Kivy With opencv. Resizing Image size

Question

I want to insert an opencv webcam video in kivy. Unfortunately, when I do this and maximize the window the image does not adjust to the screen size. Is there any way to do this ?

from kivy.app import App
from kivy.uix.image import Image
from kivy.clock import Clock
from kivy.graphics.texture import Texture
import cv2

from kivy.uix.boxlayout import BoxLayout
from kivy.uix.gridlayout import GridLayout
from kivy.uix.widget import Widget
from kivy.uix.button import Button
from kivy.lang import Builder
from kivy.core.window import Window
Window.size=(1000,1000)


class KivyCamera(Image):
    def __init__(self, capture, fps, **kwargs):
        super(KivyCamera, self).__init__(**kwargs)
        self.capture = capture
        Clock.schedule_interval(self.update, 1.0 / fps)

    def update(self, dt):
        ret, frame = self.capture.read()
        if ret:
            buf1 = cv2.flip(frame, 0)
            buf = buf1.tostring()
            image_texture = Texture.create(size=(frame.shape[1], frame.shape[0]), colorfmt='rgb')#(480,640)
            image_texture.blit_buffer(buf, colorfmt='bgr', bufferfmt='ubyte')
            # display image from the texture
            self.texture = image_texture


class CamApp(App):
    def build(self):
        self.camera= cv2.VideoCapture(2)
        self.my_camera = KivyCamera(capture=self.camera, fps=10,resolution=(1280,960))
        return self.my_camera

    def on_stop(self):
        self.camera.release()


if __name__ == '__main__':
    CamApp().run()

I am hoping that the size of the frame increases when winow size increases. When I try to change the size in Texture it gives me error. Like either shows weird images or does not open any window. It would be great if somebody could help . Thanks !

Answer 1

you can do this: change the class type to BoxLayout. adding Image widget to Boxlayout with size_hint=(1,1). use size binding in init like this:

self.image = Image(size_hint=(1,1))
self.add_widget(self.image)
self.binding(size=self.Updatesize,
             pos=self.Updatesize)

and define a function in your class like this:

def Updatesize(*args):
   self.image.size=self.size
   self.image.pos=self.pos