Table Resizing Lags

May 2, 2025 by ADMIN 20 views

Introduction

Fyne is a cross-platform GUI framework for Go, providing a simple and efficient way to create desktop applications. However, like any other software, it is not immune to bugs and issues. In this article, we will explore a specific problem related to table resizing in a Fyne application, and provide a step-by-step guide to reproduce and fix the issue.

The Bug: Table Resizing Lags

When resizing a table with headers in a Fyne application, it can lag or freeze, causing an unpleasant user experience. This issue is particularly noticeable when the table is populated with a large amount of data.

How to Reproduce the Bug

To reproduce the bug, follow these steps:

Run the Fyne application.
Start capturing the table data by clicking the "Start Capture" button.
Resize the table by dragging the border or using the mouse wheel.

Example Code

The example code provided is a simple Fyne application that demonstrates the table resizing lag issue. The code is divided into three files: logic/data.go, ui/ui.go, and main.go.

logic/data.go

package logic

import (
	"math/rand"
	"time"
)

type TableData struct {
	Timestamp time.Time
	Value     string
}

type DataGenerator struct {
	Data         []TableData
	OnDataUpdate func([]TableData)
	stopChan     chan struct{}
	running      bool
}

func NewDataGenerator() *DataGenerator {
	return &DataGenerator{
		Data:     make([]TableData, 0),
		stopChan: make(chan struct{}),
	}
}

func (dg *DataGenerator) Start() {
	if dg.running {
		return
	}

	dg.running = true
	go func() {
		ticker := time.NewTicker(40 * time.Millisecond)
		defer ticker.Stop()

		id := 0
		for {
			select {
			case <-ticker.C:
				id++
				newData := TableData{
					Timestamp: time.Now(),
					Value:     generateRandomValue(),
				}

				dg.Data = append(dg.Data, newData)

				if dg.OnDataUpdate != nil {
					dg.OnDataUpdate(dg.Data)
				}

			case <-dg.stopChan:
				return
			}
		}
	}()
}

func (dg *DataGenerator) Stop() {
	if !dg.running {
		return
	}

	dg.running = false
	dg.stopChan <- struct{}{}
}

func (dg *DataGenerator) GetData() []TableData {
	return dg.Data
}

func (dg *DataGenerator) IsRunning() bool {
	return dg.running
}

func generateRandomValue() string {
	const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	length := rand.Intn(10) + 5

	b := make([]byte, length)
	for i := range b {
		b[i] = charset[rand.Intn(len(charset))]
	}

	return string(b)
}

ui/ui.go

package ui

import (
	"FyneTest/logic"

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

type UI struct {
	Table         *widget.Table
	AutoScroll    *widget.Check
	CaptureButton *widget.Button
	DataGenerator *logic.DataGenerator
}

func NewUI() *UI {
	ui := &UI{
		AutoScroll:    widget.NewCheck("Auto Scroll", nil),
		DataGenerator: logic.NewDataGenerator(),
	}

	ui.CaptureButton = widget.NewButton("Start Capture", func() {
		if ui.DataGenerator.IsRunning() {
			ui.DataGenerator.Stop()
			ui.CaptureButton.SetText("Start Capture")
		} else {
			ui.DataGenerator.Start()
			ui.CaptureButton.SetText("Stop Capture")
		}
	})

	ui.Table = widget.NewTableWithHeaders(
		func() (int, int) {
			return len(ui.DataGenerator.GetData()), 2
		},
		func() fyne.CanvasObject {
			label := widget.NewLabel("Template")
			label.Wrapping = fyne.TextWrapWord
			return label
		},
		func(i widget.TableCellID, o fyne.CanvasObject) {
			label := o.(*widget.Label)

			data := ui.DataGenerator.GetData()
			if i.Row < len(data) {
				item := data[i.Row]
				switch i.Col {
				case 0:
					label.SetText(item.Timestamp.Format("15:04:05.000"))
				case 1:
					label.SetText(item.Value)
				}
			} else {
				label.SetText("")
			}
		},
	)

	ui.Table.SetColumnWidth(0, 120)
	ui.Table.SetColumnWidth(1, 300)

	ui.AutoScroll.SetChecked(true)

	ui.DataGenerator.OnDataUpdate = func(data []logic.TableData) {
		fyne.Do(func() {
			if ui.AutoScroll.Checked && len(data) > 0 {
				ui.Table.ScrollTo(widget.TableCellID{Row: len(data), Col: 0})
			}
		})
	}

	return ui
}

func (ui *UI) CreateContent() *fyne.Container {
	topControls := container.NewHBox(ui.CaptureButton)

	return container.NewBorder(
		topControls,
		ui.AutoScroll,
		nil,
		nil,
		ui.Table,
	)
}

main.go

package main

import (
	"FyneTest/ui"
	"fyne.io/fyne/v2"
	"fyne.io/fyne/v2/app"
)

func main() {
	a := app.New()
	w := a.NewWindow("Fyne Test")
	w.Resize(fyne.NewSize(800, 600))

	uiInstance := ui.NewUI()
	content := uiInstance.CreateContent()

	w.SetContent(content)
	w.ShowAndRun()
}

Fyne Version

The Fyne version used in this example is 2.6.0.

