如何在kivy中用图像填充画布？

Question

我如何用我的图像填充整个矩形，使其适合整个屏幕作为背景？

from random import random
from kivy.app import App
from kivy.uix.button import Button
from kivy.uix.widget import Widget
from kivy.graphics import Color, Line, Rectangle
from kivy.uix.filechooser import FileChooserListView, FileChooserIconView
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.image import Image

class MyPaintWidget(Widget):       
    def on_touch_down(self, touch):
        color = (random(), random(), random())
        with self.canvas:
            Rectangle(source='water.png', pos=(0, 0), size=self.size)        
            Color(*color)
            d = 30.
            touch.ud['line'] = Line(points=(touch.x, touch.y))

    def on_touch_move(self, touch):
        touch.ud['line'].points += [touch.x, touch.y]



class MyPaintApp(App):
    def build(self):
        parent = Widget()
        painter = MyPaintWidget()
        parent.add_widget(painter)


        return parent

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

现在它默认只在左下角显示一个小图像。我不知道如何调整图像大小或将图像居中，因为我不知道中心的坐标是什么，并且图像不会调整大小。

Answer 1

写入 .kv 文件很容易。

<MyPaintWidget>
    canvas:
        Rectangle:
            pos: self.pos
            size: self.size
            source: 'water.png'