Setting Position1 of canvas.Circle higher than its Position2 causes panic.

[brokenarmor451]

Checklist

• I have searched the issue tracker for open issues that relate to the same problem, before opening a new one.
• This issue only relates to a single bug. I will open new issues for any other problems.

Describe the bug

When I make a circle using struct initilazation, I have set Position1 value higher than Position2 and get this panic:

panic: runtime error: index out of range [0] with length 0
goroutine 38 [running, locked to thread]:
golang.org/x/image/vector.(*Rasterizer).rasterizeDstRGBASrcUniformOpOver(0xc0004a0000, 0xc00049a040, {{0x3ff0000000000000?, 0x0?}, {0x0?, 0x3ff0000000000000?}}, 0xffff, 0xffff, 0xffff, 0xffff)
	/home/armor/go/pkg/mod/golang.org/x/[email protected]/vector/vector.go:398 +0x2d4
golang.org/x/image/vector.(*Rasterizer).Draw(0xc0004a0000, {0xc793f8?, 0xc00049a040}, {{0xc020000000000000?, 0x0?}, {0x3ff0000000000000?, 0x0?}}, {0xc787f0?, 0xc00049a080?}, {0x0, ...})
	/home/armor/go/pkg/mod/golang.org/x/[email protected]/vector/vector.go:287 +0x188
github.com/srwiley/rasterx.(*ScannerGV).Draw(0xc0004a0000)
	/home/armor/go/pkg/mod/github.com/srwiley/[email protected]/scan.go:141 +0x85
fyne.io/fyne/v2/internal/painter.DrawCircle(0xc0000ae180, 0xae180?, 0xc000486720)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/painter/draw.go:37 +0x39e
fyne.io/fyne/v2/internal/painter/gl.(*painter).newGlCircleTexture(0xc00048e000, {0xc7bde0?, 0xc0000ae180})
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/painter/gl/texture.go:108 +0x75
fyne.io/fyne/v2/internal/painter/gl.(*painter).getTexture(0xc00048e000, {0xc7bde0, 0xc0000ae180}, 0xc0004868a8)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/painter/gl/texture.go:36 +0x4f
fyne.io/fyne/v2/internal/painter/gl.(*painter).drawTextureWithDetails(0xc00048e000, {0xc7bde0?, 0xc0000ae180?}, 0x4349a8?, {0x486920?, 0xc0?}, {0x43cc30?, 0x0?}, {0x18?, 0x0?}, ...)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/painter/gl/draw.go:171 +0x8b
fyne.io/fyne/v2/internal/painter/gl.(*painter).drawCircle(0xc00048e000, 0xc0000ae180, {0x486988?, 0xc0?}, {0x42a145?, 0x0?})
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/painter/gl/draw.go:31 +0xd4
fyne.io/fyne/v2/internal/painter/gl.(*painter).drawObject(0xc0002d6eb8?, {0xc7bde0?, 0xc0000ae180?}, {0x43275d?, 0x0?}, {0xabf600?, 0x0?})
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/painter/gl/draw.go:79 +0x3f
fyne.io/fyne/v2/internal/painter/gl.(*painter).Paint(0x18?, {0xc7bde0, 0xc0000ae180}, {0x90628448?, 0x7f53?}, {0xb9ae3f18?, 0x7f53?})
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/painter/gl/painter.go:89 +0x74
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).paint.func1(0xc000486a20?, {0x8b2c94?, 0x0?})
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/glfw/canvas.go:287 +0x115
fyne.io/fyne/v2/internal/driver/common.(*Canvas).walkTree.func1({0xc7bde0?, 0xc0000ae180}, {0xae180?, 0xc0?}, {0x9e0f0?, 0xc0?}, {0x8b5650?, 0x0?})
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/common/canvas.go:438 +0x277
fyne.io/fyne/v2/internal/driver.walkObjectTree({0xc7bde0, 0xc0000ae180}, 0x0, {0xc7bd80, 0xc00009e0f0}, {0x9e0f0?, 0xc0?}, {0x0?, 0x0?}, {0x0?, ...}, ...)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/util.go:169 +0x2b2
fyne.io/fyne/v2/internal/driver.walkObjectTree.func1(...)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/util.go:176
fyne.io/fyne/v2/internal/driver.walkObjectTree({0xc7bd80, 0xc00009e0f0}, 0x0, {0x0, 0x0}, {0x466e31?, 0x0?}, {0x0?, 0x0?}, {0x486c38?, ...}, ...)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/util.go:190 +0x3ec
fyne.io/fyne/v2/internal/driver.WalkVisibleObjectTree({0xc7bd80?, 0xc00009e0f0?}, 0xc000082820?, 0x200000003?)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/util.go:134 +0x4c
fyne.io/fyne/v2/internal/driver/common.(*Canvas).walkTree(0xc000000000?, 0xc000092560, 0xc000486d80, 0xc000486d50)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/common/canvas.go:459 +0x165
fyne.io/fyne/v2/internal/driver/common.(*Canvas).WalkTrees(0xc00009a240, 0xc000486d50?, 0x9fa246?)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/common/canvas.go:371 +0x3c
fyne.io/fyne/v2/internal/driver/glfw.(*glCanvas).paint(0xc00009a240, {0x0?, 0x0?})
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/glfw/canvas.go:299 +0xfb
fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).repaintWindow.func1()
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/glfw/loop.go:207 +0x8f
fyne.io/fyne/v2/internal/driver/glfw.(*window).RunWithContext(0xc0003c13b0?, 0xc000486e30)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/glfw/window.go:907 +0x4f
fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).repaintWindow(0xc000486e98?, 0xc000122880?)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/glfw/loop.go:198 +0x4a
fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).drawSingleFrame(0xc000486f90?)
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/glfw/loop.go:106 +0x1ac
fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).startDrawThread.func1()
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/glfw/loop.go:254 +0x1a6
created by fyne.io/fyne/v2/internal/driver/glfw.(*gLDriver).startDrawThread
	/home/armor/go/pkg/mod/fyne.io/fyne/[email protected]/internal/driver/glfw/loop.go:230 +0xea
exit status 2

