UI widget overview

You can use the following premade app_components to create user interfaces:

The Menu component, allows you to create menus with which you can scroll through a list of options and select an item.

Example

from app import App
from app_components import Menu, Notification, clear_background

main_menu_items = ["menu_item1", "menu_item2", "menu_item3"]


class MenuDemo(App):
    def __init__(self):
        self.menu = Menu(
            self,
            main_menu_items,
            select_handler=self.select_handler,
            back_handler=self.back_handler,
        )
        self.notification = None

    def select_handler(self, item):
        self.notification = Notification('You selected "' + item + '"!')

    def back_handler(self):
        self.minimise()

    def draw(self, ctx):
        clear_background(ctx)
        self.menu.draw(ctx)
        if self.notification:
            self.notification.draw(ctx)

    def update(self, delta):
        self.menu.update(delta)
        if self.notification:
            self.notification.update(delta)


__app_export__ = MenuDemo

You can see a more comprehensive example in the menu_demo.py.

Usage

To use a menu:

Import the Menu component:

from app_components import Menu

Define your menu items above your App class:

menu_items = [ "menu_item1", "menu_item2" ]

Initialize a variable to hold the menu in the __init__ method of your app:

self.menu = Menu(
    self,
    menu_items,
    select_handler=self.select_handler,
    back_handler=self.back_handler,
)

To initialize the Menu use the following parameters:

Parameter	Type	Description
`app`	`App`	The app to add the menu to.
`menu_items`	`[str]`	A list of strings containing the menu items.
`select_handler`	`method`	The method to be called when an item is selected and the confirm button is pressed.
`back_handler`	`method`	The method to be called when the cancel button is pressed.
`position`	`int`	Optional. The menu position to start at. Default: `0`.
`speed_ms`	`int`	Optional. The speed to redraw the UI at. Default: `300`.
`item_font_size`	`float`	Optional. The item line height. Default: `tokens.ten_pt`.
`item_line_height`	`float`	Optional. The item line height. Default: `tokens.label_font_size * tokens.line_height`.
`focused_item_font_size`	`float`	Optional. The font size of the focused item. Default: `tokens.heading_font_size`.
`focused_item_margin`	`float`	Optional. The margin on the focused item. Default: `20`.

If you are creating a multi-layered menu, also create a variable like current_menu in the __init__ method of your app to store the users menu state:

self.current_menu = None

Define the select_handler and the back_handler:

def back_handler(self):
    # Do something. If in the topmost menu, minimize, otherwise move one menu up.
    if self.current_menu == "main":
        self.minimise()
    self.set_menu("main")

def select_handler(self, item):
    # Do something based on the selection, like moving to a new menu or performing an action.

Add the following lines in your draw() method to draw the app's menu:

# in def draw(self, ctx):
self.menu.draw(ctx)

Add the following lines in your update() method to update the state of the menu:

# in def update(self, delta):
self.menu.update(delta)

Methods

You can use the following methods on a Menu object:

Method	Description	Arguments	Returns
`up_handler()`	Manually moves you up one position in the menu.	None	None
`down_handler()`	Manually moves you down one position in the menu.	None	None
`update(delta)`	Update the menu as animations are happening. You need to call this method in your app's `update()` method.	`delta`: Time difference between the last update call and the current update call.	None
`draw(ctx)`	Add the menu to the screen. You need to call this method in your app's `draw()` method.	`ctx`: The canvas that let's you add graphics or texts. See `ctx` library.	None

Notification

The Notification component allows you to create pop up notifications.

