I found that the displayLayer called after windowWillClose had been called.

It's wierd, maybe macos need to draw something after a fullscreen window closed, like the window close animation?

Maybe we can just ignore the ondraw event while "view not found" happend.

app/os_macos.go

//export gio_onDraw
func gio_onDraw(view C.CFTypeRef) {
	w, ok := lookupView(view)
	if !ok {
		return
	}
	w.draw()
}

System Version: macos 12.6.1

Gio version: gioui.org v0.0.0-20221122135904-dee53b364560

Reproduce Step: Apply full screen, then close the window.

Example code:

package main

import (
	"flag"

	"gioui.org/app"
	"gioui.org/font/gofont"
	"gioui.org/io/event"
	"gioui.org/io/system"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/widget/material"
)

func main() {
	flag.Parse()

	go run()
	app.Main()
}

func run() {
	w := app.NewWindow()
	var ops op.Ops
	th := material.NewTheme(gofont.Collection())
	for {
		var e event.Event
		e = <-w.Events()
		switch e := e.(type) {
		case system.DestroyEvent:
			go run()
			return
		case system.FrameEvent:
			gtx := layout.NewContext(&ops, e)
			layout.Flex{Axis: layout.Vertical}.Layout(gtx,
				layout.Rigid(material.Body1(th, string("hello world")).Layout),
			)
			e.Frame(gtx.Ops)
		}
	}
}

I'm writing a video player by using Gio, so lot's of image need to be uploaded to Metal.

I cannot reproduce the crash, maybe we should close this issue until i found a way to reproduce the crash.

Thank you for your help!

I found that using a combination of label, giox/contextarea, giox/menu can simulate a dropdown menu, but not perfect enough.

I think maybe a official dropdown-menu widget would be a better solution for this.

Thank you for your great help!

After using the clip op, everything work well!

package main

import (
	"fmt"
	"image"
	"image/color"
	"log"
	"os"

	"gioui.org/app"
	"gioui.org/font/gofont"
	"gioui.org/io/event"
	"gioui.org/io/pointer"
	"gioui.org/io/system"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/op/clip"
	"gioui.org/text"
	"gioui.org/widget/material"
)

func main() {
	w := app.NewWindow()
	go func() {
		th := material.NewTheme(gofont.Collection())
		var ops op.Ops
		l := layout.List{Axis: layout.Vertical}
		for {
			var e event.Event
			e = <-w.Events()
			switch e := e.(type) {
			case system.DestroyEvent:
				os.Exit(0)
				return
			case system.FrameEvent:
				gtx := layout.NewContext(&ops, e)
				l.Layout(gtx, 100, func(gtx layout.Context, index int) layout.Dimensions {
					for _, ev := range gtx.Queue.Events(index) {
						pe, ok := ev.(pointer.Event)
						if !ok {
							continue
						}
						if pe.Type != pointer.Release {
							continue
						}
						log.Println("clicked", index, pe.Type, pe.Buttons)
					}
					label := material.Label(th, 30, fmt.Sprintf("item: #%d", index))
					if index%2 == 0 {
						label.Color = color.NRGBA{A: 255, R: 200}
						label.Font.Weight = text.Bold
					}
					return addEvent(func(gtx layout.Context) layout.Dimensions {
						return layout.Inset{Top: 10, Left: 10}.Layout(gtx, label.Layout)
					}, pointer.InputOp{Tag: index, Types: pointer.Release}.Add)(gtx)
				})
				e.Frame(&ops)
			}
		}
	}()
	app.Main()
}

func addEvent(w layout.Widget, events func(*op.Ops)) layout.Widget {
	return func(gtx layout.Context) layout.Dimensions {
		macro := op.Record(gtx.Ops)
		dis := w(gtx)
		c := macro.Stop()
		rect := clip.Rect{Min: image.Pt(0, 0), Max: dis.Size}
		defer rect.Op().Push(gtx.Ops).Pop()
		// add events
		events(gtx.Ops)
		c.Add(gtx.Ops)
		return dis
	}
}

#Problem description:

I noticed that binding events to items in list works very weird.

#Software Environment

System: macos Monterey 12.6.1 Go version: 1.18.2 darwin/amd64 Gio version in go.mod: gioui.org v0.0.0-20221122135904-dee53b364560

#Example

package main

import (
	"fmt"
	"image/color"
	"log"
	"os"

	"gioui.org/app"
	"gioui.org/font/gofont"
	"gioui.org/io/event"
	"gioui.org/io/pointer"
	"gioui.org/io/system"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/text"
	"gioui.org/widget/material"
)

func main() {
	w := app.NewWindow()
	go func() {
		th := material.NewTheme(gofont.Collection())
		var ops op.Ops
		l := layout.List{Axis: layout.Vertical}
		for {
			var e event.Event
			e = <-w.Events()
			switch e := e.(type) {
			case system.DestroyEvent:
				os.Exit(0)
				return
			case system.FrameEvent:
				gtx := layout.NewContext(&ops, e)
				l.Layout(gtx, 100, func(gtx layout.Context, index int) layout.Dimensions {
					for _, ev := range gtx.Queue.Events(index) {
						pe, ok := ev.(pointer.Event)
						if !ok {
							continue
						}
						log.Println("clicked", index, pe.Type, pe.Buttons)
					}
					pointer.InputOp{Tag: index, Types: pointer.Release}.Add(gtx.Ops)
					label := material.Label(th, 30, fmt.Sprintf("item: #%d", index))
					if index%2 == 0 {
						label.Color = color.NRGBA{A: 255, R: 200}
						label.Font.Weight = text.Bold
					}
					return layout.Inset{Top: 10, Left: 10}.Layout(gtx, label.Layout)
				})
				e.Frame(&ops)
			}
		}
	}()
	app.Main()
}

While I clicked one item, the logs shows that I clicked more than one item.

