Kivy Camera display is rotated -90 degrees

问题

I am accessing my camera in android 4.4 using python with kivy framework.

This is my simple code:

from kivy.app import App
from kivy.uix.camera import Camera
from kivy.core.window import Window

class CamApp(App):
    def build(self):
        return Camera(resolution= Window.size)

CamApp().run()

But when I ran my code, it displayed this:

enter image description here

Ideally, it should look like this:

enter image description here

It looks like the kivy Camera is displaying the output with a built in -90 degrees. Is this normal or a bug? Or should I rotate the display myself?

回答1:

The Solution from Cristian does not work for me. It will throw an Parser Exception at the line where canvas.before is written:

kivy.lang.parser.ParserException: Parser: File "<inline>", line 21:
I python  :  ...
I python  :       19:        height: '48dp'
I python  :       20:        on_press: root.capture()
I python  :  >>   21:    canvas.before:
I python  :       22:        PushMatrix
I python  :       23:        Rotate:
I python  :  ...
I python  :  Invalid class name

With regards that the canvas.before and canvas.after can only be called within other Objects the following Code is working for me:

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
import time
Builder.load_string('''
<CameraClick>:
    orientation: 'vertical'
    Camera:
        id: camera
        resolution: (640, 480)
        play: False
        canvas.before:
            PushMatrix
            Rotate:
                angle: -90
                origin: self.center
        canvas.after:
            PopMatrix
    ToggleButton:
        text: 'Play'
        on_press: camera.play = not camera.play
        size_hint_y: None
        height: '48dp'
    Button:
        text: 'Capture'
        size_hint_y: None
        height: '48dp'
        on_press: root.capture()
''')


class CameraClick(BoxLayout):
    def capture(self):
        '''
        Function to capture the images and give them the names
        according to their captured time and date.
        '''
        camera = self.ids['camera']
        timestr = time.strftime("%Y%m%d_%H%M%S")
        camera.export_to_png("IMG_{}.png".format(timestr))
        print("Captured")


class TestCamera(App):

    def build(self):
        return CameraClick()


TestCamera().run()

Resources:

https://kivy.org/doc/stable/examples/gen__canvas__rotation__py.html
https://github.com/kivy-garden/garden.zbarcam/blob/20171220/zbarcam/zbarcam.kv#L22

回答2:

I think this is a bug, but you can rotate the widget if you use this code:

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
import time
Builder.load_string('''
<CameraClick>:
    orientation: 'vertical'
    Camera:
        id: camera
        resolution: (640, 480)
        play: False
    ToggleButton:
        text: 'Play'
        on_press: camera.play = not camera.play
        size_hint_y: None
        height: '48dp'
    Button:
        text: 'Capture'
        size_hint_y: None
        height: '48dp'
        on_press: root.capture()
    canvas.before:
        PushMatrix
        Rotate:
            angle: -90
            origin: self.center
    canvas.after:
        PopMatrix
''')


class CameraClick(BoxLayout):
    def capture(self):
        '''
        Function to capture the images and give them the names
        according to their captured time and date.
        '''
        camera = self.ids['camera']
        timestr = time.strftime("%Y%m%d_%H%M%S")
        camera.export_to_png("IMG_{}.png".format(timestr))
        print("Captured")


class TestCamera(App):

    def build(self):
        return CameraClick()


TestCamera().run()

This worked for me on android.

回答3:

It is better to use opencv in your kivy code. it's give you a bunch of options and tools to manipulate pictures and videos. This code is ready for PC. I had 180 deg flip problem and fix it with opencv. you can use my code and this link:https://www.tutorialkart.com/opencv/python/opencv-python-rotate-image/

import os

import cv2
from kivy.app import App
from kivy.clock import Clock
from kivy.graphics.texture import Texture
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.uix.image import Image


class KivyCamera(Image):
    def __init__(self, capture=None, fps=0, **kwargs):
        super(KivyCamera, self).__init__(**kwargs)
        # self.capture = cv2.VideoCapture("/sdcard2/python-apk/2.mp4")
        # print "file path exist :" + str(os.path.exists("/sdcard2/python-apk/1.mkv"))
        self.capture = cv2.VideoCapture(0)
        Clock.schedule_interval(self.update, 1.0 / fps)

    def update(self, dt):
        ret, frame = self.capture.read()
        # print str(os.listdir('/sdcard2/'))
        if ret:
            # convert it to texture
            buf1 = cv2.flip(frame, 0)
            buf = buf1.tostring()
            image_texture = Texture.create(size=(frame.shape[1], frame.shape[0]), colorfmt='bgr')
            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.my_camera = KivyCamera(fps=12)
        self.box = BoxLayout(orientation='vertical')
        btn1 = Button(text="Hello")
        self.box.add_widget(btn1)
        # l = Label(text=cv2.__version__, font_size=150)
        # self.box.add_widget(l)
        self.box.add_widget(self.my_camera)
        return self.box

    def on_stop(self):
        # without this, app will not exit even if the window is closed
        # self.capture.release()
        pass

    def on_pause(self):
        return True


if __name__ == '__main__':
    CamApp().run()enter code here

来源：https://stackoverflow.com/questions/50979741/kivy-camera-display-is-rotated-90-degrees

标签

android

python

kivy