High cpu usage when drawing a table with 288 items

[roffe]

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

Displaying a simple table uses 6-14% CPU on a Intel i9-9900k.

Moving the mouse pointer around in the window spikes 1 core to almost 100% CPU

clicking and marking a cell is noticeably laggy and takes upwards half a second for the blue border to move

I can see the update function is constantly being called just by moving the mouse pointer in the window which might be the culprit causing it to call SetText on all 288 entries even though nothing changed

How to reproduce

Run example program which has 288 data points that needs to be displayed in the table

Screenshots

No response

Example code

package main

import (
	"strconv"

	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
	"fyne.io/fyne/v2/container"
	"fyne.io/fyne/v2/widget"
)

var yValues = []int{6200, 5820, 5440, 5060, 4680, 4300, 3920, 3540, 3160, 2780, 2400, 2020, 1640, 1260, 880, 700}
var xValues = []int{25, 75, 125, 180, 240, 300, 360, 420, 480, 540, 600, 660, 720, 780, 840, 900, 1050, 1300}

var valueMap = [][]float64{
	{0.86, 0.90, 0.92, 0.94, 0.97, 1.00, 1.11, 1.13, 1.15, 1.16, 1.17, 1.19, 1.21, 1.24, 1.32, 1.32, 1.40, 1.45},
	{0.86, 0.90, 0.92, 0.94, 0.97, 1.00, 1.02, 1.11, 1.13, 1.13, 1.14, 1.15, 1.17, 1.18, 1.27, 1.30, 1.37, 1.42},
	{0.85, 0.89, 0.92, 0.95, 0.97, 1.01, 1.01, 1.01, 1.09, 1.10, 1.11, 1.11, 1.13, 1.14, 1.21, 1.25, 1.35, 1.40},
	{0.86, 0.90, 0.93, 0.95, 0.97, 0.99, 1.00, 1.01, 1.02, 1.07, 1.09, 1.10, 1.12, 1.13, 1.15, 1.22, 1.29, 1.34},
	{0.86, 0.93, 0.93, 0.94, 0.96, 0.97, 1.02, 1.01, 1.02, 1.02, 1.08, 1.09, 1.11, 1.12, 1.14, 1.15, 1.27, 1.31},
	{0.85, 0.91, 0.91, 0.92, 0.96, 0.97, 1.00, 1.02, 1.02, 1.02, 1.02, 1.07, 1.10, 1.11, 1.13, 1.14, 1.24, 1.27},
	{0.84, 0.92, 0.92, 0.92, 0.96, 0.99, 0.98, 1.02, 1.01, 1.02, 1.01, 1.01, 1.07, 1.09, 1.12, 1.13, 1.20, 1.25},
	{0.84, 0.90, 0.91, 0.92, 0.95, 0.97, 0.99, 1.00, 1.01, 1.01, 1.01, 1.01, 1.05, 1.07, 1.10, 1.12, 1.18, 1.22},
	{0.84, 0.91, 0.91, 0.92, 0.94, 0.98, 1.00, 1.01, 1.01, 1.01, 1.01, 1.01, 1.01, 1.06, 1.09, 1.10, 1.16, 1.18},
	{0.91, 0.93, 0.92, 0.93, 0.95, 0.97, 1.00, 1.01, 1.01, 1.01, 1.01, 1.01, 1.00, 1.06, 1.08, 1.09, 1.11, 1.12},
	{0.94, 0.92, 0.91, 0.94, 0.95, 0.95, 0.98, 1.00, 1.01, 1.01, 1.01, 1.01, 1.00, 1.06, 1.06, 1.08, 1.10, 1.11},
	{0.95, 0.90, 0.89, 0.92, 0.94, 0.97, 0.97, 0.99, 1.01, 1.01, 1.01, 1.01, 1.06, 1.07, 1.07, 1.08, 1.10, 1.10},
	{0.93, 0.88, 0.89, 0.91, 0.95, 0.97, 0.98, 0.98, 0.99, 1.02, 1.01, 1.01, 1.06, 1.08, 1.09, 1.09, 1.09, 1.09},
	{0.91, 0.87, 0.87, 0.89, 0.95, 0.98, 0.99, 1.00, 1.01, 0.99, 0.99, 1.06, 1.06, 1.08, 1.08, 1.08, 1.08, 1.08},
	{0.87, 0.83, 0.88, 0.88, 0.94, 0.98, 1.00, 1.02, 1.02, 1.03, 1.03, 1.06, 1.07, 1.08, 1.08, 1.08, 1.08, 1.08},
	{0.87, 0.83, 0.89, 0.89, 0.90, 0.97, 1.00, 1.00, 0.99, 1.00, 1.00, 1.06, 1.07, 1.08, 1.08, 1.08, 1.08, 1.08},
}

func main() {
	numRows := len(yValues)
	numColumns := len(xValues)

	a := app.New()
	w := a.NewWindow("Table Test")
	w.Resize(fyne.NewSize(1100, 800))

	t := widget.NewTable(func() (int, int) {
		return numRows + 1, numColumns + 1
	}, func() fyne.CanvasObject {
		return widget.NewEntry()
	}, func(i widget.TableCellID, o fyne.CanvasObject) {
		oo := o.(*widget.Entry)
		if i.Row == 0 && i.Col == 0 {
			oo.Hide()
			return
		}
		if i.Col == 0 {
			strconv.Itoa(yValues[i.Row-1])
			oo.Disable()
		} else if i.Col > 0 && i.Row == 0 {
			oo.SetText(strconv.Itoa(xValues[i.Col-1]))
			oo.Disable()
		} else {
			oo.SetText(strconv.FormatFloat(valueMap[i.Row-1][i.Col-1], 'f', 2, 64))
		}
	})

	for i := 0; i <= numColumns; i++ {
		t.SetColumnWidth(i, 50)
	}

	w.SetContent(container.NewMax(t))

	w.ShowAndRun()
}

Fyne version

2.3.5

Go compiler version

1.21

Operating system and version

Windows 11

Additional Information

No response

[Jacalz]

Thanks for the report. There have been quite a lot of changes to the Table widget for the upcoming release. Would you mind trying out the develop branch to see if the issue still exists?

[roffe]

A little better cpu usage. muchr snappier. also it does not extensively call the update function 👍🏻

Resizing the window so it's smaller than the table and then dragging it out bigger again crashes the test code tougt :/

[andydotxyz]

Can you provide the crash log so we can test against it please? Sounds like something that needs fixed for release.

[roffe]

This is how it should look

After resizing the window and dragging it to be bigger again

[roffe]

it doesn't crash today when i try it so wondering if it is some racecondition that made the window lock up yesterday

[andydotxyz]

Did it crash or hang before?

P.s. I think you're missing calls to Show() and Enable() in your test code

[andydotxyz]

I cannot see any CPU usage when the table is displayed. Perhaps this is a duplicate of #1946?