Window System

Normally, a RetUI application shows one screen at a time.

Sometimes you need something to appear on top of the current screen without leaving it.

For example:

• Confirmation dialogs
• Alert messages
• Login windows
• Popup menus
• Settings dialogs

This is what the Window System is for.

A window floats above your application and can receive its own keyboard input and focus.

The Window System is available in a separate package.

import "github.com/subhasundardass/retui/retui/window"

---

Screens vs Windows

Screens and windows are different.

Screens	Windows
Replace the current screen	Appear on top of the current screen
Fill the entire terminal	Have their own size and position
Used for navigation	Used for dialogs and popups
Only one screen is active	Multiple windows can be open

Use a screen when moving to another page.

Use a window when you want to display something without leaving the current screen.

---

Creating a Window

Create a new window.

win := window.NewWindow()

A new window is hidden by default.

Nothing appears until you call:

win.Show()

Usually you'll store the window in a variable so you can show, hide or close it later.

---

Setting the Title

Add a title to the window.

win.SetTitle("Confirmation")

Example

┌─ Confirmation ──────────────┐
│                             │
│                             │
└─────────────────────────────┘

---

Setting the Size

Every window has a width and height.

win.SetSize(40, 10)

• First value = width
• Second value = height

---

Positioning

Move the window to any position.

win.SetPosition(10, 5)

Move it later.

win.MoveTo(20, 8)

Move it relative to its current position.

win.MoveBy(2, 1)

Most dialogs are simply centered.

win.Center()

You can also center only one axis.

win.CenterHorizontally(screenWidth)

win.CenterVertically(screenHeight)

---

Resizing

Resize a window after it has been created.

win.ResizeTo(60, 20)

Get the current size.

width, height := win.GetSize()

---

Static Content

For simple windows, use SetContent().

win.SetContent(
    retui.Text(
        "File deleted successfully.",
        retui.NewStyle(),
    ),
)

This is perfect for messages that never change.

---

Dynamic Content

If your window contains buttons, inputs or state, use SetRenderFn().

win.SetRenderFn(func() retui.Element {

    count, setCount := retui.UseState(0)

    // Build the window UI

})

Because the function runs every render, you can use all RetUI hooks inside it.

---

Showing and Hiding

Display the window.

win.Show()

Hide it temporarily.

win.Hide()

Show it again later.

win.Show()

Close it permanently.

win.Close()

You can also toggle visibility.

win.ToggleVisibility()

Check whether the window is currently visible.

win.IsVisible()

---

Modal Windows

A modal window blocks everything behind it.

win.SetModal(true)

Example

+--------------------------------------+
| Dashboard                            |
|                                      |
|      +----------------------+        |
|      | Confirm Delete       |        |
|      |                      |        |
|      |  Yes      Cancel     |        |
|      +----------------------+        |
|                                      |
+--------------------------------------+

While a modal window is open:

• Other windows cannot receive focus.
• Keyboard input goes to the modal.
• The modal always stays on top.

Check if any modal is open.

window.IsAnyModalOpen()

Get the active modal.

window.GetActiveModal()

---

Focus

Only one window can receive keyboard input.

Bring a window to the front.

win.Focus()

Check if it currently has focus.

win.IsFocused()

Get the currently focused window.

window.GetFocused()

---

Keyboard Events

A window can listen for keyboard input.

win.OnKeyPress(func(key retui.Key) {

    if key.Code == retui.KeyEscape {
        win.Close()
    }

})

A common pattern is closing dialogs when the user presses Escape.

---

Window Information

Get the current position.

x, y := win.GetPosition()

Get the size.

width, height := win.GetSize()

Get the complete bounds.

x, y, width, height := win.GetBounds()

---

Complete Example

win := window.NewWindow().
    SetTitle("Confirm Delete").
    SetSize(40, 8).
    SetModal(true).
    SetContent(
        retui.Text(
            "Delete this file?",
            retui.NewStyle(),
        ),
    ).
    Center()

win.Show()

Result

             Confirm Delete

        Delete this file?

        Yes        Cancel

---

Automatic Rendering

You don't need to manually draw windows.

Simply import the window package.

Whenever you call:

win.Show()

RetUI automatically renders the window above your current screen.

In most applications, that's all you need.

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Best Practices

✅ Use windows for dialogs and popups.

✅ Use screens for full-page navigation.

✅ Center modal dialogs.

✅ Use SetRenderFn() for interactive windows.

✅ Use SetContent() for simple messages.

✅ Hide a window if you plan to show it again.

✅ Close a window when it is no longer needed.

---

Summary

The Window System lets you display floating interfaces without leaving the current screen.

It supports:

• Floating windows
• Dialogs
• Modal windows
• Keyboard events
• Focus management
• Dynamic content with hooks
• Automatic rendering

With just a few methods, you can build confirmation dialogs, popups, login windows, settings panels and many other overlay interfaces.