How to use Application.UsableWidth in the xlwings API way

The UsableWidth property of the Application object in Excel returns a Double value that represents the maximum width, in points, of the area within the main application window where a workbook can be placed. This measurement excludes the space occupied by fixed elements such as the ribbon, scrollbars, and the taskbar. It is particularly useful for dynamically sizing and positioning windows or user forms to ensure they fit optimally within the available screen space without overlapping interface components.

In xlwings, the Application object is accessed via the app property of a Book instance or directly through xw.apps. The UsableWidth property is a read-only attribute. The general syntax to retrieve this value is:

usable_width = xw.apps[app_key].usable_width
# or, if you have a book object:
usable_width = book.app.usable_width

Where:

• app_key is the PID (Process ID) of the Excel instance, typically accessed as xw.apps.keys()[index] or by using the active app xw.apps.active.
• book is an xlwings Book object (e.g., book = xw.Book('file.xlsx')).

There are no parameters for this property.

Code Examples:

1. Getting the usable width of the active Excel application:
   This is the most straightforward method to check the available horizontal space in the currently active Excel instance.

import xlwings as xw

# Ensure Excel is running and connected
app = xw.apps.active # Gets the active Excel app
current_usable_width = app.usable_width
print(f"The current usable width in the application window is: {current_usable_width} points")

2. Using UsableWidth to set the width of a specific workbook window:
   You can use this property to programmatically adjust the width of a workbook’s window to occupy a specific percentage of the available space.

import xlwings as xw

# Open or connect to a workbook
wb = xw.Book('Report.xlsx')

# Set the window width to 80% of the application's usable width
target_width = wb.app.usable_width * 0.8
wb.app.api.ActiveWindow.Width = target_width
print(f"Window width set to {target_width:.1f} points (80% of usable width).")

Note: Direct window manipulation (like setting Width) often requires the underlying Excel API (.api), as xlwings’ high-level API focuses primarily on data and formula handling.

3. Centering a UserForm (using the Excel API via xlwings):
   While xlwings itself does not have direct methods for VBA-style UserForms, you can use UsableWidth with the Excel API to calculate positions for shapes or other objects to simulate centered placement.

import xlwings as xw

app = xw.apps.active
usable_w = app.usable_width
usable_h = app.usable_height # Often used together for centering

# Example: Center a shape horizontally (assuming a shape width of 200 points)
shape_width = 200
target_left_position = (usable_w - shape_width) / 2

# Apply to a shape on the active sheet
sht = app.books.active.sheets.active
my_shape = sht.shapes.add_shape(1, target_left_position, 50, shape_width, 100) # Left, Top, Width, Height
my_shape.text = "Centered Shape"