ryvencore-qt 0.3.1.2

Qt frontend for ryvencore; Library for building Visual Node Editors

rvencore-qt is a wrapper around ryvencore and provides a Qt frontend for it. It comes from the Ryven project and will be the foundation for future Ryven versions. So, ryvencore-qt can be used to build cross-platform standalone visual node editors based on Python. Projects made with ryvencore-qt can be natively deployed directly on the backend, ryvencore. The development of ryvencore-qt is currently closely tied to Ryven.

Installation

pip install ryvencore-qt

or build from sources

git clone https://github.com/leon-thomm/ryvencore-qt
cd ryvencore-qt
pip install .

Dependencies

ryvencore-qt runs on PySide2 (Python bindings for Qt) using QtPy as a wrapper to (eventually, once supported) enable seamless switching between PySide2 and PySide6. Notice that ryvencore-qt does not work with PyQt, due to crucial inheritance restrictions in PyQt.

quick start

The below code demonstrates how to set up an editor with custom defined nodes. You can also find the code in the examples folder.

main.py

# Qt
import sys
import os
os.environ['QT_API'] = 'pyside2'  # tells QtPy to use PySide2
from qtpy.QtWidgets import QMainWindow, QApplication

# ryvencore-qt
import ryvencore_qt as rc
from nodes import export_nodes


if __name__ == "__main__":

    # first, we create the Qt application and a window
    app = QApplication()
    mw = QMainWindow()

    # now we initialize a new ryvencore-qt session
    session = rc.Session()
    session.design.set_flow_theme(name='pure light')  # setting the design theme

    # and register our nodes
    session.register_nodes(export_nodes)

    # to get a flow where we can place nodes, we need to crate a new script
    script = session.create_script('hello world', flow_view_size=[800, 500])

    # getting the flow widget of the newly created script
    flow_view = session.flow_views[script]
    mw.setCentralWidget(flow_view)  # and show it in the main window

    # finally, show the window and run the application
    mw.show()
    sys.exit(app.exec_())

nodes.py

import ryvencore_qt as rc
from random import random


# let's define some nodes
# to easily see something in action, we create one node generating random numbers, and one that prints them

class PrintNode(rc.Node):
    """Prints your data"""

    title = 'Print'
    init_inputs = [
        rc.NodeInputBP(),
    ]
    init_outputs = []
    color = '#A9D5EF'

    # we could also skip the constructor here
    def __init__(self, params):
        super().__init__(params)

    def update_event(self, inp=-1):
        print(
            self.input(0)  # get data from the first input
        )


class RandNode(rc.Node):
    """Generates scaled random float values"""

    title = 'Rand'
    init_inputs = [
        rc.NodeInputBP(dtype=rc.dtypes.Data(default=1)),
    ]
    init_outputs = [
        rc.NodeOutputBP(),
    ]
    color = '#fcba03'

    def update_event(self, inp=-1):
        # random float between 0 and value at input
        val = random() * self.input(0)

        # setting the value of the first output
        self.set_output_val(0, val)


export_nodes = [
    PrintNode,
    RandNode,
]

For a more detailed overview, including a precise definition of flows, see the Features Page and ryvencore.

Development

The code is not 100% PEP 8 conform, and some parts which are under development might seem messy. I'm doing my best :) feel free to improve. The individual subpackages have their own READMEs giving a quick overview which should be quite helpful to gain understanding about implementations.

Cheers.