One canvas API, multiple backends 🚀
This project is part of pygfx.org
See how the two windows above look the same? That's the idea; they also look the same to the code that renders to them. Yet, the GUI systems are very different (Qt vs glfw in this case). Now that's a powerful abstraction!
Providing a generic API for:
- managing a canvas window (
BaseRenderCanvas). - presenting rendered results with
wgpu(WgpuContext). - presenting rendered results as a bitmap (
BitmapContext). - working with events that have standardized behavior.
Implement that on top of a variety of backends:
- Running on desktop with a light backend (glfw).
- Running in the browser (with Pyodide or PyScript).
- Running from a (Jupyter) notebook.
- Embedding as a widget in a GUI library.
- Qt
- wx
- In addition to the GUI libraries mentioned above, the following event loops are supported:
- asyncio
- trio
- raw
pip install rendercanvas
To have at least one backend, we recommend:
pip install rendercanvas glfw
Also see the online documentation and the examples.
A minimal example that renders noise:
import numpy as np
from rendercanvas.auto import RenderCanvas, loop
canvas = RenderCanvas(update_mode="continuous")
context = canvas.get_bitmap_context()
@canvas.request_draw
def animate():
w, h = canvas.get_logical_size()
bitmap = np.random.uniform(0, 255, (h, w)).astype(np.uint8)
context.set_bitmap(bitmap)
loop.run()Run wgpu visualizations:
from rendercanvas.auto import RenderCanvas, loop
from rendercanvas.utils.cube import setup_drawing_sync
canvas = RenderCanvas(
title="The wgpu cube example on $backend", update_mode="continuous"
)
draw_frame = setup_drawing_sync(canvas)
canvas.request_draw(draw_frame)
loop.run()Embed in a Qt application:
from PySide6 import QtWidgets
from rendercanvas.qt import QRenderWidget
class Main(QtWidgets.QWidget):
def __init__(self):
super().__init__()
splitter = QtWidgets.QSplitter()
self.canvas = QRenderWidget(splitter)
...
app = QtWidgets.QApplication([])
main = Main()
app.exec()We support both; a render canvas can be used in a fully async setting using e.g. Asyncio or Trio, or in an event-driven framework like Qt.
If you like callbacks, loop.call_later() always works. If you like async, use loop.add_task().
See the docs on async for details.
This code is distributed under the 2-clause BSD license.
- Clone the repo.
- Install
rendercanvasand developer deps usingpip install -e .[dev]. - Use
ruff formatto apply autoformatting. - Use
ruff checkto check for linting errors. - Optionally, if you install pre-commit hooks with
pre-commit install, lint fixes and formatting will be automatically applied ongit commit. - Use
pytest teststo run the tests. - Use
pytest examplesto run a subset of the examples.