I have noticed if I set Position1: fyne.NewPos(214, 214) , Position2: fyne.NewPos(200, 200) There is no problem. But at 215, 215 and higher (I didn't test all values) gave that panic.

How to reproduce

Make a circle as in the example code, then run to see the panic.

Screenshots

No response

Example code

package main

import (
    "fyne.io/fyne/v2"
    "fyne.io/fyne/v2/app"
    "fyne.io/fyne/v2/canvas"
    "fyne.io/fyne/v2/container"
    "image/color"
)

func main() {

    a := app.New()

    w := a.NewWindow("Reporting")
    w.Resize(fyne.NewSize(900, 900))

	circle := &canvas.Circle{
	    Position1: fyne.NewPos(215, 215),
	    Position2: fyne.NewPos(200, 200),
	    StrokeColor: color.White,
	    StrokeWidth: 5,	
	}

    w.SetContent(container.NewWithoutLayout(circle))

    w.ShowAndRun()

}

Fyne version

2.3.5-rc2

Go compiler version

1.20

Operating system and version

Ubuntu 22.04

Additional Information

I have faced that issue before 2.3.5-rc2 too.

[andydotxyz]

Can you please paste the full panic not just the first line?
The file and line number info is missing in what you have pasted

[brokenarmor451]

Can you please paste the full panic not just the first line? The file and line number info is missing in what you have pasted

I am sorry, I thought it was unnecessary to paste full panic code, because I thought you can try example code and get full panic message, anyways I added it.

[andydotxyz]

Thanks. More info is always better for bug reports :)

[brokenarmor451]

I have tested your fix in the andydotxyz/fyne fix/3949 branch and panic no longer appears. But I don't think myself enough for write a review :)

[andydotxyz]

I have tested your fix in the andydotxyz/fyne fix/3949 branch and panic no longer appears. But I don't think myself enough for write a review :)

Thanks. It does help the approvers to know that the initial issue is reported fixed.

[andydotxyz]

Ready on develop branch for next release