I tried to solve it myself, but failed. :)

Thank you for your awesome probject!

panic: metal: [MTLCommandQueue cmdBuffer] failed

goroutine 1 [running, locked to thread]: gioui.org/gpu/internal/metal.(*Backend).ensureCmdBuffer(0xb694c00) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/gpu/internal/metal/metal_darwin.go:959 +0x75 gioui.org/gpu/internal/metal.(*Backend).startBlit(0xb694c00) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/gpu/internal/metal/metal_darwin.go:499 +0x46 gioui.org/gpu/internal/metal.(*Texture).Upload(0xc00009b830, {0xc00000e2b8?, 0x0?}, {0x1000000045bbc88?, 0x2?}, {0xc000da0000, 0x1?, 0x7e9000}, 0x1e00) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/gpu/internal/metal/metal_darwin.go:909 +0x27d gioui.org/gpu/internal/driver.UploadImage({0x45bc968?, 0xc00009b830?}, {0x780?, 0x438?}, 0xc00000e2b8?) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/gpu/internal/driver/driver.go:237 +0x6a gioui.org/gpu.(*renderer).texHandle(0xc0001200c0, 0xc0000afc20, {0xc000086280?, {0x4412040?, 0xc000d5a040?}}) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/gpu/gpu.go:443 +0x213 gioui.org/gpu.(*renderer).uploadImages(...) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/gpu/gpu.go:1046 gioui.org/gpu.(*gpu).frame(0xc0000d6d80, {0x45b9440?, 0xc00097a178?}) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/gpu/gpu.go:392 +0x767 gioui.org/gpu.(*gpu).Frame(0xc00096e0f0?, 0xc0004a95c0?, {0x45b9440, 0xc00097a178}, {0xae6ce40?, 0xc0004a95e0?}) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/gpu/gpu.go:359 +0x48 gioui.org/app.(*Window).frame(0xc0000c0000, 0xc0004a96a8?, {0x43c352a?, 0xc0004a9668?}) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/app/window.go:303 +0xa3 gioui.org/app.(*Window).validateAndProcess(0xc0000c0000, {0x45bd7c8, 0xc0000da000}, {0x9?, 0x0?}, 0xd8?, 0x0?, 0x0) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/app/window.go:264 +0x318 gioui.org/app.(*Window).processEvent(0xc0000c0000, {0x45bd7c8, 0xc0000da000}, {0x45b93c0?, 0xc000089a40?}) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/app/window.go:894 +0xe33 gioui.org/app.(*callbacks).Event(0xc0000c04d8, {0x45b93c0?, 0xc000089a40?}) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/app/window.go:487 +0x137 gioui.org/app.(*window).draw(0xc0000da000) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/app/os_macos.go:764 +0x2c5 gioui.org/app.gio_onDraw(0xc0000021a0?) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/app/os_macos.go:557 +0x37 gioui.org/app._Cfunc_gio_main() _cgo_gotypes.go:398 +0x45 gioui.org/app.osMain(...) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/app/os_macos.go:899 gioui.org/app.Main(...) /Users/xxx/gopkg/pkg/mod/gioui.org@v0.0.0-20221122135904-dee53b364560/app/app.go:45

Thank you!

package main

import (
	"image"
	"image/color"

	"gioui.org/app"
	"gioui.org/f32"
	"gioui.org/io/system"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/op/clip"
	"gioui.org/op/paint"
)

func main() {
	go func() {
		var ops op.Ops
		w := app.NewWindow(app.Size(400, 400))
		for e := range w.Events() {
			switch e := e.(type) {
			case system.DestroyEvent:
				return
			case system.FrameEvent:
				gtx := layout.NewContext(&ops, e)

				triangles(gtx)
				e.Frame(gtx.Ops)
			}
		}
	}()
	app.Main()
}

func triangles(ctx layout.Context) layout.Dimensions {
	size := ctx.Dp(300.0)

	b := clip.Rect{Max: image.Pt(size, size)}
	x := b.Push(ctx.Ops)
	paint.ColorOp{
		Color: color.NRGBA{0, 0, 255, 255},
	}.Add(ctx.Ops)
	paint.PaintOp{}.Add(ctx.Ops)
	x.Pop()

	p := clip.Path{}
	p.Begin(ctx.Ops)
	p.MoveTo(f32.Pt(0, 0))
	p.LineTo(f32.Pt(float32(size), 0))
	p.LineTo(f32.Pt(0, float32(size)))
	p.Close()
	s := clip.Outline{
		Path: p.End(),
	}.Op().Push(ctx.Ops)

	paint.ColorOp{
		Color: color.NRGBA{255, 0, 0, 255},
	}.Add(ctx.Ops)
	paint.PaintOp{}.Add(ctx.Ops)
	s.Pop()

	p = clip.Path{}
	p.Begin(ctx.Ops)
	p.MoveTo(f32.Pt(float32(size), 0))
	p.LineTo(f32.Pt(float32(size), float32(size)))
	p.LineTo(f32.Pt(0, float32(size)))
	p.Close()
	s = clip.Outline{
		Path: p.End(),
	}.Op().Push(ctx.Ops)

	paint.ColorOp{
		Color: color.NRGBA{144, 0, 0, 255},
	}.Add(ctx.Ops)
	paint.PaintOp{}.Add(ctx.Ops)
	s.Pop()

	return layout.Dimensions{
		Size: image.Pt(size, size),
	}
}