0,0 +1,252 @@
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package main
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import (
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"encoding/binary"
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"github.com/BurntSushi/xgb"
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"github.com/BurntSushi/xgb/render"
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"github.com/BurntSushi/xgb/xproto"
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"log"
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"os"
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"time"
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"image"
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_ "image/gif"
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_ "image/jpeg"
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_ "image/png"
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)
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func F64ToFixed(f float64) render.Fixed { return render.Fixed(f * 65536) }
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func FixedToF64(f render.Fixed) float64 { return float64(f) / 65536 }
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func main() {
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/*
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pf, err := os.Create("pprof.out")
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if err != nil {
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log.Fatal(err)
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}
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pprof.StartCPUProfile(pf)
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defer pprof.StopCPUProfile()
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*/
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// Load a picture from the command line.
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f, err := os.Open(os.Args[1])
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if err != nil {
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log.Fatalln(err)
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}
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defer f.Close()
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img, name, err := image.Decode(f)
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if err != nil {
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log.Fatalln(err)
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}
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log.Println("image type is", name)
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// Miscellaneous X11 initialization.
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X, err := xgb.NewConn()
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if err != nil {
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log.Fatalln(err)
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}
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if err := render.Init(X); err != nil {
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log.Fatalln(err)
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}
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setup := xproto.Setup(X)
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screen := setup.DefaultScreen(X)
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visual, depth := screen.RootVisual, screen.RootDepth
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// TODO: We should check that we find it, though we don't /need/ alpha here,
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// it's just a minor improvement--affects the backpixel value.
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for _, i := range screen.AllowedDepths {
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for _, v := range i.Visuals {
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// TODO: Could/should check other parameters.
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if i.Depth == 32 && v.Class == xproto.VisualClassTrueColor {
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visual, depth = v.VisualId, i.Depth
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break
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}
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}
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}
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mid, err := xproto.NewColormapId(X)
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if err != nil {
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log.Fatalln(err)
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}
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_ = xproto.CreateColormap(
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X, xproto.ColormapAllocNone, mid, screen.Root, visual)
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wid, err := xproto.NewWindowId(X)
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if err != nil {
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log.Fatalln(err)
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}
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// Border pixel and colormap are required when depth differs from parent.
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_ = xproto.CreateWindow(X, depth, wid, screen.Root,
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0, 0, 500, 500, 0, xproto.WindowClassInputOutput,
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visual, xproto.CwBackPixel|xproto.CwBorderPixel|xproto.CwEventMask|
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xproto.CwColormap, []uint32{0x80808080, 0,
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xproto.EventMaskStructureNotify | xproto.EventMaskExposure,
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uint32(mid)})
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title := []byte("Image")
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_ = xproto.ChangeProperty(X, xproto.PropModeReplace, wid, xproto.AtomWmName,
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xproto.AtomString, 8, uint32(len(title)), title)
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_ = xproto.MapWindow(X, wid)
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pformats, err := render.QueryPictFormats(X).Reply()
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if err != nil {
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log.Fatalln(err)
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}
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// Similar to XRenderFindVisualFormat.
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// The DefaultScreen is almost certain to be zero.
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var pformat render.Pictformat
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for _, pd := range pformats.Screens[X.DefaultScreen].Depths {
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// This check seems to be slightly extraneous.
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if pd.Depth != depth {
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continue
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}
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for _, pv := range pd.Visuals {
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if pv.Visual == visual {
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pformat = pv.Format
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}
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}
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}
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// Wrap the window's surface in a picture.
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pid, err := render.NewPictureId(X)
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if err != nil {
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log.Fatalln(err)
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}
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render.CreatePicture(X, pid, xproto.Drawable(wid), pformat, 0, []uint32{})
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// setup.BitmapFormatScanline{Pad,Unit} and setup.BitmapFormatBitOrder
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// don't interest us here since we're only using Z format pixmaps.
