Persisting Floating Windows Geometry After Awesome Restart

In the realm of window management, the Awesome Window Manager stands out as a highly configurable and dynamic tiling window manager for X Window System. One common challenge users face is ensuring that floating windows and their geometries persist across Awesome restarts. This article delves into the intricacies of achieving this persistence, providing a step-by-step guide to configuring your AwesomeWM setup. We will explore the underlying mechanisms, configuration options, and practical examples to help you master this crucial aspect of window management. The ability to persist floating windows and their geometries is paramount for maintaining a consistent and efficient workflow. Imagine spending time meticulously positioning your application windows, only to have them revert to default locations upon restarting your window manager. This can be particularly frustrating for users who rely on specific window arrangements for their daily tasks. By implementing a solution for window persistence, you can ensure that your workspace remains organized and predictable, even after restarts. This not only saves time but also reduces cognitive load, allowing you to focus on your work rather than window management.

1.1. Why is Floating Window Persistence Important?

The persistence of floating windows is not merely a cosmetic preference; it directly impacts productivity and user experience. Consider the following scenarios where window persistence is crucial:

• Development Environments: Developers often arrange multiple terminal windows, code editors, and documentation viewers in a specific layout. Having these windows retain their positions and sizes across restarts is essential for maintaining a smooth development workflow.
• Creative Workflows: Designers and artists frequently use floating windows for tools like color pickers, layer panels, and asset libraries. The ability to preserve these window arrangements is vital for creative tasks that demand precision and consistency.
• Research and Analysis: Researchers and analysts often juggle numerous data visualization tools, spreadsheets, and reference materials. Maintaining the layout of these windows across sessions allows for seamless data comparison and analysis.

In each of these scenarios, the manual effort required to reposition and resize windows after each restart can be significant. By automating this process, you can free up valuable time and mental energy, leading to increased productivity and a more enjoyable computing experience. Furthermore, window persistence contributes to a sense of stability and predictability in your computing environment. Knowing that your windows will remain in their designated locations fosters a feeling of control and reduces the cognitive burden associated with window management.

1.2. Overview of Awesome Window Manager

The Awesome Window Manager is renowned for its flexibility and customizability, making it a favorite among power users and developers. Unlike traditional desktop environments that impose a fixed set of paradigms, AwesomeWM empowers users to tailor their window management experience to their exact needs. This level of customization extends to every aspect of the window manager, from keyboard shortcuts and layout algorithms to themes and window rules. At its core, AwesomeWM is a tiling window manager, which means it automatically arranges windows to fill the available screen space without overlapping. This approach is highly efficient for users who work with multiple applications simultaneously, as it maximizes screen real estate and minimizes the need for manual window manipulation. However, AwesomeWM also supports floating windows, which can be positioned and sized freely, offering a hybrid approach to window management that combines the benefits of tiling and floating layouts.

The configuration of AwesomeWM is primarily done through the rc.lua file, a Lua script that defines the window manager's behavior and appearance. This file allows users to customize everything from keybindings and mouse actions to window rules and widgets. The Lua scripting language provides a powerful and expressive way to configure AwesomeWM, enabling users to create complex and sophisticated window management setups. One of the key features of AwesomeWM is its support for tags, which are virtual desktops that can be used to organize windows into different workspaces. Users can assign windows to specific tags, switch between tags, and even view multiple tags simultaneously. This tag-based system provides a flexible and intuitive way to manage a large number of windows, making it easy to stay organized and focused.

1.3. Problem Statement: The Default Behavior

By default, Awesome Window Manager does not automatically persist the geometry of floating windows across restarts. This means that whenever you restart AwesomeWM, all floating windows will revert to their default positions and sizes. This can be a significant inconvenience for users who rely on specific window arrangements for their workflows. The issue stems from the fact that AwesomeWM does not inherently save the state of floating windows when it is restarted. When AwesomeWM shuts down, it terminates all running applications and their associated windows. Upon restart, these applications are launched anew, and their windows are created with default geometries. Without a mechanism to save and restore the window geometries, the user's carefully crafted window arrangements are lost.