Example

This example app shows a notification for each button you press.

from app import App
from app_components import Notification, clear_background
from events.input import Buttons, BUTTON_TYPES


class NotificationDemo(App):
    def __init__(self):
        self.notification = None
        self.button_states = Buttons(self)

    def update(self, delta):
        if self.button_states.get(BUTTON_TYPES["RIGHT"]):
            self.notification = Notification("right!")
        if self.button_states.get(BUTTON_TYPES["LEFT"]):
            self.notification = Notification("left!")
        if self.button_states.get(BUTTON_TYPES["UP"]):
            self.notification = Notification("up!")
        if self.button_states.get(BUTTON_TYPES["DOWN"]):
            self.notification = Notification("down!")
        if self.button_states.get(BUTTON_TYPES["CANCEL"]):
            self.notification = Notification("cancel!")
        if self.button_states.get(BUTTON_TYPES["CONFIRM"]):
            self.notification = Notification("confirm!")
        if self.notification:
            self.notification.update(delta)

    def draw(self, ctx):
        clear_background(ctx)
        if self.notification:
            self.notification.draw(ctx)


__app_export__ = NotificationDemo

Usage

To use a notification:

Import the Notification component:

from app_components import Notification

Initialize the notification in the __init__ method of your app:

self.notification = None

Set the notification text in your app's code:

self.notification = Notification("This is a notification!")

Notification() supports the following parameters:

Parameter	Type	Description
`message`	`str`	The notification message.
`port`	`int`	Optional. The port from which the notification was issued. Default: `0`.
`open`	`boolean`	Optional. Whether to open the notification. Default: `True`.

Add the following lines in your draw() method to draw the notification when self.notification contains a notification:

# in def draw(self, ctx):
if self.notification:
    self.notification.draw(ctx)

Add the following lines in your update() method to update the state of the notification:

# in def update(self, delta):
if self.notification:
    self.notification.update(delta)

Methods

You can use the following methods on a Notification object:

Method	Description	Arguments	Returns
`open()`	Manually open the notification.	None	None
`close()`	Manually close the notification.	None	None
`update(delta)`	Automatically display the notification for a period of 5 seconds. You need to call this method in your app's `update()` method.	`delta`: Time difference between the last update call and the current update call.	None
`draw(ctx)`	Add the notification to the screen. You need to call this method in your app's `draw()` method.	`ctx`: The canvas that let's you add graphics or texts. See `ctx` library.	None

Yes/No Dialog

The YesNoDialog component allows you to create yes or no dialogues.

Example

SynchronousAsynchronous

This example app shows a dialog that asks you if it's a happy day and responds with an appropriate message. It calls the YesNoDialog in a synchronous way:

import app

from app_components import YesNoDialog, clear_background


class DialogDemo(app.App):
    def __init__(self):
        # Need to call to access overlays for dialog
        super().__init__()
        self.dialog = None
        self.answer = ""
        self.displayed = False

    def _no_handler(self):
        self.dialog._cleanup()
        self.answer = "I'm sorry"
        self.dialog = None

    def _yes_handler(self):
        self.dialog._cleanup()
        self.answer = "YAY!"
        self.dialog = None

    def update(self, delta):
        if not self.displayed:
            self.displayed = True
            self.dialog = YesNoDialog(
                message="Is it a happy day?",
                on_yes=self._yes_handler,
                on_no=self._no_handler,
                app=self,
            )

    def draw(self, ctx):
        clear_background(ctx)

        ctx.save()
        if self.answer:
            ctx.rgb(0, 0, 0.2).rectangle(-120, -120, 240, 240).fill()
            ctx.rgb(0, 0, 1).move_to(-80, 0).text(self.answer)
        ctx.restore()

        if self.dialog:
            self.dialog.draw(ctx)

__app_export__ = DialogDemo

This example app shows a dialog that asks you if it's a happy day and responds with an appropriate message. It overwrites the run() method to be able to use the run() method on the YesNoDialog which allows you to perform asynchronous actions based on the output of the dialog:

import app

from app_components import YesNoDialog, clear_background


class DialogDemo(app.App):
    def __init__(self):
        # Need to call to access overlays for dialog
        super().__init__()
        self.answer = None

    async def run(self, render_update):
        # Render initial state
        await render_update()

