PlayPy 0.3.0

PlayPy is a lightweight Python library for creating simple games and interactive applications with ease. It provides a straightforward API for handling graphics, input, and basic game mechanics, making it ideal for beginners and those looking to quickly prototype their ideas.

PlayPy (0.3.0)

PlayPy is a lightweight Python library for creating games, tools, and interactive applications using a retained-mode UI and scene system built on top of pygame. It focuses on rapid prototyping, composable rendering, and simple but powerful layout primitives.

Requirements

• Python >=3.11
• pygame(-ce) >=2.6.1

Installation

pip install playpy

If that does not work:

python -m pip install playpy

---

Core Concepts

Workspace

Workspace owns:

• the window
• render loop
• input state
• scene stack
• coroutine scheduler

Key methods:

ws.run()
ws.quit()

ws.queue_scene_change(scene)
ws.queue_scene_push(scene)
ws.queue_scene_pop(scene=None)

ws.step()

Scene Scope

Temporarily push a scene using a context manager:

with ws.scene_scope(scene) as (scn, handle):
    ...

Call:

handle.disconnect()

to remotely pop the scoped scene.

---

Layout Values

PlayPy uses two rectangle value types:

FRect

Relative scale values.

plp.FRect(x, y, w, h)

Rect

Absolute pixel offsets.

plp.Rect(x, y, w, h)

Final element rectangle:

(scale * parent_size) + offset

Helpers:

plp.empty_rect()
plp.empty_frect()
plp.full_screen_rect()

Rect types are iterable and support multiple constructor overloads.

---

Parenting

Any Element can contain children.

child.parent = parent

or:

parent.add_child(child)

Relationship helpers:

is_parent_of()
is_child_of()

is_ancestor_of()
is_descendant_of()

Properties:

parent
children
ancestors
descendants

---

Rendering System

PlayPy now uses a compositing pipeline.

Element.draw() returns a SurfaceHandler instead of drawing directly to the workspace.

This enables:

• outlines for arbitrary shapes
• gradients inheriting shape alpha
• subtree compositing
• layered visual effects
• future post-processing support

---

Elements

Core Elements

• Panel
• Text
• Button
• Textbox
• Line
• Scene

Effects

Effect is a subclass of Element that visually modifies its parent subtree.

Built-in effects:

• Gradient
• ButtonGradient
• Outline
• BorderRadius

Effects are ordered using z.

Typical layering:

Negative z:
    backgrounds/gradients

Normal z:
    content

Positive z:
    outlines/glows/overlays

Components

Components modify behavior/layout but do not draw.

Built-in components:

• Padding
• Font
• Camera
• Scrollable
• GlobalElement

Attach/get/remove:

element.set_component(component)

element.get_component(ComponentType)

element.remove_component(ComponentType)

or:

component.parent = element

---

Input State

Access input using:

workspace.input

Properties:

keys_pressed
key_downs
key_ups

mouse_buttons_pressed
mouse_downs
mouse_ups

mouse_pos
mouse_delta
mouse_wheel

text_input

dt
runtime
quit

Helper methods:

key_held()
key_down()
key_up()

mousebutton_held()
mousebutton_down()
mousebutton_up()

---

Hover State

Workspace hover helpers:

is_mouse_top(element)
is_mouse_over(element)

just_hovered(element)
just_unhovered(element)

just_hovered_inclusive(element)
just_unhovered_inclusive(element)

Event helpers:

@on_hover(...)
@on_unhover(...)
@while_hovered(...)

@on_hover_inclusive(...)
@on_unhover_inclusive(...)
@while_hovered_inclusive(...)

---

Events

Decorator helpers create Event elements.

@plp.on_start(target)
@plp.on_update(target)
@plp.on_quit(target)

@plp.on_scene_change(target)

@plp.create_event(target, condition)

Events attached to the main workspace are global by default.

Example:

@plp.on_update(ws)
def tick(w: plp.Workspace):
    if w.input.key_down(plp.Key.ESCAPE):
        w.quit()

---

Coroutines

Event-like functions can yield.

If a handler returns a generator, PlayPy resumes it on future frames.

Example:

def flash(_: plp.Workspace):
    for _ in range(60):
        print("frame")
        yield

Supported in:

• event callbacks
• button callbacks
• textbox callbacks
• other event-like handlers

---

Textbox Features

Textbox supports:

• placeholders
• caret blinking
• text confirmation/reverting
• character filtering
• maximum length
• coroutine callbacks

Useful arguments:

is_char_accepted=
on_text_updated=
confirm_on_click_off=

Special keys:

Backspace -> remove character
Delete    -> clear text
Return    -> confirm text
Escape    -> revert text

---

Scenes

Scenes support lifecycle hooks:

on_enter()
on_exit()
on_pause()
on_resume()

Scene changes are queued internally.

---

Cameras and Scrolling

Camera offsets descendant elements.

Scrollable extends camera functionality with built-in scrolling support.

Example:

scrollable = plp.Scrollable()
scrollable.parent = panel

---

Logging

PlayPy replaces standard exceptions/logging with a categorized logging system.

plp.log(severity, category, message)

Severities:

plp.Severity.INFO
plp.Severity.WARNING
plp.Severity.ERROR
plp.Severity.CRITICAL

ERROR and CRITICAL are treated as NoReturn.