forked from tfriedel6/canvas
/
gomobile.go
71 lines (64 loc) · 1.65 KB
/
gomobile.go
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package main
import (
"log"
"math"
"time"
"github.com/InterwebCounty/canvas"
"github.com/InterwebCounty/canvas/backend/xmobilebackend"
"golang.org/x/mobile/app"
"golang.org/x/mobile/event/lifecycle"
"golang.org/x/mobile/event/paint"
"golang.org/x/mobile/event/size"
"golang.org/x/mobile/gl"
)
func main() {
app.Main(func(a app.App) {
var cv, painter *canvas.Canvas
var cvb *xmobilebackend.XMobileBackendOffscreen
var painterb *xmobilebackend.XMobileBackend
var w, h int
var glctx gl.Context
for e := range a.Events() {
switch e := a.Filter(e).(type) {
case lifecycle.Event:
switch e.Crosses(lifecycle.StageVisible) {
case lifecycle.CrossOn:
var err error
glctx = e.DrawContext.(gl.Context)
ctx, err := xmobilebackend.NewGLContext(glctx)
if err != nil {
log.Fatal(err)
}
cvb, err = xmobilebackend.NewOffscreen(0, 0, false, ctx)
if err != nil {
log.Fatalln(err)
}
painterb, err = xmobilebackend.New(0, 0, 0, 0, ctx)
if err != nil {
log.Fatalln(err)
}
cv = canvas.New(cvb)
painter = canvas.New(painterb)
a.Send(paint.Event{})
case lifecycle.CrossOff:
cvb.Delete()
glctx = nil
}
case size.Event:
w, h = e.WidthPx, e.HeightPx
case paint.Event:
if glctx != nil {
fw, fh := float64(w), float64(h)
color := math.Sin(float64(time.Now().UnixNano())*0.000000002)*0.3 + 0.7
cvb.SetSize(w, h)
cv.SetFillStyle(color*0.2, color*0.2, color*0.8)
cv.FillRect(fw*0.25, fh*0.25, fw*0.5, fh*0.5)
painterb.SetBounds(0, 0, w, h)
painter.DrawImage(cv)
a.Publish()
a.Send(paint.Event{})
}
}
}
})
}