        # Create a yes/no dialogue, add it to the overlays
        dialog = YesNoDialog("Is it a happy day?", self)
        self.overlays = [dialog]
        # Wait for an answer from the dialogue.
        # if the answer was yes, the dialog.run() will return a true value
        # and we set an appropriate answer
        if await dialog.run(render_update):
            self.answer = "YAY!"
        else:
            self.answer = "I'm sorry"
        # Remove the dialogue and re-render
        self.overlays = []
        await render_update()


    def draw(self, ctx):
        clear_background(ctx)
        if self.answer:
            ctx.save()
            ctx.rgb(0, 0, 0.2).rectangle(-120, -120, 240, 240).fill()
            ctx.rgb(0, 0, 1).move_to(-80, 0).text(self.answer)
            ctx.restore()
        self.draw_overlays(ctx)

__app_export__ = DialogDemo

Usage

To use the Yes/No dialog:

Import the YesNoDialog component:

from app_components import YesNoDialog

Add the following line to the __init__ method of your app to initialize the inherited object:

super().__init__()

SynchronousAsynchronous

Create the YesNoDialog from your update() method and pass in the message to display, as well as handlers for what to do when the user responds with yes or no. Since the update() method gets called repeatedly, make sure it only gets called once:
```
self.dialog = YesNoDialog(
    message="Is it a happy day?",
    on_yes=self._yes_handler,
    on_no=self._no_handler,
    app=self,
)
```

Use the run() method which supports asynchronous calls. You need asynchronous calls to wait for the answer to the dialog:

async def run(self, render_update):
    # Render initial state
    await render_update()

    # Create a yes/no dialogue, add it to the overlays
    dialog = YesNoDialog("Is it a happy day?", self)
    self.overlays = [dialog]
    # Wait for an answer from the dialogue, and if it was yes, do
    # something
    if await dialog.run(render_update):
        # this sets a variable that can be used in the draw method
        self.answer = "I'm sorry"
    else:
        self.answer = "YAY!"
    # Remove the dialogue and re-render
    self.overlays = []
    await render_update()

YesNoDialog() supports the following parameters:

Parameter	Type	Description
`message`	`str`	The dialog message.
`app`	`App`	The app opening the dialog.
`on_yes`	`method`	Optional. Call the provided handler method or return `True` if answer is yes and no handler is provided. Default: `None`.
`on_no`	`method`	Optional. Call the provided handler method or return `False` if answer is yes and no handler is provided. Default: `None`.

SynchronousAsynchronous

Add the following lines in your draw() method to draw the dialog's overlays:

# in def draw(self, ctx):
    if self.dialog:
        self.dialog.draw(ctx)

Add the following lines in your draw() method to clear the background and draw the dialog's overlays:
```
# in def draw(self, ctx):
    clear_background(ctx)
    self.draw_overlays(ctx)
```

To make the dialog's answers have an effect you need to do something based on the input you have received from the YesNoDialog. Check the example for an idea.

Methods

You can use the following methods on a YesNoDialog object:

Method	Description	Arguments	Returns
`run(render_update)`	Asynchronous. Open the dialog. You need to call this method to display the dialog.	`render_update`: The method that triggers a `draw()` call when updates are complete.	`True` or `False`
`draw_message(ctx)`	Helper method to add your message to the screen. This method is called by the `draw()` method.	`ctx`: The canvas that let's you add graphics or texts. See `ctx` library.	None
`draw(ctx)`	Add the dialog to the screen. You need to call this method in your app's `draw()` method.	`ctx`: The canvas that let's you add graphics or texts. See `ctx` library.	None

Text Dialog

The TextDialog component allows you to create ask for text input.

Example

SynchronousAsynchronous

This example app shows a dialog that asks you for your name and then says hell:

import app
from app_components import TextDialog, clear_background


class TextDemo(app.App):
    def __init__(self):
        super().__init__()
        self.name = ""
        self.dialog = None
        self.displayed = False

    def _cancel_handler(self):
        self.name = "world!"
        self.dialog._cleanup()
        self.dialog = None

    def _complete_handler(self):
        self.name = self.dialog.text
        self.dialog._cleanup()
        self.dialog = None

    def update(self, delta):
        if not self.displayed:
            self.displayed = True
            self.dialog = TextDialog(
                "What is your name?",
                self,
                masked=False,
                on_complete=self._complete_handler,
                on_cancel=self._cancel_handler)

    def draw(self, ctx):
        clear_background(ctx)

        ctx.save()
        if self.name:
            ctx.text_align = "center"
            ctx.gray(1).move_to(0, 0).text("Hello " + self.name)
        ctx.restore()

        if self.dialog:
            self.dialog.draw(ctx)

