在Kivy中居中對象

Question

我想在佈局中居中放置一個圓。我目前正在做一些填充計算，但我也在尋找更好的方法，並且想象其中一個預定義的佈局可能是更好的選擇。下面是我的代碼是生產...

對於方形佈局：

對於寬佈局：

所以，這是正確的行爲，這是偉大的。但是有更好的方法嗎？ （我能想象這讓凌亂的非圓形狀，例如。）

這裏是我的代碼：

#!/usr/bin/kivy 
import kivy 
kivy.require('1.7.2') 

from random import random 
from kivy.app import App 
from kivy.uix.widget import Widget 
from kivy.uix.gridlayout import GridLayout 
from kivy.uix.anchorlayout import AnchorLayout 
from kivy.uix.relativelayout import RelativeLayout 
from kivy.graphics import Color, Ellipse, Rectangle 

class MinimalApp(App): 
    title = 'My App' 
    def build(self): 
     root = RootLayout() 
     return(root) 

class RootLayout(AnchorLayout): 
    pass 

class Circley(RelativeLayout): 
    pass 

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

而且KV：使用FloatLayout，size_hint和pos_hint

#:kivy 1.7.2 
#:import kivy kivy 

<RootLayout>: 
    anchor_x: 'center'        # I think this /is/ centered 
    anchor_y: 'center' 
    canvas.before: 
     Color: 
      rgba: 0.4, 0.4, 0.4, 1 
     Rectangle: 
      pos: self.pos 
      size: self.size 
    Circley: 
     anchor_x: 'center'       # this is /not/ centered. 
     anchor_y: 'center' 
     canvas.before: 
      Color: 
       rgba: 0.94, 0.94, 0.94, 1 
      Ellipse: 
       size: min(self.size), min(self.size) 
       pos: 0.5*self.size[0] - 0.5*min(self.size), 0.5*self.size[1] - 0.5*min(self.size) 
       Label: 
        text: unicode(self.size) # this is /not/ appearing 
        color: 1,0,0,1 

Answer 1

片段：

from kivy.app import App 
from kivy.lang import Builder 

kv = ''' 
FloatLayout: 
    Widget: 
     size: min(root.size), min(root.size) 
     size_hint: None, None 
     pos_hint: {'center_x': .5, 'center_y': .5} 
     canvas: 
      Color: 
       rgb: 1, 0, 0 
      Ellipse:  
       size: self.size 
       pos: self.pos 
''' 
Builder.load_string(kv) 

class MyApp(App): 
    def build(self): 
     return Builder.load_string(kv) 

MyApp().run() 

日本國旗：

from kivy.app import App 
from kivy.lang import Builder 

kv = ''' 
FloatLayout: 
    canvas: 
     Color: 
      rgb: 1, 1, 1 
     Rectangle:  
      size: self.size 
      pos: self.pos 
    Widget: 
     size: min(root.size)/2, min(root.size)/2 
     size_hint: None, None 
     pos_hint: {'center_x': .5, 'center_y': .5} 
     canvas: 
      Color: 
       rgb: 1, 0, 0 
      Ellipse:  
       size: self.size 
       pos: self.pos 
''' 
Builder.load_string(kv) 

class MyApp(App): 
    def build(self): 
     return Builder.load_string(kv) 

MyApp().run()