CODEWITHSUNDEEP
pythonmatplotlibuser-interfacekivy
krishnab
krishnab

Reputation: 10110

Displaying a Matplotlib plot in Kivy without using the kivy-garden tools

I am just learning to use Kivy and want to embed some plots from Matplotlib and potentially OpenGL graphics in an app. I was looking at this particular tutorial on how to use kivy-garden to display a Matplotlib plot

However, I was hoping someone might be able to point me to an example of importing a plot into Kivy without using the matplotlib kivy-garden widgets. I want to be a little plotting backend agnostic, and hence I wanted to learn to import plots directly into the Kivy widgets. Matplotlib will export an image from plt.show() so I imagine the corresponding Kivy widget needs to have a property that can receive images? Plotly exports something different, so I was hoping to understand how to directly import these different plots into Kivy.

If anyone knows some good examples of directly plotting into Kivy, it would be appreciated.

Upvotes: 1

Views: 488

Answers (1)

Mark
Mark

Reputation: 627

You can load an Image. Here is an example hacked out of some code that I use.

kivy file:

#:kivy 2.0.0

<MatPlot>:

    Image:
        size_hint_x: 12
        source: root.matplotlib_image2.source
    Image:
        size_hint_x: 5
        source: root.matplotlib_image1.source

Python: my method on_start() probably needs to be called from some other code. I think the on_start is only intrinsic with App and not other widgets. I have used this with matplotlib which as you point out can export image files.

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from pathlib import Path

from kivy.uix.image import Image
from kivy.uix.boxlayout import BoxLayout


# requires kivy element <MatPlot> from kv_mat_plot.kv
class MatPlot(BoxLayout):
    matplotlib_image1 = Image()
    matplotlib_image2 = Image()

    def __init__(self,
                 graph_directory: Path,
                 **kwargs,
                 ):

        super().__init__(**kwargs)

        self.graph_directory = graph_directory

    def load_image1(self, filename: str):
        self.matplotlib_image1.source = str(Path(self.graph_directory, filename))
        self.matplotlib_image1.reload()

    def load_image2(self, filename: str):
        self.matplotlib_image2.source = str(Path(self.graph_directory, filename))
        self.matplotlib_image2.reload()

    def reload_image2(self):
        self.matplotlib_image2.reload()
        print(f"imag2={self.matplotlib_image2.source}")

    def reload_image1(self):
        self.matplotlib_image1.reload()
        print(f"image1={self.matplotlib_image1.source}")

    def reload_images(self):
        self.reload_image2()
        self.reload_image1()

    def on_start(self):
        print(f"{self.name} on_start {self}")
        self.matplotlib_image2.source = str(Path(self.graph_directory, "one_image.png"))
        self.matplotlib_image1.source = str(Path(self.graph_directory, "second_image.png"))

Upvotes: 2

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