__app_export__ = TextDemo

This example app shows a dialog that asks you for a name and then says hello. It overwrites the run() method to be able to use the run() method on the TextDialog which allows you to perform asynchronous actions based on the output of the dialog:

import app
from app_components import TextDialog, clear_background


class TextDemo(app.App):
    def __init__(self):
        super().__init__()
        self.name = "world!"

    async def run(self, render_update):
        await render_update()

        dialog = TextDialog("What is your name?", self)
        self.overlays = [dialog]

        if await dialog.run(render_update):
            self.name = dialog.text

        self.overlays = []
        await render_update()

    def draw(self, ctx):
        clear_background(ctx)

        ctx.save()
        ctx.text_align = "center"
        ctx.gray(1).move_to(0, 0).text("Hello " + self.name)
        ctx.restore()

        self.draw_overlays(ctx)

__app_export__ = TextDemo

Usage

To use the text dialog:

Import the TextDialog component:

from app_components import TextDialog

Add the following line to the __init__ method of your app to initialize the inherited object:

super().__init__()

SynchronousAsynchronous

Create the TextDialog from your update() method and pass in the message to display, whether to mask (that means obscure) the input while the suer is entering it, as well as handlers for what to do when the user completes their input or cancels entering input. Since the update() method gets called repeatedly, make sure it only gets called once:
```
self.dialog = TextDialog(
    "What is your name?",
    self,
    masked=False,
    on_complete=self._complete_handler,
    on_cancel=self._cancel_handler)
```

Use the run() method which supports asynchronous calls. You need asynchronous calls to wait for the answer to the dialog:

async def run(self, render_update):
    # Render initial state
    await render_update()

    # Create a text dialogue, add it to the overlays
    dialog = TextDialog("What is your name?", self)
    self.overlays = [dialog]
    # Wait for an answer from the dialogue, and if it was yes, do something
    if await dialog.run(render_update):
        # this sets a variable that can be used in the draw method
        self.name = dialog.text
    else:
        # this is run when the user cancels the dialog
        self.answer = "anonymous"
    # Remove the dialogue and re-render
    self.overlays = []
    await render_update()

TextDialog() supports the following parameters:

Parameter	Type	Description
`message`	`str`	The dialog message.
`app`	`App`	The app opening the dialog.
`masked`	`bool`	Optional. Whether to obscure the text buffer with asterisks (for example, for passwords). Default: `False`.
`on_complete`	`method`	Optional. Call the provided handler method or return the text entry if the text entry is confirmed and no handler is provided. Default: `None`.
`on_cancel`	`method`	Optional. Call the provided handler method or return `False` if answer is cancelled and no handler is provided. Default: `None`.

SynchronousAsynchronous

Add the following lines in your draw() method to draw the dialog's overlays:

# in def draw(self, ctx):
    if self.dialog:
        self.dialog.draw(ctx)

Add the following lines in your draw() method to clear the background and draw the dialog's overlays:
```
# in def draw(self, ctx):
    clear_background(ctx)
    self.draw_overlays(ctx)
```

To make the dialog's answer have an effect you need to do something with the answer you received. The response from the dialog is saved in text on the dialog (for example dialog.text). Check the example for an idea.

Methods

You can use the following methods on a TextDialog object:

Method	Description	Arguments	Returns
`run(render_update)`	Asynchronous. Open the dialog. You need to call this method to display the dialog.	`render_update`: The method that triggers a `draw()` call when updates are complete.	`True` or `False`
`draw_message(ctx)`	Helper method to add your message to the screen. This method is called by the `draw()` method.	`ctx`: The canvas that let's you add graphics or texts. See `ctx` library.	None
`draw(ctx)`	Add the dialog to the screen. You need to call this method in your app's `draw()` method.	`ctx`: The canvas that let's you add graphics or texts. See `ctx` library.	None

Layouts

You can compose menu layouts out of the following display layouts:

TextDisplay: The TextDisplay component allows you to display long texts.
ButtonDisplay: The ButtonDisplay component allows you to display a button and register a handler for the button.
DefinitionDisplay: The DefinitionDisplay component allows you to display a label and a definition for the label.

