[bug] Markdown crashes on window resize

[ioxenus]

What happend?

The app crashes when there's a Markdown element (containing whatever, even just a line of plain text) and I resize the app's window. It doesn't crash if you resize quickly (or a little); so I guess it takes a bunch of update/refresh events to make the app crash.

Stacktrace:

goroutine 1 [running, locked to thread]:
github.com/AllenDang/cimgui-go/internal.(*Pool[...]).Allocate(0x104cda9a0, 0x1400025ad20)
	go/pkg/mod/github.com/!allen!dang/[email protected]/internal/pool.go:37 +0x164
github.com/AllenDang/cimgui-go/immarkdown.MarkdownLinkCallback.Handle(0x1400022f6f8?)
	go/pkg/mod/github.com/!allen!dang/[email protected]/immarkdown/cimmarkdown_typedefs.go:784 +0x34
github.com/AllenDang/cimgui-go/immarkdown.MarkdownConfig.SetLinkCallback({0x140001802a0}, 0x104c83e40?)
	go/pkg/mod/github.com/!allen!dang/[email protected]/immarkdown/cimmarkdown_funcs.go:459 +0x2c
github.com/AllenDang/giu.(*MarkdownWidget).OnLink(0x140000a3880, 0x104cd34b0)
	go/pkg/mod/github.com/!allen!dang/[email protected]/Markdown.go:95 +0x74
github.com/AllenDang/giu.Markdown({0x104b2f838, 0x3})
	go/pkg/mod/github.com/!allen!dang/[email protected]/Markdown.go:82 +0x118
main.loop()
	Projects/giu11md/main.go:12 +0x30
github.com/AllenDang/giu.(*MasterWindow).render(0x1400003c660)
	go/pkg/mod/github.com/!allen!dang/[email protected]/MasterWindow.go:253 +0x200
github.com/AllenDang/cimgui-go/backend.loopCallback()
	go/pkg/mod/github.com/!allen!dang/[email protected]/backend/backend.go:36 +0x44
github.com/AllenDang/cimgui-go/backend/glfwbackend._Cfunc_igGLFWRunLoop(0x134633410, 0x104845c48, 0x104845c94, 0x104845ce0, 0x104845d78)
	_cgo_gotypes.go:409 +0x30
github.com/AllenDang/cimgui-go/backend/glfwbackend.(*GLFWBackend).Run.func1(0x6f00000000001?)
	go/pkg/mod/github.com/!allen!dang/[email protected]/backend/glfwbackend/glfw_backend.go:264 +0xa8
github.com/AllenDang/cimgui-go/backend/glfwbackend.(*GLFWBackend).Run(0x10486dbe8?, 0x1400006eed8?)
	go/pkg/mod/github.com/!allen!dang/[email protected]/backend/glfwbackend/glfw_backend.go:264 +0x40
main.main.(*MasterWindow).Run.func1()
	go/pkg/mod/github.com/!allen!dang/[email protected]/MasterWindow.go:270 +0xe4
golang.design/x/hotkey/mainthread.Call(0x1400011c018)
	go/pkg/mod/golang.design/x/[email protected]/mainthread/os_darwin.go:36 +0x80
github.com/AllenDang/giu.mainthreadCallPlatform(...)
	go/pkg/mod/github.com/!allen!dang/[email protected]/mainthread_mac.go:9
github.com/AllenDang/giu.(*MasterWindow).Run(...)
	go/pkg/mod/github.com/!allen!dang/[email protected]/MasterWindow.go:262
main.main()
	Projects/giu11md/main.go:19 +0x88
exit status 2

Code example

main.go

package main

import (
	g "github.com/AllenDang/giu"
)

func loop() {
	var md_content = "[https://example.org](https://example.org)"

	g.SingleWindow().Layout(
		g.Row(
			g.Markdown(md_content),
		),
	)
}

func main() {
	w := g.NewMasterWindow("Markdown", 500, 300, 0)
	w.Run(loop)
}

To Reproduce

1. Run my demo
2. try resizing the window for a bit (it doesn't happen instantly)

Version

v0.11.0

OS

darwin / arm64 (macOS 14.6.1)

[gucio321]

panic: cimgui-go/internal.Pool: Allocate: Out of space!
	
	This means that you attempt to allocate too many callbacks for immarkdown.MarkdownLinkCallback.
	There are several possible solutions:
	- You forgot to call Clear() for the pool (e.g. on the end/beginning of the frame)
	- You've too many items calling Allocate without cleaning (more than 32).
	  I this is the case, plelase report an issue ane we'll increase pool limit for the type.
	
	Refer: https://github.com/AllenDang/cimgui-go/issues/224
	

You should also see this.

Generally giu should handle this. Why it doesn't?...

[gucio321]

I did an experiment:

diff --git a/Markdown.go b/Markdown.go
index 0f55f16..ee59b66 100644
--- a/Markdown.go
+++ b/Markdown.go
@@ -1,6 +1,7 @@
 package giu
 
 import (
+	"fmt"
 	"image"
 	"image/color"
 	"net/http"
@@ -82,6 +83,8 @@ func Markdown(md string) *MarkdownWidget {
 	}).OnLink(OpenURL)
 }
 
+var u = 0
+
 // OnLink sets another than default link callback.
 // NOTE: due to cimgui-go's limitation https://github.com/AllenDang/cimgui-go?tab=readme-ov-file#callbacks
 // we clear MarkdownLinkCallback pool every frame. No further action from you should be required (just feel informed).
@@ -92,6 +95,8 @@ func (m *MarkdownWidget) OnLink(cb func(url string)) *MarkdownWidget {
 		cb(link)
 	})
 
+	fmt.Println("call", u)
+	u++
 	m.getState().cfg.SetLinkCallback(&igCb)
 
 	return m
diff --git a/MasterWindow.go b/MasterWindow.go
index bd43c13..6749587 100644
--- a/MasterWindow.go
+++ b/MasterWindow.go
@@ -205,6 +205,7 @@ func (w *MasterWindow) beforeRender() {
 	// Clean callbacks
 	// see https://github.com/AllenDang/cimgui-go?tab=readme-ov-file#callbacks
 	immarkdown.ClearMarkdownLinkCallbackPool()
+	u = 0
 
 	Context.FontAtlas.rebuildFontAtlas()
 

and, u is not 0 all the time. SO this turns out to be related AllenDang/cimgui-go#345