This default behavior can be particularly problematic for users who work with applications that do not automatically save their window positions and sizes. While some applications have built-in features for window geometry persistence, many others do not. In these cases, the responsibility falls on the window manager to provide a solution. Furthermore, even for applications that do save their window geometries, the behavior may not be consistent across different applications or operating systems. This can lead to a fragmented and unpredictable experience, where some windows are restored correctly while others are not. The lack of a unified approach to window persistence in AwesomeWM can therefore be a significant impediment to productivity and workflow efficiency. Users are forced to spend time manually repositioning and resizing windows after each restart, which can be a tedious and time-consuming task. This issue highlights the need for a robust and reliable solution for persisting floating window geometries in AwesomeWM.

Before diving into the solution, let's ensure you have the necessary prerequisites in place. This section outlines the software and knowledge requirements for successfully implementing floating window persistence in AwesomeWM. Having a solid understanding of these prerequisites will not only make the implementation process smoother but also enable you to troubleshoot any issues that may arise along the way.

2.1. Basic Understanding of Awesome Window Manager

Firstly, a foundational understanding of Awesome Window Manager's architecture and configuration is essential. This includes familiarity with the rc.lua configuration file, which serves as the central control panel for AwesomeWM's behavior. You should be comfortable navigating the rc.lua file, understanding its structure, and making basic modifications. Key concepts to grasp include: window rules, which define how AwesomeWM handles specific windows based on their properties; layouts, which dictate how windows are arranged on the screen; and signals, which are events that trigger specific actions within AwesomeWM. Understanding window rules is particularly important for this task, as they allow you to target specific windows and apply custom behaviors, such as persisting their geometries. Layouts determine how windows are arranged by default, but floating windows bypass these layouts, making their persistence a separate concern. Signals, such as client::manage and client::unmanage, are crucial for detecting when windows are created and destroyed, allowing you to save and restore their geometries accordingly.

Furthermore, a basic understanding of Lua, the scripting language used to configure AwesomeWM, is highly beneficial. While you don't need to be a Lua expert, familiarity with its syntax and data structures will empower you to customize your configuration more effectively. Lua's flexibility and expressiveness make it a powerful tool for extending AwesomeWM's functionality. Understanding how to define functions, work with tables (Lua's primary data structure), and use control flow statements will enable you to implement complex window persistence logic.

2.2. Familiarity with Lua Scripting

As mentioned earlier, Lua is the language that breathes life into AwesomeWM's configuration. Therefore, a working knowledge of Lua scripting is indispensable. You should be able to write basic Lua code, understand variables, functions, tables, and control structures. This knowledge will be crucial when modifying the rc.lua file to implement the persistence logic. Lua's syntax is relatively straightforward, making it accessible to users with programming experience in other languages. However, even if you're new to programming, Lua's clear and concise syntax makes it a good language to learn. Key concepts to focus on include: variables, which store data such as window geometries; functions, which encapsulate reusable blocks of code; tables, which are used to store collections of data, such as window properties; and control structures, such as if statements and loops, which allow you to control the flow of execution in your code.

Lua's ability to handle data structures, particularly tables, is essential for storing and retrieving window geometry information. You'll need to be able to create tables, add and remove elements, and iterate over them. Furthermore, understanding how to use Lua's string manipulation functions will be helpful for parsing and formatting window geometry data. While you can often find code snippets and examples online, being able to understand and adapt them to your specific needs requires a basic understanding of Lua.

2.3. Text Editor for Configuration Files

A reliable text editor is your primary tool for interacting with AwesomeWM's configuration files. Choose an editor that supports syntax highlighting for Lua, as this greatly enhances readability and helps prevent errors. Popular options include Visual Studio Code, Sublime Text, and Vim. Syntax highlighting makes it easier to distinguish between different elements of the code, such as keywords, variables, and comments. This can significantly reduce the likelihood of making syntax errors, which are common when working with code. Furthermore, many text editors offer features such as code completion and linting, which can further improve your coding efficiency and accuracy.