Example

This example creates what could be a small game menu with three parts:

one text field that can be edited for the game player's name
one selector field where you can select an option, in this case the difficulty level
one field that displays a lot of text, in this case lorem ipsum text

import app

from app_components import clear_background, TextDialog
from app_components.layout import \
    TextDisplay, ButtonDisplay, DefinitionDisplay, LinearLayout
from events.input import BUTTON_TYPES, ButtonDownEvent
from system.eventbus import eventbus

DIFFICULTY_VALUES = ["easy", "normal", "hard"]
LOREM = """Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do\
 eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim\
 veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea\
 commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit\
 esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat \
 cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est\
 laborum."""


def string_formatter(value):
    if value is None:
        return "Default"
    else:
        return str(value)


class LayoutMenuDemo(app.App):
    def __init__(self):
        self.layout = LinearLayout(items=[DefinitionDisplay("", "")])
        self.dialog = None
        self.options = {
            (
                "text_setting",
                "Player Name",
                string_formatter,
                self.string_editor
            ),
            ("button_selector", "Difficulty selector", string_formatter, None),
            ("text", "Game Instructions", string_formatter, None),
        }
        self.app_settings = {
            "text_setting": "Naomi",
            "button_selector": "easy",
            "instructions": LOREM
        }
        eventbus.on_async(ButtonDownEvent, self._button_handler, self)

    async def string_editor(self, label, id, render_update):
        self.dialog = TextDialog(label, self)
        self.dialog._settings_id = id

    async def _button_handler(self, event):
        layout_handled = await self.layout.button_event(event)
        if not layout_handled:
            if BUTTON_TYPES["CANCEL"] in event.button:
                self.minimise()

    async def update_values(self):
        for item in self.layout.items:
            if isinstance(item, DefinitionDisplay):
                for id, label, formatter, _ in self.options:
                    if item.label == label:
                        if id in self.app_settings.keys():
                            value = self.app_settings[id]
                        else:
                            value = ""
                        item.value = formatter(value)

    async def run(self, render_update):
        while True:
            self.layout.items = []
            for id, label, formatter, editor in self.options:
                if id in self.app_settings.keys():
                    value = self.app_settings[id]
                else:
                    value = ""

                if editor:
                    async def _button_event(
                            event, label=label, id=id, editor=editor):
                        if BUTTON_TYPES["CONFIRM"] in event.button:
                            await editor(label, id, render_update)
                            return True
                        return False

                    entry = DefinitionDisplay(
                        label, formatter(value), button_handler=_button_event
                    )
                else:
                    entry = DefinitionDisplay(label, formatter(value))
                self.layout.items.append(entry)
                if id == "text":
                    async def _button_event(event):
                        if BUTTON_TYPES["CONFIRM"] in event.button:
                            return True
                        return False

                    entry = TextDisplay(self.app_settings["instructions"])

                    self.layout.items.append(entry)

                if id == "button_selector":
                    async def _button_selector_event(event):
                        value = self.app_settings[id]
                        if BUTTON_TYPES["CONFIRM"] in event.button:
                            if value == DIFFICULTY_VALUES[0]:
                                self.app_settings[id] = DIFFICULTY_VALUES[1]
                            if value == DIFFICULTY_VALUES[1]:
                                self.app_settings[id] = DIFFICULTY_VALUES[2]
                            if value == DIFFICULTY_VALUES[2]:
                                self.app_settings[id] = DIFFICULTY_VALUES[0]
                            await self.update_values()
                            await render_update()
                            return True
                        return False

                    entry = ButtonDisplay(
                        "Change", button_handler=_button_selector_event
                    )
                    self.layout.items.append(entry)
            while True:
                await render_update()
                if self.dialog:
                    result = await self.dialog.run(render_update)
                    if (
                        result is not False
                    ):  # != because we want to allow entering empty strings
                        self.app_settings[self.dialog._settings_id] = result
                    self.dialog = None
                    if result:
                        break

    def update(self, delta):
        return True

    def draw(self, ctx):
        clear_background(ctx)
        self.layout.draw(ctx)


__app_export__ = LayoutMenuDemo

A longer example of a layout is the Settings app.

