Curses Panel Extension: A Deep Dive

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Alright ! Let’s talk about Curses Panel Extension an awesome tool for creating text-based user interfaces in Python programs using the curses library. This extension allows us to create multiple panels with different content and switch between them easily, without having to deal with complicated menu systems or awkward keyboard shortcuts.

To start: what is Curses? It’s a library that lets us create text-based user interfaces in our programs without worrying about the details of terminal control sequences. And now, thanks to the curses panel extension (CPE), we can take it up a notch and add some serious functionality to our apps!

So what exactly does CPE do? Well, let’s say you have an app that displays data in multiple panels like stock prices or weather forecast. With CPE, you can easily create these panels and switch between them using simple commands. No more clunky menu systems or awkward keyboard shortcuts!

Here’s how to use it:

# Import necessary libraries
import curses
from curses_panel import panel, Panel

# Initialize the Curses library
stdscr = curses.initscr() # Initialize the standard screen
curses.noecho() # Disable automatic echoing of keys to the screen
curses.cbreak() # React to keys instantly, without requiring the Enter key to be pressed
curses.start_color() # Enable color support
curses.curs_set(0) # Hide the cursor

# Create two panels: one for stocks and one for weather
panel1 = Panel((0, 0), (24, 80)) # Create a panel at the top left corner with a size of 24x80 characters
panel2 = Panel((25, 0), (47, 80)) # Create a panel below the first one with a size of 47x80 characters

# Add some content to panel1
stocks_data = [("AAPL", "Apple Inc.", "$139.65"), ("GOOG", "Alphabet Inc.", "$1,650.02")]
for row, stock in enumerate(stocks_data):
    panel1.addstr(row + 1, 1, f"{stock[0]} {stock[1]}\t\t${' ' * (8 len(stock[2]))}{stock[2]}") # Add stock data to panel1
panel1.refresh() # Refresh the panel to display the added content

# Add some content to panel2
weather_data = [("San Francisco", "Partly Cloudy", 65), ("New York City", "Rain", 70)]
for row, city in enumerate(weather_data):
    panel2.addstr(row + 1, 1, f"{city[0]} {city[1]}\t\t{city[2]}°F") # Add weather data to panel2
panel2.refresh() # Refresh the panel to display the added content

# Display both panels and switch between them using arrow keys
while True:
    stdscr.clear() # Clear the screen
    panel1.draw(stdscr) # Draw panel1 on the screen
    panel2.draw(stdscr, 0, 25) # Draw panel2 on the screen, starting at column 25
    curses.doupdate() # Update the screen with the changes made

    key = stdscr.getch() # Get user input
    if key == ord(' '):
        # Toggle between panels using spacebar
        panel1.toggle_visible() # Hide or show panel1
        panel2.toggle_visible() # Hide or show panel2

    elif key in [curses.KEY_UP, curses.KEY_DOWN]:
        # Move up or down through the panels with arrow keys
        if stdscr.getyx()[0] == 0:
            # If we're at the top of panel1, move to panel2 and vice versa
            if key == curses.KEY_UP:
                panel1.hide() # Hide panel1
                panel2.show() # Show panel2
                stdscr.move(panel2.top, 0) # Move the cursor to the top of panel2
            else:
                panel1.show() # Show panel1
                panel2.hide() # Hide panel2
                stdscr.move(panel1.top, 0) # Move the cursor to the top of panel1
        elif stdscr.getyx()[0] == panel1.bottom + 1:
            # If we're at the bottom of panel1 or panel2, move to the other one and scroll up
            if key == curses.KEY_DOWN:
                panel1.hide() # Hide panel1
                panel2.show() # Show panel2
                stdscr.move(panel2.top (stdscr.getmaxyx()[0] // 2), 0) # Move the cursor to the middle of panel2
            else:
                panel1.show() # Show panel1
                panel2.hide() # Hide panel2
                stdscr.move(panel1.top (stdscr.getmaxyx()[0] // 2), 0) # Move the cursor to the middle of panel1
        else:
            # Otherwise, scroll up or down within the current panel
            if key == curses.KEY_UP:
                stdscr.move(stdscr.getyx()[0] 1, 0) # Move the cursor up one row
            elif key == curses.KEY_DOWN:
                stdscr.move(stdscr.getyx()[0] + 1, 0) # Move the cursor down one row

    else:
        # Handle other keyboard input as needed (e.g., quit with Ctrl-C)
        if key == ord('q') or key == curses.KEY_C:
            break # Exit the loop and end the program

As you can see, this extension makes it incredibly easy to create complex and dynamic terminal interfaces without sacrificing usability or performance. And the best part? It’s all open source and available on GitHub! So go ahead give Curses Panel Extension a try and let your imagination run wild with what you can do in Python!

Functions:
– `curses.panel.bottom_panel()` returns the bottom panel in the panel stack.

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