Consider using a text editor that also supports features like bracket matching and code folding, as these can be particularly helpful when working with large and complex configuration files like rc.lua. Bracket matching helps you ensure that parentheses, brackets, and braces are properly balanced, while code folding allows you to collapse sections of code to improve readability. Additionally, a text editor with built-in version control integration can be invaluable for tracking changes to your configuration files and reverting to previous versions if necessary. This can be particularly useful when experimenting with new configurations or troubleshooting issues.

Now, let's get into the heart of the matter: implementing floating window persistence. This section will guide you through the process, breaking it down into manageable steps. We'll explore the key components of the solution, including saving window geometries, restoring them on restart, and handling potential edge cases.

3.1. Saving Window Geometries

The first step is to save the geometries of floating windows when they are created or moved. This involves capturing the window's position and size and storing it in a persistent storage mechanism. We'll use Lua tables to store this information and a file to persist it across sessions. The core idea is to hook into AwesomeWM's signal system to detect when a new window is created or when an existing window is moved or resized. When these events occur, we extract the window's geometry information and store it in a Lua table. This table acts as an in-memory representation of the window geometries.

To make this information persistent across restarts, we need to save the contents of the Lua table to a file. This can be done using Lua's built-in file I/O functions. We'll choose a suitable location for the file, such as a hidden directory in the user's home directory, to keep it out of the way. The file will contain a serialized representation of the Lua table, which can be read back into memory when AwesomeWM restarts. The process of saving the window geometries involves several steps:

1. Hook into the client::manage signal: This signal is emitted when a new window is created and managed by AwesomeWM. We'll attach a callback function to this signal that extracts the window's geometry and stores it in the Lua table.
2. Hook into the client::geometry signal: This signal is emitted when a window's geometry changes, such as when it is moved or resized. We'll attach a callback function to this signal that updates the window's geometry in the Lua table.
3. Serialize the Lua table to a file: We'll create a function that takes the Lua table as input and writes it to a file in a serialized format. This function will be called periodically or when AwesomeWM is about to exit.

3.2. Restoring Window Geometries on Restart

The next crucial step is to restore the saved window geometries when AwesomeWM restarts. This involves reading the persistent storage file, loading the window geometry data into Lua tables, and applying the geometries to the corresponding windows. The restoration process is essentially the reverse of the saving process. We start by reading the serialized window geometry data from the file into a Lua table. This table then contains the information about the position and size of each window that was saved in the previous session.

Next, we need to identify the corresponding windows and apply the saved geometries to them. This is where the window class or instance name comes into play. We can use these properties to uniquely identify each window and ensure that the correct geometry is applied. The process of restoring window geometries involves the following steps:

1. Read the serialized data from the file: We'll create a function that reads the contents of the file and deserializes it into a Lua table.
2. Hook into the client::manage signal: As before, we'll use the client::manage signal to detect when a new window is created. However, this time, we'll use the saved geometry data to position and size the window.
3. Match windows based on class or instance name: We'll compare the class or instance name of the newly created window with the saved window data to find a match. If a match is found, we'll apply the saved geometry to the window.
4. Set the window geometry: We'll use AwesomeWM's API to set the window's geometry to the saved values. This will position and size the window according to the user's previous arrangement.

3.3. Handling Edge Cases and Errors

Implementing robust window persistence requires careful consideration of potential edge cases and error scenarios. This section addresses some common challenges and provides strategies for handling them gracefully. One common edge case is when a window is closed or destroyed before AwesomeWM is restarted. In this case, the saved geometry data for that window becomes invalid and should be removed from the persistent storage. Failing to do so can lead to errors when AwesomeWM attempts to restore the geometry of a non-existent window.

To handle this, we can hook into the client::unmanage signal, which is emitted when a window is closed or destroyed. In the callback function for this signal, we can remove the corresponding window geometry data from the Lua table and the persistent storage file. Another potential issue is when an application's window class or instance name changes between sessions. This can happen if the application is updated or if the user modifies its configuration. In this case, the window matching logic may fail, and the window geometry will not be restored correctly. To mitigate this, we can use a combination of window properties, such as the class name, instance name, and title, to improve the accuracy of the matching process. We can also provide a mechanism for the user to manually map window geometries to specific applications if necessary.

