python kivy在矩形内添加文本

如何在矩形内添加文本？我使用下面的代码并在画布内添加了一个标签，希望它能显示在矩形内。

import kivy
from kivy.app import App
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.gridlayout import GridLayout
from kivy.uix.label import Label
from kivy.uix.video import Video
from kivy.uix.relativelayout import RelativeLayout
from kivy.graphics import *

class MyApp(App):
    def build(self):
        r = AnchorLayout()
        f = RelativeLayout()
        g = GridLayout(cols=3, rows=5)
        v = Video(source='driver.mp4', state='play', options={'eos':'loop'})
        l1 = Label(text="jenkins", font_size=32)
        l2 = Label(text="git", font_size=32)
        f.add_widget(v)
        f.add_widget(g)
        g.add_widget(l1)
        g.add_widget(l2)
        with g.canvas:
            Color(.4, .1, .1)
            Rectangle(pos=(100,10), size=(100,100))
            Label(text="KSHK")
        return f

if __name__ == "__main__":
    MyApp().run()

update:这不会将文本对齐 ColoredLabel 的中心

import kivy
from kivy.app import App
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.gridlayout import GridLayout
from kivy.uix.label import Label
from kivy.uix.video import Video
from kivy.uix.relativelayout import RelativeLayout
from kivy.graphics import *
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from random import random
from kivy.properties import ListProperty


kv = '''
<ColoredLabel>:
    background_color:
    canvas.before:
        Color:
            rgba: self.background_color
        Rectangle:
            pos: (10,10)
            size: (100,100)
    '''

Builder.load_string(kv)

class ColoredLabel(Label):
    background_color = ListProperty((0,0,0,1))

class MyApp(App):
    def build(self):
        f = AnchorLayout()
        g = GridLayout(cols=2, rows=2)
        layout = BoxLayout(size_hint=(1, None), height=50)
        v = Video(source='driver.mp4', state='play', options={'eos':'loop'})
        l1 = Label(text="jenkins", font_size=32)
        l2 = Label(text="git", font_size=32)
        f.add_widget(v)


        label = ColoredLabel(text="Hello World!", background_color=(random(), random(), random(), 1))
        g.add_widget(label)


        f.add_widget(g)

        return f

if __name__ == "__main__":
    MyApp().run()

Use Label使用自定义背景颜色，然后将其放入您的布局中。例如：

from kivy.uix.label import Label
from kivy.uix.boxlayout import BoxLayout
from kivy.properties import ListProperty
from kivy.app import App
from kivy.lang import Builder

from random import random

kv = '''
<ColoredLabel>:
    background_color:
    canvas.before:
        Color:
            rgba: self.background_color
        Rectangle:
            pos: self.pos
            size: self.size
'''

Builder.load_string(kv)

class ColoredLabel(Label):
    background_color = ListProperty((0, 0, 0, 1))

class TestApp(App):
    def build(self):
        layout = BoxLayout(size_hint=(1, None), height=50)
        for label in ('a', 'b', 'c', 'd'):
            label = ColoredLabel(text=label, background_color=(random(), random(), random(), 1))
            layout.add_widget(label)

        return layout

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

update

修复 OP 的问题：

import kivy
from kivy.app import App
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.gridlayout import GridLayout
from kivy.uix.label import Label
from kivy.uix.video import Video
from kivy.uix.relativelayout import RelativeLayout
from kivy.graphics import *
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from random import random
from kivy.properties import ListProperty


kv = '''
<ColoredLabel>:
    size: (100,100)
    pos: (10,10) # no effect
    background_color:
    canvas.before:
        Color:
            rgba: self.background_color
        Rectangle:
            pos: self.pos
            size: self.size
    '''

Builder.load_string(kv)

class ColoredLabel(Label):
    background_color = ListProperty((0,0,0,1))

class MyApp(App):
    def build(self):
        f = AnchorLayout()
        g = GridLayout(cols=2, rows=2)
        layout = BoxLayout(size_hint=(1, None), height=50)
#        v = Video(source='driver.mp4', state='play', options={'eos':'loop'})
        l1 = Label(text="jenkins", font_size=32)
        l2 = Label(text="git", font_size=32)
#        f.add_widget(v)

        label = ColoredLabel(text="Hello World!", size_hint=(None, None), background_color=(random(), random(), random(), 1))
        g.add_widget(label)

        f.add_widget(g)

        return f

if __name__ == "__main__":
    MyApp().run()

请注意Rectange of ColoredLabel需要有pos: self.pos and size: self.size在标签实际所在的位置绘制。这就是为什么我在上面的级别中更改了标签本身的大小。画布大小与其绑定。至于位置，它是由 Layout 控制的，其中ColoredLabel已放置，因此将其更改为ColoredLabel类没有太大变化。将其与FloatLayout:

import kivy
from kivy.app import App
from kivy.uix.anchorlayout import AnchorLayout
from kivy.uix.gridlayout import GridLayout
from kivy.uix.label import Label
from kivy.uix.video import Video
from kivy.uix.relativelayout import RelativeLayout
from kivy.graphics import *
from kivy.lang import Builder
from kivy.uix.boxlayout import BoxLayout
from random import random
from kivy.properties import ListProperty

from kivy.uix.floatlayout import FloatLayout


kv = '''
<ColoredLabel>:
    size: (150, 200)
    pos: (50, 150)
    background_color:
    canvas.before:
        Color:
            rgba: self.background_color
        Rectangle:
            pos: self.pos
            size: self.size
    '''

Builder.load_string(kv)

class ColoredLabel(Label):
    background_color = ListProperty((0,0,0,1))

class MyApp(App):
    def build(self):
        f = FloatLayout()
        label = ColoredLabel(text="Hello World!", size_hint=(None, None), background_color=(random(), random(), random(), 1))
        f.add_widget(label)

        return f

if __name__ == "__main__":
    MyApp().run()

在这种情况下改变里面的 posColoredLabel实际上是有效果的。