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-rwxr-xr-x | examples/full-screen/split-screen.py | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/examples/full-screen/split-screen.py b/examples/full-screen/split-screen.py new file mode 100755 index 0000000..af5403e --- /dev/null +++ b/examples/full-screen/split-screen.py @@ -0,0 +1,156 @@ +#!/usr/bin/env python +""" +Simple example of a full screen application with a vertical split. + +This will show a window on the left for user input. When the user types, the +reversed input is shown on the right. Pressing Ctrl-Q will quit the application. +""" +from prompt_toolkit.application import Application +from prompt_toolkit.buffer import Buffer +from prompt_toolkit.key_binding import KeyBindings +from prompt_toolkit.layout.containers import HSplit, VSplit, Window, WindowAlign +from prompt_toolkit.layout.controls import BufferControl, FormattedTextControl +from prompt_toolkit.layout.layout import Layout + +# 3. Create the buffers +# ------------------ + +left_buffer = Buffer() +right_buffer = Buffer() + +# 1. First we create the layout +# -------------------------- + +left_window = Window(BufferControl(buffer=left_buffer)) +right_window = Window(BufferControl(buffer=right_buffer)) + + +body = VSplit( + [ + left_window, + # A vertical line in the middle. We explicitly specify the width, to make + # sure that the layout engine will not try to divide the whole width by + # three for all these windows. + Window(width=1, char="|", style="class:line"), + # Display the Result buffer on the right. + right_window, + ] +) + +# As a demonstration. Let's add a title bar to the top, displaying "Hello world". + +# somewhere, because usually the default key bindings include searching. (Press +# Ctrl-R.) It would be really annoying if the search key bindings are handled, +# but the user doesn't see any feedback. We will add the search toolbar to the +# bottom by using an HSplit. + + +def get_titlebar_text(): + return [ + ("class:title", " Hello world "), + ("class:title", " (Press [Ctrl-Q] to quit.)"), + ] + + +root_container = HSplit( + [ + # The titlebar. + Window( + height=1, + content=FormattedTextControl(get_titlebar_text), + align=WindowAlign.CENTER, + ), + # Horizontal separator. + Window(height=1, char="-", style="class:line"), + # The 'body', like defined above. + body, + ] +) + + +# 2. Adding key bindings +# -------------------- + +# As a demonstration, we will add just a ControlQ key binding to exit the +# application. Key bindings are registered in a +# `prompt_toolkit.key_bindings.registry.Registry` instance. We use the +# `load_default_key_bindings` utility function to create a registry that +# already contains the default key bindings. + +kb = KeyBindings() + +# Now add the Ctrl-Q binding. We have to pass `eager=True` here. The reason is +# that there is another key *sequence* that starts with Ctrl-Q as well. Yes, a +# key binding is linked to a sequence of keys, not necessarily one key. So, +# what happens if there is a key binding for the letter 'a' and a key binding +# for 'ab'. When 'a' has been pressed, nothing will happen yet. Because the +# next key could be a 'b', but it could as well be anything else. If it's a 'c' +# for instance, we'll handle the key binding for 'a' and then look for a key +# binding for 'c'. So, when there's a common prefix in a key binding sequence, +# prompt-toolkit will wait calling a handler, until we have enough information. + +# Now, There is an Emacs key binding for the [Ctrl-Q Any] sequence by default. +# Pressing Ctrl-Q followed by any other key will do a quoted insert. So to be +# sure that we won't wait for that key binding to match, but instead execute +# Ctrl-Q immediately, we can pass eager=True. (Don't make a habit of adding +# `eager=True` to all key bindings, but do it when it conflicts with another +# existing key binding, and you definitely want to override that behavior. + + +@kb.add("c-c", eager=True) +@kb.add("c-q", eager=True) +def _(event): + """ + Pressing Ctrl-Q or Ctrl-C will exit the user interface. + + Setting a return value means: quit the event loop that drives the user + interface and return this value from the `Application.run()` call. + + Note that Ctrl-Q does not work on all terminals. Sometimes it requires + executing `stty -ixon`. + """ + event.app.exit() + + +# Now we add an event handler that captures change events to the buffer on the +# left. If the text changes over there, we'll update the buffer on the right. + + +def default_buffer_changed(_): + """ + When the buffer on the left changes, update the buffer on + the right. We just reverse the text. + """ + right_buffer.text = left_buffer.text[::-1] + + +left_buffer.on_text_changed += default_buffer_changed + + +# 3. Creating an `Application` instance +# ---------------------------------- + +# This glues everything together. + +application = Application( + layout=Layout(root_container, focused_element=left_window), + key_bindings=kb, + # Let's add mouse support! + mouse_support=True, + # Using an alternate screen buffer means as much as: "run full screen". + # It switches the terminal to an alternate screen. + full_screen=True, +) + + +# 4. Run the application +# ------------------- + + +def run(): + # Run the interface. (This runs the event loop until Ctrl-Q is pressed.) + application.run() + + +if __name__ == "__main__": + run() |