Let's walk through the practical steps of implementing floating window persistence in AwesomeWM. This section provides a detailed guide, including code snippets and explanations, to help you integrate the solution into your rc.lua configuration.

4.1. Modifying the rc.lua File

The primary configuration file for AwesomeWM is rc.lua, typically located in ~/.config/awesome/. Open this file in your text editor to begin the implementation. The first step is to add the necessary Lua code to save and restore window geometries. This involves defining functions to handle the saving and loading of window data, as well as hooking into AwesomeWM's signal system to detect window creation, destruction, and geometry changes. The code snippets provided in this section can be directly copied and pasted into your rc.lua file, but it's important to understand what each section of code does and how it contributes to the overall solution. The rc.lua file is a Lua script, so the code you add will be executed when AwesomeWM starts up. It's crucial to ensure that the code is syntactically correct and logically sound to avoid errors that could prevent AwesomeWM from starting correctly.

Before making any changes to your rc.lua file, it's always a good idea to back it up. This allows you to easily revert to the previous configuration if something goes wrong. You can create a backup copy of the file using the command cp ~/.config/awesome/rc.lua ~/.config/awesome/rc.lua.bak. After making changes to your rc.lua file, you'll need to restart AwesomeWM for the changes to take effect. You can do this by pressing Mod4 + Ctrl + r (where Mod4 is typically the Windows key or Super key). If there are any syntax errors in your rc.lua file, AwesomeWM will display an error message and may fail to start. In this case, you'll need to carefully review the code you added and correct any errors.

4.2. Code Snippets for Saving Geometries

Here are the code snippets required to save the geometries of floating windows. This code defines functions to store window geometry data in a Lua table and persist it to a file. The first step is to define a global table to store the window geometries. This table will be indexed by a unique identifier for each window, such as its class name or instance name. The table will store the window's position (x, y) and size (width, height). Next, we need to define functions to save and load the window geometry data. The save_window_geometries function will serialize the Lua table to a file, while the load_window_geometries function will read the data from the file and deserialize it into a Lua table. These functions will use Lua's built-in file I/O functions to read and write the data. We'll choose a suitable location for the file, such as a hidden directory in the user's home directory, to keep it out of the way.

-- Global table to store window geometries
local saved_window_geometries = {}

-- Function to save window geometries to a file
local function save_window_geometries()
 local file = io.open(os.getenv("HOME") .. "/.config/awesome/window_geometries.lua", "w")
 if file then
 file:write("return ", awesome.util.table.serialize(saved_window_geometries))
 file:close()
 end
end

-- Function to load window geometries from a file
local function load_window_geometries()
 local file, err = io.open(os.getenv("HOME") .. "/.config/awesome/window_geometries.lua", "r")
 if file then
 local data = file:read("*a")
 file:close()
 local geometries = loadstring(data)()
 if geometries then
 saved_window_geometries = geometries
 end
 end
end

This code snippet defines two functions: save_window_geometries and load_window_geometries. The save_window_geometries function opens a file named window_geometries.lua in the ~/.config/awesome/ directory for writing. It then serializes the saved_window_geometries table using awesome.util.table.serialize and writes it to the file. Finally, it closes the file. The load_window_geometries function opens the same file for reading. It reads the entire contents of the file into a string, loads the string as a Lua chunk using loadstring, and executes it. The result of the execution is a table containing the saved window geometries, which is then assigned to the saved_window_geometries table.

4.3. Code Snippets for Restoring Geometries

Next, we need to add code to restore the saved window geometries when AwesomeWM starts up. This involves loading the window geometry data from the file and applying it to the corresponding windows. We'll hook into the client::manage signal to detect when a new window is created and check if there is a saved geometry for it. The first step is to load the saved window geometries when AwesomeWM starts up. We can call the load_window_geometries function at the beginning of the rc.lua file. This will read the data from the file and populate the saved_window_geometries table. Next, we need to hook into the client::manage signal. This signal is emitted when a new window is created and managed by AwesomeWM. We'll attach a callback function to this signal that checks if there is a saved geometry for the window. If there is, we'll apply the saved geometry to the window.