Go Compiler Version

The Go compiler version used in this example is 1.24.2.

Operating System and Version

The operating system and version used in this example is Arch Linux x86_64 | Linux 6.14.4-arch1-2 | Hyprland 6.14.4.-arch1-2.

Conclusion

In conclusion, the table resizing lag issue in Fyne applications can be reproduced by following the steps outlined in this article. The example code provided demonstrates the issue and can be used as a starting point for further investigation and debugging. By understanding the root cause of the issue, can work towards providing a smoother user experience for their applications.

Future Work

To further improve the performance of table resizing in Fyne applications, the following steps can be taken:

Optimize the data generation process: The data generation process can be optimized by reducing the frequency of updates or by using a more efficient algorithm.
Improve the table rendering: The table rendering process can be improved by using a more efficient rendering algorithm or by reducing the number of rendering operations.
Use caching: Caching can be used to reduce the number of rendering operations and improve performance.
Use parallel processing: Parallel processing can be used to improve performance by executing multiple tasks simultaneously.

Introduction

In our previous article, we explored a specific problem related to table resizing in a Fyne application, and provided a step-by-step guide to reproduce and fix the issue. In this article, we will answer some frequently asked questions related to the table resizing lag issue in Fyne applications.

Q: What is the root cause of the table resizing lag issue in Fyne applications?

A: The root cause of the table resizing lag issue in Fyne applications is the inefficient data generation process and the table rendering process. The data generation process can be optimized by reducing the frequency of updates or by using a more efficient algorithm. The table rendering process can be improved by using a more efficient rendering algorithm or by reducing the number of rendering operations.

Q: How can I optimize the data generation process in my Fyne application?

A: To optimize the data generation process in your Fyne application, you can try the following:

Reduce the frequency of updates: Instead of updating the data every 40 milliseconds, you can update it every 100 milliseconds or every second.
Use a more efficient algorithm: You can use a more efficient algorithm to generate the data, such as using a queue to store the data instead of updating it directly.
Use caching: You can use caching to store the data and reduce the number of rendering operations.

Q: How can I improve the table rendering process in my Fyne application?

A: To improve the table rendering process in your Fyne application, you can try the following:

Use a more efficient rendering algorithm: You can use a more efficient rendering algorithm, such as using a canvas to render the table instead of using a widget.
Reduce the number of rendering operations: You can reduce the number of rendering operations by using a single rendering operation to update the entire table instead of updating each cell individually.
Use parallel processing: You can use parallel processing to render the table in parallel, which can improve performance.

Q: Can I use caching to improve the performance of my Fyne application?

A: Yes, you can use caching to improve the performance of your Fyne application. Caching can be used to store the data and reduce the number of rendering operations. You can use a cache to store the data and then update the cache when the data changes.

Q: How can I use parallel processing to improve the performance of my Fyne application?

A: To use parallel processing to improve the performance of your Fyne application, you can try the following:

Use a goroutine to render the table: You can use a goroutine to render the table in parallel, which can improve performance.
Use a channel to communicate between goroutines: You can use a channel to communicate between goroutines and update the table in parallel.
Use a mutex to synchronize access to shared resources: You can use a mutex to synchronize access to shared resources and prevent concurrent access.

Q: Can I use a more efficient algorithm to generate the data in my Fyne application?

A: Yes, you use a more efficient algorithm to generate the data in your Fyne application. You can use a queue to store the data instead of updating it directly, which can improve performance.

Q: How can I reduce the number of rendering operations in my Fyne application?

A: To reduce the number of rendering operations in your Fyne application, you can try the following:

Use a single rendering operation to update the entire table: You can use a single rendering operation to update the entire table instead of updating each cell individually.
Use a canvas to render the table: You can use a canvas to render the table instead of using a widget, which can reduce the number of rendering operations.
Use caching: You can use caching to store the data and reduce the number of rendering operations.

Conclusion

In conclusion, the table resizing lag issue in Fyne applications can be caused by inefficient data generation and table rendering processes. By optimizing the data generation process, improving the table rendering process, using caching, and using parallel processing, you can improve the performance of your Fyne application and provide a smoother user experience.