Usage

To use layouts:

Import the different layouts:
```
from app_components.layout import *
```
Initialize a variable to hold the layouts in the __init__ method of your app:
```
self.layout = LinearLayout(items=[DefinitionDisplay("", "")])
```

Add one or more layouts:

DefinitionDisplayTextDisplayButtonDisplay

The DefinitionDisplay component allows you to display a label and a definition for the label.

Initialize the button_display in your __init__ or in your update method:

definition_display = DefinitionDisplay("Label", "value")
self.layout.items.append(definition_display)

To initialize the definition display use the following parameters:

Parameter	Type	Description
`label`	`str`	The text to display for the label.
`value`	`str`	The text to display for the definition.
`height`	`int`	The height at which to display the definition display.
`button_handler`	`method`	The handler for button events.

The TextDisplay component allows you to display long texts.

Initialize the text_display in your __init__ or in your update method and add it to the self.layout.items variable:

text_display = TextDisplay("My long text", font_size=8, rgb=(0, 0, 50))
self.layout.items.append(text_display)

To initialize the TextDisplay use the ?following parameters:

Parameter	Type	Description
`text`	`str`	The long text to display.
`font_size`	`int`	The font size to display the text in.
`rgb`	`tuple`	The color to display the text in.

The ButtonDisplay component allows you to display a button and register a handler for the button.

Initialize the button_display in your __init__ or in your update method:

button_display = ButtonDisplay(
    text="Select me",
    app=self,
    font_size=8,
    rgb=(50, 0, 0),
    button_handler=self.select_handler)
self.layout.items.append(button_display)

To initialize the button display use the following parameters:

Parameter	Type	Description
`text`	`str`	The long text to display.
`app`	`App`	The app to add the button display to.
`font_size`	`int`	The font size to display the text in.
`rgb`	`tuple`	The color to display the text in.
`button_handler`	`method`	The handler for button events.

Create an asynchronous select_handler that does something when a button is pressed:

    async def select_handler(event):
        if BUTTON_TYPES["CONFIRM"] in event.button:
            # do something
        return False

Add the following lines in your draw() method to draw the app's layout:
```
# in def draw(self, ctx):
 self.layout.draw(ctx)
```

Tokens

The Tokens component allows you to use: - functions for clearing the background and setting a color - constants for the display properties and colors

Functions

Method	Description	Arguments	Returns
`clear_background(ctx)`	Clear the badge background.	`ctx`: The canvas that let's you add graphics or texts. See `ctx` library.	None
`set_color(ctx, color)`	Set the color for the canvas.	`ctx`: The canvas that let's you add graphics or texts. See `ctx` library. `color`: The provided color as a string from the following options: `pale_green`, `mid_green`, `dark_green`, `colors.yellow`, `colors.orange`, `colors.pink`, `colors.blue`, `ui_colors.background`, `ui_colors.label`.	None

Usage

from app_components.tokens import clear_background, set_color

clear_background(ctx)
set_color(ctx, "label")

Constants

To use the pre-defined constants, import them from the Tokens component, for example:

from app_components.tokens import display_x

You can access the following variables:

For display:

display_x
display_y
display_height_inches
ppi

For fonts:

one_pt
ten_pt
twelve_pt
eighteen_pt
twentyfour_pt
label_font_size
heading_font_size
line_height

For colors:

colors.pale_green
colors.mid_green
colors.dark_green
colors.yellow
colors.orange
colors.pink
colors.blue
ui_colors.background
ui_colors.label