-- Load window geometries on startup
load_window_geometries()

-- Connect to the client::manage signal
awesome.connect_signal("client::manage", function(c)
 -- Check if the client is floating
 if c.floating then
 -- Check if there is a saved geometry for this client
 if saved_window_geometries[c.class] then
 local geometry = saved_window_geometries[c.class]
 -- Apply the saved geometry
 c:geometry(geometry)
 end
 end
end)

This code snippet first calls the load_window_geometries function to load the saved window geometries from the file. Then, it connects a callback function to the client::manage signal. This signal is emitted when a new client (window) is managed by AwesomeWM. The callback function first checks if the client is floating. If it is, it checks if there is a saved geometry for the client's class in the saved_window_geometries table. If there is, it retrieves the saved geometry and applies it to the client using c:geometry(geometry). This sets the window's position and size according to the saved geometry.

4.4. Code Snippets for Handling Signals

To ensure that window geometries are saved when they change and when AwesomeWM is about to exit, we need to connect to the appropriate signals. This includes the client::geometry signal, which is emitted when a window's geometry changes, and the exit signal, which is emitted when AwesomeWM is about to exit. The client::geometry signal allows us to update the saved geometry data when a window is moved or resized. The exit signal allows us to save the window geometries before AwesomeWM shuts down, ensuring that the data is persisted across restarts. We'll also need to hook into the client::unmanage signal to remove the saved geometry for a window when it is closed.

-- Connect to the client::geometry signal
awesome.connect_signal("client::geometry", function(c)
 -- Check if the client is floating
 if c.floating then
 -- Save the client's geometry
 saved_window_geometries[c.class] = c:geometry()
 -- Save window geometries to file
 save_window_geometries()
 end
end)

-- Connect to the client::unmanage signal
awesome.connect_signal("client::unmanage", function(c)
 -- Remove the saved geometry for this client
 saved_window_geometries[c.class] = nil
 -- Save window geometries to file
 save_window_geometries()
end)

-- Connect to the exit signal
awesome.connect_signal("exit", function()
 -- Save window geometries to file
 save_window_geometries()
end)

This code snippet connects callback functions to three signals: client::geometry, client::unmanage, and exit. The callback function for the client::geometry signal is executed when a window's geometry changes. It first checks if the client is floating. If it is, it saves the client's current geometry to the saved_window_geometries table, using the client's class as the key. Then, it calls the save_window_geometries function to save the updated geometries to the file. The callback function for the client::unmanage signal is executed when a window is unmanaged (e.g., closed). It removes the saved geometry for the client from the saved_window_geometries table and calls the save_window_geometries function to save the updated geometries to the file. The callback function for the exit signal is executed when AwesomeWM is about to exit. It calls the save_window_geometries function to ensure that the current window geometries are saved to the file before AwesomeWM shuts down.

After implementing the solution, thorough testing is crucial to ensure that it functions as expected. This section provides guidance on testing your implementation and troubleshooting common issues that may arise. Testing the implementation involves several steps. First, you should verify that window geometries are being saved correctly when windows are moved or resized. You can do this by opening a few floating windows, moving and resizing them, and then checking the contents of the window_geometries.lua file. The file should contain a serialized representation of the window geometries, including their position and size.

5.1. Verifying Persistence

The most important test is to verify that window geometries are persisted across AwesomeWM restarts. To do this, open a few floating windows, position them as desired, and then restart AwesomeWM. After the restart, the windows should reappear in their saved positions and sizes. If the windows do not reappear in the correct positions, there may be an issue with the saving or restoring of window geometries. Check the window_geometries.lua file to ensure that the data is being saved correctly. Also, check the AwesomeWM logs for any error messages that may indicate a problem with the restoration process.

It's also important to test the behavior of the implementation when windows are closed. When a window is closed, its saved geometry should be removed from the saved_window_geometries table and the window_geometries.lua file. You can verify this by closing a floating window and then checking the contents of the file. The entry for the closed window should be gone. Finally, it's a good idea to test the implementation with different types of applications. Some applications may have unique window properties that could affect the matching process. Testing with a variety of applications will help ensure that the implementation is robust and works correctly in all cases.

