initial implementation

go.mod

@@ -0,0 +1,10 @@
+module gitea.beetbox.io/Alex/pv
+
+go 1.18
+
+require github.com/linuxdeepin/go-x11-client v0.0.0-20221118020450-811d87e63fec
+
+require (
+	github.com/stretchr/testify v1.8.1 // indirect
+	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
+)

go.sum

@@ -0,0 +1,25 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
+github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/linuxdeepin/go-x11-client v0.0.0-20221118020450-811d87e63fec h1:CaVGU829QOYwWrKdvC06uMTXkrj4vwyH4UGAn92bdzE=
+github.com/linuxdeepin/go-x11-client v0.0.0-20221118020450-811d87e63fec/go.mod h1:KwpmRZ47A/0a2l9V0V6aTlkuNaqy5j1fOqMFJONuIMY=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -0,0 +1,139 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"math"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"github.com/linuxdeepin/go-x11-client/util/cursor"
+	"github.com/linuxdeepin/go-x11-client/util/mousebind"
+
+	x "github.com/linuxdeepin/go-x11-client"
+)
+
+// Give names to the events we care about
+const (
+	Pressed  uint8 = 4
+	Released       = 5
+)
+
+type dragger struct {
+	Done        chan bool
+	events      chan x.GenericEvent
+	ctx         context.Context
+	pointerDown bool
+	start       [2]int16
+	end         [2]int16
+}
+
+// NewDragger returns a new reference to a dragger.
+// This dragger can only be used to watch one drag event.
+func NewDragger(events chan x.GenericEvent, ctx context.Context) *dragger {
+	return &dragger{
+		Done:   make(chan bool, 1),
+		events: events,
+		ctx:    ctx,
+	}
+}
+
+// Watch begins the process of dragger watching for drag events
+func (s *dragger) Watch() {
+	for {
+		select {
+		case generic := <-s.events:
+			s.handleEvent(generic)
+			break
+		case _ = <-s.ctx.Done():
+			return
+		}
+	}
+}
+
+func (s *dragger) handleEvent(generic x.GenericEvent) {
+	event, err := x.NewButtonPressEvent(generic)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	code := generic.GetEventCode()
+
+	if code == Pressed {
+		s.pointerDown = true
+		s.start = [2]int16{event.EventX, event.EventY}
+	} else {
+		s.end = [2]int16{event.EventX, event.EventY}
+		if s.pointerDown {
+			s.pointerDown = false
+			s.Done <- true
+		} else {
+			s.Done <- false
+		}
+	}
+}
+
+// Distance returns the total distance of the drag event
+func (s dragger) Distance() int {
+	diffx := int(s.start[0] - s.end[0])
+	diffy := int(s.start[1] - s.end[1])
+	distance := math.Sqrt(float64((diffx * diffx) + (diffy * diffy)))
+	return int(distance)
+}
+
+func loadCursor(conn *x.Conn) (x.Cursor, error) {
+	img, err := cursor.LoadImage("default", "crosshair", 2)
+	if err != nil {
+		return x.CursorNone, err
+	}
+
+	return img.LoadCursor(conn, "")
+}
+
+func main() {
+	stop := make(chan os.Signal)
+	signal.Notify(stop, os.Interrupt, syscall.SIGTERM, syscall.SIGINT)
+
+	display, err := x.NewConnDisplay("")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer display.Close()
+
+	screen := display.GetDefaultScreen()
+
+	curs, err := loadCursor(display)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	mask := uint16(x.EventMaskButtonPress | x.EventMaskButtonRelease)
+	err = mousebind.GrabPointer(display, screen.Root, mask, x.None, curs)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	defer mousebind.UngrabPointer(display)
+
+	eventChan := display.MakeAndAddEventChan(1)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	dm := NewDragger(eventChan, ctx)
+	go dm.Watch()
+
+	for {
+		select {
+		case v := <-dm.Done:
+			if v {
+				fmt.Println(dm.Distance())
+				os.Exit(0)
+			}
+			break
+		case <-stop:
+			cancel()
+			os.Exit(0)
+		}
+	}
+}