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for _, pf := range setup.PixmapFormats {
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if pf.Depth == 32 {
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if pf.BitsPerPixel != 32 || pf.ScanlinePad != 32 {
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log.Fatalln("unsuported X server")
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}
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}
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}
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pixid, err := xproto.NewPixmapId(X)
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if err != nil {
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log.Fatalln(err)
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}
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_ = xproto.CreatePixmap(X, 32, pixid, xproto.Drawable(screen.Root),
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uint16(img.Bounds().Dx()), uint16(img.Bounds().Dy()))
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var bgraFormat render.Pictformat
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wanted := render.Directformat{
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RedShift: 16,
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RedMask: 0xff,
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GreenShift: 8,
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GreenMask: 0xff,
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BlueShift: 0,
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BlueMask: 0xff,
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AlphaShift: 24,
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AlphaMask: 0xff,
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}
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for _, pf := range pformats.Formats {
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if pf.Depth == 32 && pf.Direct == wanted {
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bgraFormat = pf.Id
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break
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}
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}
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if bgraFormat == 0 {
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log.Fatalln("ARGB format not found")
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}
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// We could also look for the inverse pictformat.
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var encoding binary.ByteOrder
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if setup.ImageByteOrder == xproto.ImageOrderMSBFirst {
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encoding = binary.BigEndian
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} else {
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encoding = binary.LittleEndian
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}
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pixpicid, err := render.NewPictureId(X)
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if err != nil {
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log.Fatalln(err)
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}
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render.CreatePicture(X, pixpicid, xproto.Drawable(pixid), bgraFormat,
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0, []uint32{})
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// Do we really need this? :/
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cid, err := xproto.NewGcontextId(X)
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if err != nil {
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log.Fatalln(err)
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}
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_ = xproto.CreateGC(X, cid, xproto.Drawable(pixid),
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xproto.GcGraphicsExposures, []uint32{0})
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// Load data into the pixmap. Also see xgbutil/xgraphics/xsurface.go.
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// We're being lazy and resolve the 1<<16 limit of requests by sending
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// a row at a time. The encoding is also done inefficiently.
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bounds := img.Bounds()
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Lstart := time.Now()
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row := make([]byte, bounds.Dx()*4)
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for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
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for x := bounds.Min.X; x < bounds.Max.X; x++ {
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r, g, b, a := img.At(x, y).RGBA()
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encoding.PutUint32(row[x*4:],
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(a>>8)<<24|(r>>8)<<16|(g>>8)<<8|(b>>8))
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}
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_ = xproto.PutImage(X, xproto.ImageFormatZPixmap,
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xproto.Drawable(pixid), cid, uint16(bounds.Dx()), 1,
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0, int16(y),
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0, 32, row)
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}
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log.Println("uploading took", time.Now().Sub(Lstart))
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// TODO: SHM, for an example see https://github.com/BurntSushi/xgb/issues/28
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var scale float64 = 1
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for {
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ev, xerr := X.WaitForEvent()
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if xerr != nil {
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log.Printf("Error: %s\n", xerr)
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return
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}
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if ev == nil {
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return
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}
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log.Printf("Event: %s\n", ev)
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switch e := ev.(type) {
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case xproto.UnmapNotifyEvent:
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return
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case xproto.ConfigureNotifyEvent:
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w, h := e.Width, e.Height
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scaleX := float64(bounds.Dx()) / float64(w)
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scaleY := float64(bounds.Dy()) / float64(h)
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if scaleX < scaleY {
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scale = scaleY
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} else {
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scale = scaleX
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}
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_ = render.SetPictureTransform(X, pixpicid, render.Transform{
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F64ToFixed(scale), F64ToFixed(0), F64ToFixed(0),
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F64ToFixed(0), F64ToFixed(scale), F64ToFixed(0),
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F64ToFixed(0), F64ToFixed(0), F64ToFixed(1),
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})
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_ = render.SetPictureFilter(X, pixpicid, 8, "bilinear", nil)
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case xproto.ExposeEvent:
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_ = render.Composite(X, render.PictOpSrc,
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pixpicid, render.PictureNone, pid,
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0, 0, 0, 0, 0 /* dst-x */, 0, /* dst-y */
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uint16(float64(img.Bounds().Dx())/scale),
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uint16(float64(img.Bounds().Dy())/scale))
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}
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}
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}
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