5.2. Common Issues and Solutions

Here are some common issues that may arise during implementation and their solutions:

• Windows not restoring to correct positions: This could be due to incorrect window matching. Ensure that the window class or instance name used for matching is consistent across sessions. You can use the xprop command to inspect the properties of a window and verify its class and instance name.
• Errors in rc.lua: Syntax errors in rc.lua can prevent AwesomeWM from starting correctly. Carefully review the code you added for any typos or syntax errors. Use a text editor with Lua syntax highlighting to help identify errors.
• File permissions: Ensure that AwesomeWM has the necessary permissions to read and write the window_geometries.lua file. If the file is not writable, AwesomeWM will not be able to save the window geometries.
• Conflicting window rules: Other window rules in your rc.lua configuration may be interfering with the geometry restoration process. Check your window rules and ensure that they are not overriding the saved geometries.

5.3. Debugging Tips

Debugging AwesomeWM configurations can be challenging, but there are several tools and techniques that can help. One of the most useful tools is the AwesomeWM log file, which contains error messages and other debugging information. The log file is typically located in ~/.cache/awesome.log. When troubleshooting issues, always check the log file for any error messages that may provide clues about the cause of the problem. Another useful technique is to use the print function in your Lua code to output debugging information to the log file. You can print the values of variables, the results of function calls, and other information that may be helpful in diagnosing issues. For example, you can print the window class and geometry before and after applying the saved geometry to verify that the values are being set correctly.

In conclusion, implementing floating window persistence in Awesome Window Manager significantly enhances the user experience by preserving window arrangements across restarts. This article has provided a comprehensive guide, covering the necessary prerequisites, step-by-step implementation, and troubleshooting tips. By following these instructions, you can create a more consistent and efficient workflow in AwesomeWM. The ability to persist window geometries is a valuable feature for any window manager, and AwesomeWM's flexibility makes it possible to implement this functionality with relative ease.

6.1. Benefits of Persistent Floating Windows

The benefits of persistent floating windows extend beyond mere convenience. They contribute to a more organized and predictable workspace, reducing cognitive load and improving focus. When windows are restored to their previous positions and sizes, users can quickly resume their work without having to rearrange their windows manually. This saves time and reduces the mental effort required to manage windows, allowing users to focus on their tasks.

Persistent floating windows also facilitate a more consistent workflow. Users can develop a mental map of their workspace, knowing that specific applications will always be in certain locations. This consistency can improve productivity and reduce errors. Furthermore, persistent floating windows can be particularly beneficial for users who work with multiple monitors. By saving the window geometries for each monitor, users can ensure that their windows are restored to the correct screen after a restart.

6.2. Further Customization Options

The implementation described in this article provides a solid foundation for floating window persistence. However, there are many opportunities for further customization and enhancement. For example, you could extend the implementation to support different window layouts or to save the window state (e.g., minimized, maximized) in addition to the geometry. You could also add a graphical user interface (GUI) for managing the saved window geometries, allowing users to manually save and restore window arrangements. Another area for customization is the matching of windows. The current implementation uses the window class as the primary key for matching windows. However, you could use other window properties, such as the instance name or the window title, to improve the accuracy of the matching process. You could also allow users to configure which properties should be used for matching.

6.3. Final Thoughts

By mastering the techniques outlined in this guide, you'll be well-equipped to create a highly customized and efficient AwesomeWM environment. The ability to persist floating windows is just one example of the many ways in which AwesomeWM can be tailored to meet your specific needs. Experiment with different configurations and explore the vast array of options available to you. With a little effort, you can transform AwesomeWM into the perfect window manager for your workflow. Remember that the key to success with AwesomeWM is to understand its underlying principles and to be willing to experiment and customize your configuration. Don't be afraid to try new things and to learn from your mistakes. The AwesomeWM community is a valuable resource, so don't hesitate to ask for help if you get stuck. With dedication and persistence, you can create a truly awesome window management experience.